If the output is smooth enough... probably.Would it be feasible to use something like a 48v led PSU and a boost converter
Voltage is voltage. Should be fine.
The other thing to check is if it has a soft limit on current. I.E. It's rated for 15 amps max. If you try to pull 30 amps from it, does it attempt to do this and just liquify and let out the smoke (or blow fuse), or, does it sag the voltage back such that it never draws more than 15 amps, and you can just set the max voltage and walk away and it'll eventually get there as fast as it can?
It says it has adjustable current, not just adjustable voltage, so.. it should be smart enough to not murder itself. Should be as simple as setting the current as high as it'll allow or the highest your batteries can take if lower (or less, to de-chineseify it), add a fan to it anyways (to give it fuckin' hope), and the voltage to the end voltage you want to hit.
If you want to limit the charging current to 10A, you can do that. If you want to limit the voltage to 76 or 83v, you can do that.
You won't get the full rate power through it though, 76v @ 10A = 760 watts.
Considering it's rated for 120v @ 15A = 1800 watts, but claims to be only a 900w power supply... something is going to choke.
I'd say it's good enough. I suspect it won't handle much more than 7 amps for more than a minute or two without frying.
In any case, buy two, fry one