48V500W Rear Driving BikeConversion Kit

[docw009]

Looks like water got in there. You will need a 13S BMS with an on/off switch, with the same current rating as your battery. Probably 25A? And it needs to fit inside the case. Also, a balance BMS is better in my opinion,

This might fit, but it's not a balance BMS and it's only 15A.
https://www.aliexpress.com/item/32858872545.html?spm=a2g0o.productlist.0.0.643998c31Cv0rd&algo_pvid=7cd50bd9-b4de-422d-ada2-a679b7552b38&algo_expid=7cd50bd9-b4de-422d-ada2-a679b7552b38-11&btsid=63407ef2-60f9-46e0-b67f-46f2884c7944&ws_ab_test=searchweb0_0,searchweb201602_1,searchweb201603_53

This is a 25A balamce BMS, but it probably won't fit, and the cable may not match.
https://www.aliexpress.com/item/32995469828.html?spm=a2g0o.productlist.0.0.643998c31Cv0rd&algo_pvid=2462992e-b14c-4596-a0d0-d6c6becdc408&algo_expid=2462992e-b14c-4596-a0d0-d6c6becdc408-12&btsid=8a506803-d500-453b-833d-5ad823eb15ec&ws_ab_test=searchweb0_0,searchweb201602_1,searchweb201603_53

Looks like a metal rail on the left that is constraining the size of your BMS in your picture. If the BMS can sit on top, then you have a lot more freedom of choice.

Unless you are very fortunate, the balance cable will either be a different size header or they will reverse the wire order. If you're willing to resolder the 13 wires in the balance cable, there will be more choices,

Perhaps the battery vendor will sell you a new BMS.

 

[billi]

OK thanks

But

Looks like water got in there.

, the battery was never used , and not outdoors since i have it ....

Well i guess i just pay or get a replacement BMS and hope it will not blow again

 

[docw009]

A closer look and now it looks like a MOSFET overheated. Maybe there was a short circuit that you didn't notice.

 

[torker]

Since he mentions a noise when using the switch. Is it possible the switch shorted?

Actually looks like that large white wire was laying across the leg of the fet.

 

[billi]

Hello ,
Has been a while ago since posted
I bought one of those Rad bikes start of March and ride through the troubled times 1500 miles so far

But back to my battery problem and my other bike

I assume the cells are ok ,
The seller of the battery tells me that their or this BMS will do https://bmsbattery.com/bmspcm/835-16901-7s-10s-13s-lithium-ion-mini-bms-20amps-without-balancing.html#/110-cells_in_series-13
I guess the 12 white and one red plug on my burnt on will fit this one
But the black one on the new one does what ?
As well on top of my one there are 2 thick ones attached to burnt BMS
These i assume are the Plus and Minus of the whole bank
[imghttps://endless-sphere.com/forums/download/file.php?id=266763img]
Sorry i did not manage to insert the picture from 1. page
Can you guys advice me how to keep that simple , and what that black cable does ?

Thanks

 

[docw009]

Is that the same BMS that came with the battery? Good, if it is, then it will be easy to connect. You will have to re-attach the three wires on the old BMS, and the wires for the on/off switch. Verifiy it's the same model circuit board and replace like for like on the wires. Plug in the 13 pin connector last. The BMS is not activated til that happens.

-You will have the same 13 pin connector.
-There will be two paired wires for the ON-OFF switch.
-One wire, usually marked B- goes to the negative terminal of the battery cells.
-One wire, usually marked C- goes to the negative pin of the charge plug.
-One wire, usually marked P- goes to the negative pin of the battery output.

 

[amberwolf]

I assume the cells are ok

While this is likely based on the previous posts in the thread, you should still measure between each of the wires from cells to BMS, to ensure they are all about the same voltage, and none of them are too high or too low.

The seller of the battery tells me that their or this BMS will do https://bmsbattery.com/bmspcm/835-16901-7s-10s-13s-lithium-ion-mini-bms-20amps-without-balancing.html#/110-cells_in_series-13

If your battery is, as it appears, to be 13 groups of cells in series, then yes, it should work. It looks very similar to your existing BMS, so the connector you already ahve for the balance wires may fit without modification or replacement. It is a 20A BMS, so should handle the 500w your 48v system needs, up to 1000w peaks, wihtout overheating and blowing up the FETs (which looks like what happened to your original).

There is one spec it doesn't state a value for, though:

Balancing Current - each cell

While it's not terribly important, it does affect how long it takes to fix any imbalance that occurs. So if they'll tell you what it is, it would be nice to know for the future. 20mA to 50mA is common (but pretty slow...higher is better).

 

[billi]

Thanks doc
I thought there are only 2 , but ok had a closer look on the pic , you mean the 3 fat black ones ( on is a bit burnt )

Good, if it is, then it will be easy to connect. You will have to re-attach the three wires on the old BMS, and the wires for the on/off switch.

-You will have the same 13 pin connector.
-There will be two paired wires for the ON-OFF switch.
-One wire, usually marked B- goes to the negative terminal of the battery cells.
-One wire, usually marked C- goes to the negative pin of the charge plug.
-One wire, usually marked P- goes to the negative pin of the battery output.

Well the 13 pin one is clear
then on my old BMS are two white wires soldered onto the BMS , should be the ON-OFF switch
and a paired black one ( seems that is attacked on the new BMS already

So the A,B,C ones you refer to, are the the three fat ones on the top end ?

Thanks doc

 

[billi]

Thanks Mr Wolf

I assume the cells are ok

While this is likely based on the previous posts in the thread, you should still measure between each of the wires from cells to BMS, to ensure they are all about the same voltage, and none of them are too high or too low.

Yeah i have to order a Multimeter , mine got lost
So you mean each of the 13 cables attached to one probe of the meter and the other probe where ? Or you mean between each of the six pairs of white wires ( guess i remember thats the way from a vid i saw )

Ok i will ask them when i order

Thanks