Author Topic: lipo 7s+7s / 6s+7s /6s+6s? on a 1000W 48v bike  (Read 6224 times)

Offline Void7775

  • Confirmed
  • New Member
  • *
  • Posts: 24
lipo 7s+7s / 6s+7s /6s+6s? on a 1000W 48v bike
« on: March 30, 2017, 01:38:26 PM »
hi.
please give arguments for the choise you recommend.
the voltages written on the controller are 41-48v 22A
1. will the 7s+7s be too much and the controller will shut off?
2.will the 6s+6s be too little when the battery would be mostly consumed and the controller will shut the battery because of the low voltage? or would the voltage go lower than 41 because it will be under load?
3.will the 6s+6s performance be low after half the battery is consumed?
4.charging 6s and 7s separately with one balance charger is possible, right?
5.on a 6s+7s I have a problem finding the same C in my country. for example would it be ok to link 6s 10C constant/25C maximum 10 seconds and 7s 25C constant ? is there a minimum number for C needed for my setup? would 10C be ok?
6.is it ok if I match 6s 5200mah with 7s 6000mah? I know it will cut off the battery sooner, but will there be damage in the long term?
7.am I benefiting of the full power of the motor if I have 20C and 6s+7s 5000mah? or must I have something like 6s+7s 10.000mah to get full power?
thanks
« Last Edit: March 30, 2017, 01:57:38 PM by Void7775 »

Offline Pwd

  • Confirmed
  • Bachelor of Magic
  • ****
  • Posts: 151
Re: lipo 7s+7s / 6s+7s /6s+6s? on a 1000W 48v bike
« Reply #1 on: March 31, 2017, 02:08:11 PM »
What controller are you using?

Offline Dias

  • Confirmed
  • New Member
  • *
  • Posts: 8
Re: lipo 7s+7s / 6s+7s /6s+6s? on a 1000W 48v bike
« Reply #2 on: May 24, 2017, 05:33:01 PM »
1. not sure
2. I have 12s setup too, you should NEVER EVER go below 3,5 V per cell (meaning 42 V), and possibly not below 3.7 V, there is barely any energy left (like 15% depending on C) but you shorten lifetime significantly
3. yes, performance goes down by a lot, bike goes lazy around 46 V (maybe tweaking the drive in app could help, had no luck so far but havent tried to for over 6 months now)
4. yes, this should work as long as all the batteries are same, you charge each cell to 4,2V and if all of them behave the same its good to go - if there is a weak cell, it will weaken the rest too
5. and obviously I mentioned this in 4) before even reading don't use different batteries together, they behave different too, it would work but I seriously doubt anyone would recommend this...C rating depends on mAh and "quality" of the cell, better cells can charge/discharge faster, if you have 10 C constant you can use 3000 mAh battery for 30 A drive but expect no more than 10km range
6. no its not, the discharge rate of batteries is not linear, its a curve and if the drive wont realize that some of the batteries are already <3.5 V and some still 3.7 V eg., again - it would probably work but show me someone recommending this
7. power is a matter of voltage, amperage = distance, 5000 mAh = 15km 10000 mAh = 30 km (approx)

Simply: for the 48V go for 13S setup, the bike will run faster for a longer time. Btw: I run LiPO with bulk charger + BMS (not like you need BMS all the time, batteries will stay balanced for some time but the BMS of mine protects over/under voltage too)
« Last Edit: May 24, 2017, 05:36:15 PM by Dias »