Help please - 6ah power tool batterys repurposed

[Greenvlx]

Hi guys
I have some 6ah power tool betterys i would like to repurpose as a battery pack for an electric mountainboard. As far as i know they use 5s2P 18650 cells with 15a constant discharge and 3ah/cell. I plan on making the pack 10s but i am unsure how many i need in parrallel If i wanted to run 2 motors with a max of 90amps. Am i right to assume this is 90amps required divided by 15a constant discharge per string? Also these batterys already have a bms in the 5s2p configuration so would it be possible to have seperate bms and then wire the individual packs in series parrallel as required or would i need to make the pack with a new bms?
Any help is much appreciated.
Thanks
Shane

 

[flippy]

you would need to put at least 6 in parralel. so a 10sp8 pack would be bare minimum if you do not want to destroy the pack in less then a year. 10 would be preferable.
this is assuming each motor is 45 amps.
it is always recommended to have a single BMS that is rated for the use it will see.

but i wonder: how will you be able to hold on to a board with 3.5kW of pulling power? if the board has enough grip you will pull a 0-100kph in 0.5 seconds or something.

 

[Greenvlx]

The motors i was hoping to use were2 x 6372 enertion r specs with 80a max current each 190kv. So im guessing this is unobtainable from these cells then?
Holding on is the fun part!!!
Thanks
Shane

 

[flippy]

you can run them with 90A peaks but sustained is a whole difference story.
try getting the specs sheets and find out the actual sustained rating. pulling 3.5kW from that motor for more then a few seconds will burn it out real fast.

making a 10s10p pack will be sufficient for this application and give you decent lifespan. you can peg it down to 10s6p but i would recommend against it if you want the battery pack to last.

 

[LockH]

Hi. May/may not be relevant? But Dewalt just announced:

Seen here:
http://flexvolt.dewalt.com/en-us

Tks
L