AGM vs Flooded Bulk Times
PT keeps asking whether AGMs will spend more time in Bulk at the same charging rate. I found a good example where that can be measured, using ah64id's test with his PD4655 on his pair of Lifeline...
Forum Discussion
Looking at my own 50-90s with Wets to see what the AGM advantage would be. Hmmmmm.
A. Using a single 100 amper run with Honda 3000 on four 6s (458AH) at 50% start. (100/458= 22% charging rate)
Constant 100a to 72% SOC in one hour then amps tapered, stopped charge at two hrs -Restored 173AH (Trimetric count) to 87% SOC.
If I had AGMs and amps never tapered during the second hour, that would be 200AH restored instead of 173, taking the bank to 94% SOC (it might have tapered a bit before that even with AGMs, but never mind)
Or, to get the same 173 restored that would be 73 after the first hour, taking 73/100 x 60 = 44 minutes, saving --16 minutes--- of generator time. And a thimble full of gasoline?
B. Another example where now I use two chargers (100 + 55) but on 6 Wet batteries at est 55% start. Temp was 40F in January, bank down 276 AH from whatever the capacity was--worked out to be about 614AH.
(153/614 = 25% charging rate)
Got 153 amps for the first 21 minutes,(54AH) then amps tapered for next hour and 39 minutes,(155AH) total 209AH restored (Trimetric) to est 89% --So a 55-89 in two hours.
Now let's say I had AGMs and amps never tapered from that 153, and just do the 55-89 with AGMs no tapering.
209/153 = 1.37 AGM hrs vs 2 Wet hrs, saving-- 23 minutes--- of gen time. and a little more gas this time.
I cannot use any more charging amps than the 155ish with my Honda 3000 so I am maxed there. I could stay inside the 2 hr gen time limit with more AH of AGM bank if I need more AH per day ( I don't), which I would get anyway if it were 70F instead of 40F in that example, but I don't know where I would cram more than six into my little 5er! Six batts is quite a load as it is.
Anyway, there are some actual numbers that illustrate what you would be kicking around trying to decide if it is "worth it" to you to have AGMs vs Wets for your 50-90s.
A. Using a single 100 amper run with Honda 3000 on four 6s (458AH) at 50% start. (100/458= 22% charging rate)
Constant 100a to 72% SOC in one hour then amps tapered, stopped charge at two hrs -Restored 173AH (Trimetric count) to 87% SOC.
If I had AGMs and amps never tapered during the second hour, that would be 200AH restored instead of 173, taking the bank to 94% SOC (it might have tapered a bit before that even with AGMs, but never mind)
Or, to get the same 173 restored that would be 73 after the first hour, taking 73/100 x 60 = 44 minutes, saving --16 minutes--- of generator time. And a thimble full of gasoline?
B. Another example where now I use two chargers (100 + 55) but on 6 Wet batteries at est 55% start. Temp was 40F in January, bank down 276 AH from whatever the capacity was--worked out to be about 614AH.
(153/614 = 25% charging rate)
Got 153 amps for the first 21 minutes,(54AH) then amps tapered for next hour and 39 minutes,(155AH) total 209AH restored (Trimetric) to est 89% --So a 55-89 in two hours.
Now let's say I had AGMs and amps never tapered from that 153, and just do the 55-89 with AGMs no tapering.
209/153 = 1.37 AGM hrs vs 2 Wet hrs, saving-- 23 minutes--- of gen time. and a little more gas this time.
I cannot use any more charging amps than the 155ish with my Honda 3000 so I am maxed there. I could stay inside the 2 hr gen time limit with more AH of AGM bank if I need more AH per day ( I don't), which I would get anyway if it were 70F instead of 40F in that example, but I don't know where I would cram more than six into my little 5er! Six batts is quite a load as it is.
Anyway, there are some actual numbers that illustrate what you would be kicking around trying to decide if it is "worth it" to you to have AGMs vs Wets for your 50-90s.
