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New Rolls 445 Ah Batteries, 6.35 OCV with LOW Sp. Gr.

Rob7

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Nov 4, 2021
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Hello Folks .. I have register to the forum becuz I have a battery situation that I need help understanding. Thought I'd bring it to the experts. Thx in Advance. Just bought eight Rolls S6 L16-HC 445 Ah 6v … to incorporate into existing, whole house solar system.

I made two mistakes, right off the bat .. #1 ... Didn't check the SG (at delivery) or before charging and #2 ... added 1/4" of H2O to top off ... Then did a 24 hr < 20 amp 12v charge to a pair of the 6v in series. Final open voltage is 6.35V … with a SG of about 1.215 after temp correction for a 60* battery temp. … WHAT ? I said .. Why is the SP so low, with a good OCV? Figured, prolly cuz of adding H2O when I shouldn't have. So I did a equalization on these two 6v, in series, one hour with a 20A Xantrex charger. … The SG came up .015 to 1.230 . But … There's a long way to go to get to 1.270 .. Which is why I'm here to get some expert advice, before doing anything else .. PLEASE advise :) !!


Is this a normal occurrence with LA Batts? Is there a problem with these Rolls batts, or just with me :) ? How do you all think I should proceed to get SP.Gr. to a new battery level ? Thanks in advance :)
 
I have 16 s550 5 years old now. When I purchased most of my solar system the battery’s were the first things delivered and were 6 months from manufacture then. Schneider inverter was back ordered due to a hurricane. I purchased two small changers and burned them out trying to get SG up. At 8 months old I finally got my charge controllers the first time they got a real charge you could hear them boiling from across the room. It took a lot of cycles to get them to all have very similar SG. About 8 came up great the rest were 1 at a time, at about 1 per month. I would equalize monthly at 60 volts ( 48 volt system). Be sure fully charged before equalizing. I was in contact with rolles with a open trouble ticket for like 6 months. They told me when new the led does not have as much surface area. The etching increase the surface area which makes them work better. It sounded like they were trying to drag their feet on warranty to me but they finally all came around. My experience was higher SG always seemed to be on negative end. If you have a cell staying low move it to the negative end. Be sure and read up on absorb time. They need lots of it. 4 to 6 hours. Rolles has some YouTube stuff out there and specifically on the math to calculate the bulk and absorb. If you are cycling then 40 % or more you won’t get SG above 1.260. If you only use 10% and charge the same for a couple of days they will get to 1.280. That is how you know to start scaling back the absorb time. Rolles says 1.260 is the ideal SG from their L16s.
 
Here is a source for more information:

i used this for my batteries:
 
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Did you buy them dry and add electrolyte? This is best way to buy deep discharge heavy weight batteries.

If not, what was the date code on batteries when you got them.

Lead-antimony batteries have high self discharge rate of about 15%/mo. and distributors typically do not do a good job of keeping them charged to prevent sulfation.
 
Thank you guys for a prompt answer.
The batteries were wet when I got them. Manufactured this last July and here it is Nov. ... My concern is that even if they were discharged the 5% - 10% per month that the Rolls claims, ... wouldn't charging bring a new, un-sulfated battery up close to 90% - 100% rather than the 70% ... I've got the whole 48v string on the "magna sine" for the weekend .. then will do an equalize this coming Monday .. I'll let Ya'll know how the SpGr. looks then .. Thanks for the help
 

You didn’t say what you were checking with like this one myself. Amazon​

Unitec 74274 Battery Hydrometer Hydro Volts​

 
Maybe 5%-10% self discharge if kept in a refridgerator. Rolls is from Canada so may be use to colder temps.

Lead-calcium auto/marine are better and they typically run about 10% per month.
 
Not directly addressing OP's issue, but Rolls also has an excellent youtube channel called Rolls Battery Engineering (https://www.youtube.com/RollsBatteryEngineering). It's a bunch of recorded webinars by one of their tech guys, Steve Higgins. He's a great guy, really easy to deal with. When we had questions about our batteries we just emailed him and he got right back to us!

Edit: OP - don't equalize, you need to absorb for longer to get the SG up!!!!
 
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