Polaris Vector eBike battery rebuild

[2fast2green]

Hi guys
I have an eBike Polaris Vector, 2012 version not working due to a dead battery. I opened the battery and I found the BMS totally "cooked" ! The cells also are in bad condition.
The original battery is a 29,6 8S 6A lithium. I'd like to rebuild the battery with Sony Konion VTC4 2100 mAh 3,6 V, with an 8S5P configuration, 40 cells, I have a 28,8V 10.5Ah, probably the controller works fine also with nominal 0,8V less <> the original one.



The problem is the battery connector, it have 2 bigger connector for positive and negative, and 4 more little connectors, I don't know their function. Probably two are a battery-in-frame check, but the other 2 ? temperature sensor ? regen on/off ?

Two questions :

- the bike has a regen function, I need a special BMS to manage the current coming back to the battery ? I can disable this funcion cause I check it and the Wh coming back to the battery are near nothing !
- how I can manage the 4 little connector ?

Thank for your help.

 

[mangoboy7]

Hi,

I've got the same problem as you. I'm having to rebuild a dead battery for my Polaris Vector. I'd like to ask if you could take pictures of the final battery build.

To answer your question, I referenced the eBike posting here: http://www.ebikeschool.com/how-to-build-a-diy-electric-bicycle-lithium-battery-from-18650-cells/
It looks like the 4 little connectors are part of the BMS that manages the balance of the charge every time you plug it in. Thats just an educated guess. You should take close up pictures of the specific wires in question as well as the board so everyone can see where it's plugged into.

Also, someone can correct me if i'm wrong but I don't believe you can utilize 40 18650's. You're going to end up with a voltage much higher than what the current motor is built for. My math for that is as follows
Sony Konion 3.6v * 40 = 144volts
I think you're only going to be able to use 8 18650
3.6v * 8 = 28.8

I"m new to this stuff so feel free to correct me where i'm wrong.

 

[BikeFanatic]

I am also looking at a used polaris , any chance you could post a few more closeups of the batteries and connections? I was thinking of trying LIPO replacement battery.

 

[amberwolf]

Sony Konion 3.6v * 40 = 144volts
I think you're only going to be able to use 8 18650
3.6v * 8 = 28.8

How about 5 parallel strings of 8 series cells?

 

[2fast2green]

Hi guys
i confirm you i'm projecting on a 5P8S, finally i'll have 28,8V instead of the original battery 29,6V, but I don't think it could be a problem for the controller.

However I'd like to share with you an idea. The Polaris Bike has the regen cability, we notice tha the battery "dead" everytime in regen status.

Probably I'l disble this funtion

I'll post the photos later

 

[2fast2green]

My first solution : i changed the bms with a better one, i equalized the original cells and i disconneted the unknown 4 Pins. I tryied ed everything works fine. Tomorrow i'll try to recell with the konion cells.

 

[mangoboy7]

Sony Konion 3.6v * 40 = 144volts
I think you're only going to be able to use 8 18650
3.6v * 8 = 28.8

How about 5 parallel strings of 8 series cells?

i'm newb and I called it. Thanks for the correction.

 

[mangoboy7]

My first solution : i changed the bms with a better one, i equalized the original cells and i disconneted the unknown 4 Pins. I tryied ed everything works fine. Tomorrow i'll try to recell with the konion cells.

can you take pics of assembly and note the steps you took to get this done? PLEASE :lol:

 

[jazz]

I am also interested in the steps for rebuild. Thanks

 

[mangoboy7]

My first solution : i changed the bms with a better one, i equalized the original cells and i disconneted the unknown 4 Pins. I tryied ed everything works fine. Tomorrow i'll try to recell with the konion cells.

Hey @2fast2green, any updates? I'd love to hear how this project went. Close ups of the new set up, including the wiring of your new BMS would be great. PLEASE help us polaris vector owners out. Thanks.

 

[Muramura]

Hey,

I would really appreciate it, if you told us how you replaced the battery system with 18650. And it would really help us Polaris guys getting off our horrible battery packs for ones that would actually do something.

Just at least give us the bare minium of what parts you bought and how you connected them and what you did you make sure it didnt go boom boom hahah

Thanks hope to hear from you.