I think there’s your problem. Those cells are probably not high discharge like the 25Rs or HE/HG cells.
Nice to hear that. Just ordered me some raspberry PI heatsinks, will equip the mostfests with them and hope to get same results 
If you have the space, go with a bigger one. I currently have four 20mmX20mmX6mm, but I think a bigger one like Chaka uses would work better.
I’m on ebay right now looking for a big one wich I will cut a rectangle in the Space Cell 3 enclosure. I’m thinking about mounting the VESC directly on the inside of the heatsink while the outside will have direct contact to the wind. The mosfets facing inwards will get the small raspberry pi sinks.
just wondering how the heatsinks are mounted onto the MOSFETS?
Thermal paste then shrink tubing with a hole cut out for circulation.
Any updates about this problem? I have the same thing but on the flats 
With a fresh start i can go to my 40-42km/h top speed, no problem, but then the speed starts to decay and i can only go 35km/h and then 25-28km/h. If i then get some headwind i only go like 18 or so. Sucks alot! I like the 40km/h speed
Same thing if i carve and coast at 25km/h and then i want to go fast and pump full throttle, then it stays put at 25km/h and i can’t go faster. Stop the board, wait for 20sec and then i off again to 40km/h for a small period of time.
SK3 192kv single drive 12mm belt 10s3p space cell VESC 83mm wheels 84kg rider
It seems pretty stupid but I didn’t notice until recently, I am not a skater/longboarder so I really didn’t know this one obvious thing. Believe it or not I overtightened my wheels / axle nuts and that squashed the bearings a bit, the wheels had a bit of resistance, now I loosened them enough that they don’t move laterally and if I spin them by hand they spin for more than a minute. Before they were too tight (they used to spin like 20s max that way), enough to make the VESC overheat more on small hills. Now the VESC with my single 6374 still limits my speed on medium hills (6% grade, I’m ~220lbs) but at least I can do them.
Also, increasing motor max from 40A to 50A or even 60A (I’m using 50A batt max setting, using 40 li-ion cells) actually helped me increasing the initial speed so that the board starts to slow down / overheat later (this doesn’t work if the hill is very long unfortunately).
Another stupid thing that can help you is carving (zig zag motion) instead of going straight 
^^ To add on top of that, in winter (colder weather) it will overheat less because of external temperature, I noticed that a 10deg C drop in temperature is enough to affect my rides.
But yes, I agree that a smaller motor should overheat less, heatsinks help, some airflow in the enclosure and a fan will be my next steps and if that will not be enough I will go dual
If it’s any consolation I’m guilty of doing this too - even with washers you can over tighten the nylock nuts.
1 Like
Sounds like my issue with my VESC overheating. Have you installed a heatsink? What VESC are you using? Some VESC’s are more prone to overheating with certain setups than others.
I don’t have a heatsink. The vesc I am using is the 4.12 with 2.18 firmware.
First ting I Will try is cut my vesc loose because now it is glued to my enclosure and the 3 mosfets are drowning in it Should glue it on some other components. If this doesn’t work then the heatsink is next to try out. Don’t feel like cutting in my enclosure, it’s so clean and slick now
For your VESC, I suggest adding a heatsink. They are only a couple bucks on Ebay. Make sure you attach them with some thermal paste so the heat transfers well. I used shrink tube to secure mine, but there are a number of ways.
1 Like