Battery has 3 wires but controller has only 2 connectors...

[g1nko]

I have a 36v LiFePO4 battery with 2 red V+ wires and 1 black ground wire. I want to use an Infineon controller, but it only has 1 red V+ connector and 1 black ground connector on it.

Is there a way to make this compatible, or are the two just inherently not going to work together?

 

[wesnewell]

Ground wire would be common. One red wire is the discharge wire and the other is one is probably a charge wire. The largest wire would be the discharge wire. To be sure, you'd need to post a picture of where they connect to the battery/bms.

 

[g1nko]

I opened the battery case. There are two wires from the battery to the connector at the top of the photo that go to the controller. It's the connector from outside the case to the controller that splits into three wires:

http://imgur.com/iBcJmbv
http://imgur.com/TLl6TJn

 

[g1nko]

Answered my own question. I put a multimeter on the outside connection where the black/red are connected and it's coming out hot at 40 VDC.

I don't know why they split the red coming out to the chinese controller that came with the battery, but clearly I can rewire that and put a two-pole Anderson connector on it for the Infineon controller.

 

[d8veh]

They've done it like that because some controllers have an ignition wire that needs to be connected to the second red wire. The ignition wire is sometimes referred to as the "lock" wire, "key" wire or anything else. Does yours have one?

 

[g1nko]

I split back the shrink wrap on the wire that connects the battery to the controller. There's a single red wire coming out of the plug to which two red wires are soldered. Those are the two that connect to the controller that came with the battery.

There's no lock or switch on the controller itself, but the controller that came with the battery clearly needs the second red wire. There's a lock/ignition on the battery, but that's all internal: lock off = no juice out of battery; lock on = juice.

Since I'm not using the "free" controller, but replacing it with a 2-wire Infineon controller, I think I'm OK just rewiring the pigtail that comes out of the battery to the controller from 3-wire to 2-wire.

 

[wesnewell]

Pretty much all controllers have the capability of an "ignition" wire. On some it's red, on others it may be another color, and on some it may not even be hooked up. Depends on who wired the controller. On the infenion controller I had (EB215) the ignition wires was a pair that ran to the on/off button on the throttle.