I bought a new "Omni" brand (this is a more well-known reputable local brand) 6v 4Ah lead acid battery for one of the rechargeable lanterns at home. I decide to test its capacity as a benchmark reference. I used EBD-USB+ and alligator clips (note that the alligator clip and wires likely have some resistance drop so it may not be that accurate..)
The Omni website doesn't have a detailed specs so I just cross-referenced other branded 6v4Ah Pb batteries to get the 5-hour discharge rate (0.2C), which is around 0.67A. I also am not sure what cut-off voltage to use, I might have set too low @ 4.20v (have I damaged the battery slightly?) Probably 5.10v is a correct cut-off voltage?
(I checked data and @ 5.20v, the capacity readout was already around 3700mAh.)
(When in use in the rechargeable lantern, I believe the lantern may not have a low-voltage cut-off and it just tries to drain the battery completely??)
This seems like a good battery, it was priced at Php350 (around US$7).
I then charged it using a 6v2A PB charger I bought during Banggood’s flash sale 2 months back (received it just recently).
It’s labeled a YASO-0602:
Charging the drained Omni 6v4Ah battery shows this graph:
So far this is my only stand-alone 6v lead acid battery charger (my only other method of charging is by placing inside the rechargeable lamp and plug to outlet for charging)
(I wonder if using a hobby charger like iMax B6, ISDT, iCharger will charge in the same way?)
Not sure if it’s a “good” charging curve but it looks good. Seems to take about 3 hours to charge to near-full.
reading the above graph:
- charging rate starts at around 1.8A (from 6.6v to 6.9v) and slowly decreases charging current [charger’s indicator is red ‘charging’]
- when voltage reaches 7.0v, the charging current starts to drop more quickly
(note: the voltage readout is NOT the battery, but the charger; since I connected the EBD-USB+ to the charger’s alligator clamp and then the output to another USB-alligator clamp to the lead acid battery)
- the voltage increases slowly from 7.0v up to 7.3v, with charging current decreasing around 1.7A down to around 0.4A when it reaches 7.3v
then the voltage drops suddenly to 6.9v and current is around 0.2A (slowly decreasing) [ the charger’s indicator turns from red to green at this point ] I think the charged capacity reading when it turned green was around 3800mAh
(I think it’s called ‘float’ charge when charger indicator turns green)
(note: the voltage reading of the EBD-USB+ is the voltage output of the charger, not the voltage of the battery)
The charged capacity seems to nearly match the discharged capacity.
The labels indicate “max initial charge current < 1.2A”
the lead-acid charger I used was charging at an initial current of 1.8A, will this have damaged the battery?
