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Alan Nyhus 05-10-2020 10:35 AM

Weird electrical issue.
 
Testing yesterday, I had a weird electrical issue happen. A little background...the electrical system is clean, simple, no factory wiring of any kind being used, high quality ground cables and connections, all connectors soldered. Single battery up front in the stock location.

Halfway through second gear, the car died as if the ignition had been shut off. Back at the trailer, the battery showed zero voltage. Not low voltage but 0.00 volts. It had been 13.8 before the run. With the spare battery installed, there was a big arc when the + cable was attached to the battery...like a dead short. Both batteries are AGM type. With a test light and volt meter, we checked everything back and it turned out the starter was the source of the dead short. Put the spare starter in an all was good and finished the day out with no issues.

So...here's my question. Could a broken plate in the battery cause the battery to short internally, taking out the solenoid at the same time? Or could the solenoid have shorted and killed the battery?

It acted almost like a car does when the positive power cable grounds to a header tube. I saw this a couple of times years ago and in one instance it actually exploded the battery.

Thoughts? -Al

Roberte 05-10-2020 11:00 AM

Re: Weird electrical issue.
 
How about the field coils grounding to the housing?
That has bit me before. Bob

Todd Gross 05-10-2020 11:05 AM

Re: Weird electrical issue.
 
I would think the shorted solenoid would be the culprit. A plate shift in a battery can kill the Battery, but should not harm a piece of hardware like a solenoid, being that it is down stream. Possibly, it could harm something software-like, such as an ECU, but not a high current solenoid. One way to confirm is to carefully and keeping distance, attempt to recharge the dead battery to see if it would recover.

Tom Goldman 05-10-2020 11:23 AM

Re: Weird electrical issue.
 
I would definitely suspect a shorted alternator.
Although some race alternator suppliers recommend against them ,I always use a fusible link at the alternator connection.

Patric Fox 05-10-2020 11:29 AM

Re: Weird electrical issue.
 
Batteries can do some weird things, I have seen bad cells, plate problems, and I seen one reverse polarity, where the positive terminal became negative and the negative was positive.

Mark Ugrich 05-10-2020 11:59 AM

Re: Weird electrical issue.
 
I’ve seen alternators short and drain a battery, plugging in a new starter probably wouldn’t fix that.Short to ground in the starter field windings/armature would make sense.I don’t think a shorted solenoid would cause what you describe.I have seen shorted or worn solenoids engage the starter until the battery runs out of current though.What orientation is the battery mounted in? Like was said , I’d try slowly recharging the battery. It might come back if nothing melted internally.

Jim Hawkins 05-10-2020 12:38 PM

Re: Weird electrical issue.
 
Alan, I work on electric forklifts and all kinds of dc battery powered industrial equipment. From your description the problem was what you found, the solenoid or armature in the starter. Usually the contacts weld and will not turn off. Direct short to ground not very common.
Did the cables start to overheat? Seems like it took your battery down real quick.
The short must have created a open circuit in your battery, inner cell connector burnt open. If the battery reads 0 volts and will not charge it has a open circuit internally. Probably a better situation if that is what happened, acted like a fuse rather than something else like the cables melting and catching fire until the battery current flow dropped.
If the problem originated at the battery should not have damaged the starter. Path of least resistance would have been in the battery itself.

Alan Nyhus 05-10-2020 12:42 PM

Re: Weird electrical issue.
 
Battery is mounted in the normal, transverse location in the factory location (Chevy Nova). The plates in the battery are oriented front-to-rear in the battery.

No over heated cables or burnt connectors when it happened. -Al

Alan Nyhus 05-10-2020 12:58 PM

Re: Weird electrical issue.
 
Quote:

Originally Posted by Tom Goldman (Post 614288)
I would definitely suspect a shorted alternator.
Although some race alternator suppliers recommend against them ,I always use a fusible link at the alternator connection.

Tom, I hadn't considered the alternator. It's a late model G.M. 76 amp. converted to single wire with a toggle switch in line to activate it. -Al

rboyle 05-10-2020 03:20 PM

Re: Weird electrical issue.
 
You can bench test them both now that they are out of the car qnd see which causes the problem. Use jumper cables if it's easier. If the battery holds a charge with nothing hooked up try adding the starter back into the circuit. If it arcs like last time it's the starter.


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