Left fridge on. Discharged Battery. What next?

morey000

So, after my trip, I turned the Norcold temp to off.  Not realizing that that doesn't turn off the battery- so, I just drained my new deep cycle battery down to nothing.  Like 2.1V   really nothing.  But- it's been dead for less than a day.  I can't be the only one who has ever done this.  What next?

1. Do I go battery shopping?  i.e. did I permanently kill it?
2. Do I plug the T@B into AC and let the AC/DC inverter charge the battery. (I just did that)
3. Am I better off letting my smart solar charge controller charge the battery?
4. I have a fairly smart battery charger that will charge at 6 amps.  Should I just hook that up to the battery?  

pthomas745

If you plugged it in the converter should charge it back up, in theory.  What do you mean by 2.1V?  Measured by what? 

Batteries just don't die by being discharged.  But batteries only have so many "cycles" to them, and the deeper you discharge them the fewer cycles you have left.  (Not saying this battery hasn't kicked over, because batteries are deeply strange beasts).  So see if it charges with the converter first, and then go from there.

Find the "Cycles vs Lifespan" section of this FAQ.

https://www.solar-electric.com/learning-center/batteries-and-charging/deep-cycle-battery-faq.html

morey000

Measured by my volt meter directly on the battery.  But - with whatever load the fridge and inverter might be trying to pull from a discharged battery.  Don't know if they still draw current under 11 volts or so.  

anyway- from my reading, I think you're right.  I've probably just taken a little life out of the battery.  It wasn't dead long enough for sulfates to form crystals on the cells, and my inverter fan is going and sending current to my battery now.  So, it's charging.  

ScottG

My original battery had a propensity to drain down to ~2V just from phantom drain. (This was before they started shipping T@Bs with battery cutoffs and before I knew better...) The discharge was so dramatic I'm still not convinced the battery wasn't defective from the start.

Despite the abuse, I was still able to charge the battery back up and dry camp with it for a long weekend (abusing it even further). It was most definitely toast by the end of the season, however.

The moral is that if you've only beat it up this once, it's probably got plenty of life left. Please let us know how it turns out after you get it charged up.

Cbusguy

I would use the smart charger.  One time typically wont kill a battery.  

davel4wa

Two choices, disconnect the battery via the battery disconnect switch or keep your rig plugged in. The new converter units have smart charging built in to keep your battery charged without damaging the battery. Depending on the actual electrical location of the battery disconnect switch, i.e. does it also isolate the converter, you might be able both disconnect the battery and have the converter charging the battery. Even if you disconnect the battery it is a good idea to have a smart charger on the battery. 

Sharon_is_SAM

@davel4wa, the nuCamp battery disconnect isolates the battery from the charger/converter.  So, you can either charge via the charger/converter with the battery switch on or via an independent smart charger with the disconnect turned off.