Do AGM's charge quicker?
Looking to cut generator time. Have solar but sometimes have little to no sun when dry camping. Read AGM's charge up to 5X faster than flooded. How can that be, converter charger only puts out so mu...
Forum Discussion
landyacht318 wrote:
https://marinehowto.com/how-fast-can-an-agm-battery-be-charged/
My 5+ year old northstar AGM with 1000+ deep cycles is now requiring 5+ hours once 14.7v has been reached, for amps to taper to 0.5% or less of its 90 Ah capacity. The absorption time was much less than this when new, yet it still retains impressive voltage being discharged 45AH at near twice the discharge rate at which it earned that 90AH rating.
We have seen when going up in higher charging rates, Bulk gets shorter and Absorption gets longer. Also we know that LY's battery is older and will now have less capacity than when new. Let's pretend it is now 85 instead of 90. Let's also pretend he is using the same charger, current-limited to 30 amps, since he got that battery.
Charging rate was 30/90 = 33.3%
Charging rate is 30/85 = 35.3%
Full was 0.045 amps
Full is 0.0425 amps
So absorption portion of total time will be longer in proportion to the total time, but total time should be a bit less for 85 than 90.
Going to 0.0425 instead of 0.045 will take longer.
To throw a scuz into all that, ISTR reading from Mex? somewhere anyway, that an older AGM might have higher than 0.5 per for its "full" due to some condition factors. That is contrary to the reduced capacity though.
