BMS Battery controller, battery and Bafang motor

[ThomoT]

Hi All,

I recently purchased the following from BMS BAttery:
12 MOSFETS Controller 48V
Bafang 350W 48V BPM Permanent Magnet Brushless High Speed Motor
EV-4810LF-05 48V/10Ah LiFePO4 Pack
Throttle.

Does anyone have any experience with these products? They came with a cable to connect the battery to the controller. Everything plugs together well. I'm running with just those four items connected, no hall sensors.

I am having some problems and would appreciate some help. Full details are below. If you can suggest anything that would be helpful, I am all ears!

I have the motor in a wheel and hooked up the battery and controller. I turned the key on the battery, turned the throttle and I get nothing. After fiddling for a bit I finally got the motor to spin but when I turned it off and on again, nothing happened again.

I initially thought this was to do with sensorless motor, so I spun the wheel to see if that would work. It didn't.

Eventually I figured out that I could get it to work consistently if I had the key on the battery "on" and the hot plugged the battery to the controller. Motor spins no worries. So this appears to be either the controller doing something to the battery to stop it working or vice versa.

The controller and battery have three wires for power: Gnd, +V and power key on/off lock. http://www.ecitypower.com/pdf/912Mosfet.pdf

I checked the voltage on the battery when I turned the key without the controller and it gives me 53V. Pretty normal.

I checked it with the controller and it goes up to about 20V then down to ~11V within a second.

When I hot plug the battery, the controller gets 53V and it works fine.

It is as if the controller is stopping the battery from delivering what it should. Maybe it is that key on/off wire? So tonight I disconnected that wire to see what happens. The battery got its 53V but it didn't do anything. So I think it needs the wire!

 

[bzhwindtalker]

I have a similar issue with mine when starting with voltages greater than about 38v, but not on the power supply! (?)
I found that plugging a small wire with a big 5ohm resistor in parallel before plugging the positive makes it ok! It also reduces arcing on the connectors. then you can unplug it some seconds after. I will try to put it on the switch to see if it makes any difference. I think i tossed my first controller from them due of this issue :/

 

[ThomoT]

Hi, Thanks for the feedback. Are you saying you put a 5 Ohm resistor in series with the +V or the key on/off wire? Any idea how this helps? I suspect a delay might help.

 

[liteCycles]

I think the sensorless controller may be in programming mode. It is automatically cycling thru the various modes. Since it now spins by its self at a slow speed it has identified your motor. Unclip the grey looped wire coming out of your controller and you should be good to go.

 

[Hyena]

I think the sensorless controller may be in programming mode. It is automatically cycling thru the various modes.

Where did you hear about this with the bmsbattery controllers ? I haven't heard of it...

 

[GrayKard]

I think the sensorless controller may be in programming mode. It is automatically cycling thru the various modes.

Where did you hear about this with the bmsbattery controllers ? I haven't heard of it...

I read the same thing here: http://endless-sphere.com/forums/viewtopic.php?f=4&t=13659

Here's an the relevant section from the first post:

I mounted the controller on the handlebars of my Raleigh bike in place of a small 36V/15A controller. The bike has a 24V GoldenMotor Mini Motor that I've been running on 36V. I first tried to get the motor to run with just the 3 phase power wires connected but it was a no-go. In two configurations the motor sounded like it was running smooth but the wheel wasn't moving so I assume it was turning backwards, the other 4 combinations produced a hammering affect. I figured it wasn't gonna work so I connected up the hall sensor cable which didn't work properly at first. I ended up swapping the green and yellow wires on both the phase wires and in the hall connector to get it running smoothly. After it was running I did find I could yank the hall cable and it would continue to run, kinda cool I guess, but after cycling power it hammered again.

OK so I figured the thing wouldn't work sensorless , not a huge deal, but then things got a bit confusing. I connected the two white wires together to check what I thought was a speed suppressor function and the wheel started spinning, then it stopped tuning but the motor sounded like it was spinning backwards. The best I can figure is the white wires put it into some sort of program mode where the controller tries different combinations. Instructions would have been really helpful at this point but basically what i did was cycle power and hook up the white wires and when it spun forward slowly but smoothly I disconnected the white wires. After this I found I could run sensorless at all times however it takes a lighter touch on the throttle from a dead stop to prevent the hammering effect. So it does appear that this controller works both with and without hall sensors but it does work better with the sensors. With the hall sensor cable connector I could yank the throttle as fast as I wanted and the motor reacted smoothly.

Others have thought this was just a reversing wire. Not sure which it is but I have the 9 fet controllers and I did not have to try a bunch of phase wire combos I just hooked them up matching the color and then hooked up the white wires and it spun in reverse. I disconnected the white wires, cycled the power and hooked them back up and it went slowly forward. Disconnected the white wire again and I had normal direction with full speed control.

I guess it would take some tests with different phase wire combos to see if it was really programming or just reversing.

Gary

 

[Hyena]

Interesting... I just plugged my 12 fet in and rode off!