Battery Charge Rates
Battery Charge Rates
(OP)
I'm trying to calculate the charging time required for a UPS battery bank.
I have a 260 Amp/hr battery bank (120VDC - sealed lead acid type) connected to a 6 ohm, 2.5KW resistor bank for 2 hours. This test is used to simulate the maximum foreseeable load and to chart voltage and current of each cell.
At the end of the test, the battery bank is connected to a 5 amp charger.
Is there a calculation for determining the time required to recharge the battery bank?
I have a 260 Amp/hr battery bank (120VDC - sealed lead acid type) connected to a 6 ohm, 2.5KW resistor bank for 2 hours. This test is used to simulate the maximum foreseeable load and to chart voltage and current of each cell.
At the end of the test, the battery bank is connected to a 5 amp charger.
Is there a calculation for determining the time required to recharge the battery bank?





RE: Battery Charge Rates
TTFN
RE: Battery Charge Rates
RE: Battery Charge Rates
RE: Battery Charge Rates
I'll take a messurement next time to verify. Any other ideas would be greatly appreciated.
RE: Battery Charge Rates
Is it designed for constant current output, so you'd expect the output voltage to increase as the batteries got charged?
TTFN
RE: Battery Charge Rates
Found a good info source in the Exide website. An equation listed for lead acid type batteries:
Charge Amp = ((Battery Amp x Battery Hrs x 1.10 / Specified Charge Hrs) + L) x 1/K1 x 1/K2
Where:
L = other load on batteries during charging
K1 = derate for temp (1 to 122F / .8 to 131f / .6 to 140F)
K2 = derate for altitude (1 to 3300ft / .8 to 5000ft / .6 to 10000ft)
1.10 factor for charger conversion lead acid batteries.
This should work for most lead acid batteries regardless of manufacturer. This should get you to the 90% charge range - which, to my understanding, is an industry standard. The last 10% can take quite a bit of time.
Very close to IRstuff's post. Thanks!!
Just a quick note ... the info stated that some newer chargers have output current curves that will give more accurate time.