Battery - connection simple question ...if you know the answer

[Simon.j.crossley]

Hi, Im working on a repair for a Kakhoff that had a dead battery but a little stuck and my ebike knowledge is pretty poor.

My battery experience is limited to small stuff for high power mtb lights.

Anyway could someone offer help and explain what the connections are from the OEM battery below: I got the plus and neg but lost on what the C , D & R are meant to connect to / what their porpoise is.

I stripped the old BMS out of the battery as it was faultily and pulling current when the battery was off the bike to the point where after restoring the battery using a hobby charger it was hot to the touch after 1/2 hr.

The cells have been tested and seem to be ok, with no heat produced during discharge or charge, my issue is I have a BMS (Chinese), but the connection to the bike via the 5 pin socket isn’t there on the BMS.

I don’t mind if the bike doesn’t get the info but I would like to use the OEM charger with it, Im unsure what the 3rd pin on the charge should be connected to and what it is communicating to the charger.

Any pointers would be great


s

 

[Nealh]

The board you show is part of a closed system and involves hand shaking protocols, so changing the BMS for a generic China one will not likely work with controller/motor combo & display. Five wire battery connections usually means bad news.
C = could be charge.
D = could be discharge.
R = unknown.
The three wires are thin so are sensing wires and likely part of the comms/hand shaking between the original BMS /controller & display.

C & D being Yellow & Green may also be Tx/Rx comms signals.

 

[Simon.j.crossley]

Thats a good shout, I tried the battery in the bike without BMS and found it functioned ok but no capacity information on the display. That would Without the origanal BMS Im unlikely to find out but as it functions its not a big problem, especailly as it was cheap and a bit of fun to see if I could get it to work.

Just need to get the OEM charger to work with the new BMS now, Still unsue what the "third" wire is on the charger.

 

[wheeliepete]

Just need to get the OEM charger to work with the new BMS now, Still unsue what the "third" wire is on the charger.

You will prob. find the OEM charger will not switch on charge voltage/current because it needs a signal which the new BMS has no function to do so, but good luck with a work around.

 

[cyclebuddy]

Third wire is likely hand-shaking as suggested (to ensure you have the correct charger connected), or else it's likely to be a thermal trip (to shut down the charger if the cells over-heat whilst charging). My own charger uses both.