Most of my rides are short <20km so I’l make pack to suit, then have a second battery I can swap in if needed. This keeps the bike light most of the time, and simplifies the battery. I already have a bunch of LiPo laying around, the controller is currently only good for ~60V with 63V caps and IRF3006 fets.
A simple series connection of three 5s5Ah LiPo packs gives me ~300wh in a 15s5Ah pack that easily fits in a saddle bag, making for easy mounting, off bike charging, and easy swapping if necessary. Later if I decide to make a more permanent bigger pack, I’ll double up in parallel and mount it to the down tube.
This is what it looks like.
As you can see the series connection of the three pack just uses the existing connectors, then I have an adapter the coneverts to Anderson PP45 connects that I like to use for the main connection to the controller.
For charging I’ll bulk charge most of the time, as these packs have always stayed pretty balanced.
The bulk charger will be a 240w BMSBattery charger
For balancing I have just order one of these little guys
, which automatically correct any imbalance greater than 0.02V. Then plan is to occassionally throw these on the balance leads of each pack once charged to check and correct any imbalance.
Low voltage control will be handled at a pack level by the controller.