low power issues from Sevcon gen 4 size 6 w/ 75-7, DVT programming PLEASE HELP!


1 µW
Sep 8, 2023
Hey all,

purchased a carbon wrapped 75-7 from Calfee Designs, along with a Sevcon gen 4 size 6 in order to try to build a "death fx" out of my 2019 zero FXS. Got it all mounted, wired up, took it out for a spin and noticed less power than the stock 75-5, and the motor cuts out at 60 mph (quite jarringly, I almost ate it the first time). Calfee designs is currently helping me trouble shoot, I purchased an IXXAT USB to CAN adapter and a DVT license, read all the manuals I could find... and still can't get it up and running well.

I extracted the .dcf from my original stock gen 4 size 4 in order to compare with the programming of the size 6 i purchased. I'm attaching my .dcf files from both here, just in case anyone has some good knowledge and can spot any issues.

Have been working on verifying that the encoder offset is correct, and I believe it is, but I'm sure I'm not doing it the correct way... I just tried to pinpoint the "dead spots" in the offset where the wheel locks up and won't spin, calculated the midpoint between them, and then added 90 degrees, making sure the wheel spins the correct way (forward, preferably). Is there a more accurate procedure for this? I'm sure the guys at Calfee Designs offset it correctly, but they mentioned that things can change with installation, etc, so I'm trying to verify.

There's a few other parameters that are dissimilar between the two dcf files that I'm going to play around with...

Anyone have any ideas?

thanks in advance