Votol EM150-SP controller short circuit?

[MaartenZonneveld]

Hi, I am new on this forum and was not able to read all the Votol controller related items (did a scan though but could not find related item).
I have a problem when connecting my Votol EM150-SP (with CAN) to my battery of 72V (also when QS-motor is not connected). It looks like a too large current is drawn from the battery and as a consequence the BMS of the Battery (self build 20S battery with 40A BMS) goes into discharge protection and switches off the power. I contacted QS motors for advice and they only could advise me to read out the controller software settings to check if that is correct. Unfortunately the connection with the controller can only be established when controller is connected to 72V supply (which is not working due to the described problem... ).

Potential problems I can think of:
- Problem is caused by battery/BMS (is 40A version large enough or should I have used larger one (60A)?
- Problem is caused by controller (short circuit, controller settings)?
- ......?

Both potential problems can be solved by ordering new stuff of course, but I am wondering of any of you have experienced the same or have an idea how to solve ??

Thanks in advance for your help!!

 

[j bjork]

I think your bms is waay to small if you want to use something like what the controller is capable of. However, it should defenetly be enogh when you dont even have the motor connected.

Are you sure you get a decent output from the bms, can you test with another load?
If it is a problem with the battery for example, it could shut down because of that.

I dont understand if you found the votol EM150 or not, but here it is:
https://endless-sphere.com/forums/viewtopic.php?f=7&t=95969

 

[MaartenZonneveld]

Thanks for quick reply!

I did some tests with the battery indeed, connected a 'building lamp' of 1000 watts (220V, so less for 72 Volts), which worked fine.

I was also surprised that when connecting the Controller (without motor connected) to the battery significant sparks occur in the battery cable connector (which indicate high current and in the mean time shows damage on the connector surfaces after multiple attempts to connect). Would have expected low current needed when only connecting the controller...

Do you know if controller settings could influence inrush currents (this was the suggestion of the QS motor support team)?

I will do some additional power tests with the battery tonight to confirm!

 

[j bjork]

Well, you have capacitors in the controller that draw high current when you first connect it. But that should be done in under a second. So if you try once and get a spark, then if you try again right away there should no spark.

When the controller is turned off, there should be almost no draw except that initial spark.

 

[MaartenZonneveld]

Hi Bjork
Thanks very much for this suggestion, I tried and indeed the controller stays connected the second time .
Based on your feedback my assumption would be that the BMS I have is too small for the inrush current and goes into discharge protection. So I will go for the simple solution, I just ordered a 80Amps BMS to replace the current one (40 Amps) and for the time being (till I have the new one) I will follow your suggestion and reconnect quickly when BMS protection switches off to temporarily overcome this issue.

Thanks again and

Will keep you posted on progress...