I could imagine it being even a cm longer or something such that brackets only fit one pack or the other but not both... but turns out that's not the case.
I contacted Pushkar and the two packs are basically interchangable. There are two issues:
- The display's percentage remaining.
- The 'motor' (I think Pushkar says motor when referring to Innotrace controller?) has a low voltage cutoff. WW sets it to 3.0v/cell.. so for 52v pack they set cutoff to 43v and for 48v they set it to 39.2v. But that means either:
- Cutoff is set to 43v for the 52v pack, but that means if you put in a 48v pack cutoff is not at 3.0v/cell but rather 3.3v/cell, so you can't use last 15% of capacity in 48v pack.
- Cutoff is set to 39.2v for the 48v pack and now you can use all its capacity, but if you stick in a 52v pack the 39.2v cutoff is ~2.8v/cell... which isn't really good to constently be doing.
But for me, I don't care about percentage remaining, I like just knowing volts. And with cutoff set for 48v pack using a 52v pack I trust myself to not let it overdischarge. And if I do its on me.
So yeah I told Pushkar:
I'm kinda making a bigger deal over this than is really needed.. just got home from a ride.. 30 miles with 2800ft elevation, 3 hour ride (2.5 hour moving time-- after every climb I need a couple minutes, haha).. pack is at 51.2v aka 3.655v/cell aka ~6.82AH remaining according to BMS. I was being very conservative with assist, but still.. its going to be pretty rare I actaully use up entire 52v pack's 720wH. But this was charging to 4.2v/cell, charging to 4.1v/cell will knock off an aH or two.. and then I dunno it just ends up being range anxiety.. I don't want to ever cut a ride short because I'm not sure I have enough battery left. I think that's mostly it.