is my battery ruined?

[DE88ROX]

Went to pick up my TT this morning to start loading it for the upcoming races at Michigan. I soon noticed that the power tongue jack was dead in the water. Didn't take long to figure out that although i had the trailer plugged into shore power, The power cord wasn't plugged into the outlet. (inlaws pole barn).

So its been dead about 4-5 weeks. Currently have the trailer home and the battery on the charger. The cells all have plenty of water.

Was just curious about damage done, if any. I read that running them dead is not a good thing and damage shouldn't occur if recharged in a "timely manner" (whats considered a timely manner anyway?)

Thoughts?

[wa8yxm]

Survival odds depend a bit on the battery

True deep cycle, Run down that long, I'd give them around 50% chance

Marine Deep cycle, half that (25%)

Regular starting batteries, about 5%

Suggestion: charge and test.. Only way to tell for sure.

[DE88ROX]

update: put the battery on the trickle charger for about 24 hours. still wasnt showing charged. made the trek to in laws to borrow a bigger charger/starter. ran it on that for a about 20 minutes and put it back on the trickle. Still wasnt showing "charged" (green light) I decided to risk it and put the battery back on the trailer after hooking everything back up. I unplugged the trailer from shore power, went inside and checked the battery level on the wall panel and it showed full. Now I know the tank gauges can be faulty, so i wasn't quit sure if I should trust the battery one.

I had a genny at the races with me. Its not a Honda so I don't like to run it a lot. but I do in the morning when everyone else fires theirs up for coffee and such to just refresh the battery. also run it when ever the the DW needs a blow dryer or microwave. I even played music on my phone via stereo and outside speakers for a few hours Saturday night. and the battery held its own.

This trip is the only boon-docking I do all year, and I was really stressing about not being able to run everything that needs a battery to run, (fridge,water pump etc)

but it all went good, great time as always, my driver didnt win but had a strong finish.

Thanks again for all the input/advise!

-ROX

[Dakzuki]

I had the same thing happen. When you lose shore power the parasitic loads drain the batteries down to nothing with the battery switch on. I changed my storage strategy. Now I have the battery switch set to OFF and have a charger/maintainer on the batteries. I have mine permanently mounted in the battery compartment hooked up to the batteries. If power is lost the charger just stops and switches off. No parasitic loads.

I have a Noco Genius but any good charger/maintainer should do it. You just need to make sure it completely disconnects and puts no load on the batteries when it loses AC power. No point in adding parasitic load.

[kennethwooster]

Missed with batteries for years, as a farmer and Farm equipment dealer. It might make it ok, but i"m sure the life had been hurt. I had mine go down last fall, do to leaving heater fan on by accident. Had to install new roof and told them of the down batteries, as I had no way to charge where I was at. They promised me they would charge the batteries. I suppose they didn't. In the meantime we got freezing weather. They held a partial charge, but since we would be gone for several months I replaced with new batteries. That is your choice. Since it is winter it might make it, but my guess is it is dying. Take it to someone who can charge it all the way, then take a testing unit that can put a load on it. That will tell you how good it is. If will will hold up under a load test you will probably be ok. Be sure and charge back up after a load test.

[tatest]

My experience with deep discharge of deep cycle batteries is that it costs some capacity and shortens the useful life. I think you can probably do more damage leaving them on a charger not designed for maintenance, e.g. many RV covpnverter chargers.

Starting batteries are easier to damage with a single really deep discharge, but seem to be a lot more tolerant now than they were in the 1950s when you could kill a battery leaving the headlights on overnight in winter.

[rhagfo]

Install a disconnect switch, no need to have on shore power all the time. My battery will hold a full charge for two months easy.

[keymastr]

At the least you will have lost some capacity. The fact that you caught it after just a few weeks is a plus but in my experience any battery I ever had bottom out was not very good after that. Either week or would lose it's charge after a day or two. One in my daily driver lasted another 2 years because it was driven/charged everyday but would not start the vehicle on the third day of no use. You won't know until you know. If it were me I would swap it out. Cheaper than a raceday ticket to the race.

[DE88ROX]

Thanks for all the info!! I bookmarked the "12 volt side of life" for future reading, a lot to take in right now.

I'll keep you posted how it goes this w/e. Thanks again!

[Dakota98]

gbopp,

Thanks for the " 12 volt side of life" that is the best information I've ever read on charging deep cycle batteries. I read several online articles trying to understand how I should charge my 2- six volt batteries. Somewhere along the line things got fussy & I mixed and matched too much information thinking I was doing the right thing. WRONG !!!
Understanding how your charger functions is very important also. I have a "smart charger" but theres been a DUMMY USING IT.

[gbopp]

Charge it and see what happens. Did you ever read The 12 Volt Side of Life? Maybe it will be helpful.

A couple years ago I left my two 6 volt batteries freeze, they were slushy not frozen solid.
I thawed and charged them, they're still in service today. But, I will be replacing them this fall or next spring.

Maybe you will luck out and your battery will be okay.

Let us know.

[RJCorazza]

I suspect your battery will survive. You are correct that flattening a battery is damaging, as is leaving it discharged over time. I have no references or data, but I have read that starting batteries are generally ruined after 10 or so complete discharges. Deep cycle batteries are more tolerant of complete discharge by design (thicker plates).
Read up on equalization charges.