Group 27 AGM mid life performance report
My 90AH Northstar AGM battery is now 38 months old, and has accumulated ~465 deep cycles. When I cycle it, generally I consume 35 to 65AH nightly, average about low 40's Since June of 2015 it ...
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So charging at a 72% initial charging rate, which is like a Lifeline AGM thing, not like my lower order AGMs with their 27% limit, amps tapered at about 62% SOC (using no heat loss) at min 24
Then the lower voltage charger (Schu) started to taper leaving the higher voltage charger (MW) still doing its 40 max till its amps were also tapered by the battery rising.
At minute 40 you were at about 80% SOC allowing 5% for heat since min 24 and then at about 100% SOC by min 120 allowing 10% for heat. But it was not really full or else all the amps were going to heat by then.
So the above calculations would have to allow some more for heat to get the SOCs to come out right, but the general picture is there.
I don't have a comparison for that profile, but it does seem clear that maybe we need to look more closely at the 80-100 SOC AGM charging rate advantage where so much goes to heat? I don't have good numbers for Flooded on that though. Bogart just says heat loss goes sort of crazy above 80% SOC.
I hope to do a charging profile of my 200AH worth of new AGMs (27% charging rate limit specified) with my 55 amper at 14.8, using the Trimetric to keep track fairly soon. Whatever the results, it could be an apples to oranges thing though, compared with the above older Lifeline type of AGM's profile.
Then the lower voltage charger (Schu) started to taper leaving the higher voltage charger (MW) still doing its 40 max till its amps were also tapered by the battery rising.
At minute 40 you were at about 80% SOC allowing 5% for heat since min 24 and then at about 100% SOC by min 120 allowing 10% for heat. But it was not really full or else all the amps were going to heat by then.
So the above calculations would have to allow some more for heat to get the SOCs to come out right, but the general picture is there.
I don't have a comparison for that profile, but it does seem clear that maybe we need to look more closely at the 80-100 SOC AGM charging rate advantage where so much goes to heat? I don't have good numbers for Flooded on that though. Bogart just says heat loss goes sort of crazy above 80% SOC.
I hope to do a charging profile of my 200AH worth of new AGMs (27% charging rate limit specified) with my 55 amper at 14.8, using the Trimetric to keep track fairly soon. Whatever the results, it could be an apples to oranges thing though, compared with the above older Lifeline type of AGM's profile.
