batt drain help. (alt)

[ooimpalaoo]

ok so i have a 71 k10 new bat new alt. if i leave the batt hooked up over night it will be dead when i get up to go to work the next day. after going throught all the wires headlight switch, ignition switch, starter cable, draw test, going crazy i did the simple thing and disconected the wire going from the batt to the alt now in not getting the spark that i was when i was hooking the batt up..... soooo im guessing that is it....now wtf is going on????? i was told somthing about a regulator?? wtf is that and what does it have to do with the alt? please help me out im so sick of removing my ground wire every night.. thanx

[hugger6933]

On the drivers side of the truck under the hood mounted on the radiator support is the voltage regulator. That would be the item I think to change out to solve your problem

[65 C20]

I can't help you out but you may get a better respnse over in the electrical forum.

[TwoFiftyShifter]

I had this a couple months ago

Changed the voltage regulator. $22. All fixed.

The cool Voltage regulator test is to pull the positive battery cable WHILE the truck is idling. If the truck stays running, the voltage regulator is fine

[VetteVet]

Originally Posted by TwoFiftyShifter

I had this a couple months ago

Changed the voltage regulator. $22. All fixed.

The cool Voltage regulator test is to pull the positive battery cable WHILE the truck is idling. If the truck stays running, the voltage regulator is fine

A battery drain is nothing more than a current running through a load whether its through a light left on or a sticking relay in the horn relay or voltage regulator. In your case it was the voltage regulator.

Pulling the battery cable is not a valid test of anything. It will only show that the alternator is putting out enough voltage (current) to keep the engine running. What it will do is throw the alternator into an unregulated state, because the voltage regulator can no longer sense the state of charge of the battery. Usually the alternator will default to full output based on the engine
RPMs. Any sensitive electronics like a distributor (HEI) module could be damaged.

The best test for a battery drain is to place a multi meter between the disconnected negative battery cable and the negative battery terminal with the multimeter on the 10 amps scale and with the engine off, and everything turned off on the vehicle. This test should be done with a fully charged good battery to avoid any internal shorts in the battery itself.

If the meter reads more than 3 or 4 milliamps .003 amps, that is unacceptable in most cases. If there are hacked up harnesses or added circuits by the OP then all bets are off.

Most all these drains are key off, and in the voltage hot all the time, loads. I/E. the alternator, the regulator if external, the horn relay (if the horn is disconnected, it would be blowing otherwise and obvious).

The procedure is to start disconnecting along the positive path of the trucks circuit. One at a time and leave them disconnected in case there is more than one draw.

Starting with the alternator, then the external regulator then the horn relay etc. until the multimeter amp draw drops to near zero. You can also use a test light, watching for it to dim or go out.

Memory items like radio presets will draw a small amount so the reading may not go to zero. It sometimes occurs when the owner has wired in a stereo system and has connected it to a hot positive source without a switched off capability.

[1969c10joe]

A friend had this problem once in a while his battery would be dead in the morning. I drove by his house one night his brake lights were on it was the switch didnt notice it in the daytime. As mentioned already sound systems are usually culprit. I installed toggle switch to shut all power to radio even though digital clock doesnt draw much. yes a multi meter is a great tool to own good luck hope its easy to find

[1969c10joe]

Originally Posted by 1969c10joe

A friend had this problem once in a while his battery would be dead in the morning. I drove by his house one night his brake lights were on it was the switch didnt notice it in the daytime. As mentioned already sound systems are usually culprit. I installed toggle switch to shut all power to radio even though digital clock doesnt draw much. yes a multi meter is a great tool to own good luck hope its easy to find

it just dawned on me that the brake lights maybe they werent sticking on all the time that was thirty years ago

[leftybass209]

Originally Posted by ooimpalaoo

ok so i have a 71 k10 new bat new alt. if i leave the batt hooked up over night it will be dead when i get up to go to work the next day. after going throught all the wires headlight switch, ignition switch, starter cable, draw test, going crazy i did the simple thing and disconected the wire going from the batt to the alt now in not getting the spark that i was when i was hooking the batt up..... soooo im guessing that is it....now wtf is going on????? i was told somthing about a regulator?? wtf is that and what does it have to do with the alt? please help me out im so sick of removing my ground wire every night.. thanx

Simply disconnecting the negative (or positive) battery cable won't "fix" anything except for a poor connection at the battery. Poor connections don't cause parasitic drains on the battery, they only cause increased electrical resistance. Pay close attention to what VetteVet said, as knowing that stuff is critical to owning an old vehicle. Most new technicians couldn't help you either, because there's no diagnostic port in these trucks.