LifePo4 Charge Performance
Thinking seriously about replacing our two GC2's with a pair of 100ah LifePo4's. Hearing a lot of chatter about how lithiums accept a charge much quicker than lead cells. Very familiar with how ou...
Forum Discussion
My ugly graph gives the charging times for a 220AH FLA bank when doing a 50-90 at 70, 55, and 35 amps. Let's compare those times to do that 88AH with LFP with those same three charging rates.
70 amps initial charging
LFP - 88/70= 1 hr 16 min
FLA- 2 hr 9 min
129/76 = 1.70
55 amps initial charging
LFP - 88/55 = 1 hr 36 min
FLA- 2 hr 19 min
139/96 = 1.45
35 amps initial charging
LFP - 88/35 = 2 hrs 31 min
FLA- 2 hrs 57 min
177/151 = 1.17
In this scenario, you see how the time advantage of the LFP shrinks as the charging rate is reduced. With solar at its low amps, you can see how that would fit in.
Before getting LFP, if "faster charging" is your reason to do that, it would be a good idea to do this sort of calculation and be able to tell how much of an advantage you can get with your existing amp size charger, what size charger you would need to make it "worth it", and see if your rig can handle that increase in charger amp size--especially if it would require a higher wattage gen to run it.
Money is not the only factor--there is the temperature "thing" that you may or may not be able to work around.
PT. the SiO2 spec says they have a slightly higher internal R than a regular AGM.
EDIT--change the scenario for the OP to do a 40-80 instead of a 50-90 and you can see why--constant amps at 45 amps with FLA and almost the same for LFP. Scenario is Everything!
70 amps initial charging
LFP - 88/70= 1 hr 16 min
FLA- 2 hr 9 min
129/76 = 1.70
55 amps initial charging
LFP - 88/55 = 1 hr 36 min
FLA- 2 hr 19 min
139/96 = 1.45
35 amps initial charging
LFP - 88/35 = 2 hrs 31 min
FLA- 2 hrs 57 min
177/151 = 1.17
In this scenario, you see how the time advantage of the LFP shrinks as the charging rate is reduced. With solar at its low amps, you can see how that would fit in.
Before getting LFP, if "faster charging" is your reason to do that, it would be a good idea to do this sort of calculation and be able to tell how much of an advantage you can get with your existing amp size charger, what size charger you would need to make it "worth it", and see if your rig can handle that increase in charger amp size--especially if it would require a higher wattage gen to run it.
Money is not the only factor--there is the temperature "thing" that you may or may not be able to work around.
PT. the SiO2 spec says they have a slightly higher internal R than a regular AGM.
EDIT--change the scenario for the OP to do a 40-80 instead of a 50-90 and you can see why--constant amps at 45 amps with FLA and almost the same for LFP. Scenario is Everything!
