I want to build a 18650 battery for my downhill bike with a Bafang BBSHD motor, using Samsung 30Q batteries.
I don't want to fiddle with the controller capacitors, so I need to stick to just under 60 volts.
I pedal the bike a lot and only use the motor for short bursts with the throttle (30 amps for about 30 seconds), or I use just a bit of PAS if I'm going up a really steep hill (about 5 amps).
At the moment I have a 14s7p 21.7 Ahr battery, and this easily gives me 3 good rides, so I feel that it's overkill and heavy.
If I build a new battery I think that I could get away with a 6 or 9 Ahr (2S or 3S) although I'm a bit worried about voltage sag at 30 amps?
Is it safe to use the 30Q at 15A per cell for short bursts like this?
I'll put a temperature sensor and cutout in the pack.
Would I be safer with the 3S configuration that would draw 10A per cell?
Will I achieve anything by running a 15S at just below 60V fully charged (cell voltages 4.0 V), or should I just go for a standard 14S with fully charged cell voltages 4.1 (57.4V pack voltage)?
I know that I will get a better life by running the cells at 4 volt vs 4.1 volt, but will I pack a bit more power in the 15S battery and is it worth the extra hassle?
I don't want to fiddle with the controller capacitors, so I need to stick to just under 60 volts.
I pedal the bike a lot and only use the motor for short bursts with the throttle (30 amps for about 30 seconds), or I use just a bit of PAS if I'm going up a really steep hill (about 5 amps).
At the moment I have a 14s7p 21.7 Ahr battery, and this easily gives me 3 good rides, so I feel that it's overkill and heavy.
If I build a new battery I think that I could get away with a 6 or 9 Ahr (2S or 3S) although I'm a bit worried about voltage sag at 30 amps?
Is it safe to use the 30Q at 15A per cell for short bursts like this?
I'll put a temperature sensor and cutout in the pack.
Would I be safer with the 3S configuration that would draw 10A per cell?
Will I achieve anything by running a 15S at just below 60V fully charged (cell voltages 4.0 V), or should I just go for a standard 14S with fully charged cell voltages 4.1 (57.4V pack voltage)?
I know that I will get a better life by running the cells at 4 volt vs 4.1 volt, but will I pack a bit more power in the 15S battery and is it worth the extra hassle?