electrical drain

[68'barracuda]

OK...i have a 68 cuda it has a drain coming from somewhere (i think the old ignition module) but not sure where... have to swich battries about 1 a week, if u jump it off it will not start when you kill it , even after it nas run 30 min... any ideas??????

 

[pettybludart]

Sounds like its running off the battery(altenator not chargeing)Take your alt. off and have it checked at Parts store.If fine,I,d be looking at the regulator.There,s a few electrical gurus here,hope they can chime in.

 

[68gtxman]

Sounds like its running off the battery(altenator not chargeing)Take your alt. off and have it checked at Parts store.If fine,I,d be looking at the regulator.There,s a few electrical gurus here,hope they can chime in.

I agree totally with Pettybludart!

 

[cudavert]

I've seen alternator diodes go bad so that the power will back-feed through the alt and drain the battery. If you disconnect the fat red output wire, and touch it to the output post and see if it sparks. Alternator sounds bad anyway.

 

[67Dart273]

Yup. Stick a voltmeter across the battery when running. When warm and charged, the battery voltage should run about 13.8---14.2, in no case below 13.5 and not above 14.5. Check at a good fast idle ---to up to simulate low to med. cruise RPM

You still have the original style 69/ earlier regulator? Take a clip lead and hook the two connecting wires together, see if the voltage climbs up some with RPM increase. If so, bad regulator. If not, either bad field wiring or bad alternator.

If not voltage increase, move down to the alternator. Compare battery voltage to voltage at the alternator stud at a good fast idle. If the stud is very high, 15 or more volts, but the battery is low, much below 13.5, you have a wiring problem in the charge line/ bulkhead connector/ ammeter.

If battery and stud are both low, take your clip lead, unhook the field wire from the push--on terminal of the alternator, and clip the alternator field terminal to the output stud. Again raise RPM and see if either the output stud or battery starts to climb. If not, bad alternator. Might be as simple as worn/ stuck/ gummy brushes

If you actually think you have a drain, IE battery goes down sitting, remove the ground cable, and put a 12 v test lamp in series from ground to the battery neg terminal. If it lights or glows (examine in shade or garage low light) you have a drain.

 

[MOPARoldtimer]

I know that 67Dart273 meant to tell you this: if you find you have a drain at the battery, pull the fuses one by one until it goes away. Then you'll know which circuit it's on.

 

[67Dart273]

I know that 67Dart273 meant to tell you this: if you find you have a drain at the battery, pull the fuses one by one until it goes away. Then you'll know which circuit it's on.

Yup and if none of the fuses kill the drain, unhook the alternator output stud.

 

[cudajim]

I would use an ammeter instead of a light bulb in series with your battery cable to see how much current you're pulling. You may be pulling low milliamps which may not show up with a light bulb. I do agree that by pulling fuses you should be able to narrow down where the current draw is going.

 

[67Dart273]

I would use an ammeter instead of a light bulb in series with your battery cable to see how much current you're pulling. You may be pulling low milliamps which may not show up with a light bulb. I do agree that by pulling fuses you should be able to narrow down where the current draw is going.

You ALWAYS want to start FIRST with a lamp. This is because, even if using the highest current scale on your meter, if the load "just happens" to be more than the meter can handle, you can blow a meter fuse, or even damage the meter.

But even if just using a typical 12V store--bought test lamp, most of them will glow at very little current---useful in most situations.

I did not say anything about using a meter because I wanted to keep "the start of things" simple.