Car Alternator & Regulator? - Page 1
Forum section: electronics / beginners

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: February 29, 2016, 08:48:02 pm
content: The alternator in my car has died, and I believe its the regulator.Its a 320amp alternator, so have no intention of replacing the whole thing.I'm considering making a replacement regulator, as the one supplied didn't seem to be overly reliable.I'm not sure what the connections are, namely, the solder point circled in green.Also, with the alternator wired up on the bench, 14volts applied across the alternator (to simulate the battery), 14volts connected to the "S" terminal, and a globe connected to the "L" terminal, should I see voltage across the field windings? I assumed so, but maybe I'm chasing an issue that doesn't exist.Thanks!

author: Simon
author_rank: Unknown
timestamp: February 29, 2016, 09:12:52 pm
content: 320A in a car ? are you sure ?Gee the large military vehicles that I design for only have 450A

author: Chriss
author_rank: Frequent Contributor
timestamp: February 29, 2016, 09:32:59 pm
content: 320A no way, but however...Can you pls give some infos about your car?Maybe I can help you with schematic.

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: February 29, 2016, 09:45:47 pm
content: It's an aftermarket 320 amp alternator.

author: tautech
author_rank: Super Contributor
timestamp: February 29, 2016, 09:59:13 pm
content: Quote from: AmmoJammo on February 29, 2016, 09:45:47 pmThere'd be a reason you upgraded the original.....massive loads?

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: February 29, 2016, 10:51:58 pm
content: Yes. Should i expect to see voltage across the field winding with the regulator powered up?

author: tautech
author_rank: Super Contributor
timestamp: February 29, 2016, 11:56:46 pm
content: Quote from: AmmoJammo on February 29, 2016, 10:51:58 pmCouldn't say for sure, we can't see the pinouts or how you've got/had it wired.

author: Simon
author_rank: Unknown
timestamp: March 01, 2016, 06:42:05 am
content: Quote from: AmmoJammo on February 29, 2016, 09:45:47 pmI'd say you got conned. Most cars have a 40-60A alternator, a 320A alternator will be so much bigger at the same speed, you can't just replace it unless you made substantial modifications to the car. Perhaps it's not powerwul enough for your loads and that has damaged the regulator. As well as the regulator you will also have a rectifier that has to take the full current. I assume that the higher the output the more current the regulator needs to put into the field winding. Might be tricky.

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: March 01, 2016, 07:00:00 am
content: So now that we haven't actually discussed anything related to the original question.I still have a 320amp aftermarket alternator, and I've personally measured over 300amps from it, but the belt will slip... It can also stall the 4 litre straight 6 engine at idle.Should the regulator be putting voltage to the field winding/coil, even without the alternator spinning?Assuming the alternator is still installed in the car, and wired up to work properly... I turn the keys on, but don't start the car... the battery light on the dash comes on... is the alternator regulator energising the field coil?Edit: the point circled in green in the above picture appears to connect to one of the stator windings... I'm not sure why this would be, or if it would be needed on a different regulator? (some diagrams show this connection, others don't?)

author: Simon
author_rank: Unknown
timestamp: March 01, 2016, 07:04:59 am
content: I'm not sure if they still use the battery light as a small start up for the field coil, that's what they did in old cars. I tried once putting power onto that pin on an old aternator but also got nothing from it, I think they need turning reasonably fast before anything happens. Perhaps you can use a drill to turn it (with no load or a low load) to simulate an engine and see if it works then. The regulator usually send PWM to the field coil and varies it to keep the voltage output constant with speed. Maybe that has blown or your rectifier is faulty. If you can get at the rectifier you can test the diodes, they carry the most current so maybe they have blown.

author: Porch
author_rank: Contributor
timestamp: March 01, 2016, 07:23:05 am
content: You have not given us the required information.4L straight 6. I would say you have a Jeep with a lot of lights. I still don't think this is a 300+ amp alternator. That might be peak, like when buy an audio amp and it says 2,000 watts and in tiny print next to that it says peak. If the regulators are known to give out, then that alternator can't handle it's own power.Toyota tends to use 70 amp "one wire" alternators. One wire to the battery, one for key on. Regulator on board.Honda uses the ECM/PCM to PWM the alternator directly. So no regulator on the alternator.GM uses whatever they had extra of in the parts bin. The high powered alternators in the fancy cars have water cooling (and still make less power then 300 amps).So without knowing what the heck you have, can't help you.

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: March 01, 2016, 07:29:29 am
content: Its an aftermarket 320amp alternator, with a regulator that has a GM style oval plug.The alternator is fitted to a Ford Falcon wagon, but none of this has anything to do with the questions...

author: Zero999
author_rank: Super Contributor
timestamp: March 01, 2016, 09:17:49 am
content: It's all relevant to the original question. You just can't see it.Did the alternator come with a manual/datasheet? Do you at least have a part number?Have you tried opening up the regulator module to see if there's anything burnt out or is it potted?There are numerous alternator regulator ICs available. You could try using one.https://www.google.co.uk/search?q=alternator+regulator+IC&ie=utf-8&oe=utf-8&safe=active&gws_rd=cr&ei=C13VVszmFMLTPNPtgdgJ

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: March 01, 2016, 09:24:51 am
content: I found pictures of a regulator with the same dimensions, but a different external connector.The unknown soldered terminal is labelled "Ps"Anyone know what it does?thanks.

author: amyk
author_rank: Super Contributor
timestamp: March 01, 2016, 11:50:30 am
content: It depends on what the exact setup is, but Google "alternator voltage regulator schematic" for some examples...

author: orbiter
author_rank: Frequent Contributor
timestamp: March 01, 2016, 02:39:42 pm
content: @AmmoJammo..The last post on this page may be of help..http://www.pirate4x4.com/forum/chevy/511200-alternator-wiring-question.html

author: ProBang2
author_rank: Frequent Contributor
timestamp: March 01, 2016, 06:23:00 pm
content: Quote from: AmmoJammo on March 01, 2016, 07:00:00 amYes. The current through the battery light goes to the alternator and there straight from the regulator to the rotor-coils.Whithout this initial magnetisation the alternator wont produce current at all.QuoteThis connection is used in some cars as tachometer-signal.Especially with Diesel engines. ( No RPM-signal from the ignition, YOLO?)Another posibility is: In modern cars with "Smart-Charging-System (SCS)" is this a connection to the "Engine-Control-Modul (ECM)", aka "Powertrain-Control-Modul (PCM)".At first sight I dont believe it in this case.

author: haveissues
author_rank: Contributor
timestamp: March 01, 2016, 11:19:20 pm
content: If you google the part number of that voltage regulator you posted a picture of, vrh2005-95, it would suggest it is a toyota/lexus part so maybe look into how the charging system works in a Toyota for a clue?

author: bills
author_rank: Frequent Contributor
timestamp: March 01, 2016, 11:42:26 pm
content: Should the regulator be putting voltage to the field winding/coil, even without the alternator spinning?No.The item in green is probably a voltage sense connection, were is it connected?

author: ProBang2
author_rank: Frequent Contributor
timestamp: March 02, 2016, 12:38:06 am
content: Quote from: bills on March 01, 2016, 11:42:26 pmVery simplified picture of the world. It depends of the car.Interesting: The english wikipedia describes your scenario.https://en.wikipedia.org/wiki/Alternator_%28automotive%29#Field_regulationThe german wikipedia describes my scenario.https://de.wikipedia.org/wiki/Lichtmaschine#Ladekontrolllampe_bei_der_DrehstromlichtmaschineCorrect are both.

author: bills
author_rank: Frequent Contributor
timestamp: March 02, 2016, 12:57:47 am
content: No! with the engine not running the field would be at max because the reg would be sensing low voltage.It would be hard to start the motor with a 300+ amp alt. full field current.

author: ProBang2
author_rank: Frequent Contributor
timestamp: March 02, 2016, 01:38:02 am
content: Quote from: bills on March 02, 2016, 12:57:47 amThere is no "Full field current". The current is limited (Battery light, additional resistors, voltage drop of two diods.)down to 200 - 400 mA.Unfortunately I cant get any exact shematics about alternators, used in Toyotas, or even alternators with 320A.(Couldn´t it be a decent Ford,VW, Audi, Porsche, Seat or Vauxhall/Opel?).And yes: I am a noob in electronics. I think of myself as a beginner. Perhaps you are an ace there.On the other side: Think a little moment about my avatar. And then guess, which field is mine?

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: March 02, 2016, 01:53:28 am
content: Field winding measures like 4 ohm, so worst case it draws like 3amp during cranking, so no issue.However. I'm fairly sure the battery light goes off during cranking, meaning the alternator is off anyway. (Globe no longer being powered by the ignition switch)

author: Adam60
author_rank: Regular Contributor
timestamp: March 02, 2016, 04:32:04 am
content: Can you take a bigger picture of the whole alternator and send it to me or post it on here. I wanted him to PM me because I wanted more details that just take up space here and are unnecessary for the conversation.

author: tautech
author_rank: Super Contributor
timestamp: March 02, 2016, 05:12:18 am
content: Quote from: Adam60 on March 02, 2016, 04:32:04 amAnd you can't/won't share your knowledge on the forum?

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: March 02, 2016, 08:34:20 am
content: I measured the field voltage again, this time on ac, rather than dc, (probably should have considered that before) and saw something like 2 volts....So then I wired it up to a battery, spun it up to maybe 1500-2000rpm using an impact driver, and still no charge?Stuffed around trying to work out what was going on, then I remeasured the field voltage, and it was basically goneI suppose that does relate to it charging for 2 minutes of driving, then dropping out

author: amyk
author_rank: Super Contributor
timestamp: March 02, 2016, 12:14:34 pm
content: You can find plenty of schematics of alternators, just need to find the right one for your model. Some examples:http://www.rowand.net/Shop/Tech/images/AlternatorWiringSchematic-1970Buick.jpghttp://www.rowand.net/Shop/Tech/images/AlternatorWiringSchematic-1974Buick.jpghttp://www.rowand.net/Shop/Tech/images/MergedWiring-1970Buick-InternallyRegulated.jpghttp://asavage.dyndns.org/Nissan/Maxima/FSM_1982/FSM_1982_EL-021-1b.jpg

author: Neverther
author_rank: Regular Contributor
timestamp: March 03, 2016, 09:51:00 pm
content: No battery connected when testing like that = rectifier boom as current has no way to go, with capacitor on the output it might survive.Prettymuch every one of them use the light to provide current to the rotor coils. In that video I use T10 with five 5050 leds and spinning it with drill. The current does not need to be great to get it started up.The vreg in most cases is just comparator with some temperature compensation. The B+ terminal is monitored against reference and output is connected usually to npn transistor on the ground side of rotor. As explained before, the idiotlight goes to the positive of the rotor coil. If the bulb lights up, the regulator is usually working (altough in some cases the cars detect if the wire is not connected instead of just using regular bulb or the regulator has resistor to ground from the light for broken brush detection).The field connection from the rotor supplies current to the rotor via diode as the alternator starts working, its about the same as the voltage coming from the idiotlight so no current passes through the light once running.It is usually the rectifier that dies, or brushes. Checing the rectifier means desoldering it from the stator to check each diode individually.Dead diode on the output to rotor positive -> no current for the rotor positive apart from the light so it might work for a while. If the car has voltage monitor with separate exitation instead of the simple light it, might show it working for some time.Shorted rectifier diode -> no output at all.In the first pic I see they are the normal pressfit diodes, 60A ones here cost about fiver a piece, new rectifiers cost 25 to 60.And then you buy bmw/merc and wonder why you need to enter the battery serial number for charging system to work...

author: Adam60
author_rank: Regular Contributor
timestamp: March 04, 2016, 01:30:44 am
content: Sorry for late reply. In order to diagnose this issue instead of bouncing all over the place, lets gather the following information:1) Make and model of car2) Size of alternator output cable? Was it changed when you installed new alternator?3) Ground is provided by block? Back cover of alternator must be clean and tight to provide rectifier ground4) What are the voltages on each of the three wires to the regulator and what letters are assigned to them?5) Make sure the wires are all capable of carrying rated amperage.6) How many batteries are you running? This setup should probably have run dual alternators. Do you have any cooling setup fot this alternator? Shrouds?7) I can get you through this. Stick with me and do as I ask and we can solve this.On a sidebar, Transpo electronics build the best rectifiers and regulators in the world. They are top notch and no offense, but you will not build a better unit. I have used literally thousands of their products with great success.Lets figure out your problem.

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: March 04, 2016, 05:27:19 pm
content: Quote from: ProBang2 on March 01, 2016, 06:23:00 pmThanks heaps for your help!As you've said, the field winding should be energised even without the alternator spinning, I swapped out the regulator, and sure enough, we're charging againI'm still not entirely sure what the soldered connection on the regulator does, and in future, I may still want to make my own regulator, as I'd like to be able to adjust the voltage depending on what I'm doing at the time. (13.8volts while cruising, 15volts while putting a heavy load on the alternator for example)I used a regulator intended for a Toyota, as it was available locally easily, whereas the original regulator with the GM connector doesn't appear to be used on anything Australian delivered.I've added a diode to the sense wire to get a bit more voltage from it, about 14.8volts cold, which drops to 14.5volts hot. (the original regulator was around 15volt cold, 14.7 hot)And thanks for absolutely nothing to all the internet mechanics who were more interested in giving an answer, than actually reading the question they were answering. I thought that asking on an electronics forum, as opposed to a car forum would eliminate this issue, but clearly I was mistaken

author: tautech
author_rank: Super Contributor
timestamp: March 04, 2016, 07:00:43 pm
content: Will battery charging be one of this alternators tasks?The voltage you've tweaked it to with the additional diode might be a tad high.Wouldn't want to see you back soon asking why it's fried your batteries.

author: ProBang2
author_rank: Frequent Contributor
timestamp: March 05, 2016, 05:42:11 am
content: Quote from: AmmoJammo on March 04, 2016, 05:27:19 pmGlad to hear I could help you. I wish, I could be more helpful...To be sure do a last check, please:- Start the engine.- Activate some electrical load (driving light, rear window heater, a/c ventilation on high)- Engine should be at 2000 RpM- Now measure the voltage at the battery with this conditions.- 14,5 - 14,8 Volt present: It´s all fine, you´re done.- Not present (probably much less): There is a defective diode (as mentioned from "Neverther")[ Yes, that´s possible. The alternator has with no load the right voltage but is not able to provide current with load. ]I have really no clue about the solder connection...In car-electrics it is quite uncommon to use solder connections under enviromental influence (dust, wetness, vibrations).Connectors with crimped wires are in use. In safety-relevant wiring (airbags, srs, crash-sensors) is soldering strictly forbidden.As "tautech" mentioned: The charging voltage is important.The correct voltage depends on your battery.A lead- Batterie (marked with "Pb", what a coincidence) has a max charging voltage of 14.4 Volt.A calcium/calcium or calcium/silver battery can be charged with 14.8 Volt.Above this voltage the fluid in the battery will forming bubbles. These bubbles are pure hydrogen. A few will stick some time at the metalplates. After all they all will evaporate out of the battery. Bubbles on the plates decreasing the reactice surface (fluid/plate). Lost hydrogen sinks the level of the battery-fluid. This decreases the reactive surface further. The current flow over the smaller reactive surface increases (concentrating). This increases the forming of bubbles. More bubbles...and so on and so on...The battery is not immediately killed. But it shortens her lifetime. And the battery should be regulary refilled.If it is possible. Some batteries are ultrasonic welded with no possibility to refill.Sometimes the openings for refilling are hidden under stickers and/or sliding plates.Your charging voltage is OK. No worries...[I hope, nothing is lost in translation. Or wrong translated. English is not my primary language...]

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: March 05, 2016, 06:00:05 am
content: Batteries are all sealed AGM, they've been charged at 15volts for the past 2 years without issue.I didn't like it much, and prefer the 14.8volts of the new (modified) regulator.Voltage doesn't drop, even with a 100+amp load on it.

author: ProBang2
author_rank: Frequent Contributor
timestamp: March 05, 2016, 06:12:52 am
content: Quote from: AmmoJammo on March 05, 2016, 06:00:05 am

author: broz
author_rank: Regular Contributor
timestamp: March 06, 2016, 09:09:50 pm
content: Just wondering if you checked for the most common alternator fault before diving into the regulator...what condition are the brushes in? If they are significantly worn, then this is most likely your problem and not the regulator itself (brushes are a much cheaper and easier fix than swapping and modifying regulators. However, if you've already determined the brushes are good, then just disregard this.

author: Adam60
author_rank: Regular Contributor
timestamp: March 06, 2016, 10:52:21 pm
content: There is a "sense" wire on this alternator I believe. It goes from the battery to the "S" terminal on the regulator. If this wire is open, it will tell the regulator to turn on the transistor duty cycle close to 100% and charge high. Check this wire to make sure it is not open. Simple voltage test. Secondly, as I said in an earlier post, Transpo is a world leader in regulators and rectifiers and when one of their components die, I question what happened to it. Possibilities range from defective rotor, to brush issues, to poor grounds which I believe on that unit are provided by the back cover and rectifier body. Make sure that this unit is very clean and tight at all connections to that regulator or you will find yourself with the same issue again. Lastly, I am guessing you are running stereo equipment on this car and sudden inrush current could also have caused it to fail. Not much you can do there. Best bet is to split the system and go to two alternators. I have done this before with great success. Both systems must be equal in order to work properly. That's for another day.Good luck.

author: RobertBG
author_rank: Regular Contributor
timestamp: March 07, 2016, 05:23:06 am
content: You've just got to love some of the responses from the condescending know it all'sIf you're not happy with the output voltage you can swap in a adjustable regulator.I run a external that's adjustable with a rheostat on one of our trucks.Most of the time we don't need the output but if we're going to weld something or run the winch etc its there if we need it.http://www.mechman.com/accessories/external-adjustable-voltage-regulator/

author: Adam60
author_rank: Regular Contributor
timestamp: March 08, 2016, 03:59:14 pm
content: Not sure who the condescending people are that you are talking about or if i am included in that group, but I think overall that most people who respond mean well. I think we all want to help people out and perhaps sometimes we get a little more exuberant about our answers than we should or perhaps we don't read the question properly and go off on the wrong tangent and give information which is unrelated, but I don't see any posts here that are condescending.As for the output voltage, the OP can do what he wants with it but most batteries, especially AGM and Gel-cells, do not like high voltage so i think people are just trying to help. My comment was just wondering why the original voltage regulator failed. I am never satisfied with just replacing something. I need to know why it failed so that it can be repaired properly. If not, then we are just parts replacers.