How do SGs change as batteries age?
My LA batteries are 14 months old now, carefully watered, EQ every 4-6 weeks and generally the cells are fairly close in SG after an EQ. After the first 2 months (broken in) the batteries averaged 1.277 SG. A year later the average SG after an EQ and 3 hr rest is now 1.268. I guess I could EQ the hell out of them but judging from SG readings during an EQ I don't think they would come up much more if I cooked them.
Is this normal for batteries as they age? As determined by SG reading I generally cycle between 93% SOC and 75% SOC daily, rarely getting below 65% SOC.
Is this normal for batteries as they age? As determined by SG reading I generally cycle between 93% SOC and 75% SOC daily, rarely getting below 65% SOC.
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
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Chart here;
http://support.rollsbattery.com/support/solutions/articles/208145-specific-gravity-temperature-correction-factors
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A very knowledgeable member on this site (I think it was Bill or Vic ) put forward a strong argument that attempting to charge much over 90% SOC daily (excess water usage and heat) may not be the best thing. That combined with a call I made to the Crown battery manufacturer tech who wanted me to get above 1.265 at least several times a week has me currently allowing the batteries getting charged to about 1.265% SOC most days.
So I guess the question is as a battery ages is it normal to see capacity to drop about 4-5% a year?
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
I have a 5 yr old forklift battery of a lesser grade (GB) and 11 cells are fine in the 270-285 range when fully charged. I have one bad cell, that I think was poisoned. I've extended the absorb time to 3hrs now and the cell is maintaining a higher SG when the charger shuts down @ 1.255 I hope the next chance I get to equalize and monitor, will bring it up the little extra. I suspect it has lost a good bit of capacity even if brought back into line.
The equalizing cycle on a charge controller or a charger is just that, and good for a Maintenance equalizing when batteries are in good shape, it will help mix the electrolyte and do allow for some correction. Corrective equalizing will help remove sulfates that have hardened on the cell and either put them back into solution (ideal) or have them fall off and drop to the bottom of the cell(not so great). I would continue to equalize and see if your cells don't come up more. Corrective equalizing is done on a fully charged battery and SG is checked and recorded hourly. When no cell improves after 2 hours you are likely at the best recovery you can expect.
A few days ago I gave it 8 hrs of absorb over 2 days (batteries rested between absorb cycles, no load) at 59.1v. The bank was drawing 7.5 amps at the end. I then EQd for 4 hours at factory specified 61.9v but saw little change in SGs after the first 2 hrs. Four hour rest before testing. Average SG is now 1.271 so better but... I think that's the limit.
What am I doing wrong? I'm beginning to suspect that Crown has too low of an absorb voltage published and by following it for the first 10 months I had the batteries I may have damaged them by following their charging specifications.
After doing a bit of research for other battery manufacturers with L-16 batteries
Trojan says absorb at 59.2v
Rolls shows 60.0v absorb
Crown Deep Cycle wants 59.5v absorb
My Crown 6CRP525 paperwork wants 58.1v absorb. Crown tech support on the phone was weary of going up to a 58.5v absorb.
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
Try a longer absorb at 58.3V, for 16 hrs??? just trying to brain storm...
hth
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West Chilcotin, BC, Canada
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
KID #51B 4s 140W to 24V 900Ah C&D AGM
CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM
Cotek ST1500W 24V Inverter,OmniCharge 3024,
2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
West Chilcotin, BC, Canada
When the batteries were only 6 months old and I could get the SG up to 1.277 I didn't worry about it but now I can't get them all the way up.
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
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In post #8 you EQ'ed. did you get a lot of mixing (bubbling)? How hot did the battery get?
Have you tried an EQ daily for 2 or 3 times?
with the ending absorb rate being about 1% of battery capacity
that being the case I think you will have to do A,B & C as a set
A) go closer to or equal to near zero % (EA 4 amps?) ie, stay in Absorb daily over the winter
B ) start at the recommended Absorb voltage [ and increase in increments of .2V if you are not happy (after the first week or so) ]
C) do an EQ with the gen every 2 to 3 days, or daily, to see if you can maintain or gain on the SG readings.
All this is a process of discovery. "The truth is out there..... somewhere'' Fox Mulder
hth
KID #51B 4s 140W to 24V 900Ah C&D AGM
CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM
Cotek ST1500W 24V Inverter,OmniCharge 3024,
2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
West Chilcotin, BC, Canada
I suspect you may be correct.
Last night we went out for 7 hrs so I used the mini split to heat the house with outside temperatures dropping below 30 while we were gone. It really dropped the batteries to the point to where I didn't enter absorb until 1pm today. Still, I'm very impressed with the mini-split. Thanks for your earlier posts about mini splits. Mine is primarily for cooling but is sure is nice for occasional heating.
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
A fair amount of bubbling while equalizing, The batteries went up from 58 degrees to 75 degrees during that long multiple absorb and EQ session.
In the past I've considered equalizing every few days but figure I would probably do more damage than good in the long run.
Thanks for helping with this.
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
What I've read, take it for what it is worth.
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