6V deep cycle batteries

Frank, Frank, I believe you may have missed a day in solar school. Solar doesn’t always completely fill your batteries. Clouds, rain etc. A back up small inverter generator is essential. And a genny isn’t always ready...no gasoline, fouled spark plug and the genny doesn’t work! Next, RV batteries aren’t a legacy to pass to your great-grandchildren...nor Biblical. Use them respectfully and buy new ones.

How many years do you want them to last? :)

I would run equalization after 10-12 days of such charging - if possible.
Get more solar too.

95% of what? That is the question! Your capacity gets less and less as you do successive incomplete recharges. Your "SOC reader" will not show that correctly unless you keep lowering the bank capacity figure set into the SOC reader. But you don't know how much to lower it each time :)

In practical terms, watch your "morning voltage" before solar gets going and the furnace is not on at the time. It will get lower and lower, say 12.3, 12.2, 12.1, etc You can go lower, but as you note, you will need a full recharge as soon as possible (no fixed time--in a couple weeks or whatever)

The big thing is when you do that 100% recharge, DO NOT believe your SOC reader to tell you when you are there. Go by the battery SG rising to nearly 1.300 or a bit less and holding that while doing your "overcharge" that follows your initial "full" recharge.

When you see the cells bubbling when they START to bubble they are charged.

I guess hydrometers are as popular as proctologists. Solar panels are like a lot of other things, they need to be factored for a reasonable "worst case".

I would not worry for at least two weeks. About noon it would be OK to initiate an equalization voltage to shorten up the absorption time.

My AGM are keeping me in ignorance bliss - no SG or established procedures for equalizing.

But I remember that before equalizing the battery should be fully charged first, - or whatever it's "full" is by that time.

Slownsy wrote:
Have had som very overcast weather the last 4 days, batteries down to 82% in morning back to 95% afternoon, how long can this be don before a 100% recharge becomes essential.
Frank

Im sure you can get 100% with solar.

Whats your bulk voltage set to? ( I may even do 15 volts to get amps in fast as possible.

How long are you doing absorb and at what voltage? Do 14.8 for the rest of the day. By sundown thats about all you can get unless you use a generator.

Whats your float voltage? ( It should never get to float when boondocking IMO.) Or set the float high like 14.4. or better.

But do you have solar? Using generator?

Just my opinion though.

With flooded lead acid battery you can do partial state of charge (PSOC) for a week or so and then bring them back to almost(?) full capacity with a long dose of high equalization voltage. In the past, we've done this without obvious problems. It no doubt reduces their lifespan but you gotta do what you gotta do.

Some lead acid batteries last longer under PSOC conditions than others, usually those with "carbon" supplements like Trojan's SmartCarbon in the T105RE and their Premium and Industrial lines. Or Outback's Nanocarbon AGMs.

I am not sure a 100% charge IS Essential. But so long as you are keeping them over 75% it should be rather a long time.. Month or more.

Actually with DEEP CYCLE batteries like you have so long as over 50% but the lower you go the shorter the time.

What is the absorption voltage set at?