Thanks, I just borrowed this like 10 year old DSLR to try some photogrammetry out!
I tried getting the chip off while fully assembled but all the dang heatsinking makes the ground plane hecka hard to heat from top only.
I just ordered something I needed quite bad, a second hot air gun for dumping heat on DRV chips. This will allow me to blast air at the perfectly bare underside of the ESC directly under the DRV chip. Should work a charm I think. I even got some long curved nozzle for the job!
I installed an NRF51 module and JST connectors, re-did motor detection and correctly set gearing and wheel diameter.
Took it for a ride and tops out at 55km/h until I get a 20s battery. The motor is a MY1020 style inrunner with 10 poles.
Tried raising battery amps from 70 to 75 and started getting ABS overcurrent again.
Full throttle up a steep hill for ~20 seconds got me up to ~53Ā°C MOSFET temp.
Finally getting logs and a stable connection, just need to force my phone to keep GPS on with a locked screenā¦
The cable size probably doesnāt have anything to do with electrical stability but I would say that 14awg is a bit thin for the power youāre pushing
Yeah, it definitely is. Iād like to replace them with 10 or 8 gauge cables and beefier bullet connectors. Same for battery cables. Itās just what the Chinese shipped the motor with and Iām slowly upgrading parts.
Iād also like to mount the thermistor onto the windings directly.
Iāll see what happens when I get a 20s BMS and finish a new batteryā¦
Iād also like to confirm my plan for mounting the little FOCer to the box body. Iāve searched around but havenāt found much info on how to properly heatsink the mosfets. I know they can short if they touch the heatsink, so Iād rather make sure Iām doing this properly. Apologies if Iām asking about something obvious.
The plan is to use 4mm metal standoffs that are screwed to the bottom of the alu box. Then Iāll use 0.5 mm isolating washers (fishpaper-like material) and Iāve got a 0.5 mm silicone thermal pad, that Iāll put under the mosfets. Iāve measured the spacing on the heatsink that came with the Little FOCer and itās the same dimensions: 4mm plastic standoffs with 0.5 mm washers and what appears to be 0.5 mm silicone pad. The mosfets should be 4mm.
Is there anything special to be careful about? Anything I should do differently?
The mounting scheme is similar to the CFOC2 and how the guide outlines it. You can also simplify the mounting hardware by using 5mm spacers and 1mm thermal pad. Just use good quality thermal pad.
Hi everyone, I have already ordered everything for diy onewheel except the control unit. I really want a little focer. Do you know when it will be in stock?
Cool! Nice job so far. Be sure to let me know once youāre ready to boot up the new STM. Thereās some preliminary checks I advise doing to make sure everything is operating as it should be
I did an 11km stress test ride, FINALLY with GNSS data (curse MIUI for making things difficult).
Found out my motor isnāt an MY1020, but a GoldenMotor BLDC-108 10 pole inrunner rated at 48V 1500W, 3000W peak. Basically no info on the internet of people using this motor, not much info from the manufacturer either. I donāt know how much faster Iāll be able to spin it above itās 5kRPM rated speed without the magnets flying off, kinda bummed. Could use a higher gear ratio without losing top speed.
Top speed is 55km/h. Running 70A battery 120A motor. Raising any of these even by 5A gets me overcurrent. 35kHz switching didnāt help, observer gain is already half of what was detected. Iām not sure how high I can set ABS max, right now at 155A.
When trying to do a burnout, the overcurrent only happens on a grippy surface when the motor just starts to spin with full throttle, right above 2k ERPM. When starting from standstill it seem to vary a little and happens between 3-4k ERPM.
Did 7 full throttle runs up a 15% grade hill. 30m elevation change in 200m, regen braking all the way back down. Started thermal throttling on the 4th run up, decided I didnāt need acceleration temp decrease. Motor case was at 50Ā°C after the 7 runs, so it seems to be handling the power really well.
If by chance the log is of any use to you Shaman, I could send it to you.
Overall, Iām very happy with how itās all performing.
I might look into replacing either the motor or the whole scooter. Sell it with itās original controller, make a profit and look around for a new hostā¦
