Electrical system issue....help

[Charles Furman]

I over charged my 6V optima battery and now I have an electrical problem. Before I start tearing things apart, I would like to hear what you think is the most likely problem spot.

Here's the story: I set my charger on 6V/50 amps and left it on too long. The battery cables were not disconnected from the battery. The battery got extremely hot. After everything cooled down, I tried to start the truck and got absolutely no response. I replaced the battery with a spare and was able to get the guages (gas & amp)to work when I turned the ignition key on and the headlights worked, but when I step on the starter pedal absolutely nothing happens. I am sure I fried something, but I am not sure what. I'm guessing I fried the starter. Is there some kind of fuse in the battery cable?

What are your thoughts?

[JBNeal]

If you are running a stock electrical system, the starter motor would be untouched until the starter switch is closed. Voltage passes from the battery to the starter switch stud up to the voltage regulator, then to the ignition switch and gauges.

With a different 6V battery installed and no starter motor engagement when the switch is closed, I suspect the battery cables are at fault. Either the terminals aren't tight, or there is enough copper corrosion inside the cable sheath that the cables' internal resistance is too high for the 6V battery to turn the starter motor.

An easy test is to disconnect the voltage regulator charging circuit and jump start with a 12V battery, then remove the jumper cables and see what happens to the 6V battery after the engine gets to operating temperature. Once the engine is hot, turn the ignition off, wait a couple of minutes, and see if the engine can be re-started with the 6V battery. If not, time for new 2/0 cables with soldered lugs.

Another option is to connect jumper cables from the 6V battery to the starter switch and ground one of the starter mounting bolts. If this setup allows the battery to start the engine, the battery cables have too much internal resistance and should be replaced.

[Reg Evans]

If your ignition switch was off I don't think overcharging the battery would harm anything but the battery. Like 49D said check your cables and maybe remove the switch on top of the starter and touch the neg. battery cable to the copper contact on top of the starter. If it turns over the starter switch is at fault.

[coW52Dodge]

I bet 49 is spot on, suggesting it is a cable or terminal.

When you start the truck, do your gauges go back to zero without it starting? If so, something is either drawing a lot of current or a battery connection or cable is bad.

That would eliminate the starter switch being the cause.

If it draws a lot of current, the cables from the battery and the battery itself would likely get warm to the touch.

If the battery and the cable isn't getting warm, it likely is a bad connection. If either the cables or battery get warm quickly, you have some sort of short. Be careful as that could be dangerous. Perhaps report back, if that's what you're seeing.

Note that the following assumes your truck is still positive ground*. if your truck has been changed and has a negative ground*, use the opposite polarity on the battery:

Using one side of a booster cable, leaving the other side dangle, try bridging the ground* terminal to something that should have a good ground under normal conditions, like on a clean bare metal spot on the engine. If it now starts, you likely have a bad ground connection somewhere.

Should it not start, I'd check all my connections from the battery to the starter.

* (ie the '+' terminal, on positive ground system but the '-' on a negative ground system)

Edited June 5, 2011 by coW52Dodge

[Dodgeb4ya]

My guess-A second low charged battery or a cable issue.

Bob

[Don Coatney]

I wonder if the Optima manufacture has any information about over charging and what happens to the battery when this happens? Also I wonder what the voltage was on the over charged "hot" Optmia battery? With a wet cell battery you will get something over 2 volts per cell but with an Optima is it possible to get a lot more? Anyone have any ideas?

[MBF]

If you're going to try to jump w a 12V batt, make sure that the positive (ground) cable is disconnected from the battery. Run your jumper cable to the disconnected ground cable, and after it starts, disconnect the 12V jumper and reconnect the ground cable to the 6 v battery. Jumping 6 w 12 is a good way to blow the top off a 6 volt batt-I learned that when I was a kid. Mike

[Big50Dodge]

a while ago about starting the 6v system with a 12v battery. I did the same with my charger - except it wasn't an optima, it was a std regular old battery. The top is no longer on the battery. I'm not buying another 6v to replace it, I have a few 12v batteries kicking around in various stages of charge, and I want to swap over to 12v anyways. BUT.... there is always a but... I haven't run my truck at all this year and it should be started. How can I start my truck with a 12v battery..? Dare I say... safely..?

On to the question of changes to 12v.. I have found that a jeep inline 6 dist is really close to what would work in a 236 inline 6. Probably would work in the 218, 230 and others too. The key words here are "really close". Unfortunately, not quite close enough. So the next thought is, what about the guts of the jeep dist inside the pilot house dist. That poses a few questions - mainly for me, the positioning of the internals. They are probably "keyed" to something. Any thoughts on "keying" the internals ? I'm guessing that if things are not lined up properly, you couldn't get the timing set accurately.

Sorry to high jack the thread...

[Dave72dt]

You don't need to switch to a 12v distributor. Just use a resistor in line or an internal resistor coil with the original dist. and you'll be fine.

[greg g]

You can run your truck on 12 V just don't turn on any 6 V stuff, and if I were doing it I would take the genny off line. a ballast resistor in the the ign to the coil circuit would be recommended but if all you want to do is start it and run it for a few minute, it shouldn't be a problem. extended running with out the resistor will burn the points up at an accelerated rate. Your starter will be fine as it is much stronger built than 12V stuff.

[MBF]

Make sure you disconnect the fuel guage at the back of the guage before you turn on the key. Same with any 6 volt radio. Mike