2S2P S-605 for 12V, 936Ah
This evening I pulled 81-84A (a little more current than the 4hr rate) from them for almost 6 hours. SG was 1.175 with voltage at 11.5V with 480Ah extracted. By Roll's published reference, they are very near 50% SoC based on a 4hr discharge curve and SG. That puts them very near rated capacity at 4 years old. I've abused them for the better part of the last 3 years:
1) Rarely charging them to full with only 1-2 equalizations/year - mostly out of guilt.
2) Letting them sit at about 12.5V (about 70-80% capacity).
3) Shallow but aggressive cycles of about 1.5kWh with discharge currents of 200A and charge currents of 300A but never quite hitting the 15V absorption for these batteries.
I can't help but think the short (15 min) 300A charges (0.31C) do a little something for desulfation, but I'm just guessing.
These were a $600 craigslist find (about 1/3 new price). The prior owner was running these batteries flat every night in his 24/7 off-grid "grow house." Yes. Verbally, that's what he told me they were for. After about a year of abuse, he decided he needed to go big and went with even bigger batteries with much more capacity. His loss was my gain.
Mostly just a testament to the durability of Rolls FLA when only moderate care is given to their health and with deliberate abuse.
This evening I pulled 81-84A (a little more current than the 4hr rate) from them for almost 6 hours. SG was 1.175 with voltage at 11.5V with 480Ah extracted. By Roll's published reference, they are very near 50% SoC based on a 4hr discharge curve and SG. That puts them very near rated capacity at 4 years old. I've abused them for the better part of the last 3 years:
1) Rarely charging them to full with only 1-2 equalizations/year - mostly out of guilt.
2) Letting them sit at about 12.5V (about 70-80% capacity).
3) Shallow but aggressive cycles of about 1.5kWh with discharge currents of 200A and charge currents of 300A but never quite hitting the 15V absorption for these batteries.
I can't help but think the short (15 min) 300A charges (0.31C) do a little something for desulfation, but I'm just guessing.
These were a $600 craigslist find (about 1/3 new price). The prior owner was running these batteries flat every night in his 24/7 off-grid "grow house." Yes. Verbally, that's what he told me they were for. After about a year of abuse, he decided he needed to go big and went with even bigger batteries with much more capacity. His loss was my gain.
Mostly just a testament to the durability of Rolls FLA when only moderate care is given to their health and with deliberate abuse.
