Multiple BMS

I've purchased a set of 10 Swagtron hover board batteries to power my ebike build. These are a 9s1p 2.9Ah pack with a BMS that handles charge, discharge and temperature monitoring. My initial plan was to run 5 of these packs in parallel then wire the two "bricks" in series for 66v nominal.
I'll be bulk charging as one large pack through an XT90S.

My question was how the packs would respond to one BMS cutting power making for a 4p on one side and 5p on the other of a serial connection. I'm assuming the cells in the 4p would see 20% more amps and subsequently hit LVC which would then eventually cut off the entire pack.

Would it be better to wire them as 5 bricks of 2S then parallel those packs? To my thinking this would permit a single BMS to disconnect 2 packs/1 brick, but leave the other 8 packs/4 bricks operational but experiencing 20% higher amp draw.

Although I can't get specifics on these BMS, they are supposed to provide 600w from 9s1p so should be individually capable of 15a.

The flip side of which is how having individual BMS handle a bulk charge and I must admit I'm not well enough informed to make a intelligent guess on that. My assumption is that I may need to charge the packs individually every so often to maintain balance.

Any input greatly appreciated.

-Grant

This is a good read:
View attachment parallel_strings.pdf

Thanks for that. It seems I'm probably not going to be able to run with the existing BMS' although I may do a few test runs.
Starting to think perhaps a different battery source would have been easier to deal with, even one without BMS.

Just cut the bms's and buy a new bms for the full pack, parallell all the batteries to one string. It'll work

I haven't yet torn down the packs to see how easily they can be reconfigured. If they are welded 9s1p it might be a challenge.

In hindsight multistar 16000s would have been easier.

Doesn't look too hard...bit of snipping and soldering and you're done. (this is 2p pack)

Mine are ATL pouch cells with, I assume, welded tabs. I'll need to get a look at how they are connected.
18s 100a BMS might be an easy solution that would run hobby lipos down the road.