Hi Hummie, The iron is need to lead the magnetic flux. In our setup there are no stator teeth, so it is less iron to close the magnetic flux.
Outside pure iron, inside iron lamination.
This is the flux density over one magnet, its an average of 0,76 Tesla.
This is the thermal view of the truck at max. penetrating and ambient temp of 26° C Drive tests will follow on our social media channels with our new model which is in build.
The maximum safe recommended charging temperature for lithium cells is 45 Celsius, and I would charge closer to 25 to maximise cell life. You may want to find a way to drop that a few degrees or warn customers to wait for the unit to cool down after use. Also it may not look the coolest, but you could probably integrate a slight heatsink into the metal of the trucks if you tried
http://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures
Hello anorak234, this temperature is in the discharge range from -20° C to 60° C. The charge temperature range is like you said from 0° C to 45° C. At all time the temperature is measured by the controller, and the controller throttles the current if the temp goâs to the limit. So if you charge the truck with the temp above, the system waits till the temp is in a non critical range. To degree the heat (the whole hanger is an aluminium heatsink) we could increase the surface of the hanger. Overall, for max. penetrating (this is quite not the normal case) itâs a very acceptable value.
Thatâs the outside of the truck meaning the inside is way hotter
Florida heat is also very unfriendly to motors which is one reason i use large well ventilated ones that arenât sealed.
@JayKay Wow. Just⌠wow. This is very impressive.
When can i get a drive system to test?
ok i just backed it!
if anyone here has some serious interest in these you should probably do this as well because they just have 13hours left and are still missing 46% 
We are searching for distributors in dfferent countries who offers test rides.
But you can also buy one, test it and if you are not happy with it you can send it back within 2 weeks. Of cause without big traces of usage.
Very likely available from December 2017.
Do you use thermal paste to help cool the components like in a computer? and do you think its possible to integrate small batteries inside a deck and keep it flexy?
BTW im loving this project, very impressive feat of engineering and well thought through from what I see 
Crazy cool. This will be the most normal looking e-skate ever built. However, it annoys the crap out of me when I hear the words high torque and high speed followed by 2s2p or 4s1p in the same sentence. Only thing it will do is confuse people who donât know anything about e-skate electronics. What is the target weight for these in your mind? Even a lighter guy will struggle to move with such a low voltage. Has to be what, 5 amps at 8.4 volts per motor? Thatâs only 42 watts per motor, for 168 watts total. Almost everything on the market is at least 300 watts, and those are very weak systems already. 1000-2000 watts is standard torque, high torque is 2000-4000 watts. Then theres very high torque at 4000+ watts. So this is very low torque at best.
Not trying to pull you down or anything, itâs just misleading to say high torque with 168 wattsâŚ
Since they are using 21700 they could be using the Samsung 30T, 30A without much problem, even more for short bursts, this brings everything to almost 900W with both trucks, even an Panasonic 21700B could provide 15A with a decent capacity
I think they are using the NCR20700b
regardless, the issue will be heat in the esc. As it is right now, even the vesc 4.12 can only do 25 amp continuous. Those fets are tiny on that esc, no way it can do more than 5 amps con, if even thatâŚ
I really donât know, once you go down on voltage rating on the MOSFETâs, the rdson also go lower, so probably they produce less heat for a given current than the 4.12, but i agree that heat has to be managed
The other issue is going to be sag. Youâll sag down from 4.2 to 3.4 at 15 amps with those cells. That means 6.8 x 15 = 102 watts per motor x 4 = 408 watts total. Range will be like like, 15 city blocks before your sagging below the low voltage cutoff at 15 amps at best, probably more like 5. Again, assuming 15 amps is even possible.
Again, not trying to tear this project apart, just giving my analysis of the concept. Iâd still love to see it done. Maybe you can prove me wrong?
Either way, itâs clearly misleading to say high torque or high speed. The Carvon EXO uses the koolwheel motors, so itâs limited to 700 watts total. At that even the acceleration when I tested it at the SPD2 was very weak for my taste (not trying to hate on carvon, just trying to compare watts with what Iâve ridden before).
Am assuming u meant carvon EXO not carvon EVO the evo is 5000watts total in dual and EXO is 300 watt per motor carvon doesnât use koowheel motors for Evo just EXO btw itâs like koowheel motors but Jerry design on it
Yes, my mistake. Thank you. The little he talked to me at SPD2, he told me they are koowheel motors moved out of the hub and on a carvon designed mounting system. Probably redid the can and magnets.
Hello evoheyax,
Thank you for your comment.
We fundamentaly have to difference between power, meassured in W and tourque, meassured in Nm.
The tourque at the same power depends only on the max. speed! And a low system voltage requires a higher current for the same power, which you can splitt to four motors. In our first statemaent we tried to explain the system, couse you canât look to one parameter and appraise the system.
Over all we see there is much discussion about our e-truck, work or work not⌠however at the moment we produce our serie and then you have to feel the e-truck.
Driving, not talking
There are some new interresting cells on the market which we are testing at the moment.
