I tried to post this into one of the two other lengthy IP22 goes straight to absorb threads, but when I hit post it just took me to "Page not Found." So trying a new thread.
Pretty much same as everyone else, with a slight twist. IP22 30/3-12 volt, Rev 2, all up to date. When I try to charge an AGM battery that's sitting at 12.4 volts resting.... guess what happens? Yup, straight to absorption.
I started by stripping everything out of my system, so now it's just IP22, 2x 24" 10AWG leads, battery posts. Battery not connected to anything else. Battery is a Lifeline Group 24 start AGM battery. Changed fuse in IP22 (though it looked fine). Mains power is in a building, so steady/ample.
I first contacted Lifeline, who cheerfully sent me a brand new battery, thinking it was a problem with one of the cells or something in my one-year-old Lifeline AGM. I connected the new battery to my outboard motor and ran the tilt up and down a bunch of times until the battery rested at 12.4 volts (because the Lifeline tech guy thought well maybe it's because the new battery is at 12.8 volts and nearly full, though that still made no sense). But anyway, that wasn't it because now the battery has been sitting at 12.4 volts for a couple of months (as I sporadically try to charge it, to no avail because it always goes staright to absorb).
There's really nothing else I can remove from this setup. Charger, short wires, battery. That's it.
Okay, but this IP22 will charge an LFP battery. I guess because there is less resistance. I have three Victron 200ah 12.8 Smart batteries, and all charge just fine. Also two 100ah Battleborns. Bulk for however many hours is necessary, while the voltage slowly climbs to 14.2 and it flips to absorb. Just as you would expect. On the Battleborns, since they don't need external BMS etc., I charged them with the exact same "stripped down" setup as I used on the AGM: Charger, two short cables, battery (while I was there watching it the whole time). So that proves the setup of my two-short-cables-only can work on a battery with exceptionally low resistance (LFP).
But if I put it on an AGM battery, nope, straight to absorb. It's like the IP22 is insanely sensitive to resistance, and even a brand new, high-quality AGM has more resistance than an LFP battery so it just can't be used? That said, there is a setting for "Normal" (lead acid) batteries, so clearly it's intended to be able to charge chemistries other than LFP.
I'm perfectly willing to give up on the IP22 and buy a non-Victron charger going forward; but right now I really just need to get this battery charged (at least this one time) and have not yet bought another charger. Any ideas or workarounds?
BTW, I don't want to change this particular battery to LFP, because it's the start battery for my boat, and I prefer AGM for that.
