outside temp for lead acid batteries/true dod while using

stormtracker78

New Member
hi im starting a 400 watt solar system maybe up to 800 and i have a question about lead acid batteries i live in brownsville texas AWESOME SUN but daily around 95 or more degress i know if its cold batteries are hard to charge but say i have a setup 200-400 amp battery bank in parralel to keep it at 12volts would i need to keep them cool or inside with a battery monitor i could run an extension to them but im worried about loss would like to leave them outside in shade also all over the internet for agm/sla dod charts are wrong does anyone have a correct one under load i can follow? thanks
 

stormtracker78

New Member
Ty I was wanting to set up a system for hurricane season that runs down here from June to November to have backup power for essential items I really appreciate the info offhand do you know is it the same for lithium ion batteries will high temperatures outside affect them?
 

OnTheRoadAgain

Solar Addict
Basically yes. Either one will have a shorter life if kept in a hot environment, with exceptions.
But sometimes you just can't do anything about it.

I would Google High Temperature batteries because some Gel and Lithium batteries are made for warmer temperature use.

I keep my batteries in a air conditioned space and keep them on a battery maintainer at float charge.
 

stormtracker78

New Member
Yes lol btw I hear these charts are not accurate what is your opinion because they don't factor in when you're bearing a load so how do you know when to cut it off to charge?Screenshot_20210527-191830.png
 

Substrate

Solar Addict
Mr. Peukert is on the scene. Not only is he effective at reducing voltage the more you draw from it, the higher the temp the worse this gets.

BUT, if your application is going beyond what the manufacturer recommends as the max-current draw (you have those right?) you can easily go into thermal runaway!

Heat and high current cause terminal voltage to drop. Which requires more current. Generating more heat. -- runaway.

If you are hammering agm's beyond their capability, where runaway is a real concern, you MUST have a temperature-probe on at least one of the battery terminals, and a controller that will shut off discharge loads.

What I'm saying is that you may be trying to work some agm's to death beyond their design capabilities, or you need to upgrade to something like Pure-Lead.

But we're talking designing from NEW batts. Are you thinking about stringing up some old / used ones?
 

stormtracker78

New Member
I have a Ub 12100 12 volt 100 amp and a couple of mighty Max 12 volt 15 amps and I was thinking about getting a couple other ub 100 amps so those would be the batteries I've contacted the company to get the specs but for some reason they don't seem to have a DOD chart or any of the info I need they're like you can get the chart off the internet but from everywhere I researched I heard those charts are wrong don't follow those because they're inaccurate when it comes to load so I haven't actually started yet because this will be for one of hurricane hits and there's no power but I would like to know and need to know when to stop using those batteries if they get down too low but I'm thinking about doing a four or 800 watt system with a 40 or 80 amp mppt so still in the design phase but I hear those parameters are critical do not let your battery get past the point of no return
 

Substrate

Solar Addict
Ok, well this might help from PowerSonic. The UB's and other conventional agm's are similar, so these documents might help from them. Pretty comprehensive white-paper pdf about charging them, where you'll find all the temp and puekert info and so on.

Quite frequently, other manufacturers have been seen simply ripping-off the PowerSonic docs and cut and paste it into their own material anyway.

Here's the tech-manual pdf for their general purpose line:


The sad thing is, many get bored or overwhelmed, and totally miss the "Do's and Dont's" section near the very end.

And a quickie sheet for their 100ah PS-121000 which the UB should be similar to.


While obviously we all say go LFP these days, the PowerSonic docs are the best I've ever seen available to the common consumer.
 

OnTheRoadAgain

Solar Addict
I fully charge my Lead acid batteries then for capacity testing purposes, discharge them to 11.89v.

Yesterday I got exactly 50Ah on a new, Walmart Marine Deep Cycle Everstart Maxx 2 year 29C battery by this method.
It was $99.00 so you can get a solid and safe 100Ah capacity for $200 this way.

188ceb3c-cd28-4e45-b9a3-7c63664f5ef0_1.f541a013b476ddf54a88b0618c55445b.jpeg


The drawback is that it will not last anywhere near as long as a LiFePo4 pack.
Since you won't "cycle" the batteries that often (in your case), then you might expect 5 years life from them under ideal conditions.
If you store them in the heat, reduce that to 2.5 years give or take.
 

Cidpineda

New Member
I fully charge my Lead acid batteries then for capacity testing purposes, discharge them to 11.89v.

Yesterday I got exactly 50Ah on a new, Walmart Marine Deep Cycle Everstart Maxx 2 year 29C battery by this method.
It was $99.00 so you can get a solid and safe 100Ah capacity for $200 this way.

188ceb3c-cd28-4e45-b9a3-7c63664f5ef0_1.f541a013b476ddf54a88b0618c55445b.jpeg


The drawback is that it will not last anywhere near as long as a LiFePo4 pack.
Since you won't "cycle" the batteries that often (in your case), then you might expect 5 years life from them under ideal conditions.
If you store them in the heat, reduce that to 2.5 years give or take.
yesyes my battery i have 20pcs of this for my growatt spf 48 lvm es nice nice. ....... with 2 years free replacement ill take this done LIFEp04 walmart is anywhere i know LIFEp04 is great with 48volt system if 1 breaks i have to buy from china shipping wait for 3 months blahblahblah so ill stick with this battery
 

Cidpineda

New Member
I fully charge my Lead acid batteries then for capacity testing purposes, discharge them to 11.89v.

Yesterday I got exactly 50Ah on a new, Walmart Marine Deep Cycle Everstart Maxx 2 year 29C battery by this method.
It was $99.00 so you can get a solid and safe 100Ah capacity for $200 this way.

188ceb3c-cd28-4e45-b9a3-7c63664f5ef0_1.f541a013b476ddf54a88b0618c55445b.jpeg


The drawback is that it will not last anywhere near as long as a LiFePo4 pack.
Since you won't "cycle" the batteries that often (in your case), then you might expect 5 years life from them under ideal conditions.
If you store them in the heat, reduce that to 2.5 years give or take.
Ow and balancing this battery i have a H02 or H03 i think and its working good with SLA AGM and WET no problem all battery voltage is balance
 

Substrate

Solar Addict
That's because these batteries can come from different vendors and can be rebadged. On the top it is listed at 114ah, but a consumer test using the standard C/20 rate showed only 70ah. And as mentioned, these are primarily starter batteries. I suspect the "30% more cycling" is a fudge for the fact that these are the so-called maintenance-free, which is nothing more than extra electrolyte added at the factory to simulate an unattentive owner.

Since this is a FLOODED battery, a CV of 14.4v should be fine, and a charge rate of somewhere near 0.1 to 0.15C. So an 80 - 110 watt panel should be fine.
 

Cidpineda

New Member
I fully charge my Lead acid batteries then for capacity testing purposes, discharge them to 11.89v.

Yesterday I got exactly 50Ah on a new, Walmart Marine Deep Cycle Everstart Maxx 2 year 29C battery by this method.
It was $99.00 so you can get a solid and safe 100Ah capacity for $200 this way.

188ceb3c-cd28-4e45-b9a3-7c63664f5ef0_1.f541a013b476ddf54a88b0618c55445b.jpeg


The drawback is that it will not last anywhere near as long as a LiFePo4 pack.
Since you won't "cycle" the batteries that often (in your case), then you might expect 5 years life from them under ideal conditions.
If you store them in the heat, reduce that to 2.5 years give or take.
i am using this now 24pcs and its good longer to charge but with 5kw panels its nice.....why not go to lithium they said lithium is better more cheaper than lead they said ok ok ok this is a 200$ for a 100AH 12 volt battery compare to Lithiums price BUT heres the best thing we have a 2 year free replacement on this battery for what ever reason it stop working so 2 yrs plus 2 yrs = 4 yrs i think i am good with this
 

Wellbuilt

Solar Addict
They will last 2 years one day and 2 hours .🤣
I don’t see what the big deal is with the new latest and greatest battery’s I just use 16 wet cell golf cart battery’s 6 volt
they work fine for me.
I do check them 3 times a year.
They go out of balance over the winter when using the genarator.
they liked to be charged hard , I’m 3 years into this bank and I’m still reading good and my voltage
stays at around 50/51 volts in the morning winter time they get down to 49.9
I have a bank in my traler that is going on 6 years now and I’m just adding water and letting the solar charg controler
keep it up .
 

Wellbuilt

Solar Addict
Your bank my last the 2 years any thing will , it’s after that , the battery’s will diy one at a time .
I have a buddy in Georga that keeps his GC battery’s in 4 plastic containers under ground a 3 feet
he blows his battery power vent from the house with ac thru the battery box , he adds cool water to the containers
in the morning the fan comes on when he hits absorb
 
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