kudos
10 kW
After much deliberation I'm going to build my first cylindrical cell battery.
I've been using LiPo very happily for 12 years so I'm very familiar with putting them together using 6S packs.
My current 32AH battery made from four 16AH Multistar LiPo is still going after four years, cells never our of balance.
They stay this way because I charge at 6A and LVC set at 3.6V.
However, after 6k miles they are starting to get a bit puffy so I'm looking for my next pack.
If LiPo was readily available I probably would have stuck with what I know, but large LiPo packs are perma-unavailable so I'm going with 21700's.
I've ordered 72 Molicel P42A 21700 which I'm planning to put together in 12S 6P
I already have a charger for this voltage 50.4V
I've picked up 21700 spacers and I also have Nickel strip coming in 0.15mm and 0.2mm thickness', as well as 21700 size positive insulators and kapton tape.
I wanted to use the ladder style nickel strip but I could only seem to find 25 & 27mm widths which appear to be 18650 size, although I don't know for sure.
I picked up a cheapo spot welder powered by a small internal Lipo battery, I've tested with 0.10mm nickel and seems to work fine. The high power mode should be fine for 0.15mm although we'll have to see when it arrives.
Having never used a BMS and having read countless threads of BMS's ruining batteries, I'm on the fence about using one and would appreciate input from anyone who runs 18650 / 21700 batteries without a BMS.
I appreciate it's the norm to have a BMS and having never run a cylindrical cell battery before I don't know how they behave, so a BMS might be a must.
I would prefer to stick with what I know, make two 6S6P modules and combine them up. I can easily balance the cells (if required) in a number of ways including my ichargers.
This first battery will be my learning curve battery, I intend to follow it up with a very large capacity unit.
I'm in the 'you can't have a big enough capacity battery' camp.
I'll document my build here and hope to gain from the wisdom of those who have gone before.
Kudos
I've been using LiPo very happily for 12 years so I'm very familiar with putting them together using 6S packs.
My current 32AH battery made from four 16AH Multistar LiPo is still going after four years, cells never our of balance.
They stay this way because I charge at 6A and LVC set at 3.6V.
However, after 6k miles they are starting to get a bit puffy so I'm looking for my next pack.
If LiPo was readily available I probably would have stuck with what I know, but large LiPo packs are perma-unavailable so I'm going with 21700's.
I've ordered 72 Molicel P42A 21700 which I'm planning to put together in 12S 6P
I already have a charger for this voltage 50.4V
I've picked up 21700 spacers and I also have Nickel strip coming in 0.15mm and 0.2mm thickness', as well as 21700 size positive insulators and kapton tape.
I wanted to use the ladder style nickel strip but I could only seem to find 25 & 27mm widths which appear to be 18650 size, although I don't know for sure.
I picked up a cheapo spot welder powered by a small internal Lipo battery, I've tested with 0.10mm nickel and seems to work fine. The high power mode should be fine for 0.15mm although we'll have to see when it arrives.
Having never used a BMS and having read countless threads of BMS's ruining batteries, I'm on the fence about using one and would appreciate input from anyone who runs 18650 / 21700 batteries without a BMS.
I appreciate it's the norm to have a BMS and having never run a cylindrical cell battery before I don't know how they behave, so a BMS might be a must.
I would prefer to stick with what I know, make two 6S6P modules and combine them up. I can easily balance the cells (if required) in a number of ways including my ichargers.
This first battery will be my learning curve battery, I intend to follow it up with a very large capacity unit.
I'm in the 'you can't have a big enough capacity battery' camp.
I'll document my build here and hope to gain from the wisdom of those who have gone before.
Kudos