Batterys-Whats going on? How do i fix it?

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Batterys-Whats going on? How do i fix it?

Postby emccornack on Fri Oct 13, 2017 2:57 pm

Hi everyone,
So i have 8 new costco golf cart batteries for 48V. Absorb voltages, float voltages etc are set to spec. Double checked that several times. Heres my question. When i first brought the batteries on line (fully charged etc) the s.g. readings were at 12.90 or so for each battery. All was good for several days, fully charged at end of cycle etc. Then there was a couple days that were very overcast. The s.g dropped down to 12.30 at lowest. Finally got a couple days with partial sun. The s.g went up to 12.65. Now ive had a couple days of mostly all sun. BUT the s.g wont get much above 12.65 +/-. What happened?? Why wont it get fully charged again? Only way i could get it above 12.65 was to equalize for a few hours. But then drop back down to 12.65 after a few days.My first thought was to raise the absorb voltage, but thats scares me as im already a volt or so above recomendation Im sure theres a few battery gurus out there that would have the answer. Im stumped. I

Thank you all for any help or ideas, or explainations...

Ernie

P.S. Absorb time is set for 4.5 hrs.
emccornack
OutBack Whiz
 
Posts: 38
Joined: Tue Jan 26, 2016 4:22 pm
My RE system: 12 265W panels, 3048T Inverter, 8-6volt golf cart batteries (interstate) FlexMax charge controller, Mate3, Fndc. Off grid.

Re: Batterys-Whats going on? How do i fix it?

Postby blackswan555 on Fri Oct 13, 2017 10:30 pm

What are your voltages ? And how much absorb time are you actually getting ? But
way I could get it above 12.65 was to equalize for a few hours. But then drop back down to 12.65 after a few days
Suggests a little more absorb time needed,
It is also good practice to fully charge until SGs stop rising then EQ untill SGs stop rising on installation (commissioning charge, You can still do it now & I would suggest) As although they come "fully charged" most have just been filled with correct SG eloctrlite & you do not know how long or well they have been stored,
The other thing to remember is batteries take around 70 cycles to "Run in" so your SGs can be a bit mixed for a while, At about 70 Cycles, It is time for EQ again and you will see an improvement in performance on that one.

I suggest you have a good read of the Rolls manual, It applies to most FLAs with a little difference in charge voltages, http://www.rollsbattery.com/wp-content/ ... Manual.pdf

Tim
My comments are based on my experience and research, They are not endorsed or checked by Outback.I am an independent British electrician living in Spain, So please take this into account when reading /acting on my post`s.
blackswan555
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Posts: 2516
Joined: Sat Aug 30, 2008 5:50 am
Location: Ibiza Spain,
My RE system: Other peoples, VFX "E" versions, FLA`s, Generators.

Re: Batterys-Whats going on? How do i fix it?

Postby emccornack on Sat Oct 14, 2017 10:36 am

Thanks for your reply BlackSwan. Peak voltage for system is 50-51V. Drops down to 48.5V over night. (refer, lights, etc). Thanks for the link to Rolls, a good read. They say a b attery is fullly charged at 12.65? Thats my highest s.g max reading now. So does that mean a fully charged new battery (12.90) is supposed to drop down to 12.65, and that becomes its new fully charged reading? Ive increased my absorb time to 5 hrs. It hasnt made much differnce , a couple points more on hydrometer is all. So im not sure if im ok with it like this, or theres something else im missing or should do.
Ernie
emccornack
OutBack Whiz
 
Posts: 38
Joined: Tue Jan 26, 2016 4:22 pm
My RE system: 12 265W panels, 3048T Inverter, 8-6volt golf cart batteries (interstate) FlexMax charge controller, Mate3, Fndc. Off grid.

Re: Batterys-Whats going on? How do i fix it?

Postby blackswan555 on Sat Oct 14, 2017 10:24 pm

They say a battery is fullly charged at 12.65? Thats my highest s.g max reading now. So does that mean a fully charged new battery (12.90) is supposed to drop down to 12.65, and that becomes its new fully charged reading?
Do not worry about the "numbers" too much for now, They will stabilise over a few charges (probably around 1.270) It is what they are doing is the important bit, If they are still rising with more charge, They are not "full"
Ive increased my absorb time to 5 hrs. It hasnt made much difference , a couple points more on hydrometer is all.
Suggests it is still rising :smile:

What is your absorb voltage ? Do you have remote battery temp sensor installed ?

Tim
My comments are based on my experience and research, They are not endorsed or checked by Outback.I am an independent British electrician living in Spain, So please take this into account when reading /acting on my post`s.
blackswan555
OutBack Emperor
 
Posts: 2516
Joined: Sat Aug 30, 2008 5:50 am
Location: Ibiza Spain,
My RE system: Other peoples, VFX "E" versions, FLA`s, Generators.


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