BMSBATTERY kit - Battery to Controller question

dabeindan

1 mW
Joined
Oct 27, 2012
Messages
16
Location
Chicago, IL
Greeting everyone, just received my kit from BMS, have it spread all over my living room trying to make sense of wiring, connectors, etc. Looks like I am missing some small wiring pieces so hoping to get some confirmations here before I fry the components.

The KU93 controller power wiring has 3 wires, thick red (+), thick black (-), thin red (switch). View attachment 1
The battery end has only two poles, marked "+" and "-". Battery and lock view 1.jpg
The key lock is just a mechanical lock for securing the battery, does not have an electrical switch. There is a switch on the other end of the battery (on/off), but no exposed wiring..

---------------------Below is their descriptions of the controller wiring-------------------
Power wire (3P Plug)
Red: Power Anodic; Black: Cathodal; Red(small Connect Red to Red(small wire): power on.
Disconnect Red to Red(small wire): power off.
--------------------------------------------------------------------------------------

So the question is, do I:
1) Connect controller thick red wire to battery "+", and then thick black to "-" and leave the thin red disconnected?
2) Same as 1 but also connect the controller thin red to the battery "+"?
3) Or do I have this all wrong.
my very first attempt, sorry for the newbie question. thanks in advance for all the help.

Laurent.
 
this is kinda tricky for newbies to understand, but the controller has two different paths for the current to flow through. the big red wire supplies the current to the mosfets that goes on to the motor. the thin red wire supplies the current to the electronic circuits inside the controller that turn the mosfets on and off.

when you wire it up, you connect the big red wire to the battery directly, and you put the switch for the circuit current in the thin red wire. when the switch is off, then the mosfets will not work and they are effectively turned off even when the big red wire is still connected. so that is how the controller is activated, by turning on and off the switch in the thin red wire.

in most controllers, when the circuit current is turned off, there is no current drain from the battery. in some controllers they have started using small drain down resistors across the capacitors on the inputs to the mosfets. these resistors will drain the battery down if the large red wire is left connected even when the circuit current is off.

i am not familiar with that controller, but i bet someone here will know if it has the drain down resistors if they have one.
 
Good answer, but if that was a bit much to understand fully,

Yes, connect the little red wire to the battery +. Without it it won't run the bike. Many just use the plug from the battery to the controller as a switch. When you connect the battery, the caps in the controler cause a rather suprising spark. This is normal, but it can damage the connectors, particularly the cheaper types.

But leaving the battery connected can cause much worse damage to the battery if not charged and ridden daily.
 
If you got your whole kit from BMSBatttery, then hopefully you have a throttle with a red switch on it, If so, you have 6 wires from the throttle: 3 work the throttle; two the switch; one the LEDs. There's two joined together (green and brown IIRC). You join them to the thin red one from the controller however you like. The other one (yellow) you connect to anywhere that has battery voltage like the thick red one.

Wired like this, the red switch will work as a standby switch for the controller and the LEDs will come on when you activate the controller. When the controller's on standby, it still uses a bit of current, so only leave it like that for a ferw hours. Disconnect the battery if you want to leave it for more than 12 hours.

The two wires from the battery go to the thick red and black wires on that three-way connector on the controller. They usually supply the matching connector in the bag of wheel nuts.

Could you provide some links to your battery and motor, then we'll be able to check that everything is OK? It worries me a bit when I see that 22amp controller and what looks like a 10aH battery. Don't use that controller with a Q100 motor or it'll smoke within about 5 miles.
 
Dnmun, Dogman and d8veh. Thank you for your help and directions. It’s making sense now. I did it two ways and both worked.
1) With a simple throttle, three wires, no LED or switch, I combined the controller thin red and thick red to the battery red.
2) 2nd throttle with battery level LEDs and a red switch, in addition to three wire throttle connector I connected the brown/green to the controller thin red and yellow to thick red enabled the both the LEDs and allowed the switch to turn on/off the system.
This is just a bench hookup, and the connectors supplied are far from ideal. I plan on ordering some Anderson power poles to improve some key connections and post pics when I do the final install.

Below are the links to the controller, battery and motor. This came as a kit so I sure hope they are compatible. Thanks for looking out.
http://www.bmsbattery.com/controller/363-universal-brushless-hub-motor-controller.html
http://www.bmsbattery.com/36v/466-24v-lithium-ion-little-frog-abs-shell-ebike-battery-pack.html
http://www.bmsbattery.com/front-driving/349-bafang-350watts500watts-bpm-motor-e-bike-kit.html
 
dabeindan said:
Below are the links to the controller, battery and motor. This came as a kit so I sure hope they are compatible. Thanks for looking out.
http://www.bmsbattery.com/controller/363-universal-brushless-hub-motor-controller.html
http://www.bmsbattery.com/36v/466-24v-lithium-ion-little-frog-abs-shell-ebike-battery-pack.html
http://www.bmsbattery.com/front-driving/349-bafang-350watts500watts-bpm-motor-e-bike-kit.html

That setup should be OK. A more powerful battery would have beeen better, but then installation gets more complicated.
What forks are you going to put the motor in? You have to be careful with alumininium/magnesium ones that the washer fits neatly in the dimples before tightening the nuts. That normally means that you need the eccentric "C" washers from Ebikes.ca or you need to deepen the drop-outs by about 2.5mmto re-centralise the axle. You need at least one decent torque arm. There's not enough thread to put a ready-made one on the non-wire side IIRC. If you have steel forks, it's no problem.
 
Back
Top