Dead Batteries

herbert007 wrote:
My son took it home and it was charged up to 12.5. Put the charger on overnite and it came back to 13.8. Everything is good. Thx for all the input.

13.8V suggests a float charge. Turn off the charger and let it sit for an hour then check. Even with a good battery, it will drop back to around 12.7V after sitting with no load.

If that goes well, swing by an auto store. Most will do a load test at no cost. Even if the voltage looks good, it may have lost much of it's storage capability and it will show up in a load test. You don't want to go out boondocking and find out, the battery really was still a problem.

My son took it home and it was charged up to 12.5. Put the charger on overnite and it came back to 13.8. Everything is good. Thx for all the input.

Contrary to conventional wisdom, not all batteries are doomed if drained down significantly. I don't know the scientific reason or if it's the type/brand of battery, but I've had good success bringing some back from the dead, and have them last another two years or so.

Also not mentioned yet, is some battery chargers will drain the batteries if power goes off while they are connected. I had a battery maintainer from HF on my chassis battery and my son disconnected the power cord for his use and after a day of being disconnected my battery SOC was 11.8v. Recharged and all was good again. How long were your batteries without power? Days or weeks?

Before you next trip, make sure they are charged to somewhere around 12.7v (after disconnecting the charger and letting them sit for a 1/2hr).

If that does well, take it to the local auto parts store and have them load tested.

If that goes well, you've likely dodged a bullet.

If not, plan on getting new batteries prior to the next trip.

How long was the circuit breaker off?

When plugged in there is a charging system that keeps the battery charged. This function stops if there is no power from the dead circuit.

11.8 is pretty much dead and that has harmed them greatly, 12.70 is charged and at 12.40 you need to recharge ASAP. I think your talking starting or chassis batteries, in that case I would go to Sam's Club and get some new ones. The Duracell Penn State brand lead acids are a very good value and they also have the AGM's if you hate battery maintenance.

There are a few items that are always using the battery. Radio presets, co detector, propane detector and on some units the main board that a remote control interfaces with. Have your battery thoroughly tested as you just might not have a useful battery anymore if it was drained too low.