sla runtime issue

[Flashanator]

runnng a halogen dc light drawing 11amps, how much runtime should I get from a 12ah SLA fully charged?

Its just going flat too fast, maybe batt is a dud.


thx

 

[TigerhawkT3]

Most SLA runtimes are tested with C/10 or C/20 rates, which would be 1.2A or 0.6A for a 12Ah batt. I haven't come across derating formulae, but I would hope for 30-40m for your 11A application.

 

[Flashanator]

thanks for that,

im getting maybe 20-25mins tops, tho its an old battery.

 

[ifor powell]

The formula is peukerts law. The dropoff can be big. The leasure batteries I just bought for my camper have a 20 hour rating of 108 Ah but the one hour rating is only 39Ah

Ifor

 

[mdocod]

In my experience, a 7AH SLA in good new condition only lasts about 15 minutes into a ~10A load. But it will handle 30 amps, for about 30 seconds, lol...