Battery drain
Thread Starter
Registered User
Joined: Feb 2021
Posts: 76
Battery drain
I have a 78 delta 88. Trying to find out why my battery is draining. I have the right specs on the battery. My clock doesn’t work. I make sure everything is off after driving any information is appreciated thanks
Registered User
Joined: Jul 2019
Posts: 92
From: Cincinnati, Ohio
Try taking your battery and alternator out and have them both checked at an automotive parts store. If they both check out fine use a multimeter on the battery to find what system is drawing. Use u-tube to watch videos on how to do that, there are several. Usually you'll find that the alternator just isn't putting out enough voltage to charge the battery. It's a slow death for the battery. If you have a voltage meter on the vehicle look to see if you have 14.2 volts at Idle.
Last edited by EdwardB; Dec 23, 2021 at 10:25 AM.
Oldsdruid
Joined: Dec 2007
Posts: 10,634
From: Southside Vajenya
How often is this happening? Overnight, weekly, monthly?
First, check alternator output. If you don't have a multimeter, you can get one at a chain parts store or Harbor Freight for less than 20 bucks.
With engine running, check alternator output voltage at the output post. It will have a heavy gage red wire on it. Should be 14 volts. If not, bad alternator.
Then check voltage at the battery (+) terminal. Should be same as alternator output voltage. If not, there's a wiring problem.
If these check good, time to start searching for a current draw.
Let us know what you find on alternator and battery. We'll go from there.
First, check alternator output. If you don't have a multimeter, you can get one at a chain parts store or Harbor Freight for less than 20 bucks.
With engine running, check alternator output voltage at the output post. It will have a heavy gage red wire on it. Should be 14 volts. If not, bad alternator.
Then check voltage at the battery (+) terminal. Should be same as alternator output voltage. If not, there's a wiring problem.
If these check good, time to start searching for a current draw.
Let us know what you find on alternator and battery. We'll go from there.
Registered User
Joined: Nov 2009
Posts: 3,009
From: Red Oak, Texas
Check to find the drain like this. Dissconnect your ground from the battery. Connect a test light to the ground terminal and ground the test light. If you have a drain the test light will be on. If you have a drain, pull fuses one at a time until the light goes out. When the light goes out that is the circuit that is causing the drain. This does not work if your alternator is causing the drain.
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