Deep cell battery

[supton]

Not sure what forum... Just got a NTU camper. Got it home and checked the battery; -4V. Huh? I expected flat but not negative. (And yes, I know how to use a multimeter!) no date of purchase, and the prior owner said it was at least four years old, and I suspect it's been drained a few times--so I plan to just replace. But any idea if it can go negative? I haven't checked on the charging wires, for some odd reason they used a black wire and a green wire. Will look at manual later.

 

[stockrex]

volt is the diff, -4v is 4v.

 

[mrsilv04]

At this point, assume nothing. Who knows what has been done to the wiring on the camper, especially if one wire is black and one is green. Does the camper have an inverter in it (usually located under the refrigerator), which will automatically (over)charge the battery... as many of them do?

 

[EdwardC]

Look as if a couple of the cells reversed. It can happen when some of the weaker cells go to zero while the other cells are still putting out current, kind of like reverse charging those dead cells. I would grab a new battery, and like what the others said, check all the wiring. If you want to keep the old battery, you could try discharge the battery back to 0V with a very low current drain, like a 1k resistor, top off the cells with distilled water, then slowly charge back up.

 

[supton]

Yeah, I'm dubious as to the quality of the convertor. Haven't dug far enough yet, but I suspect it's a cooker model. Forgot to write down the model when I had the camper open.

 

[Rand]

IF you have AAP near you, they have deep cycle batteries for about 110-120$ which you can use the 35% off, 40$off 100, or 50$off 100 coupons on.

 

[Nick1994]

If you have the room, when my dad had a camper a couple years ago we got 2 6V golf cart batteries and wired it to 12 volts. Those deep cycle golf cart batteries lasted a looong time on a charge.

 

[supton]

I almost don't want to bother with the battery. It would be useful for running the fridge while driving, 'cept it'll run the battery flat pretty quick. Could use the LPG instead while moving. When stationary, I'll be using 120V. I suspect it'll be a couple of years before I do any sort of boondocking where I'll want to be off the grid. I think I just talked myself out of replacing this battery...

 

[redbone3]

Just hook up a charger and see if it charges up. If it does you can get it tested at any car parts store. If it doesn't charge take it to a car parts store and sell it to them for scrap.

 

[Nick1994]

Originally Posted By: supton

I almost don't want to bother with the battery. It would be useful for running the fridge while driving, 'cept it'll run the battery flat pretty quick. Could use the LPG instead while moving. When stationary, I'll be using 120V. I suspect it'll be a couple of years before I do any sort of boondocking where I'll want to be off the grid. I think I just talked myself out of replacing this battery...

Our camper didn't have an option for running the fridge off battery. It was always run on propane and would actually run ice cold for at least 5-7 days on a tank of propane.