An AGM is just a slightly different Lead Acid. The chemicals are the same. The way the electrolyte is held in place is different. Thus the very slight different 'floating voltage'.
The biggest load the Spark EV battery would ever see is: powered down, headlights, flashers, brake lights, radio on and you are making an Onstar phone call, all at once.
Still, nothing compared to cranking an ICE with its DC starter motor.
The one thing that might mess with a Li-ion 12V replacement is the 'Anti-sulfation' cycle/routine the APM does periodically. It's a pulsed AC voltage, as I understand it.
I haven't done a lot of research on the subject, yet. But there are automotive and motorcycle 12 V Li-ion replacements and they have built in Hi-Lo voltage protection with the BMS that is built into the battery case.
What about under hood temps when it's 100° and you are running the AC, for hours?
I don't have all the answers... few really...
The biggest load the Spark EV battery would ever see is: powered down, headlights, flashers, brake lights, radio on and you are making an Onstar phone call, all at once.
Still, nothing compared to cranking an ICE with its DC starter motor.
The one thing that might mess with a Li-ion 12V replacement is the 'Anti-sulfation' cycle/routine the APM does periodically. It's a pulsed AC voltage, as I understand it.
I haven't done a lot of research on the subject, yet. But there are automotive and motorcycle 12 V Li-ion replacements and they have built in Hi-Lo voltage protection with the BMS that is built into the battery case.
What about under hood temps when it's 100° and you are running the AC, for hours?
I don't have all the answers... few really...