IBT_2 BTS7960 Motor Driver Review - Avoid
Posted: 31 Aug 2020, 02:49
The IBT_2 BTS7960 is a very affordable motor driver which claims to support up to an impressive 43A over a wide voltage. It can be controlled via 3.3V logic so it looked an ideal match with the ESP8266 or ESP32. However all is not as it seems.
Looking at the design of the board, the heat sink and the terminals I never thought it would be able to handle 43A, but I was only looking to handle 20A to 25A. However even this is well beyond what the IBT_2 board could handle. The issue isn't the BTS7960 controller chips as they seem to have all the features you would desire with over current, over temperature, under voltage and short circuit protection. However it was this high level of protection on the BTS7960 that lulled me into a false sense of safety. I thought that if the heat wasn't properly dissipated by the heat sink then the BTS7960 would just shut down. This might be the case, but designed caused other problems prior to the BTS7960 shutting down.
Only after my unit failed did I find out that the IBT_2 board had many design issues. The killer problem in my situation was the lack of a direct physical and thermal connection between the BTS7960 chips and the heat sink. Yes that is right the heat from the BTS7960 has to transfer through the PCB to the heat sink. Not knowing this I had setup a temperature probe on the heat sink to see if the IBT_2 appeared to getting too hot. Well the design of the IBT_2 attempting to transfer the heat through the PCB was my down fall. I had planned to place an additional heat sink directly on top of the BTS7960, but the heat sink I planned to use wasn't being cooperative, so I put that a side for the moment. I after running the IBT_2 for several times with more than 5 minutes testing in each cycle, I noticed that the electrolytic capacitor on the motor power input look to have swollen on top slightly. I wasn't sure if this was really the case, so I left it. The heat sink temperature was running below 60C, so I thought it was all running well within parameters. I think let the set up run for a couple of hours....
On my return to the set up I found there was no current flowing to the load. I also found the electrolytic capacity had an out of body experience. At first I thought there might have been a problem with the motor power supply I was using, but I doubt this was the problem. It certainly wouldn't have been too high a voltage as it only had a 9V DC output.
After doing some testing of the IBT_2 board I found that the half of the H bridge that was active was dead, but the other half still worked. It was at this point that I found the review on Amazon for the IBT_2 BTS7960 motor driver board with the explanation of the heat sink design fault. This review also points out several other major design or manufacturing problems with the IBT_2 board that are leading to boards being short circuited when leaving the factor. It might be just me, but I think the suggested solutions are a bit too much of an effort to rectify the IBT_2 if you are intending to purchase the board. If you have already purchased the board, then that is up to you.
I still think the concept of this motor controller is a great idea and the BTS7960 chips seem to be good. The problem is the implementation. I have seen another BTS7960 motor driver board on Aliexpress, but it also lacks sufficiently large terminals. It doesn't come with a heat sink and the layout would make it difficult to place a sufficiently large heat sink in the correct location.
Looking at the design of the board, the heat sink and the terminals I never thought it would be able to handle 43A, but I was only looking to handle 20A to 25A. However even this is well beyond what the IBT_2 board could handle. The issue isn't the BTS7960 controller chips as they seem to have all the features you would desire with over current, over temperature, under voltage and short circuit protection. However it was this high level of protection on the BTS7960 that lulled me into a false sense of safety. I thought that if the heat wasn't properly dissipated by the heat sink then the BTS7960 would just shut down. This might be the case, but designed caused other problems prior to the BTS7960 shutting down.
Only after my unit failed did I find out that the IBT_2 board had many design issues. The killer problem in my situation was the lack of a direct physical and thermal connection between the BTS7960 chips and the heat sink. Yes that is right the heat from the BTS7960 has to transfer through the PCB to the heat sink. Not knowing this I had setup a temperature probe on the heat sink to see if the IBT_2 appeared to getting too hot. Well the design of the IBT_2 attempting to transfer the heat through the PCB was my down fall. I had planned to place an additional heat sink directly on top of the BTS7960, but the heat sink I planned to use wasn't being cooperative, so I put that a side for the moment. I after running the IBT_2 for several times with more than 5 minutes testing in each cycle, I noticed that the electrolytic capacitor on the motor power input look to have swollen on top slightly. I wasn't sure if this was really the case, so I left it. The heat sink temperature was running below 60C, so I thought it was all running well within parameters. I think let the set up run for a couple of hours....
On my return to the set up I found there was no current flowing to the load. I also found the electrolytic capacity had an out of body experience. At first I thought there might have been a problem with the motor power supply I was using, but I doubt this was the problem. It certainly wouldn't have been too high a voltage as it only had a 9V DC output.
After doing some testing of the IBT_2 board I found that the half of the H bridge that was active was dead, but the other half still worked. It was at this point that I found the review on Amazon for the IBT_2 BTS7960 motor driver board with the explanation of the heat sink design fault. This review also points out several other major design or manufacturing problems with the IBT_2 board that are leading to boards being short circuited when leaving the factor. It might be just me, but I think the suggested solutions are a bit too much of an effort to rectify the IBT_2 if you are intending to purchase the board. If you have already purchased the board, then that is up to you.
I still think the concept of this motor controller is a great idea and the BTS7960 chips seem to be good. The problem is the implementation. I have seen another BTS7960 motor driver board on Aliexpress, but it also lacks sufficiently large terminals. It doesn't come with a heat sink and the layout would make it difficult to place a sufficiently large heat sink in the correct location.