The Stovebolt Site Forums The Shop Area The Electrical Bay Alternator/Generator Question

OK guys so I find out my alternator is bad. I was looking into putting a 100 amp alternator on 59 Apache, but what is this talk about a generator??? Where is it and how do I know what ampage max it will allow? Sorry Im new to all this and never new of generators? Is this an option or a part that is mandatory and works hands in hand with alternator? I have a 283 in it, thanks to all.

nothing optional about either - alternators are the later replacement for generators, different technology, same function .... if you have one, you don't have [or need] the other, either "generates" voltage/current to keep the battery charged while the engine is running, and supplies power for accessories .... why do you want to put a 100 amp alt on it? plan on having lots of power sucking accessories?

Bill

To continue with Bill's question... Unless you are going to put in A/C and/or a very large stereo system there is no need for a 100 amp alternator. In fact, if the ammeter in the dash carries all the truck current you may need to change it out or add additional circuitry to keep the needle from pegging.

Thank you kindly guys for the ideas and suggestions. So I guess the answer is yes i would want to put AC in and electric wipers and a radio with amp eventually, but not in near future. So the options I saw were 60-80-100-120 amp. What is the OEM for us? Should I just stick to 60 amp?

60 amp would be fine for all you want to do, original generator was about 45a I believe

Bill

I'm going to answer, but just from the stereo with an amp side of the question. If you want to do a stereo with an amp, go for the 100 amp alternator. If you want to go with a smaller alternator you will probably want to add a mid size capacitor to the stereo system, otherwise you won't get a clean punch from every not, maybe every few notes instead. I've never built a stereo system for one of these truck, but I have built several systems for people over the years.

Thank you all, now lets say that I do want to put a system in it later on that may use a little more power than the norm, what does this mean...." In fact, if the ammeter in the dash carries all the truck current you may need to change it out or add additional circuitry to keep the needle from pegging." How do I fix this issue or will it necessarily be an issue if i put a 100 amp alternator.

"if the ammeter in the dash carries all the truck current" [you need to "shunt" the ammeter] .... you will not have any problems with the TF gauge if the wiring is sound and according to the factory diagram, it carries only the current that charges the battery .... OTOH an ammeter doesn't tell you as much about the condition of the system, and with a LOT of electrical goodies added, a voltmeter is considered better

Bill

Squeeze I am trying to understand really I am but Im a work in progres,:). What do you mean by TF gauge (what is that). How do I know if it is sound? To simplify things and avoid any issues I bought a voltmeter, and want to disconnect the ammeter, Im assuming that is the "Amp" gauge on dash????? So I guess my question is if I do have an "amp" gauge how do I disconnect it and avoid issues and connect a voltmeter so I will not have to use a shunt and two be safer and more up to date on technology?

TF = Task Force, the series truck you have, 55.2-59 .... yes "Amps" means ammeter - don't have a schematic for the change, but you can learn some about it here, there's an article toward the bottom, although it discusses newer Dodge wiring, you might puzzle out the principles - and someone else here may have a simple diagram for GM trucks

there's no problem with the technology you have, it's been working fine for decades on thousands of vehicles, including yours and mine ... the main issue is age, so you might consider how good your present wiring is and how much previous folks have messed with it, not too hard to install a new repro harness, including a fuse panel for the goodies

Bill

OK so maybe I will stay with ammeter if it wont peak out once i put a 100 amp alternator on it. Why are others saying that the amp will peak out and that I will need a shunt and blah blah if it only measures the curent to the battery. My interpretation of your statement is that the amount of current is not much and nothing to worry about. So again my question why do others seem concerend about a 100 amp alternator on our original ammeters? THe wiring looks good nothing i can see that looks bad on the wiring and I really do not have a load now, but in future do want to put more electrical stuff. Can you point me to where I can get a reprodcution harness and a fuse panel. When you say repro harness, it makes me think that I should have a lot of wires haha but all i see is a red gauge wire and a green wire i think going to a little box in the hood to the side and then i believe the red gauge wire goes to ammeter r something like that.

OK disregard last reply, after reading into it further i have seen more bad things about amp meters and nothing on volt meters. I would hate for a shunt to fail and risk of fire and making all go bad if it fails opposed to a voltmeter which has no risks of fire. So my new question is how can I "disconnect: my current amp meter and install the voltmeter instead, like one of these add on voltmeters and not an indash voltmeter? Will I be ok to drive my truck with the alternator until I can get it to shop so they can disengage the amp meter and install voltmeter?

OMG, no I don't think you'll be ok to drive your truck

read more and you'll find nearly every vehicle involved in a major accident in your town has a voltmeter

didn't you start this thread by saying the alternator was bad? how can you drive it?
call a tow operator and have the truck taken to an auto electric shop to be repaired, tell them you want a high output alternator, a volt gauge and brand new wiring harness

WEll its bad but I can start the truck. Autozones tester showed it was not charging correctly, but If i jump battery I can start it and drive it to mechanics, just not sure if that will ruin anything? I read that if I change from ammeter to voltmeter i have to move the wires that were connected to ammeter. arghhh!!! I am not trying to spend too much money on convrting truck at this point if I don thave to. I sort of want the best of both worlds. I already orderd the 100 amp alternator, so I guess to avoid from having to reroute wires connected to the ammeter I will stick with it and attach a shunt? is that correct?

Or can I install the 100 amp alternator, I dont have much need for amps at this point i.e. power windos, seats, radio, ac, etc.. can I just install it then have a shunt installed? or what would be the best thing to do to save guard from fire keeping my ammeter in place aside from a shunt? Squeeze am I frustrating you hahaha, dude thank you soo much for the answers thus far I have spent last 2 hours just researching stuff and im not trying to buy a whole new harness $400. I did see an engine harness $60 which I assume consists of the ignition and alternator to ammeter wire, but the OEM engine harness I assume will not fix the increased amp issue so i am back t a shunt. So bottom line is it there anythin else that I can instal to ammeter to help with safety of current though ammeter?

if your trucks wiring is in good condition and not a rats nest from 50 years of previous owners messing with it, all you need to do is replace the alternator, you don't need to add anything, particularly not something you don't understand - if the wiring is a mess replacing the complete harness is your best insurance against a future electrical fire ... most vendors have a complete reproduction harness with the alternator upgrade for around $200, 400 is way too much

the original generator on your truck with a V8 would have been 45amp, sized to deal with every available electrical accessory operating at the same time [wipers, heater, radio and all lighting including clearance lights, foglights and a spotlight].... a 100 amp is very much overkill, useful only if you plan on electric fans on the rad, high power halogen lights, power windows, AC, a stereo amp big enough to break windows, etc etc

the highest reading of the ammeter will be just after you start the truck and the charging system [generator or alternator] is replacing the drain from the battery ... the highest output alternator you can get doesn't change that, although some will say that alternators can surge at first until their regulation kicks in - I've never seen that with the vehicles I've put alternators of 65-85 amps on ... fix what's broken now, make sure the wiring is in good condition, especially all connections clean and tight, and start learning about how the electrical system works so you can recognize future problems as they arise

Bill

Thank you kindly, I think I will request the special order be changed to a 60 amp or maybe 70 amp system. Do you have any favorite classic truck sites or vendors that you cna guide me too that sell the harness mentioned just in case.

To bypass the alt. connect all the wires from both terms on one term. With a 55-65 amp. alt the factory amp. gauge will work ok. I have that on mine & it never peaks.

Guys am I more concerned about the wire going directly from alternator to ammeter as causing a fire if not in good shape or are pretty much any of the wires taillights, headlights, horn, etc.. also a concern on these trucks that have all current going through the ammeter? The voltage regulator appears to show its age rusty, but I dont see any wires showing cuts or scrapes. If the main worry of fires is the wire going from alternator to ammeter can i just run a heavier gauge wire and replace?

ALL connections need to be clean and tight as the start to avoiding electrical fires, "just running a heavier gauge wire" is not the approach, understanding the particular system is, and having the correct gauge wires everywhere

if you have an external voltage regulator, are you sure you have an alternator? is the regulator like this or is it like this? - the first is the regulator for an externally regulated alternator, it is as likely to be your problem as the alternator itself ... the 2nd one is an original regulator for the generator system - the regulator and wiring have to be changed to switch to an alternator - see here to identify what you actually have, and then get to discussing your situation with a qualified auto electric shop, switching to an internally regulated alternator [10 or 12SI] will be beneficial

Bill

OK mine looks like like the second picture as the wires are coming out of sides and not the top as the first picture shows. Yes i have an alternator, im slow but not that slow haha. So you are you saying that the regulators were for generators? The regulator there now has wires attached to it and like I said looks identical to your picture on #2. Is this the proper set up, or could it possibly be an old set up and nactive at this point since i have an alternator

Does anyone have a picture of an alternator attached to an ammeter? I am trying to identify the small box next to the rgulator as well as some other box on the other side. How can I post pictures on here so I can show you guys what I am talking about.

Both alternators and generators have regulators. The regulator controls for output voltage AND for output current. It will limit voltage if at max current - as current drops (battery is charging) then regulator will increase voltage to whatever it is set for.

The ammeter in automotive common setups measures ONLY the current in or out of the battery - that is why it is zero at center and + at one end and - at the other extreme end. You could have a one megawatt alternator in truck
BUT if the battery only wants 30 amps that is all the ammmeter will read.

IF mine I would have all wiring and components between battery and alternator (or generator) sized for full current of the unit plus 10% AND for the voltage.

I am just an industrial and power plant electrician. ALL alternators and generators I worked with had at MINIMUM a voltmeter and an ammeter. You need both to know the full story.

The submarine battery I worked with had a meter +5,000 to - 5,000 amp.

IF my truck I would have a battery current charge / discharge meter on dash. This would be a shunt unit to minimize wire length and voltage drop. In the engine house I would have voltmeter and ammeter for alternator (generator?) output.

Dan Bentler

mejia, the smaller 'box' near the regulator is the horn relay .... the regulator shown on the black firewall is the original style for a generator [rectangular and 3 wires] - the one on the red firewall is the style for the externally regulated alternator [square and 4 terminals], the direction it's facing is meaningless, but if yours is the 3 terminal rectangular one, it's the regulator for a generator and likely has been jumpered for installation of an internally regulated alternator [the one with an external reg looks like this from the back] - if you don't know which type of alternator you have, how did you order one?

to post some pics upload them to a host site someplace [like photobucket] and then paste a link here so someone can identify what you have .... it might also help you to get a shop manual and look at the wiring diagram in it while reading all about the factory electrical system

Bill

OK so I ordered it by going to autozone and plugging in my vehicle info. Its a one wire GM style alternator from proform chromed out. I ordered by looking at the back of the now trashed alternator and noticed that it had a red wire that went to i think starter then to the regulateor jumped as you say then it had another red wire that was also attached to the one bolt on rear of alternator and other end to the side plug section of alternator. I know I suck at descriptions. After hearing sooo many horror satories about higher output alternators pegging ammeter and direct currenbt going to ammeter and fires I truly was afraid to connect the 100 amp alternator, but after installing it which to me is a huge accomplishment along with a new chrome alternator it was perfectly fine no pegging of ammeter or nothing, man I was glad! NOw if I can just figure why my turn signals are acting weird I thought it was the alternator causing it, but its not. when i put on right flasher my hazards come on, sometmes when i turn on tailights the flasher wont work, or sometimes i turn on a flasher for tail lights to come on, just weird. Dont know what to do. I had all the connections installed, although i did notice that from the beginning the flashers would come on but were slow in flashing or delayed. The electrical guy said that the flasher he installed was too big for my truck and that was the cause of the problem. I dont buy that because like i said if i turn of tail lights my flasher will work fine and no delay but if i turn on tail lights and flasher sometimes delay sometimes freezes and sometimes hazards come on instead hahaah weird. My next task I guess, any suggestions?

can't help about the signals, you obviously have some unknown aftermarket setup as the originals had no hazard function, but here's the factory signal wiring diagram, sounds like there might be some wires incorrect

Bill

Thank you for the schematic squeeze. I do have an aftermarket universal signal indicator I will mess with it tonight, thanks again.

Squeeze so it turns out after close i have the regulator like the one in your red fuirewall example. New alternator and relatively new battery, I am thinking maybe its the voltage regulator. How can I test it to see if it is that and not alternator?

I'd suggest having a reputable auto electric shop put their test equipment to it, they'll be able to tell you exactly what's what

also for the universal signal problems, see Cletis' tip here, which may give better hints about the correct wiring and flasher

Bill

OK so I took an even harder look at alternator. I have a red wire going to the one wire battery plug in the back of the alternator. I also had a red wire going from the #2 on alternator sensing wire to the back of the alternator attached to the same battery plug then its connected to the starter and then to battery. I am not giving up yet, have a few more things I want to try before I hand it to the electrical guys haha, come on guys dont give up on me. I have a proform 100 amp alternator one wire set up. Should I disconnect the red wire from the voltage sensing plug and just run a straight 10-12 gauge wire to battery??? Or should i stick with current set up? I actually had battery working but overnight it died on me again. Battery has been fully charged and alternator also tested good. Any odeas other than giing up and letting someone else play with my truck? I can test connections with my meter if need be.

looking hard isn't what's needed, understanding what you're looking at and whether it's right or not is ... if you have a one wire internally regulated alternator, then the regulator on the firewall is meaningless, and should have been removed .... if you killed a fully charged battery overnight, then something is obviously wired very wrong, and I'd think you're lucky the battery died before the fire started .... it's not a matter of "giving up", take it to a professional and get it done right before you hurt yourself

Bill

I agree with you but at the same time I have not messed with the wires from previous set up which did work until alternator very old alternator fnally crapped out. I am not doing anything without researching first, which to me means understanding the mechanics of how the system works, trust me. All I am asking is for a bit of guidance from someone who has a bit more knowledge than I do. I do appreciate your suggestion to take to mechanic, but I refuse only because although I do not know all I have learned a lot about hw the alternator works and difference between 3 wire and one wire, what voltage regulator does, safety, etc.. Just need that reassurance that what I am about to check is the correct method of examining the circitry. For instance , the box I spooke about earlier I have now determined is simply a shunt with a fuse attached to it, which is a safety mechanism as well as controlling how much "juice" goes to ammeter. The fuse is good so shunt is doing its job. I will check all connections on shunt today, I will take the wire from sensor conector on alternator off and see if that works, I will check the battery wire to make sure that it is not crimped, cut ext., and I will rev the alternator until it kicks in and check voltages. The first time that I installed the alternator the battery was still pretty much drained form the first alternator going out. Now it is fully charged. Anyways that is what I am going to do. Any other suggestions aside from taking to expert?? Now I will give it a go and see, if this does not work definite trip to mechanic.

Ok Alternator and battery back in, system is charging! I took out the wire going to #2 on alternator and presto holds charge now. NOw if i could only figure out my flashers/taillights, and figure out what all is attched to the shunt I will be happy. Any ideas guys? I know for a fact that the battery wire going from alternator is also going to the shunt, then I also have a green wire that appears to be going into a junction box inside of car.

[quote=mejia11]I agree with you but at the same time I have not messed with the wires from previous set up which did work until alternator very old alternator fnally crapped out. I am not doing anything without researching first, which to me means understanding the mechanics of how the system works, trust me. All I am asking is for a bit of guidance from someone who has a bit more knowledge than I do.

For instance , the box I spooke about earlier I have now determined is simply a shunt with a fuse attached to it, which is a safety mechanism as well as controlling how much "juice" goes to ammeter. The fuse is good so shunt is doing its job. /quote]

I have no idea of what you are referring to by shunt. In my experience they are a resistor used to derive a 50 mV signal for instrumentation. They are rated in DC line amps anywhere from 5 to 5,000 and either 50 or 100 mV "output". They will often (the better ones do) have 4 terminals 2 big ones for the DC line and two litttle ones for the 50 mV output (often 10 32 screw)

They have no other use or control capability.

Send picture of this thingy you are talking about.

Dan Bentler

Dang it I am going to have to figure out how to host photos. But yes it does have 4 terminals but all same size wires going into it except for a blue one which is thinner. I have 2 red wires and one green wire going into it, on the other side of the shunt "thingy" I have a jumpered red wire going into two of the terminals with a fuse coming out of it.

Little more now that it sounds like a real shunt. It should be made of brass and that should be pretty solid ie 3/4 x 3/4 or so. On it somewhere should be some resistance value like 0.04198
and XX amps and 50 mV. If it has numbers like this send them here and we can go from there. If it has manufacturer same send that also.

Dan Bentler

Ok just went out and the box that I speak of is a black plastic with 4 terminals on each side. Anyone have any idea what it would cost to rewire the whole truck haha... I'm almost at that stage, I dont have anything other then essentials, horn, headlights, heater, dasg, dimmer, ignition, etc..

HAR-019, $195, from a Stovebolt sponser right there in Texas

Bill

Thanks Squeeze, I'm all about supporting "supporting vendors." Any idea what it would cost to actually have sone re-wire my truck considering I obviously know little about this stuff?

no idea what a shop would charge, but it's not brain surgery, nearly plug and play if you have the shop manual with it's wiring diagram and various pics and take your time .... always gets confusing if you try to figure out how to do it "better" than originally designed, but the line guys who put it together in the first place just followed the instructions

Bill