2021-04-23, 07:34 PM
Just few words to add to Sean and IronMan comments.
The IBT2 may be a frustrating experience with bad parts, incomplete soldering, missing components (I have one with missing resistors). On my side, I wanted to test the concept, code compatibility and the drivers behaviors with an oscilloscope. My main concern after these tests is heat dissipation :
- I am not certain that the board design follows the BTS7960 manufacturer recommendations in term of heat transfer (lateral heat transfer through PCB tracks)
- The implementation of the radiator on the back of the PCB is by no means enough to transfer heat properly and thermal conductive paste might not be sufficient either at high/continuous current. The reason, at least for the boards I have tested, is the lack of heat transfer through the PCB. A possibility is to increase the amount of solder of the through holes ; I have undertaken the mod for the sake of understanding but it is not very satisfactory in term of design. I may be able to complete observations with IR camera during next weeks but I suspect it will not pass the tests.
I have no ideas about long term reliability (especially with thermal stressing).
Regarding safety, the BTS7960 has a thermal safety control and will shutdown if temperature is too high. The datasheet is rather explicit on the consequence in term of component lifetime reduction should repetitive thermal shutdown occurs. It may advisable to apply the controller thermal sensor (ADC pin 2) directly on one of the BTS7960 rather than on the radiator...
All in all, it may be acceptable as a low cost solution for modest currents (I have tested up to 6A continuous so far) and with some understanding of the necessary checks and modifications to the board and peripherals. Having spare will certainly make sense...
Best regards,
Xavier.
The IBT2 may be a frustrating experience with bad parts, incomplete soldering, missing components (I have one with missing resistors). On my side, I wanted to test the concept, code compatibility and the drivers behaviors with an oscilloscope. My main concern after these tests is heat dissipation :
- I am not certain that the board design follows the BTS7960 manufacturer recommendations in term of heat transfer (lateral heat transfer through PCB tracks)
- The implementation of the radiator on the back of the PCB is by no means enough to transfer heat properly and thermal conductive paste might not be sufficient either at high/continuous current. The reason, at least for the boards I have tested, is the lack of heat transfer through the PCB. A possibility is to increase the amount of solder of the through holes ; I have undertaken the mod for the sake of understanding but it is not very satisfactory in term of design. I may be able to complete observations with IR camera during next weeks but I suspect it will not pass the tests.
I have no ideas about long term reliability (especially with thermal stressing).
Regarding safety, the BTS7960 has a thermal safety control and will shutdown if temperature is too high. The datasheet is rather explicit on the consequence in term of component lifetime reduction should repetitive thermal shutdown occurs. It may advisable to apply the controller thermal sensor (ADC pin 2) directly on one of the BTS7960 rather than on the radiator...
All in all, it may be acceptable as a low cost solution for modest currents (I have tested up to 6A continuous so far) and with some understanding of the necessary checks and modifications to the board and peripherals. Having spare will certainly make sense...
Best regards,
Xavier.