My Lyric Ranger has one good battery pack and one bad one, so I've been looking at alternatives. After some voltage and resistance measuring I figured out how to connect four 12v SLA batteries in series to the terminals which stick up where the original batteries would plug in. In this pic, the positive lead from the SLAs is on the right and the negative lead on the left. This was just a quick lashup to see if it'd work at all, which it did - motor, lights, and horn. I didn't actually ride the thing, just ran it a short distance at very low speed while walking beside it. The terminals are paired to halve the current each connection carries, so the terminal just next to each of the wires could also be bridged to them.
I'm not suggesting actually using SLAs, but this shows that a single 48v-or-vicinity pack (of whatever chemistry) can be connected.
- Gnarly test wiring - not for Actual Use :-)