battery going dead

[tymaster79]

Hi all, new to site. I need some help!
Original problem was truck not starting...after I shorted the solenoid to get started, would start everytime. But, after having new battery charged, now my battery keeps loosing power after sitting for a week. I don't drive truck every day, so that could be part of the problem, but doesn't seem like battery should loose power from just sitting for a week. My battery gauge still shows about 9Volts when I turn the key on, but doesn't have enough juice to start. Oh yea, I did replace the negative battery terminal when I had the solenoid problem. I suspect a short somewhere, but not sure where to go from here...HELP!!!!!!!!!

[19_Chevelle_69]

Welcome to the site, glad to have you!

- Unhook the NEG cable from the battery.
- run a 12v test light from the battery to the cable. It should NOT glow if doors are closed, and all accy's are off. If it DOES, you have a problem drain in a circuit.
- open the door, and remove dome lamp bulb
- start pulling fuses one-by-one and check to see if the light has gone out.
- if the light stays lit when you pull a fuse, put that one back in and try another.
- when you find the fuse that turns the light out, that is the circuit that is causing your "parasitic drain"

Post back and let us know what you find.

[tymaster79]

Hey thanks for the advise. I'll try your suggestions...all sounds pretty logical.
A secondary question...from the neg batt terminal, there is the main wire going to the mount bracket of the alternator (I think), then there's a secondary wire going to the frame. What's the purpose for this secondary ground...and when troubleshooting, what do i do with that secondary wire?

[19_Chevelle_69]

The large wire should go to the engine block (sometimes to the ALT bracket). This is the starter ground.

The smaller wire should go the body (usually the fender) This is the body/accessory ground.

There may also be a ground strap that runs from the rear of the passenger side head to the frame. This is the chassis ground.

As long as the frame, body, and engine all have a ground, you should have no trouble. Make sure the engine has the largest wire, as the starter can pull a couple hundred amps when cranking.

80% of ALL electrical problems are caused by a BAD GROUND.

[tymaster79]

Well, I hooked a test light between neg batt terminal and ground cable...light didn't turn on.

I put a new battery in couple months ago, so I'm going to return my battery and get a new one. Hopefully that fixes all my problems!

I'll keep you updated.

CHEVY UP!

[19_Chevelle_69]

OK, the only other thing that comes to mind at this point is a possible drain through the alternator. If the diodes fail internally, they can allow the battery to discharge to ground over time. Usually 4-7 days. A drain of this type will probably not show itself with the test light trick...

[tymaster79]

Well, I took my battery back and the stores tester showed it to read about 11.3 Volts. It didn't say it tested OK, so hopefully it was bad. I got a new battery so that eliminated that component. I did check the test light on the neg term before connecting and opened the door (turned on dome) and the light did light up...just checking.

Time will tell, if I still see a drain in the next week, then I will probably replace the alternator.

I guess I thought if the alternator was going bad, I would see a drastic drain even when the engine was running and cause other problems.

Time will tell...thx.

[Bent]

you know, my truck does the same thing! i just forgot because i haven't drivin it for some time now lol ;D

[19_Chevelle_69]

The ALT can drain the battery but still charge OK. A bad diode will just discharge the battery over time.