This was interesting to watch. I find it interesting that the circuit breaker is the higher power dissipation device. It's easy to get tunnel vision on the FET resistance when after a certain point it becomes far less significant. After looking it up, I'm not surprised to see that you had a tough time sourcing the obsolete Infineon FETs. Surface mounted P-channel FET SIRA99DP-T1-GE3 is in stock at Mouser and IPB180P04P4L02ATMA1 will be very soon and both have a lower RdsON, but you do have to manage heat transfer through the PCB rather than directly on the TO-220. And of course you need a circuit board. It looks like you're set for your one-off implementation, but if you ever want a little PC board to hold some/all of this let me know and I can probably whip up some artwork for you to send to somebody like OSH Park or Seeed. Different topic: I have yet to crack it open but I know one of my H batteries is really weak. I'm pondering just gutting it and going JK, but also considering replacing the contactors on the "good" battery with something like InPower SSC3-200B. I might have missed a video but have you looked into solid state contactors for the KS2 batteries?
Thanks for your comment and I will keep your offer in mind. H to JK is a good idea. I am in the process of converting two Ecotreks to JK's and should be done in a month (waiting for parts). I have looked into solid state contactors briefly. Replacing just the contactors is not a good idea just to avoid the high overhead. Solid state contactors are expensive and uni-directional. The Ecotrek contactors are bi-directional and robust. The weak link is not the contactor but the complex discrete electronics and all the wiring connections. For half the price of a solid state contactor, you can buy the JK BMS that has a bi-directional solid state contactor built-in.
This was interesting to watch. I find it interesting that the circuit breaker is the higher power dissipation device. It's easy to get tunnel vision on the FET resistance when after a certain point it becomes far less significant.
After looking it up, I'm not surprised to see that you had a tough time sourcing the obsolete Infineon FETs. Surface mounted P-channel FET SIRA99DP-T1-GE3 is in stock at Mouser and IPB180P04P4L02ATMA1 will be very soon and both have a lower RdsON, but you do have to manage heat transfer through the PCB rather than directly on the TO-220. And of course you need a circuit board. It looks like you're set for your one-off implementation, but if you ever want a little PC board to hold some/all of this let me know and I can probably whip up some artwork for you to send to somebody like OSH Park or Seeed.
Different topic: I have yet to crack it open but I know one of my H batteries is really weak. I'm pondering just gutting it and going JK, but also considering replacing the contactors on the "good" battery with something like InPower SSC3-200B. I might have missed a video but have you looked into solid state contactors for the KS2 batteries?
Thanks for your comment and I will keep your offer in mind. H to JK is a good idea. I am in the process of converting two Ecotreks to JK's and should be done in a month (waiting for parts). I have looked into solid state contactors briefly. Replacing just the contactors is not a good idea just to avoid the high overhead. Solid state contactors are expensive and uni-directional. The Ecotrek contactors are bi-directional and robust. The weak link is not the contactor but the complex discrete electronics and all the wiring connections. For half the price of a solid state contactor, you can buy the JK BMS that has a bi-directional solid state contactor built-in.