A little battery help?

[Captain Bill]

I'm currently in Georgetown Exuma and have managed to put my old AGM batteries to death by not understanding a setting in my new solar controller a and severely overcharging them. The only house battery available to me is a single hybrid style deep cycle marine/rv battery which I know is not a proper deep cycle battery. I need to make it last six weeks until I return to the US. The battery does not have a proper amp/hr rating but I suspect that it is rated at about 160-170 Amp/hrs based on its reserve rating of 300 minutes which I have been told is a 25 amp rating. I use about 80 amp hours over night and have sufficient solar to charge the battery and carry the house loads during the day.

I'm not happy about the battery i bought either it has a manufacture date of march 2017 and was at only 12.27 volts sitting on the shelf. It did not seem to be taking a charge very fast as it would only take 25 amps when I started to charge it. I would have expected it to take at least 40 amps at that state of charge. Should I equalize it tomorrow? Does anyone have any suggestions on what I can do to make this battery last six weeks and handle my house loads. I have generating capacity to charge everyday even without the solar so cloudy days are not an issue.

Thanks Bill

[laika]

Do you have a hydrometer to test the cells? Or what's the voltage once you've brought it to full charge? That and you'll probably get a good idea of what it can take once you start watching the voltages during discharge.

Anyway you can bring down the overnight load?

Just spitballing form the sidelines here, but if you still have a reliable start battery and you'll be back in the states in 6 weeks the stakes aren't too high. Sorry to hear about the fried AGMs though.

[Zil]

After a long charge to dust the shelf time, I would do a equalizing charge. If you can keep the battery charged, you should be ok for a month or two. many use those marine batteries without much problem. Your 80 ah doesn't sound very much load to recover, if it is not any heavy ampere.
20 hour rating is usually interpreted as 1/2 reserve capacity.