in theory, a battery charger should work on it's own, it looks at the battery, talks, then puts the power to it.
if the battery is too low to talk it wont charge. or another way to look at it. these chargers work from umm i want to say like 97 volts up to like 255 or something like that.(dont quote me but i think they'll reject the 277 wildleg input, which sucks). meaning the lowest they can charge is.. well, in theory 97 volts. they can boost voltage to match the pack but won't buck it. so if your pack is sitting a 5 volts, or 50 volts, its literally too low for them to do.
this wont work here, and it's a real shitty way to revive a dead pack but, can give you an idea...i have a 40kwhr pack that is 4x12 volt cells in series., the reason i got them is, they wired them wrong and the heaters are on the battery side of the bms, meaning when it gets cold out, they turn on the heaters, but if the battery volts drop to cutout, don't care, the bitch stays on until they are at zero volts.. anyways. my 48 charger won't revive a battery, that is a well...non existent thing in lithium world. or supposed to be. my 12 volt on the other hand, has a recover mode that will put power into anything, but do so current limited. i hook it to one of the 12 volt batteries and fire it off, it brings that one battery up and then, the balancer that is also on it, feeds that to the rest of the batteries in the system to bring them up as well. it hops that 12 volts to each battery..which eventually restores the 48volt system to a voltage that allows me to then put the real charger back on it.
i have used something similar on other packs before, charge up one leg, wires and alligator clips work wonders, or pads with neodynium magnets on them, that way you can reach into a pack and clip the power where you need it, on the nickel bus. charge a P arm and the bms will route it to the others if its a passive, then eventually wake up to charge the battery normally, or if no wake up, its a few days but spihon charge the thing up. (note this wont work on the energica, it uses a stupid system to balance its batteries which is even fucking worse for the race bikes) but you could charge each arm or segment, individually until you hit them all... in an absolute worse case.
aaron
cough cough.... do at your own risk.