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Too many amps?

miller

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Okay boys and girls...gonna show my hand here. Total ignorant when it comes to electrical stuff. But, from what I hear...gotta have it.

Question is this. Have a 69 model 440 motor, in a 64 model Plymouth, with stock 64 wiring. Round back alternator that came on the 69 motor. Alternator was working great, but looked like crap, so had a rebuilder go through it, clean it up.

Alternator is an 80 amp! Going by my manuals (yeah, I can even read), even on the high side for 69 model B-bodies, seems a 75 amp is the norm.
Will I be okay with the 80 amp? That along with a stock 64 mechanical voltage regulator. Kinda understand that the VR keeps things at bay, long as it's working right.
 
You will be fine, but many cheap "hi current" alternators do not have enough output at idle due to fewer turns per loop in the stator windings.
These are the windings visible through the slots in the case.
Original factory windings had 12-13 turns in each grouping, and used smaller wire, and were hand formed, modern rebuilds often have only 7-8 turns per loop, being wound by a machine.
If yours has the lower number of turns, do not be surprised if output seems weak at idle, though your shop may have done a good job.
For $, a really good shop can rewind the stator with 12 turns per loop as I described.
 
Appreciate that, Darthomas!
I'm thinking about opening my new(?) VR, just to have a look, probably test too.

Any thoughts on any wiring changes needed? Haven't decided amp/volt gauge yet, since considering building my own panel.
 
When I rebuilt the dash on my 63 I bypassed the amp gauge. I had heard about the possibility of failure with these old gauges and installed a aftermarket volt/temp/oil press gauge set.
 
The bulkhead and ammeter are always 2 things to look into while doing any changes since they're weak links. When sizing your wire don't forget to take length into account, there's a reason why automotive wiring always seams small for the given draw. When thinking along the standard thought process (12AWG = 20amps, 14AWG = 15amps etc) they do look small but the current carrying capabilities go up significantly with shorter runs and better quality wire. Just do your research. Good luck.
 
You do not have enough stuff in that car to draw the 80 amps not a worry you should change to a electronic regulator they have ones that look original but are electronic
 
Amperes are requested by the car. Alt gives what the car demands ( if able to do it ).

You can get thousand amps alt output, but if the car request 45, the alt will provide just that.

Think on an AC wall outlet, able to feed your phone charger the same than a hair drier, refrigerator, washer machine etc... amd your cell phone won't burn, neither the wall outlet itself or breaker ( if correctly selected )
 
Thanks to all for some great info!
Shouldn't have any excuse (two sons electricians, but on houses and buildings), I'm strictly nuts and bolts.

I'll stay with the mech VR, since I still know how to work on 'em. Yes on changing gauges. Probably need to be careful on battery group, and sure don't have any 'extras' on this thing. Not even plans on a radio...only music I want to hear is the motor.
At least I feel better about the alternator. Was hoping it was a 50 amp.
 
my advice... find an alt able to give around 45 to 50 amps, BUT IDDLING ( if car requires, then alt will be able to give it )...

If you search for a cheap and stock look ( well, close to stock ), go with an stock 78 amps alt, equipped on 80s cars, and be sure it gets the smaller pulley. This alts usually go on $40-$60 rate on any parts shop. If your car gets a single field setup with mechanic VR, just need to ground one of the fields to make it work ( search for a recent thread called TWO FIELD ALTERNATOR ).

These alts are a bit wider ( one or 2 milimeters ), so can be a tight fit, but fits. I just used a longer belt ( 74 Big Block ) to sway the back of alt meeting with block

The alt rate stated at specs is usually the max amperage able to give, which usually is close to be reach at around 1800 to 2000 RPMs. Your iddle is way lower by far, and usually is barelly half of the max output
 
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my advice... find an alt able to give around 45 to 50 amps, BUT IDDLING ( if car requires, then alt will be able to give it )...
Much appreciated, Nacho!
At least for now (if I live long enough to fire this thing off), plan to try what I have, with plenty of system checking. Only in layman terms, and research, it has been described to me regarding amps, like simply having a larger pond of water to get what's needed. The 80 amp would only send out what's 'needed', limited by what the VR is allowing. So, if my understanding is right...the VR is the key.
Something else keeping in mind, is the battery. Right in line with what Darthomas brought up in his post, about 'boiling' out the battery. The re-charging amp rate needs to work together with the batteries amp rating, or group. That, the way I understand it, is what keeps the battery up...but not too up.
Any rate, believe me, if I run into any issues on it, I'll jerk that 80 amp, like a (lol) hot rock!
 
The battery will request amperage as far is chemically unbalanced, like any other device on the car. Once again, a thousands amps alternator won't provide load if is not requested for any device. It won't boil out the batt. If the battery is already charged, won't matter what is the alt load capacity, since won't get load requested.

Even VR is the key, if alt is not able, the VR will mean nothing

Trust me, when you turn on the lights while car is iddling will notice the need of a bigger alt. This need from factory is what made our charging system to burn around... Even worst when ppl upgraded for a bigger capacity battery without take care still for the alt.

( if adding any electrical upgrade, like relays for the lights, don't feed relays from batt. Will get you unnecesary load running through the ammeter )

Read this
http://www.dodgecharger.com/forum/index.php/topic,33574.0/all.html

And get upgraded the charging paths
 
Sorry my total beginner question - but when shopping for a new alternator - what's the difference between a round back and a square back - is it what it sounds like? Bought the car with some kind of aftermarket 60 amp alternator, but when switching to some electrical fans, EFI and some other parts I noticed that I need more. Should I remove the one I have and check or can you tell from pictures?
 
Round back and square back is just about rear case design/shape, not output.

Roundbacks gets diodes pressed in to the case, squarebacks began to be more "serviceable" with diodes attached to metallic plates, easy to remove and service.

Squarebacks began in 72 with slight changes at the end of 70s
 
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i just stumbled on this thread; good info! i'm electrically challenged too. my '69 r/t has been using a 60 amp aftermarket round back for quite sometime. always discharged at idle in gear and would barely keep up idling in neutral. i found the original 35amp stock alternator and stuck it on this morning. no more discharging in gear. i don't have a clue why the 60 amp didn't work at low rpm, but it didn't. put a little rpm on it and it starts charging. i'm thinking about buying a 35 amp rebuild kit and re-do the 60 amp turd.
 
Honestly, I would go for a 80s stock replacement alt. But hey! That's just me.

If you are keeping stock mech VR, will need to ground one of tne brushes..

Search for a thread called TWO FIELD ALT CONNECTIONS, or something like that... Its a recent thread.
 
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