I have been building an electric scooter which is now complete and working fairly well.
https://endless-sphere.com/forums/viewtopic.php?f=12&t=59873&start=25
The idea is to continuously improve on the build now, with better controllers, motor and batteries. The batteries are 60V worth of GBS 60Ah cells which I got for free but most likely have about a years worth of useful life in my application.
All this time I have been spying up purchasing 18650 60V or 72V 1.5kWh packs to connect in parallel which would shed an easy 50lbs and allow the scooter to have far greater performance with less battery sag.
However I have discovered just recently that connecting such packs with separate BMS units is a bad idea, so it is back to the drawing board! :?
Now I am thinking I could still try and obtain ready build battery packs but in custom configurations, where I can then wire up a suitable BMS unit and then package in a storage case within the bike. The individual packs could be something like 5S18P, 5S18P and 6S18P with connections between the pack with 2 or 3 suitable gauge wires to share the load evenly.
The challenge is to find a suitable not crazy expensive BMS system. I see Orion do a BMS junior, but only works for 48V systems. :?
The other option is to skip the BMS and balance initially with a BC168 first then have the charger set to cut out at 4V per cell for normal non balance charges and controller set to cutoff at 20% before LV limits. I would prefer to have a BMS for sure, but it does sound like the 18650 cells hold their balance very well so a monthly manual check would be potentially ok.
Would welcome thoughts on sensible direction and product choices. The other option is to build my battery packs also, but there are numerous challenges in that regard beside buying the materials and spot welding machines in my case.
cheers
https://endless-sphere.com/forums/viewtopic.php?f=12&t=59873&start=25
The idea is to continuously improve on the build now, with better controllers, motor and batteries. The batteries are 60V worth of GBS 60Ah cells which I got for free but most likely have about a years worth of useful life in my application.
All this time I have been spying up purchasing 18650 60V or 72V 1.5kWh packs to connect in parallel which would shed an easy 50lbs and allow the scooter to have far greater performance with less battery sag.
However I have discovered just recently that connecting such packs with separate BMS units is a bad idea, so it is back to the drawing board! :?
Now I am thinking I could still try and obtain ready build battery packs but in custom configurations, where I can then wire up a suitable BMS unit and then package in a storage case within the bike. The individual packs could be something like 5S18P, 5S18P and 6S18P with connections between the pack with 2 or 3 suitable gauge wires to share the load evenly.
The challenge is to find a suitable not crazy expensive BMS system. I see Orion do a BMS junior, but only works for 48V systems. :?
The other option is to skip the BMS and balance initially with a BC168 first then have the charger set to cut out at 4V per cell for normal non balance charges and controller set to cutoff at 20% before LV limits. I would prefer to have a BMS for sure, but it does sound like the 18650 cells hold their balance very well so a monthly manual check would be potentially ok.
Would welcome thoughts on sensible direction and product choices. The other option is to build my battery packs also, but there are numerous challenges in that regard beside buying the materials and spot welding machines in my case.
cheers
