Hello, I've got 6 X 100aH batteries. I have finally received all of my solar bank equipment. I'm ready to set up the battery bank and will be chaining it up to keep 12v. Before I set it up on the system I want to know if I should pre charge the each battery individually or is it safe to charge them altogether at one time. I will be using a 110v to 12v basic charger for the first charge, then put them online after such. I want to make sure the first charge is 100% full. I thank you and appreciate all the help you can give me on this subject. My system is noted in my profile.
When do I give my battery bank it's first charge?
- Thread starter tera3yte
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MisterSandals
Participation Medalist
What kind of battery?
What are their current voltages?
Is there a specific voltage the maker recommends to charge to?
Do the batteries have BMS's that prevent them from being charged together? Or connected together in parallel or series?
What kind of battery? Universal Battery - AGM type - 100aH - 12v - UB12100 (I'm assuming they are lead acid batteries)
What are their current voltages? 0 - They've never been charged.
Is there a specific voltage the maker recommends to charge to? They didn't come with any literature but the ad for them said could be wired so I could get 12v or 48v. Meaning, if I were to choose 12v (which I have) I could charge up to 13v - 13.7v or so. I've seen over 14v on some chargers.
Do the batteries have BMS's that prevent them from being charged together? Or connected together in parallel or series? I couldn't tell you as (A) I don't have any literature and (B) I haven't a clue what a BMS is. Seeing as they were built literally for solar i'm assuming parallel and series are a thumbs up.
I just really want to know what is best "in general". Do I charge the batteries one at a time...or...all at once for their very first charge.
What are their current voltages? 0 - They've never been charged.
Is there a specific voltage the maker recommends to charge to? They didn't come with any literature but the ad for them said could be wired so I could get 12v or 48v. Meaning, if I were to choose 12v (which I have) I could charge up to 13v - 13.7v or so. I've seen over 14v on some chargers.
Do the batteries have BMS's that prevent them from being charged together? Or connected together in parallel or series? I couldn't tell you as (A) I don't have any literature and (B) I haven't a clue what a BMS is. Seeing as they were built literally for solar i'm assuming parallel and series are a thumbs up.
I just really want to know what is best "in general". Do I charge the batteries one at a time...or...all at once for their very first charge.
MisterSandals
Participation Medalist
If their voltage is 0, then they are probably ruined.
But, that is unlikely that they would be so low. Do you have any way to test the voltage? Do you have a volt meter? This is the most basic of tools you will need for working with batteries.
You can likely charge them all together but it would be a good thing to know what state they are in (as in what is their voltage) when you get them. You will want to label your batteries and keep track of things like the initial voltage.
If you charge them together, in parallel, you should connect them like this:
diysolarforum.com
But, that is unlikely that they would be so low. Do you have any way to test the voltage? Do you have a volt meter? This is the most basic of tools you will need for working with batteries.
You can likely charge them all together but it would be a good thing to know what state they are in (as in what is their voltage) when you get them. You will want to label your batteries and keep track of things like the initial voltage.
If you charge them together, in parallel, you should connect them like this:
How do I charge my batteries or cells using a charger?
[see [URL='https://diysolarforum.com/threads/battery-faq.200/']Forum Thread[/URL] this is taken from for more] Here's a current representation of 4 batteries with the same internal resistance in parallel being charged with a 50 amp charger. [IMG...
diysolarforum.com
I have just never charged them since I received them brand new. I assume they can't have a charge during shipping. But that's assumption for you. I don't have my meters yet so I can't check. I'm mainly concerned with keeping all my charges balanced for the 6 batteries. Thanks for that link. Good info for how to wire a bank for maximum efficiency.
JoseAgustinV
New Member
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New batteries will come charged, at 12.x voltage, dont know what is the specific voltage but i soppose that depend on battery type.
An AGM battery its completely dischared at 10.5V so be carefull if you dont know what you are doing or you will ruin your batteries, i discharged my AGM battery to 10.5V by mistake just one time and it lost about 70% of its max capacity so be carefull and triple check the config of your SSC when you are installing the system.
Silentpower
Over Rated
If they are new, and lead acid flooded, could it be possible they were supplied dry with acid to add?
If they are sealed vrla agm/gel lead acid, 0v means they are scrap.
If they are lithium, be VERY CAREFUL about putting a charger on them as overheating and fire could result.
The bottom line is that pretty much all batteries are toast when the terminal (connecting posts) are 0v.
Please let us know what chemistry the batteries are.
If they are sealed vrla agm/gel lead acid, 0v means they are scrap.
If they are lithium, be VERY CAREFUL about putting a charger on them as overheating and fire could result.
The bottom line is that pretty much all batteries are toast when the terminal (connecting posts) are 0v.
Please let us know what chemistry the batteries are.
Silentpower
Over Rated
Sorry reread... Agm.
boondox
Chief Engineer, RedNeckTech Industries
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No, AGM batteries do not have a BMS, it is up to your charger to control charge. Make sure your charger is set for AGM batteries or you will ruin them. Whether to hook them up in series or parallel depends on what voltage your system is going to be. 14V is not too high for a AGM charge, in fact it will go a little higher, I can't remember AGM absorb voltage off the top of my head.
JoseAgustinV
New Member
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Well, I ruined my battery using the default AGM settings on my SSC, low voltage cut off is usually 10.5V for those default AGM settings which if not right, I just changed the SSC to User-defined battery type and reset the Low voltage cut off to 12.0V to avoid damaging my next battery. You have to check what are the correct SSC settings for your battery, using the default settings is not always the best choice.
Was that on your MPP all in one unit?
JoseAgustinV
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How long does an AGM hold it's initial charge from the factory? I have had 3 of them in the shipping boxes for almost 3 years. I hope they haven't discharged too much. They've been in my storage unit through all the seasons here in Maine.
Last edited:
MisterSandals
Participation Medalist
Without actually checking the voltage, all the guessing in the world is not going to answer your question. You NEED to test the voltage.
And, given the new info that the batteries have been left to rot for 3 years, my guess is that the batteries have significantly discharged and degraded.
Still usable, i dunno.
What is your aversion to testing the voltage yourself?
JoseAgustinV
New Member
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Batteries self-discharge may vary depending on manufacturer or battery type, I think AGM is about 1% to 3% every month, you should check the batteries voltage with a multimeter.
I don't think those batteries will be in good shape though.
The ability to do so. I don't have any meters yet.
I don't have the capability to test anything yet. I've ordered my meters but they haven't shown up yet. It's been 3 years just to gather up what I have now. It's not cheap by any means and I'm certainly not rich or even up to middle class.
I hope I don't have to trash them. I can't afford more. It took me 3 years to get the six I have now. I didn't want to start a system with only 3 100aH AGM batteries. I know it would be useless for what I need. So, reading that you can't add on to an existing bank on a system, I decided to wait till I could afford more batteries. Now?...ya well now. Starting to look like poor people aren't entitled to go off the grid.
JoseAgustinV
New Member
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Do you have any way yo charge your batteries? AGM batteries should not be left discharged for long periods and 3 years is a lot, also be careful not to overcharge them.
These are the batteries I bought. 3 are fresh and 3 haven't been charged since factory 3 years ago.