Troubleshooting MiniPro BMS?

[dex]

Hello Everyone!

I recently bought a used Segway MiniPro, it my first device like this, and it had very low miles on it, so I figured it worked well.

I've ridden it a bit now, but have found a defect with the unit - it keeps loosing communication to the BMS. I'll get one red LED lit up on the back of the MiniPro, and the BMC information in the app will not show. 

If I hit the battery I can sometimes get it to work (red light will go out, and I'll be able to get top speed again), but more often than not the BMS isn't communicating, and I am speed limited.

I've taken the battery off the MiniPro and double checked the connections between the battery and main board, and they all look good. The main board itself looks to be in very good condition.

I was wondering if anyone has any suggestions or further troubleshooting tips I could do to get this to work.. Running at the limited speed is very annoying!

Thank you for your help!

[FreeRide]

Did you try contact cleaner on the battery connector both sides even though they look clean?  Someone may have tried to clean them with something in appropriate.  use a magnifier on the board where the connector is you may be able to see a hairline crack, you may need to remove the board and look on the other side.  Of course the fault may be in the battery. Not familiar with the - one red light on the back error condition.  

[dex]

1 hour ago, FreeRide said:

Did you try contact cleaner on the battery connector both sides even though they look clean?  Someone may have tried to clean them with something in appropriate.  use a magnifier on the board where the connector is you may be able to see a hairline crack, you may need to remove the board and look on the other side.  Of course the fault may be in the battery. Not familiar with the - one red light on the back error condition.  

Thanks for the suggestions. I did use contact cleaner to clean out the battery contacts on both the battery and main board. I did pull the main board out to check the solder joints at the battery connector, didn't see anything out of the normal there..

Apparently when the MiniPro loses communication with the BMS, it will light one of the red LED's in the tail light (if i recall, its the second from the left LED).

I should also mention that when I pull the battery, I'm getting a green flashing LED on the battery pack.

My concern is that maybe there is a bad connector/connection inside the battery pack.. I really don't want to have to pull that apart..

[FreeRide]

Green on the battery is good, means it's at a good charge level. Of course pulling the battery could have fixed it.  If you never have an issue charging it sounds likely so far the problem is in the mini. 
All the cables routed nice, no way for the battery to put any pressure on the board when mounted? 
too bad you don't have a battery to swap to isolate which side the issue is on. Controller use to be available for around $100,  Not sure how easy they are to get now. 
maybe someone will have more details on where to look. 

[dex]

6 hours ago, FreeRide said:

Green on the battery is good, means it's at a good charge level. Of course pulling the battery could have fixed it.  If you never have an issue charging it sounds likely so far the problem is in the mini. 
All the cables routed nice, no way for the battery to put any pressure on the board when mounted? 
too bad you don't have a battery to swap to isolate which side the issue is on. Controller use to be available for around $100,  Not sure how easy they are to get now. 
maybe someone will have more details on where to look. 

The battery seems fine - it charges OK as far as I can tell. When I took it off the mini, all the cabling looked nice and tucked away where it should be.

I agree - I wish I had a battery to swap with so I could isolate the issue to either the battery or the main board..

[Rocky Romero]

On 7/10/2020 at 10:49 AM, dex said:

The battery seems fine - it charges OK as far as I can tell. When I took it off the mini, all the cabling looked nice and tucked away where it should be.

I agree - I wish I had a battery to swap with so I could isolate the issue to either the battery or the main board..

I also bought a used MiniPro “as is”.

The battery is dead with no lights coming on.

I put a working battery on the unit and it does not respond.  So I have a dead battery and dead MiniPro for parts.

I would like to get the dead battery working again, even if I take it apart.

Anyone have thoughts on repairing a dead MiniPro battery?

 

➰

[FreeRide]

First step on dead battery is to plug it into the charger outside of the mini pro and leave it for a while, sometimes a long while.  

If no luck; Second step is to try to wake up the BMS/battery by applying a voltage or charger directly to the large battery connector, not the charge port. There is a thread on here about that, people making little leads to try and wake the battery with the mini's supply.  

I may be opening a battery soon to swap the cells, or take out the BMS, if I do I'll take pictures.  

There are some pictures of battery disassembly around on the forum somewhere.  Once open you need to measure each cell and try to either revive each one individually or replace them, until you can changer the pack and then test to see if they balance, and discharge the pack and see how far out of balance they are.

 

Edited August 10, 2020 by FreeRide

[Rocky Romero]

6 hours ago, FreeRide said:

First step on dead battery is to plug it into the charger outside of the mini pro and leave it for a while, sometimes a long while.  

If no luck; Second step is to try to wake up the BMS/battery by applying a voltage or charger directly to the large battery connector, not the charge port. There is a thread on here about that, people making little leads to try and wake the battery with the mini's supply.  

I may be opening a battery soon to swap the cells, or take out the BMS, if I do I'll take pictures.  

There are some pictures of battery disassembly around on the forum somewhere.  Once open you need to measure each cell and try to either revive each one individually or replace them, until you can changer the pack and then test to see if they balance, and discharge the pack and see how far out of balance they are.

 

Thanks for this.

I have two dead MiniPro batteries and will do the first step that you suggest.

The other steps will require research, patience, and knowledge.  I’m good for two of those three areas.

➰

[Avefenix]

Hi, I am having the exact same issue. I removed the battery pack and disassembled to check voltage of each battery cell pack and they all are good. The total output voltage is 59, but in the app it only show 76% and the speed is limited to 10 km/hr. The app doesn't display the battery information as it used to. 

Any idea of what could be the problem? 

[Nikos]

Sorry for the outdated post but i have the same issue , i've figured out that Resistors R3 and R4 ,right next to the connector, are fried and cannot read the Ohms . If someone with a healthy PCB could tell me the resistance would be great. I believe that is the issue that it won't charge beyond 79% is because the BMS does not communicate with the main board.