Battery Totally Dead

[greg g]

SO it appears that the last time I used my P15, I left the fog lamps on, and they completely drained the battery.  I connected my old Sears battery charger (at the 6V setting) and it pegs the charge meter and then after about 30 seconds the internal breaker trips shutting the charger down.  So should I leave it on and let the charger and auto reset breaker do their things, or should I jump the car with 12V and let the genny try to charge the battery or should I switch the charger to 12 V hoping the Amp draw will half according to Dr. Ohm, or should I take the battery out take it to a shop and let them do the commercial charger at 6V to see what happens.  

 

That battery is relatively new I believe I bought it a year ago in April.

[desoto1939]

take it to a commercial battery charger.

 

Rich Hartung

[JerseyHarold]

No offense, but are the charger leads connected to the battery correctly?  

 

This happened to a friend years ago who borrowed my charger and left it connected wrong on his battery. The ammeter on the charger was flying back and forth like a ping pong ball for hours, and you could fry eggs on top of the charger.

 

If the connections are correct, the battery probably has an internal short.

[Robert Horne]

What I did was hook my battery charger to a spare headlight terminal, and then from the second headlight terminal to the battery,

 

for a few minutes.        After a few minutes, my battery charger would work ok without the headlight attached...

[TodFitch]

What I did was hook my battery charger to a spare headlight terminal, and then from the second headlight terminal to the battery,

 

for a few minutes.        After a few minutes, my battery charger would work ok without the headlight attached...

Bingo! I was going to suggest that. Use a 6v light bulb as a current limiter until the battery gets charged enough to be in the range the charger is designed for. Probably better for the battery too to start slow on recharging it.

[greg g]

have one of those rheostat style heater switches, would that work inline betweent he charger and the neg terminal 

[TodFitch]

have one of those rheostat style heater switches, would that work inline betweent he charger and the neg terminal 

Probably yes.

 

As I understand it, you want to trickle charge a totally dead battery until the charge comes up a little. Then you can bulk charge it at a high current. Then you want to decrease the charge rate as it gets near full. And finally, if you leave a charger on it, you need just enough to keep the float voltage.

 

By putting some resistance in the line between the battery charger and the battery, you are basically converting it to a lower amperage charger for that first step.

[greg g]

I pulled it out and took it to a local shop whose charger still does 6V.  When they initially connected it it was taking 7.2 amps, The tech set the rate for 3 amps, and is going to leave it on a timer for 4 hours.  He said he will check it again in the AM, and hook it back up with about 6 amps for a hour or so.

 

But it tested goos no shorts, but down to 1.5 volts.