Connecting 12V batteries in series, concerns?

[IGBT]

I have an application where I need 48V to run a 3kW electric outboard on our sailboat.

I was going to go with the Epoch 48V 100AH battery (the marine one in the nice 15" x 15" footprint) but was concerned with the weight so I ordered four of the 12V 100AH group 24 Li-time batteries with blue tooth and low temp cut-off.

I know from Will's video that these use a decent BMS that is designed in-house by Li-time. How confident are we that the mosfets in these can handle the breakdown voltage when one of the batteries hits charging limit and cuts out? I am hoping Li-time would have addressed this concern and used 60V or 80V mosfets but have any of you used the group 24 or the group 31 trolling motor battery in a 4s setup?

edit: Since Li-time actually states: "LiTime allows for a maximum of four 12V lithium batteries to be connected in series, resulting in a 48-volt system." I am going with the idea that they did the engineering and didn't cut corners on the reverse breakdown voltage of the mosfets

I guess if someone had a dead group 24 that they have pulled the BMS out we could check the actual part numbers and look up the specs to see what part they actually used and then look up the specs.

 

[sunshine_eggo]

edit: Since Li-time actually states: "LiTime allows for a maximum of four 12V lithium batteries to be connected in series, resulting in a 48-volt system." I am going with the idea that they did the engineering and didn't cut corners on the reverse breakdown voltage of the mosfets

That's the idea.

I guess if someone had a dead group 24 that they have pulled the BMS out we could check the actual part numbers and look up the specs to see what part they actually used and then look up the specs.

Critical that you individually charge all 12V to full and then parallel charge them to full before placing in series. All four batteries must be at true 100% SoC when you string them in series.