Batteris with less than 1 volt

[rcottle]

I have a mid 70's ezgo golf cart. It is 36 volt. The batteries are about 2 years old. I was driving it after a charge and it had plenty of power and the cart just stopped and the lights went very dim. I depressed the pedal a couple of times and i was able to limp it back home. But is was extremely slow. The next day I was unable to charge it. I checked the voltage and found that I had less than 1 volt across all batteries. Upon disconnecting each battery to isolate them I am finding i have less than 1 volt in each battery. A fully discharged 12v battery will read about 10.5 volts. I assume a 6 volt should be half that, maybe 5 or 4 at the worst. Does anyone have an idea how I could discharge 6 batteries to less than 1 volt each. I am assuming all the batteries are now useless. I am concerned that whatever took this out may do the same thing on a new set. Any thoughts?

[scottyb]

Bring the batteries back up. They may be okay. Check the water but, do not add any if the plates are still covered. Use a 12v charger on them (2 at a time in series) until they all read 6v and then connect to the cart charger again. BUT FIRST disconnect the cart positive or negative lead ... you have a short. First place I would look on that old system is the speed wiper assembly. Don't let those batteries set depleted any longer start battery CPR immediately WELCOME TO BGW !!!!

[iaefebs]

I would check again with a different volt meter. Somethings not right here.

[rcottle]

Thanks for the help guys. I've checked with a second one, a fluke, and sadly it is correct. With regards to the 12 volt charger, all i have is the new style smart charger and it gives me a fault upon hooking it up. i have considered jumping them with a vehcile and cables but was a little nervous about exploding one not know what the problem is. Had thought about just hooking it to a single 12v it bring it back up. Your thoughts?

[scottyb]

My thoughts are that if you leave those batteries in that extreme state of discharge for another day they will be junk cores... If they were healthy, they will survive being drawn down that low once. But they will not survive being left down that low.
I would go buy a 12v charger (capable of producing 15 amps) and try reviving them. new batteries are going to cost upwards of $100 each. I posted a drawing of how to connect a 12v charger to 2 6v batteries to bring them back up...

[rcottle]

thanks for the quick response. They are probably junk now. This problem occured last weekend and I was out of town and could not work on it until now. With regards to the source of the original problem, that has put me in this lowly state, i need to get that sorted out or I will be killing set two. You mentioned the speed wiper which is interesting. I hadn't thought about that. Here is what i have done.

A couple of weeks prior to the battery problem I was having some lighting problems. I notice that the lights were burning very dimmly without the switch on. I wiggled the switch a bit and it went away. I assumed the switch was bad. A little later the lights would not work at all and will flipping the switch, the head light flashed brightly and went out. Upon checking the next morning I found both bulbs blown (i didn't have a fuse in the circuit).Upon further checking i found i had 4 volts on the lighting circuit even when the lighting hot wire was disconnected (i replaced the switch). Something was back feeding. I isolated the motor and the solenoid switch but was not able to make the voltage go away. I decided to just install new lights and the day after is when i had the battery problem. I didn't fully appreciate the magnitude of that decision at the time. How do i check the wiper?

[scottyb]

Check the cart for a frame grounding. Any voltage in the body or frame is a no no ..... The Speed wiper board can be a trouble spot in the old carts ...

[scottyb]

You are probably going to need more than 1 volt in the pack to test so.... can you use jumper cables to a 12v battery or such? I would start by disconnecting your lighting circuit....

[rcottle]

thanks for the post guys. i found the source of the problem. the main cable between the motor and the negative battery terminal had worn thru and was shorted to the frame. i am currenting trying to revive the batteries. Finally got them back up to the point that the charger will come on. maybe they are not completely toast. Anyone every heard of using epsom salt and distilled water to help revive the batteries?

[scottyb]

Originally Posted by rcottle

thanks for the post guys. i found the source of the problem. the main cable between the motor and the negative battery terminal had worn thru and was shorted to the frame. i am currenting trying to revive the batteries. Finally got them back up to the point that the charger will come on. maybe they are not completely toast. Anyone every heard of using epsom salt and distilled water to help revive the batteries?

Try it without adding anything but Amperage, before you resort to voodoo and snake oil