Is my motor/controller stuffed?

[Dreddydave]

Hi all;

So I got a new 48v, 1000w hub motor and controller from BMSBattery. Assembled on the bike and blipped the throttle, but it only spun up smoothly about a third of the time. The rest of the time it's just stone dead. It's then I noticed that the motor/halls wires from the hub were pinched at one point, so I cut them short and re-wired the plugs on. Again, it was able to spin up a couple of times but now doesn't do anything. Now for the technical:

Battery puts out 51.5v without anything connected, but then shows 12v with just the controller connected (no motor). The halls sensor/power wires coming out of the controller are 2.5v, when they should be 5v according to the circuit board. The halls sensor wires, without the motor connected, are putting out ~3.5v from the controller (?). Connecting just the 2.5v wires to power the halls and testing the sensors spinning the wheel backwards consistently shows 0v for each sensor.

Inside the motor looks ok, but I can't test the continuity of the wires because there's just too much epoxy holding it all together. Inside the controller looks ok too, but perhaps some of the capacitors could be stuffed from when the motor wires were damaged? Any ideas?

Cheers, Dave.

 

[jtdiode]

Can you explain where you are measuring the battery voltage at when you say it drops to 12 volt with the controller connected.

 

[dogman dan]

Starting to sound like the bms on the battery. If so, far from the first time.

 

[fechter]

I agree, it's not going to run with only 12v coming out of the battery.

If you can get to the BMS, try measuring the voltages on each cell wire connection. If one wire has a bad connection, it can cause the BMS to shut off the output.

 

[dnmun]

can you post up pictures of the "pinched" wires? it sounds like you may have shorted out the phase wires, but no way to know from what you said.

 

[John in CR]

What batteries are they? It sounds like dead lead batteries to me that may look like they have a charge based on voltage, but as soon as you put a load on them they can't support a load and voltage drops so low that the controller won't even work.

 

[Dreddydave]

Wow, lots of great suggestions to give me something to look into. I'll see if I can answer all the questions:

1. Measuring the battery voltage from the output of the battery connector; the same 2 wires that the controller connects to. I've just opened the plug to expose the red/black pins so I can measure the voltage while the controller's connected. 51.5v when not connected to controller, drops to 12v when connected.
2. I've opened up both the controller and motor but hadn't thought of checking inside the battery for the BMS... good suggestion. I'll have to check that out tomorrow, because I'm heading out to the pub after work tonight
3. Sorry haven't got pics right now of the pinched wires, but they were the motor power phase/phase sensor wires going between the hub and controller. The plastic sheilding was a little melty inside there, so expecting it would have shorted a bit.
4. Battery is a 48v Li-Ion NiCoMn with a 20A continuous BMS. Yeah I'm thinking the BMS may have blown when the motor phase wires shorted a bit, and now it's limiting output.

Thanks for all the help guys! I'll respond back once I've done some more testing, or if there's anything else I should clear up

 

[Dreddydave]

OK I've opened up the battery and tested the BMS. 51v input and output when there's nothing connected to the battery, but when the controller is connected to the output of the BMS the output lowers to 12v. The input to the BMS is still 51v though, so it's definitely the BMS that is lowering the voltage.

So does this mean the BMS is stuffed? Or is there a safety measure in the BMS that it's lowering the voltage because something in the controller is broken (considering it only lowers the voltage when the controller's connected)?

 

[Dreddydave]

*FIXED!*
Sorry for the triple post

Controller has 3 wires for input power, red, black and a smaller orange wire. The wiring diagram has the helpful:

"Connect Red to Orange(small wire): power on.
Disconnect Red to Orange(small wire): power off."

But neglects to mention that if you hard wire the orange to red so it's "always on", it won't actually turn on when you connect it to a battery. I'm guessing it's a controller safety measure. So it needs a switch so you can connect to the battery while off, turn on the battery, then turn on the controller. Just putting this out there to help others if they have a similar issue