Can I Use a 13S 48v BMS as a 11S @ 40v? (Ebike)

tunzafun001 on 15/11/2024 - 13:09

Have an ebike with a 36v Bafang 200w hub motor. It struggles a bit with the hills here.

10S5P - 36v battery pack has had it. Heaps of room in the pack. So thinking of adding an extra row in series to make it just over 40v (mild upgrade for the hills).

Thinking I buy a generic 48V BMS off Ali Express, but only use 11 of the 13 outlets?

Controller should be ok (I'll check component ratings first). Controller won't cut out with the extra row, but the BMS should cut it off instead.

Currently this is what happens. Ie. Bike total is at 34v, but cuts out..as pack 2 on the BMS drops to 3v.

So back to the question, since I can't find a 11S BMS, I'm assuming a 13S should do (and just use 11 of the 13 connections)?

Cheers

Electrical & Electronics Battery Monitor Electric Bicycle

Comments

MS Paint on 15/11/2024 - 13:23

There's hills in Mildura?
Che0063 on 15/11/2024 - 15:39

+1

No, this will not work unless you have a way of configuring the BMS to expect only 11 out of 13. In all other cases, and if the BMS is properly designed, it will not allow any current if it does not detect voltage on any of the cell taps.
- tunzafun001 on 15/11/2024 - 16:36
  
  Cheers. I was looking at this..which suggests its anywhere from a 6S to a 13S.
  
  I assumed you just bridge a couple of the outlets. Ie. Wire it so 11, 12 and 13 are monitoring the same pack?
  
  https://www.aliexpress.com/item/1005002766306434.html?src=go…
  
  *Edit - this shows it better - ie. Only using 7 of the 12.
  
  https://www.ebay.com.au/itm/154008535856?chn=ps&_ul=AU&mkevt…

Can I Use a 13S 48v BMS as a 11S @ 40v? (Ebike)

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