robbob2112
Doing more research, mosty harmless
The AC charger is a INTELI-POWER 9100 mod # PD9180AL.
The DC to DC charger is a Renogy 12V 50A DC to DC Battery Charger with MPPT
BTW - if it hasn't been mentioned we all appreciate you hanging your system out there so we can all learn
... it can be hard to have some dick tell you that you are doing things wrong...
Does the Renogy DC-DC charger have any way to set the cutoff voltage or is it listed in the manual....Do you have the bluetooth option so you can set the voltage profile? I see it has a Li profile, but that usually means Lithium Ion instead of LiFePO4 batteries and that can mean a less than ideal charge profile. If it will let you do 'custom' that can be better than the default Li
So here is the working theory - you are driving 5 hours - the DC-DC charger is doing its thing, but the cuttoff voltage for charging is higher than the one for the BMS or it doesn't have one and relies on the BMS to cut things off.... in any case it just keeps trying to push current into the batteries.... you other battery does its thing and cuts off the current... the burned battery tries to cut it off and in fact things it did... but at least one MOSFET is shorted and it keeps allowing current and eventually you let out the smoke.
Looked at the manual - I can't find anything in it to show the output voltage is adjustable - seems to be made for FLA batteries and that is it. This means it is never actually charging your batteres to full.... It needs to charge to 14.6v and hold there for a little while to let your cells equalize and balance.... once disconnected they will settle to 13.6......
Will defer to the egg guy on how much trouble this is in the long run.... I don't think it will actually hurt so long as it gets 14.6 from some source... like the DC-DC charger or solar panels and a MPPT.

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