I'm considering replacing my lead acid starting batteries on my boat with something like this. 500F @ 16v Starting battery module https://www.maxwell.com/images/documents/ESM_Manual_Install_4_15.pdf
I understand the high current risks associated with capacitors vs batteries. I had an older 12v 8d battery explode on the boat, my guess is that it was off gassing due to age and condition and the off gassing ignited.
I have seen what happens when a lead acid battery explodes, and the gas / acid is bad. What kind of gases/explosion/fire from a capacitor?