agm battery charge issue
what would cause a AGM battery to reduce its charging amperage, without the voltage reaching the set voltage cutoff in a CC mode stage of a charger example, battery is at 13.6 yet a pd9245 in boost...
Forum Discussion
My opinion and experience--yours may vary:
From the discussion it does sound like there is possible voltage drop between the converter and the battery. As mentioned, don't forget the negative connection. My last 2 trailers used the frame for the return negative path (which also "grounds" the frame) with a whole bunch of negative wires lugged under two, too small, self-taping screw on the frame. Quite a bit of potential voltage drop as those connections would age. I added a solid negative wire in both cases.
However: why all the concern about getting to 14.4 on AGMs? While that will finish the charge faster, my Trojan T-105 AGM batteries spec a 2 hour limit at that voltage to avoid gassing. In addition, PD is real proud of their periodic 14.4 to prevent stratifying the electrolyte. But AGMs don't stratify so the period voltage blast is not needed. The PD rep that I last spoke with indicated that their research has shown that 14.4 will not hurt, but also is not needed.
The Trojan T-105 AGMs like to float at 13.5 and will get to 100% charge in a few hours with my charger set at 13.5 continuous. I verify this with a battery monitor. The last static test that I ran came up with .1 voltage higher than Trojan's full charge spec voltage (battery disconnected from load or charger sitting over night for 18 hours.)
From the discussion it does sound like there is possible voltage drop between the converter and the battery. As mentioned, don't forget the negative connection. My last 2 trailers used the frame for the return negative path (which also "grounds" the frame) with a whole bunch of negative wires lugged under two, too small, self-taping screw on the frame. Quite a bit of potential voltage drop as those connections would age. I added a solid negative wire in both cases.
However: why all the concern about getting to 14.4 on AGMs? While that will finish the charge faster, my Trojan T-105 AGM batteries spec a 2 hour limit at that voltage to avoid gassing. In addition, PD is real proud of their periodic 14.4 to prevent stratifying the electrolyte. But AGMs don't stratify so the period voltage blast is not needed. The PD rep that I last spoke with indicated that their research has shown that 14.4 will not hurt, but also is not needed.
The Trojan T-105 AGMs like to float at 13.5 and will get to 100% charge in a few hours with my charger set at 13.5 continuous. I verify this with a battery monitor. The last static test that I ran came up with .1 voltage higher than Trojan's full charge spec voltage (battery disconnected from load or charger sitting over night for 18 hours.)
