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

Re: Weird electrical issue.
 

How about the field coils grounding to the housing?
That has bit me before. Bob

Re: Weird electrical issue.
 

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.

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.

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.

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.

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

Re: Weird electrical issue.
 

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

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.

bablee: Weird electrical issue.
 

I am thinking = Probably something downstream of battery.

It will be not hard to troubleshoot the systems and the battery.

Let us know what you find.

Be well!

Re: Weird electrical issue.
 

Be very careful with arcs around dead batteries, think hydrogen bombs. They will blow up in your face !

Re: Weird electrical issue.
 

Cautiously checked the battery today and it's toast. No continuity between the negative and positive terminal and it won't accept a charge. -Al

Re: Weird electrical issue.
 

depending on you have your batterys installed ,, the plates can short real easy if your terminals are front to back in the car , terminals tend to squash against each other from the continues hard launches (guilty,i have mine the same ),, batterys do weird stuff

Re: Weird electrical issue.
 

Checked the starter yesterday...no bad bearings letting the armature touch the case, no signs of any arcing or overheating. The old solenoid did seem to engage and kick the drive out fine. The starter is a Powermaster 9400 Ultra Torque: https://www.jegs.com/i/Powermaster/713/9400/10002/-1

I purchased a new, high quality solenoid from a local alternator and starter rebuilder and everything checked out fine on their test equipment.

I suppose it's possible that the issue originated in the battery. I think I'll put something under it and between the top hold down strap and the battery to give it some cushion. Maybe vibration killed the battery?

I'll have our local rebuilder bench check the alternator, as well.

Re: Weird electrical issue.
 

Do not mount the battery with the face of the plates facing Forward and rearward the thin part of the plates need to face front to rear if not your just asking for trouble, Been there done that long ago!

Re: Weird electrical issue.
 

Curious Alan,, how old is the battery ? On a side note Ralph, it’s a Stocker so it MUST be mounted in the stock location....

Re: Weird electrical issue.
 

I started second guessing myself after I read that the cables and such were not hot.Probably the internal connection broke in the battery. I know of another group of PS/B racers that had a similar issue using 18 volt power tool batteries. Bike would leave then shut off after second or third gear. Then restart at times and be ok. Turned out to be a poor connection inside the battery.

Re: Weird electrical issue.
 

An AGM battery could be a solution and a prevention for the future???

Re: Weird electrical issue.
 

He said that both batteries were AGM type
I think a lot of people missed that

Re: Weird electrical issue.
 

Every experience I've had with a short is... at the end of the "hot" or "melted" wire is the problem, if no hot wires I vote battery.

Re: Weird electrical issue.
 

Used the starter in question today on a 585 inch, 14:1 BBC that was on the dyno. No problems! -Al

Re: Weird electrical issue.
 

It was new in April of 2019. -Al

Re: Weird electrical issue.
 

Seems as though MURPHY may have been involved in this ...