Lithium E-Motion Charging

Power wheelchair board for REAL info!

POWERCHAIR MENU! www.wheelchairdriver.com/powerchair-stuff.htm

Lithium E-Motion Charging

Postby cdb0ewm » 01 Aug 2022, 17:18

One of my issues with the lithium battery packs is the need for balancing. I had the chance to open up an E-Motion wheel's battery pack which has 21 small lithium batteries and what appears no balancing wires. The charger is a simple plug.
How are these packs charged and balanced?
Emotion.JPG
cdb0ewm
 
Posts: 156
Joined: 23 Jun 2013, 23:44

Re: Lithium E-Motion Charging

Postby Burgerman » 01 Aug 2022, 17:20

Either those are not lithium, and are metal hydride, or you opened the wrong end. Well you opened the wrong end either way.

If they are lithium then the balance board which is the BMS that balances these will be at the opposite end.

Looks like 7S lithium 18650 cells or 21700 ones by the connections, and so 29.4V charge.
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: Lithium E-Motion Charging

Postby wheelinghome » 01 Aug 2022, 17:30

cdb0ewm wrote:One of my issues with the lithium battery packs is the need for balancing. I had the chance to open up an E-Motion wheel's battery pack which has 21 small lithium batteries and what appears no balancing wires. The charger is a simple plug.
How are these packs charged and balanced?
Emotion.JPG


which version of the e-motions is that? M15 or M25?
wheelinghome
 
Posts: 44
Joined: 17 Mar 2016, 18:54

Re: Lithium E-Motion Charging

Postby cdb0ewm » 01 Aug 2022, 18:17

These are M15, The bottom has very similar busbars as the top.
The charger only has a 24v positive and negative input
cdb0ewm
 
Posts: 156
Joined: 23 Jun 2013, 23:44

Re: Lithium E-Motion Charging

Postby Burgerman » 01 Aug 2022, 18:40

Somewhere there is a BMS that controls max cell voltage (to balance the pack)
If theres really no BMS circuit there then they are using so called "safe" cells. These have the BMS inside each cell. One per cell.

Like this.
Image

Generally a bad idea as these are unreliable, and cant take much current either. I very much doubt any manufacturer would use those. And it takes up space reducing capacity. And so a simple BMS board will probably be hidden in there somewhere that you are not seeing. They are small.
User avatar
Burgerman
Site Admin
 
Posts: 65050
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: Lithium E-Motion Charging

Postby shirley_hkg » 02 Aug 2022, 04:45

Burgerman wrote:Either those are not lithium, and are metal hydride, or you opened the wrong end. Well you opened the wrong end either way.

If they are lithium then the balance board which is the BMS that balances these will be at the opposite end.

Looks like 7S lithium 18650 cells or 21700 ones by the connections, and so 29.4V charge.

A back view may help.

Besides, you can tell what kind of cells ther are by measuring their voltages, if they were not dead .
NiMH 1.2V
Lithium 3.65V

Yours looks a 3P7S lithium battery pack.

Those extra links are likely balance leads to PCB directly.
Attachments
20220802_113344.jpg
shirley_hkg
 
Posts: 3918
Joined: 31 Dec 2010, 13:42


Return to Everything Powerchair

Who is online

Users browsing this forum: No registered users and 267 guests

cron

 

  eXTReMe Tracker