Alternator only charges at 3000 rpm


96 Kw. Alternators are used in modern automobiles to charge the battery and to power the electrical  24 Jan 2018 as part of the integrated battery charging system in automobiles. Alternator only charging on high rpm Tech Talk. Oct 15, 2009 · On my 2000 Astro, 197,000 miles, the alternator cuts out at high rpm. Jan 16, 2014 · Well it depends on what you mean by "electricity. Replied by snshd on topic Alternator/battery high voltage at high rpms sounds like a shorted battery to me, the alternator keeps thinking it needs more charge. Problem with direct driving the alternator is you will have to run the engine near max RPM to get good power from it. Got truck to 3000 rpm needle returned to normal. 2 volts might well be considered perfect on a hot day. 1. It takes 3 amps to generate the amplification factor for 100amps or 100/3 = 33. :thumbsup: Earlybird, was your prob the same as mine? And at what rpm does your alternator kick in - (according to the book this could be up to 1000. If you remove the alternator, make sure you tag each wire with the correct label for reinstallation. 29V 3000 rpm = 13. So I guess that the alternator isn't charging at low rpm. We offer twin  15 Mar 2019 The battery is there to power the electrical components of the bike when 5000 rpm, to confirm if it is getting the correct amount of charge from the bike. By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. 4000. 6 sometimes 13. But the battery seems to be fine. I tried taking it back to the store I got it from and they said that it was no longer under warranty even though I only have about 3000 miles if that on the alternator. 3500. The Superturbine(R) Alternator weighs a whopping 32 LBS!!! compare to PMA's based on the Delco 10-si series, weighing in at a mere 10 lbs. it charges at 14. The only other 530i a 2002 model I have put a new alternator in was charging around 14. The battery is less than a year old, and is a sealed AGM battery that seems to take and keep a charge just fine (I don't need a trickle charger). 13. Common Symptoms of a Bad Alternator or Charging System If the light illuminates only intermittently, it usually indicates worn-out or bad Ask an assistant to start the engine and hold engine speed at about 1500 RPM. You noted in #13: With the engine charging high at first cranking the tach reads pretty good, and continues to read ok until the engine is idled down so the alternator basicly shuts off - then the tach just won't go back up with max rpm being perhaps 1,000rpm, even with the engine turning between 1500 and 2,000 rpm. Aug 16, 2016 · Later in the evening, the light came on again but only below 1500 RPM and the meter was ⅓ and around 1 volt. I start the car after it has been sitting for several hrs, the battery light comes on, after a few minutes the lights start dimming then shut off, the clock shuts off, everything shuts down to keep the engine running. You MUST have a voltage regulator somewhere in that circuit or your alternator will not charge. Re: Battery Light - Charging Problem? I started having issues with my battery light coming on at around a constant 3000 rpm, both while driving and if I purposely idel it that high. They will charge at 500 rpm once they excite. Alternator not charging until high revs. But a basic alternator will produce charging current anyt on my Bosch Alternator only read 5. Measure the diameter of the crank shaft or drive pulley and the alternator 30 amps at 3000 alternator rpm/40 amp model Some have experienced Jeep fires as the alternator attempts to fully charge a fully depleted battery, only to have a An alternator should put out between 13. 0 v. I know that with alternator charging I can expect a drop in RPM but is not just a drop, is a really big difference in overall performance, vacuum signal is 3" lower than without alt and doesn't matters if I raise the idle a bit, continue to be rough and exhaust sounds like the engine is missfiring, also the "clic clic clic" sound at the distributor is really weird I don't know how your setup is, but on my boat the only battery that is being charged by the alternator while underway is the one the switch is turned too. Jan 14, 2014 · Be sure that the engine is running at a high enough rpm for the charging system to function (especially if running a one-wire alternator excited at a specific rpm). It varies from Jan 27, 2019 · I've worked in a variety of hands-on professions and love to write about topics that can save readers from needless expenses. 05 4. Alternator not charging at low RPM. 5 volts at idle. Wires within the alternator cut through a magnetic field Alternator only charges at LOW rpm 5. a wire needs Oct 03, 2012 · That seems a little high, so I put the meter on it and got reading of 15. 4 VDC and only be 0. • The engine to alternator pulley diameter ratio determines at what engine rpm the alternator will begin to charge. 2. That worked for about 2 months. That way you can get your alternator charging while driving. 5v ,showing it was charging some. ) It means that the control lines are not correctly connected to the alternator or are broken or shorted somewhere. While going home, the light faintly appeared again! At 3000 rpm it should read 14. If it doesn't get the voltage up enough, I'll try the 2. alternator and it would be on at lower RPM's and then it would go off But it holds a full charge, always starts, and the volt meter says 12. Even if I'm at a really low 800 rpm idle, A 2" alternator pulley puts me at 1900-1950. If you over drive the alternator you could run the engine at say 1500 rpm and get good power from the alternator and good fuel economy from the engine. I have a 91 Explorer. 3000 3500 4000 4500 Vx (V) Palt (W) Palt vs. My turn finally came to replace the alternator on my D2, I can’t see any documented replacement on the alternator since manufacture. 12 Aug 2019 How to identify charging system problems and how to measure a good This disguises the fact that this only occurs at higher alternator shaft speeds. 11v on all 3 +- . Start the engine and let it idle. Some alternators will charge at idle but most companies recommend the car be at higher rpms for good charging, try driving the vehicle for 20 – 30 minutes and see what that does. When it runs in its normal speed range (about 2000 to 10000 RPM), the voltage regulator that is designed to work with it keeps the output at the proper voltage for charging a 12 volt automotive battery (about 14 or 15 volts). 5kVA to 5. 3v at idle but above that at around 2k and up it would act normal aka why pepboys thinks its good. 11 and 3000 RPM was 12. Oct 28, 2013 · 1994 ls400 alternator not charging - removed the alternator & took it to a local shop that rebuilds starters & alternators - guy says it's putting out 14. . I have a manual 3. on, the battery being boosted would have more current to send to the starter, and by having the radio off, it wouldn After the pretest, with the engine off, check the battery voltage. All their performance charts show at 3000 rpm’s you get 13/16ths of max power. As of the beginning of this project, my 1960 Bugeye Sprite still had its original generator. 2. It would barely Mar 13, 2013 · Hey, The 3 wire internally regulated alternator does not charge the battery when at low RPM. I see the big terminal is marked BAT for battery, but what are those two prongs for on the right? I think my problem is related to how we modified the downpipe and wastegate plumbing. . Steve Maas Long Beach, California, USA November, 2007. They are both very close to the alternator, and I only have this problem once the engine has heat soaked So in my case there would be no way I could run a underdrive, but you may be able to get a way with it if you have not other charging problems. Once the battery has "recharged", the voltage settles down to about 13. when it gets to higher rpm the alt. I've replaced the + & - battery cables, the two cables from the alternator to the + battery terminal and I've replaced the battery and alternator with a new Motorcraft from Ford. I decided to approach the problem from a different direction Typical alternator efficiencies are in the 54%-60% range. Wires between alternator and and starter / starter and battery are solid. Recently I have had to go as high as 1,500 RPM's in order to achieve the same results. However once it has sufficient rpm to produce more than the voltage required, it will have minimal ripple on the output since it has a 3 phase full wave rectifier. (2) A Max Charge Regulator Kit is required for 24 volt, Dual-Alternator or Twin Engine . 5 amps. Alternators can charge the battery at idle rpm because they usually have a smaller pulley, so in fact they spin faster than a generator for the same engine rpm. 5 if your car idles at 900 rpm's your alternator is turning at 2250 if your rzr idled at 2250 it would charge at idle. My old alternator died. There are 2 wires that go the alternator and of course the one charge wire. When i slowly bring the revs up to around 1300-1400 rpm`s the lights go off I tested the alternator charge on the battery with a tester and at idle speed the reading is +- 11. 1500 RPM on the alt you are likely only going to get less than 20 amps out You are making excellent power at that point on the curve, and speaking to the tech working on your car, we seem to be in agreement that there is more LOAD on the system than the alternator can overcome until nearly 3000 engine RPM. It would only charge slightly when driving at high rpm. If you suspect this problem, it's only a matter of time before the alternator gives up. I had the alternator replaced but the problem continues. The ignition power wire to the alternator will be purple. 1500 rpm = 13. 2 or so volts due to a voltage regulator. At 3000 RPM, all my dashboard gauges turn to the right, then turn all the way down to the left. For example: when you start the car the engine is running approximately 1000rpm. And that's just holding at 12. It will self-excite, meaning that it can start charging and stop charging all on its own. for it to start charging you have to rev the engine to about 3000 rpm and then it kicks on to start charging. 5kVA 3000rpm 50Hz or 6kVA to 7. When i get a jump the battery reads 13. Nov 26, 2016 · Hi there, my alternator was charging 13. With the new Autosone alternator, at more than 3,000 RPM, my voltmeter on the dash would spike all way to the top and random warning lamps on the dash would flicker. If that does not work you either have a bad alternator or a dead cell in your battery…good luck If I charged battery with cables truck would run off battery until charge ran out. If you slow the alternator rpm to a point where it cannot produce sufficient voltage output (even with maximum field current), then obviously it cannot charge the battery. 5kVA . We can offer 12V direct current options for battery charging. Seems that the alternator is not charging enough at that low rpm. The BA6 was first available in 1974 so that's when VW started to install them. It should be about 12 volts. 5 volts. 35 amps at 2000 alternator rpm’s/63 amp model 48 amps at 3000 alternator rpm’s/63 amp model 53 amps at 4000 alternator rpm’s/63 amp model Amp’s/RPM’s of 72 Amp unit . 02 volts, the battery cables are good. When I disconnect the battery the car shuts off. Only do this for 30 seconds Like most other systems on late-model vehicles, charging systems have become smarter and more complex. 3ish?? That makes no sense to me. 7 volts. 5 as the engine went higher, then when it got up to the point where the battery light goes out it dropped to ~13. alternator output voltage for several speeds. The alternator is a relatively simple component containing only a few parts, but it plays a critical role in the operation of any gasoline-powered vehicle. But it does not have a connection for the proofmeter cable and I can't tell what my RPM is. A one wire alternator was only used for limited applications and has distinct disadvantages. When the truck is idling at low RPM, the charge supplied by alternator is not sufficient to run truck and charge battery of reverse polarity. I move it to position two and the solar panels are routed to the charge controller which in turn charges the batteries. The GEN light is on. When I blip the throttle, the GEN light goes out and and the volts spike on the voltmeter gauge. The alternator doesn't charge until you rev the engine over 4000 RPM, just once, then it's fine the whole time it's running. 5,000 RPM alternator shaft speed is normally required to reach maximum output. to make specific suitable function of the activity Oct 22, 2016 · Alternator not charging battery at high rpms I recently had an issue with my alternator. I did have one that took 850 rpm to excite, but only that one out of the 14 or 15 I have used. (When you Re: Charging battery with alternator I remember in the older days the advice for jump starting usually told us to turn off the radios and all electrical items in the car being boosted, the idea was that by not having lights, etc. Vx for various alternator speeds at full field 1800 rpm 3000 rpm 4000 rpm 6000 rpm 5000 rpm Figure 4: Alternator output power vs. It should be about 14-15 volts. I'm at a total loss (ha)! Any ideas what could cause this? Mar 29, 2007 · Re: Proper Charger/Controller for engine to alternator setup Phil, As Ken says, your alternator will come with a built-in regulator that will maintain a constant voltage output regardless of the rpm you have it set at, and thus the amps output will be dependent on the voltage, IE state of charge, of the battery bank that you are charging. He had the same problem and went thorugh 2 140 amp alternators before switching to 100 amp and has gone 6 months with no problems. Turns out it appears the Renogy panels provide a small amount of charging even on cloudy days and I don't have big power needs. I can only say about the Summit racing ones since they are the only 1 wire Alt's I have used. but if you let your car idle for a few seconds it will drain your battery. Generally 1200 rpm's = 10amps, 1500rpm's = 20 amps, and 2000rpm's = 35 amps, max output is reached at 4500 rpm's (51 amps). A 65amp alternator should put out 65amps in these conditions if working properly. New alternator only charges on first start. It is possible your idle revs are too low. but it should kick in by 2500 rpm. This is on a 51 amp Prestolite alternator that is typically used on marine engines. (a one wire alternator may require 3,000 rpm to start charging) Check the battery voltage. 1000. A previous owner hacked up the wiring pretty badly. Unless specified, all tests should be carried out with the engine running at 3600 RPM. The RPM output is now low and when I drive it and take my foot off the gas pedal it shuts off. 0 mustang alternator only charges after car has been running for awhile. I managed to nurse the car home by revving it a lot, and after 2 miles suddenly all the electrics came back to life. 1500. Jan 24, 2014 · since our Fraser Island trip during the last holidays I have an issue with my car not charging the battery anymore. The problem may be internal with the alt. This is why when you have a loose alternator belt or a defective belt tensioner, you only hear the squeal when you hit the gas initially after you start the engine, not with the engine idling. Turn off the engine and disconnect the tester from your equipment. I wouldn't trust the charge-discharge guage unless I was to verify and confirm that a Usually an alternator with bearings failure makes a loud grinding noise. yes thats correct, I just want to be able to charge the batteries directly from the car alternator. Delco alternators are typically rated at 5000 rotor RPM (don't have data for Bosch, but it's probably similar), and with typical drive ratios of 2. If I charged battery with cables truck would run off battery until charge ran out. I bought a truck recently and I am attempting to get the alternator to charge. it full throttle and get close to 3,000 RPMs, my battery light and park brake lights  This will be about 3000rpm for the alternator. We pulled the alternator off (again). I am thinking the alternator will only supply enough volts for the operation of the motor. I have brought the RPM up to 3000 in the pits and it would still not charge only after a run of 6000 shifts/lights would the volt meter read 14+ volts. My KB280DT LX is not charging at engine idle speed. ever notice how increadibly small the pully is on your alternator? Like the size of a silver dollar. 4 at idle and 12. When towing an rv with a battery to charge you need to turn on the headlights. Most regulators have a thermostatic element/sensor that will cause the battery charge level to vary with OAT, the colder it is the higher the fully charged battery's terminal/post voltage will be. The one wire alternator has no voltage sensing lead which means that it can only regulate the +12V (actually +14V) at the alternator. I ve gone through all of the components so many times I don't know what else to even check. With a volt meter, I checked for voltage at the alternator B+. if the regulator was only giving out 12 volts then it would still be enough to power everything, but the battery would die after you start Apr 27, 2012 · I have a 1987 mercury sable ls with a 130amp alternator. nearly $200 for a freaking alternator only to have dead batteries . so. Alternators have spring loaded brushes that make contact with a spinning component called a rotor. revv it up and touch the alternator output? I measured it, it put out a steady ~14. Are there two separate circuits for it? Like a low rpm one and then a different one above 3000 rpm? View 8 Replies Similar Messages: Ford Wiring/Electrical :: 1976 F250 - Alternator Not Charging Mar 03, 2008 · The auto alternator is designed to push 100amps or so at 3000 rpm. 3 volts and slowly kept dropping till the rpm's went back down and it kicked back in (suspiciously like the way a battery drops a bit if you measure it The stock alternator was junk. minute to get to 50 Hz (1 x 3000 rpm / 60 s = 50 Hz) and an alternator with . An automotive alternator probably needs to run at least 1500 to 2500 RPM. Voltmeter at the battery shows only battery voltage, 13 volts, fresh off a charger. An alternator won't start charging until it gets over it's cut-in RPM, then it will keep charge until the engine is turned off (or maybe until the alternator's RPM drops too low). engine speed below 3,000 rpm An alternator is an electrical generator that converts mechanical energy to electrical energy in This machine was used as a generator producing 3000-volt , 133-hertz, . ) Start engine and run at idle. The wheel turns at 12 RPM. With the engine at 2000 RPMs, the meter should read between 14. The thing is none of the performance charts say the horsepower to drive the alternator. My corrado developed this problem fairly recently. May be but I doubt it. Test the alternator terminals when this happens. This happens only when I start the engine. Solid and dashed plots correspond to analytical and experimental results, respectively. Many auto parts stores will test your charging system for free. 24 Oct 2018 Learn the steps to make sure the alternator is the real issue with this You just installed a new alternator, so why is the alternator / battery light . After the pretest, with the engine off, check the battery voltage. 6 volts. The car currently has no gauge cluster installed, so no, there is no charging light even in the circuit. The battery, water seperator and if i recall correctly the diff lock light is on. Aug 19, 2002 · If i drive around, chances are, when i come to a stop, the voltage will drop to about 12. Then it will also take about that same time ( a tad more or less) to charge an almost fully charged battery. 0L Tech. I also have a 1700watt hifonics brutus amp with 2 12's hooked up to it. 9 volts with the car running. It was also used on the 1976 912E but because only 2099 of those cars were made, it didn't help our cause. Alternator Conversion. Re: alternator charging then stops at high rpm Using digital multi meter. 60 at all rpms. A reduced output may be a sign that the alternator is failing, but the drive belt and wiring should be inspected before replacing the alternator. That is not true, but it is possible it is overloaded at idle. The charging system needs to be bigger if you keep your RPM's up and turn off accessories when your RPM's are down you will be fine. 6 Rick, from Motorrad Elektrik, sent me some parts to troubleshoot with since I do have the Omega 400 watt charging system upgrade but I do have a question: oh yeah, the problem is that the alternator light stays on ALL the time, instead of going off at about 3000 rpm when the system winds up enough. After reaching 2000 RPM, even when coming back to idle, the alternator was charging. With the vehicle up to temperature the alternator is only putting out 13. 6. My car seems to idle pretty quiet so could the idle be to low. Highest amperage ratings are usually found in the 5-6000 RPM range. While driving on highway 1000 k later saw needle dropping while I was at low rpm. Once started the alternator runs the I tested the battery voltage and it was 6v! With the engine idling it was still only 6v, so the alternator clearly wasn't charging. Nov 21, 2017 · Many modern engines operate well under 2,000 rpm until they reach highway speeds of about 60 to 70 mph. I would like to install an alternator on one of the cart axis, so I can charge a 12V car battery - 20Ah. 87v 2nd VRR is the old OEM and I only did the 3000 rpm test because it began to smoke and drip black junk. 16 Feb 2009 $3000+ for 3 - 110s, 2-220s, and a larger moved box, with the right to tear out all my . 6000 engine RPM, battery temperature and alternator temperature. Today’s computer-controlled charging systems tailor the charging rate not only to the electrical demands on the battery and alternator, but also to changing driving conditions. Now if I turn on the a/c the voltage will jump back up to 14 v, or if i rev the car past 3000 rpms it will also jump up to 14 v. The alternator does not charge the completely dead battery whereas the generator charges the dead battery. " An alternator will always produce a constant 14. Nov 08, 2017 · PA performance aims for 2000 rpm alternator shaft speed at idle. The 10. You need a "floating ball" battery tester to check the specific gravity of your battery's fluid (assuming you do not have a sealed battery), and an inexpensive multimeter. The alternator will output more power than the electrical devices and the charging battery can use, unless you  If you are only replacing one or two of the components it is important to look at the plug to determine which system At 3000 RPM it should be 54 VAC (18 X 3). Probably 3:1 so a 2400 rpm alternator shaft speed would translate to a 800 rpm engine speed, but I certainly am not sure of the Alternator Shaft ratio to Engine Crankshaft Pully ratio. If you're not sure what the alternator shaft speed is, you can determine this with the pulley ratio. It is internally regulated. 4v after it is revved. 4 to  24 Nov 2016 Alternator Testing: High-Draw Accessories Bringing Change In the past, the job of the alternator or generator was simply to recharge the battery after startup At 14 charging volts, the total current draw for these accessories and the truck engines where the average engine speed is about 3,000 rpm. Jan 19, 2019 · A charging system voltage drop check can help you locate the source of an under-charge or over-charge condition due to problems in the wiring or connections between the battery and alternator. However by that logic there would be zero charge at any rpms, but I'm getting charging voltage, it only happens after I rev the engine up. Even if I run the RPM's up to 3,000, the charging system is still only charging at 12. The bit I need help with is how to instruct the alternator to start charging other than revving the engine. Recently my 328's charging system has not been keeping the battery charged. Because a car’s crankshaft generally operates at around 1,000-4,000 rpm, a car’s alternator is designed to put out good charging voltage and amperage around 3,000-12,000 RPM. Consequently, if the alternator doesn’t maintain rated charging voltage at lower engine speeds, the battery will discharge under heavy accessory loads. 2 when reved to 3000 rpm then it gets to idle, it remains at 14. I think 3000 is a bit too excessive, especially on a cold engine) Problem was similar, no tacho, no charge, alarms etc. I charged the battery over night, started right up. Over charging After having a rebuilt alternator installed in my 2002 Escape, I am having an overcharge issue. My truck is a gmc envoy and doesnt have the stupid hall sensor on it like newer vehicles have and if I rev the engine above 4200rpm the alternator stops charging and I go down to resting voltage at the batteries. While going home, the light faintly appeared again! The stock alternator was junk. once you rev it and it kicks on you can let it idle and it'll be charging. Symptom: You start your car, and the alternator won't charge until you blip the throttle to 3 or 4,000 rpm The issue: Doug Tompsett found some information on it, basically it boils down to the 'exciter wire' not doing it's job. for my truck's size of the crank pulley and the alternator pulley I would be spinning the alternator at some insane speed and Jul 02, 2010 · The alternator on the nbs only charges as demand dictates it to charge. You seem to believe that it is "not charging" at idle. Your alternator starts working after going to 2000 RPM because that’s where the alternator’s self activation occurs. This will cause the system to charge. There's plenty of info on removal and replacement of parts, but no test procedure to rule out a bad alternator or regulator. 5500. The "correct" charging voltage is somewhat a function of OAT. I returned to the auto repair shop again and discovered that they had given me a rebuilt alternator - a bad rebuilt one. 3. The only job the alternator has is to charge my battery and it does a fine job doing that. When selecting a larger alternator check real close your pulley reduction between the crank and alternator. even if, when you consider which you not have your unique alternator, you in all probability have 2 problems now as maximum aftermarket reman alternators do not artwork good, and in all probability ruined your pcm by skill of now. I think you need to take a few readings or it's just guess work, I had weird charging issues from a bad connection on the back of the alternator, I removed the plug and connected with spade terminals to ensure a good fit, prior to that I also had issue with a dodgy regulator, but that was the opposite effect of boiling the battery! It will only be able to put out this 100 amps at about 1200 RPM or higher. Mar 08, 2010 · - i got a "rebuilt" alternator from a parts store and the voltage regulator was only charging 12. To understand the difference, you must first learn about what causes an alternator to stop charging. 2 or lower, I changed the alternator and still doing the same, now don't go higher than 13. It would take a hurricane force wind to turn a small wind turbine fast enough to even start charging a battery. Voltmeter said my battery is 12. Not too long It's weak and does a poor job of charging the battery. This is the only way you are going to determine what is going on. Discovery 2 alternator only charging at high engine rpm. To start with, I'm only assuming that the alternator should be charging properly at idle. If the alternator isn’t putting out enough current to keep up with the electrical loads that are placed upon it, or the charging voltage is low, don’t automatically assume the starter or alternator is bad and needs to be replaced (unless you’re bench testing the unit out of That slows down the process. For battery charging to occur, the alternator's voltage must exceed the battery's voltage. my alternator only charges when it feels like it, so I often end up with dead battery 4 Answers. you have to do this procedure all the time when you start it up. c) Related Power: 3000 watt Maximum speed of motor: 3000 rpm. So you may indeed not see much indication on a voltmeet untill abou 3000 RPM. This time they gave me a brand new alternator. Since it was showing some wear, we (and it took both of us) replaced it with a new one and tightened it up. I'm putting this on my 8N. not powered. Formerly Blue245Ti, 245GT-Turbo, and, originally 242GT-Ti. Nov 21, 2011 · The situation is this, I would like to power a Delco 1 wire 100 amp alternator with a 3/4HP 12v DC motor, I would have an automobile battery to start the motor, and for the alternator to maintain, plus I would like to have enough power to run an additional 30 amps (max) of accessories. Alternators on cars and trucks are usally run 2 to 3 faster than the engine turns. As good as an alternator is at replenishing your car battery; it can only recharge it to the point that it has a decent amount of life left in it and is able to accept a charge. First of all the car alternator is designed to turn at 3000 rpm to generate it's full power, such speeds are impossible with windmills, you will be able to achieve a max of 500 rpm with a windmill that makes you use 1/6 of the full power of the alternator which is not practical unless you are after a couple of watts only. so double the amount of what it read at 1000rpm, then at 3000rpm is  11 Apr 2014 I read in previous posts on this forum that the ELD Enable only disables error reporting and will not have any . Essentially, the alternator turns the mechanical energy of the engine's rotating crank shaft into electricity through induction. I only needed to use the alternator once in two years. At least you don't have to chase wiring. You don't have this problem with the 3 wire. 8 at idle, but when at high rpm always when to 13. Obviously the internal regulator went bad so i replaced thr alternator. Sep 24, 2014 · The problem now it's only barely charging, the light will go out around 3000 rpm but the voltmeter shows there s not much output happening. My mechanic thinks there is a loose connector somewhere. The clutch behaves quite differently, depending on the state of charge in the battery - If the battery is low, the regulator turns the alternator 'full on' and that extra load can make the clutches slip . 4 V (indication of alternator NOT working). It could very well be 2:1, which would put the engine speed at 1,000 rpm for a Alternator Shaft speed of 2,000 rpm. 98v and at 3000 RPM 11. Periodically the alternator gauge shows that it is charging at a low level and the battery icon on the insturment panel lights up. 2hours. The alternator on your Dodge, whether it's a car, truck or van, is an essential piece of its electrical system. If it did all day both the alternator and regulator would probably self destruct. 4500 . Bad battery, bad alternator, or drive belt are the most likely culprits. Alternator in my 85 turbodiesel won't charge until I rev the engine to at least 3000 rpm, after a while of just sitting and idling, it slowly begings not to charge. If the alternator is required to deliver a substantial output at low engine rpm, check The drag (70 Javelin) car wiring is all run by me, only thing stock I am using is the ALT & REG. This SUPER-ALTERNATOR is WAY MORE POWERFUL than the PMA's you are used to seeing on E-Bay. A car battery, by definition, has a finite life and will not last forever. If I'm just crusing along at 2000 rpm it is 2) charging light glows when ignition is in ON position 3) charging light still glows when idling 4) charging light goes away around 3000 rpm Have made sure the belt is tight (double belt type). For example, with an improperly functioning alternator, the battery will quickly drain. so it will not start back up once you shut it off but if you hold the rpm While the battery supplies the electricity needed for that initial spark, it only has enough power to get the car a few miles down the road, and that's where the alternator comes in—it continually charges the car battery while the car is in motion while also simultaneously operating all the electronic components of the vehicle. Putting a meter on the back of the alternator (output stud) reveals only battery volts (12VDC or less as the battery discharges, engine running, at any RPM), no charging volts. (if the engine has been recently run it may be higher, maybe 13 volts or so. Alternator RPM. 28V If the battery voltage is low (from sitting, just after a cold start, or extra loads) the voltage reading is about 13. Is this too high? Alternator over charging? Regulator not working correctly? How can I test it to narrow down the problem(if there is one?) Engine is a SBC with an original delco alternator and external regulator. 5:1 the alternator should be capable of max output at about 2000 engine revs. 2500. So I hooked up my digital meter and revved it up and the volage went to 16volts. I have an inclined cart mounted on rails moved by a winch. That said, the Denso alternators only need about 2500-3000 rpm to cause the alternator to start charging. Most of the time that is enough. 4 V. If you find a low mileage 912E at the junkyard, grab the alternator and part out the wiring harness. new serpentine belt. 4 volt at 20 degree celcuis - mine only Alternator charging voltage regaulators from 14 - 14,5 Volts? > maximum charging The Delco alternator would put out its regulated voltage and full capacity at cruising RPMs but would only put out ~13. Aug 07, 2017 · Ford Wiring/Electrical :: 1976 F250 - Alternator Not Charging Aug 7, 2017. As far. A charging system is being discussed: An engine in run at 2000 RPM, the headlights highbeams are ON and the Blower Fan is set to high speed. Replaced alternator, problem seemed fixed but light remained on. If the battery is fully charged it will not charge. It had been working fine, although I was noticing my headlamps dimming when I go WOT and the RPMs hit 4000 or above. <<>> In North new alternator. 5 volts) flows back through the light and as the 2 volts difference is not enough to make the light work it goes out . Oct 03, 2012 · That seems a little high, so I put the meter on it and got reading of 15. Every morning I let it run for 10-15 and it never dies an my alternator only does 12. 3 volts and slowly kept dropping till the rpm's went back down and it kicked back in (suspiciously like the way a battery drops a bit if you measure it Mar 03, 2008 · The auto alternator is designed to push 100amps or so at 3000 rpm. It should measure volts in both DC and AC, and resistance in ohms. - It was doing all discharging and no charging at any RPM and at any load. I can afford We just put an alternator and a new battery on my Suzuki XL7 this past weekend. This did not happen before the repairs. Thanks Will edit - sorry, realised in my sleepy haze that I might not have been that clear about something. Oct 29, 2019 · Causes of Alternator Not Charging the Battery. We found that they had connected the voltage regulator to the horn relay for some reason. I know that with alternator charging I can expect a drop in RPM but is not just a drop, is a really big difference in overall performance, vacuum signal is 3" lower than without alt and doesn't matters if I raise the idle a bit, continue to be rough and exhaust sounds like the engine is missfiring, also the "clic clic clic" sound at the distributor is really weird Dec 14, 2018 · Alternator light goes out at circa 3000 rpm but no change in battery voltage was created by lohr500 We have a battered old 2004 Jimny which we use around the fields for my kids to learn to drive in. If your car is slow to start, troubleshoot immediately. The last 5000 rpm’s only gaining 3/16ths of power. 04 volts less than the reading recorded at the battery. breakdown obvious after 19 years … I can't find a single word in the service manual to diagnose a charging problem in a 2002 FLHTCUI. I even have one on a 933 Cat that works just fine. The only purpose of the fusible link there is to protect the battery should the alternator go bad and over charge. 0" should spin the alternator to 16,625-17,062 RPM, which is really pushing it. at 2. Alternators are usually made to spin at 3x engine speed. Alternator is about 6 months old. <<>> In North Generally, to fully charge a battery, you need to drive on the freeway for 20 minutes with a minimum RPM of 3000 without traffic and without any electronic devices turned on inside the car, as well as exterior lighting. The alternator is not putting enough power to keep the light out. Battery is fully charged. 3L Mazda 6 mild rpm pulsation Alternator only starts charging when taken over 3000rpm The bit I need help with is how to instruct the alternator to start Jul 21, 2017 · Alternator output is not rpm related. I have a problem with my 2012 Honda Civic EX: The alternator only works/charges when my headlines are ON. 2) The 1 wire type alternator is self-exciting, which means, below a threshold RPM level (I've heard it's between 1200 - 1700 RPM), the alternator doesn't do any charging at all unless you first rev the engine to kick the self-exciter in. new battery trickled charged before installing. Oct 20, 2016 · It's probably shutting off the alternator for high speed. I think 3000 is a bit too excessive, especially on a cold engine) And at what rpm does your alternator kick in Diagnosing Alternator Charging System Problems Over the years Harley Davidson has used many different alternator systems. 19 Jan 2019 I. the reason your car can charge at idle where the rzr really cant is because if you look at the size of the pulleys on your car the reduction ratio is something like 2. I'd be happy with that. in the range of idle speed of 750 rpm to the cruise speed of 3000 rpm. 0 and 14. At that speed the alternator will not work, so I am also adding a 1:20 gear The charge regulator in most alternators relies on a minimum voltage, which can only occur at a particular revs. The two modes can accomplish as much as 10% load reduction on the 61 A/h battery at 5A/h charge rate would fully charge from dead in 12. In other words, if it takes about 15 minutes to fully charge a dead battery off of the alternator. The plugs that go to the back of the gauges are essentially just hanging there. Until recently the easiest way to tell the systems apart is by looking at the plugs that connect the stator to the regulator. It is recommended that if you use a fuse in the charge wire that it should be 10-20% greater value than the alternator output. I set up an old 35 amp alternator to run off a 1/3 hp 1,750 rpm washing machine Each alternator would charge a seperate 12 battery. The output of the alternator is higher than that of the generator. My battery is less than a year old so i don't think it is the main problem. The alternator gave expected voltage and amperage output as long as the engine was at medium to high RPM. If I start the vehicle again, the alternator B+ terminal reads like 12. is the rotational speed in revolutions per minute (RPM). Now every time the engine goes over 3000 rpm's the voltmeter drops and all the lights dim Each alternator has a design amp output (at spec voltage) versus rotor rotation speed. Re: Alternator/Charging Question I think the alternator is suspect, or at least, it's not operating like he needs it to. It seems the alt just doesn't charge at idle which according to the AAP thing is about 550-600rpm. So, keep the transmission in 4th if you have a 5 speed auto. I noticed when i hit 3000 rpms the head lites and dash lites became noticably brighter. Most people mistakenly identify a 3 wire alternator as a one wire alternator (I know, I was one of those). The speed of . Gotten the same result from two different alternators. The only connection needed for a 1-wire alternator is the output charge cable. Symptoms as follows: - Battery lost it's charge quickly, car stopped after having the front lights on - checked the voltage gauge in the dashboard, as long as I rev the engine (2500-3000 RPM) the needle goes up. Below 3000 rpm the tell-tale red battery charge light on the dash would illuminate. I just installed a set of underdrive pulleys and now it wont charge at idle. Current is being measured at the alternator output wire and voltage is measured at the battery. I'm having a strange charging issue on my '08 CRD. 0L Bit of history, about 15,000km ago I replaced my old alternator with a 130a model, changed the tensioner and belt (both). I was having issues with my old alternator The curve is not straight either. I put an alternator in it and noticed that it was only charging around 13volts. Mar 13, 2013 · Hey, The 3 wire internally regulated alternator does not charge the battery when at low RPM. As you ride to the next light (at 3000+ rpm) the battery will charge but at only 1. Made sure alternator wiring harness is not corroded and isn't loose. 3000. And, when it charges, it might stop charging for no reason and I end up with de Tachos usually come with simple instructions of how to adjust the reading to your engine, this is determined by the number of poles on your alternator and the diameter of the pulleys that drive it, no maths involved with the Faria I fitted to my boat, just a simple table of usual set ups, if you don't have a take off connection on your alternator, this too is a simple job. 22 Nov 2018 The old alternator started charging past 2000 RPM After changing the alternator, the behavior is the same with only a difference: the trigger  38, car revving @ 3000rpm 14. The battery only purpose is to start the car and run accessories when the engine is not running. Since I had added an ammeter, I'd been able to observe the generator's clear inability to keep up with the electrical load. Aug 22, 2012 · that alternator is pcm controlled. My mechanic and I worked on the car today and found the alternator belt loose. For a small petrol engine this would be around 800rpm, a diesel around 500rpm. This is for fuel savings supposedly. It's an 89' 1. If it is at lower RPM, that implies everthong id OK anyway; You won't see the voltage rise from 12 ish to 14 ish until the battery has 'reloaded' the charge used during the starting actions. Oct 19, 2016 · Re: Alternator not charging battery at high rpms « Reply #5 on: 19 October 2016, 04:58 PM » To expand on Harv's comments; instead of buying another alternator not to mention the remove and replace of the alternator, consider replacing the voltage regulator set which comes with brushes if I recall correctly. Dose the car alternator not have 3 stage charging, if not dose it have any way of telling the current required so as that not to over charge. This will be about 3000rpm for the alternator. Jul 02, 2010 · The alternator on the nbs only charges as demand dictates it to charge. It is always best to charge a dead battery with a battery charger prior to putting an alternator into operation. Mar 20, 2010 · Best Answer: The GM CS130 alternator is about the only one that charges much at all at lower RPM. With this set up, we pushed on to Bigger Town. If I set rev-limiter to 7k rpm, the 2. The battery is only 2 years old, a DieHard gold series. At 1500-2000 rpm when the alternator is running fast enough to produce a sufficient charge rate and it should be around 13 to 14 volts. For a small petrol engine this  21 Mar 2015 Brise alternator, only starts to charge when the engine revs are above 3000rpm? Above 3000rpm everything works fine. No Charging below 3000 RPM?? VW MKIV-A4 TDIs (VE and PD) Does the alternator light come on? If the alternator isn't getting fed on its exiter wire (the blue one on the two pin connector) it won't charge till it self exites which happens around 2500-3000 RPM. 6 volts -installed back into car not putting out voltage - checked the voltages with multimeter still no good - replaced the plug going to the alternator b/c it was brittle & falling apart- still not getting a charge - battery in good shape does 2010 express have a voltage relay. with both voltage and frequency proportional to RPM. 5000. 2 - 14. the generator to charge the batteries with a battery charger to power the inverter. Your equipment needs for this are very simple. Without it, it will still charge, but not until you rev the engine over 3000 rpm or so. So if your alternator's "true idle speed" [link to truth about idle article] is 1700 RPM chances are during idle your alternator is only producing 40 or 50 amps or even worse, not charging at Aug 11, 2007 · Judging an alternator's performance based on voltage is not an accurate test. The Alternator is the same on all the 650GS models 29 amps @14v, or 400 watts but BMW specifies that at max RPM so you see less at lower RPM Make a list in a spreadsheet of what your accessories are consuming and use formulae to convert watts to amps etc to get an idea of the load Three output wires deliver 3-phase electricity. Aug 04, 2014 · I am working on a school project. Belt is tight, and new, tensioner (diesel only) is free, and all pulleys are in line. It’s easy to misdiagnose these problems as being a bad battery instead of a bad alternator. I assume one wire sends the tach signal, how does the turn on work? Search titles only Mar 29, 2007 · Re: Proper Charger/Controller for engine to alternator setup Phil, As Ken says, your alternator will come with a built-in regulator that will maintain a constant voltage output regardless of the rpm you have it set at, and thus the amps output will be dependent on the voltage, IE state of charge, of the battery bank that you are charging. IT works like this battery power (12 volts) flows through the light to the alternator and puts it on when the alternator starts to charge the extra voltage from the alternator (14. The alternator has a wide range of RPM whereas the generator has a narrow range of RPM (rotation per minute). Also when driving, if i reach 3000 rpm in a gear, or stay above 40 mph, the display will read 14. The battery charger I use at the moment is 100amps with 3 stage charging. 3V and ~5A at idle. my alternator "sometimes" start charging 3 minutes after the engine has started and sometimes it won't charge at all. ES16F Series – 1 phase – 4. when i measured the voltage, i get ~12v when the engine is off, ~9. In other words, when the engine is on and the car is running, the alternator provides the required electrical load for all the equipment and typically doesn't offer much more than about a 5%-10% overhead for the topping-off charge. A lot of people get confused when they begin to have electrical problems with their vehicle. 1982 242Ti - black, M46. Nov 22, 2018 · The old alternator started charging past 2000 RPM. The alternator should be tested with the engine idling and electrical accessories, such as the radio and headlights, turned off. Any thoughts? Thanks. 5 or 3. In a 2G DSM it's about 70 mph in 5th gear and about 3000 rpm (but we all  The alternators on all but the earlier twins (70's) are rated at 280 watts. My concern is my alternator is only putting out 13. 5v - when it's told to. 23 Oct 2017 Ducati 750GT Bevelhead Alternator Replacement. 2000. It's a Delco-Remy. if the regulator was only giving out 12 volts then it would still be enough to power everything, but the battery would die after you start Sep 25, 2009 · Ultimately that's cheaper than having them check parts of it (as outlined above) because they would charge you for that time as well. As soon as I hit the gas, or even tap it it works fine. components of alternators that include DC-DC convertor, motor, battery and controller. So, if you have a 100 AMP alternator, you'd want around a 120 AMP fuse. Diagnosing alternator problems can be a bit tricky because the electrical system in a car comes from two places, the battery and the alternator. 5 when the engine is running but not revved, ~14. Honda’s Dual Mode Charging System For many years Honda and Acura have utilized a dual mode charging system to increase fuel efficiency and to decrease the drag on the engine when starting. 4 volts about at 2500rpm. Anybody elses ever Aug 05, 2009 · Well I've been having some charging issues lately on my 2002 gmc 2500hd 6. 01-05v The battery reading at idel was 12. so you may not have much over 12 volts even at 3,000 RPM. Most common solutions would be be a bad alternator, bad connection, or The car currently has no gauge cluster installed, so no, there is no charging light even in the circuit. Since your car runs on a 12 volt system, this is enough to power all your 12volt appliances and charge the battery. A bad battery ruins a good alternator and a bad alternator ruins a good battery. I also get my battery light and dome light turning on during this overcharge period. It's not. Increased RPM to around 3000 and all went back to normal. 7 volts with the engine running at 1,600 rpm? Is it possible to modify a car alternator so that it starts producing a current at 3000 RPM instead of  No battery warning light on with ignition on, engine not running Note: - to double check the belt isn't slipping, rev engine to 3,000rpm with the lights on, stop  The maximum advisable rotor speed for Brise Alternators is 18000 RPM, therefore When the alternator is charging, this terminal becomes the same as battery  My alternator wasn't putting out enough voltage to charge the battery and run the . 10 15 20 25 30 35 40 45 50 55 0 500 What makes me think it is the pulley size is that when the motor is running and I put my voltage meter across the battery posts, I am getting less than 13 volts. Because like the others said, an alternate can't charge that many batteries at once and configuration that is setup to try to do so simply makes no sense. it ought to be disabling and overloading the alternator at incorrect cases. Feb 13, 2016 · My car idles at 900 rpm The belts tight Everythings connected The weird thing though is my laser never died once on me , I can sit at idle with my heat ,radio , sub, defroster, lights all on and She'll idle till the cows come home. 9, and the batteries charge. The alternator or battery light comes on with the key in “on” but the engine not started, then goes out immediately after the engine starts, goes off no more than 5 seconds after the engine starts. If the alternator is not receiving power from the ignition switch then it isn't going to generate power. ator both good. The alternator is capable of generating 1. Is this a classic knackered alternator A one wire alternator is used where you do not want to have any connection from a vehicle to operate an alternator. They are usually designated by amperage out put such as a 22- amp or a 32-amp system. Red Battery light on at gauge cluster. Jun 29, 2009 · I changed my alternator yesterday, my car needed to be jumped for the past week. 31V 2000 rpm = 13. At higher rpm, the voltage goes up to around 13. After changing the alternator, the behavior is the same with only a difference: the trigger is now at 2800 RPM. The battery has stopped charging on the vehicle, but will hold a charge for a few weeks if charged up from a mains charger. If the difference in voltage readings is less than 0. (Yes, this is a design feature of most Ford alternators. Aug 20, 2011 · By adjusting the rate of charge we stay close to a fixed time. I have a Ford 3000 Diesel with a Delco 12 volt alternator. Without an aftermarket stator and windings, RPM over 6000 will not generate any additional amperage. Reducing RPMs below 4500 reliably increases the voltage. atv's are the same type setup. can really pump a charge. 23. I have a 200 amp The belt is only about £12 so try changing this first. At 3000 RPM charge current is reduced and remains relatively flat out to 5000 RPM. It should be reading 14VDC, especially at higher RPMs. 1. Older vehicles with generators tend to require much more maintenance than newer models, but there's no hard and fast rule for how long an alternator will last. the car was in idle with no load Oct 29, 2019 · Causes  4 Apr 2001 The charge regulator in most alternators relies on a minimum voltage, which can only occur at a particular revs. I replaced the alternator brushes last fall (about 3,000 miles ago). So an engine idling at 800 RPM has its alternator spinning at least 1800 RPM. 8 16v. The alternator in most cars is typically sized to match the demands of the running car. Once the rpm lowers, it will start charging again and the light will go off/gauge return to normal. 50 - 13. The main fault is . Then the light came back on, and this time the alternator was not charging at all. Mar 31, 2016 · The battery reading at idle was 11. if you don't rev the motor it won't kick on therfore it won't charge the battery. 30V at all rpms. I'll give you a little Jan 28, 2013 · I'm a little confused as why it would be only above 3000 rpm. It is load related. I think that you need to find a better mechanic. And yes we figured out how to remove the alternator without taking off the axle , exhuast, etc. 3000 RPM as cruise speed were taken as parameter. It uses the dash light as an excitor wire to engergize the regulator on start up. I don't see this when the battery behaves perfectly and the alternator consistently puts out 14. it read 6. Under those revs there is not enough volts generated to start charging. Why would the battery light flicker when accelerating to 3000 rpm Battery light usually means alternator not charging. I have a 200 amp Excursion - King of SUVs - Alternator Only Charges Full Battery - Stumped - OK, I'm totally stumped and ready to go to the dreaded dealer service department. Nov 13, 2019 · Understanding Alternator Output Ratings When you hear that an alternator is “rated at 100A,” it can mean a handful of different things depending on where you received the information from. 0 petrol and did the swap myself within an hour - it turned Aug 22, 2004 · Powermaster 1 wire setup - not charging? This is crazy. 9 when driving, batteries are 1month old and I am using the alternator we replaced, 140 amp. 6 volts on the alternator output wire clearly shows that the alternator is not charging. The vehicles operates and charges normally unless the rpm gets above a certain point and then the alternator goes offline. Testing Your Charging System . The alternator is smaller in size and requires less space If at idle you alternator is spinning at 2400 RPM this is good news for you, but most modern vehicles that speed is more commonly between 1600 - 1900 RPM. 5 and 15 volts of power. A 50 Hz alternator runs at 3000 rpm. 6 volts to the battery and it is slow to get up to that point in comparison to other vehicles I have worked on. Irritatingly, interstate cruising speed is about 4750 RPM. Most likely, it plugs in from the side (right at the very back) like the illustration above. If the alternator isn’t putting out enough current to keep up with the electrical loads that are placed upon it, or the charging voltage is low, don’t automatically assume the starter or alternator is bad and needs to be replaced (unless you’re bench testing the unit out of Since a Deere B runs full bore at around 1200 - 1300 RPM, the generator needs the smaller pulley than the drive pulley on the engine to reach max output of 8 amps. At idle speeds of about 650 RPM it can only produce 50 amps or so. 1000 2000 3000 4000 5000 6000 What to do before installing a high output alternator • Seek the advice of your engine supplier. 5 would be minimum. When I come to a stop I increase the RPM's from 700 to 1000 or 1100. Made sure battery terminals were good. My local garage insist that I need a new alternator and/or battery. Oh I dont think I ran a "excite" wire as I am running a full MSD IGN setup. Most alternators do not start charging until they reach 1,000 RPM alternator shaft speed. Follow this guide on how to test an alternator in under 10 minutes at home to ensure hassle-free driving. A bit of history: this past summer, I replaced the regulator after the "Alternator Workshop" light came on, and measuring voltage at the battery showed that it was charging at a little over 15V. battery only a couple yeas old but will get it tested to make I replaced the alternator on my wife's 2003 GMC Sonoma 2. Only the rate of charge changes because of the voltage regulator. Since it changes with engine RPM, that pretty much changes the focus to the alternator/regulator, which is a good thing. Alternator only charges at LOW rpm 5. Dec 03, 2019 · If your car is slow to start, most likely you have a bad alternator or a bad battery. Put the new alternator on and still not charging the battery becuase my meter is only showing 11. Compare your multi-tester reading against the recommended voltage (amps or volts) listed in the using the Alternator Identification Chart, Alternator Specifications or equipment manual. That means they will charge the battery at lower ENGINE rpm but the alternator itself is spinning faster than a generator does. Crank RPM, 500, 750, 1000, 1250, 1500, 1750, 2000, 2250, 2500, 3000. 1985 245Ti - blue, M46. On my way into work this morning the tack dropped to 0 rpm's while the battery light was on, could still take it to 3000 rpm and the tack would work as well as the battery light would go out. 9. If you are running over 4K RPM's iirc your charging system will stay charging once you dip down below that and running too much accessories will slowly drain your battery. Jul 08, 2011 · It doesn't start charging until the engine reaches 3,000 rpm - Answered by a verified Chevy Mechanic We use cookies to give you the best possible experience on our website. alternator only charges at high rpm, belt and alti. If this doesn't work, it's likely the alternator needs doing. 0 amps at 1500 alternator rpm’s/72 amp model 23 amps at 2000 alternator rpm’s/72 amp model 50 amps at 3000 alternator rpm’s/72 amp model 62 amps at 4000 alternator Many times an alternator is not working properly because of poor electrical connections in the charging circuit. Turned on the car with headlights OFF, it's still 12. Q) The indicator light is on. If the battery is really weak or dead, the alternator cannot bring it back to life. My alternator only charges when the battery is fully charged. I used my voltmeter on my battery while the car was running and saw that the alternator was only kicking out about 12. 30V 2500 rpm = 13. When an alternator tries to charge a dead battery it must work at 100% capacity, but an alternator is designed to work at 100% for only short periods of time due to the heat it produces. 2L 2wd truck a month ago and the pigtail wire harness a couple days ago. Sep 22, 2008 · if the big red wire 4g,is the only one hooked up on it then you have a one wire alternator. (At least you have a volt meter!) The readings on the blue and green wires are about right without a functioning voltage regulator. I recently had to replace mine that wasnt very old. Many times an alternator is not working properly because of poor electrical connections in the charging circuit. In fact, if the alternator is not working perfectly, your Dodge will soon begin to experience serious problems. As the battery charges, the clutch plates slip less and less Aug 29, 2013 · I'm not sure what the alternator is but will check. Idling for hours will just drain the battery. Tur on speed is 635 to 650 RPM, and it will put out 55 amps at 1600 rpm, 73 amps at 1800 rpm, 84 Mar 31, 2016 · The battery reading at idle was 11. You need to do a load test to determine the amps the alternator can put out at say 3000 rpm under load. alternator only charges at 3000 rpm