I have a custom board that uses 70mm hub motors. I’ve ordered the original batch of 4 mototrs from diyeboard.com. They worked great, and I was going through one or two per year. So I made another order of 6 motors to use as spares. diyeboard didn’t survive the pandemic, so I was glad I did.
I didn’t get to the new batch until now two years later, but when I mounted them, the new motors ran like shit - slow and no power up hill. I put the old one back on just to make sure, worked as normal. I measured the internal resistance of the new batch using a vesc as well as a volt meter using a resistor and doing some math. Resistance of new motors is nearly DOUBLE of the old ones. It was same product page, same part number. I opened them up, to see what changed. They look identical, same number of poles, same number of magnets.
Now to my question: What are my options? I’m out $400 for unusable motors. What changed? Are they using cheaper wire, or shit magnets or possibly both? Is it possible to rewind them myself without any expertise in the subject? Is it safe to try using old coils from the old motors with new cans and rubber from the new batch?
OTHERS BEWARE They looked just like these: