Latest update;
The spec says the 48v pack's charging voltage is 55vdc...not 57.6 as I would expect. Something to do with the architecture. Anyway, no charger I am in possession of is capable of being dialed down to that voltage.
The tech I spoke to has not yet chimed in with any suitable charging device, and I cannot find anything myself. Even the Progressive Dynamics Li chargers can't be used in series to provide that. I suppose if I really wanted this to work I'd have to have a special charger made. That just seems weird.
And especially if I can't dial down my Outback controller, ain't no way I can use that pack.