First Electric Skateboard Build

[vedder]

The current draw from the battery will only be high on high duty cycles, so when going slowly you can have high torque and high motor current without drawing much from the battery since the motor inductance, input capacitors and PWM work like a switched mode power converter. For this to be safe you need and ESC with current control and/or current limiting. If the ESC does not measure and care about the current, you can get very high battery and motor currents when giving full throttle on low speed with hub motors and high battery voltage.

For the VESC you can configure different current limits for the motor and battery. You can for example set the motor current limit to 80A and battery current to 30A, which should work nicely with dual motors on a space cell. The motor current in each motor will then be able to reach 80A until you have reached 3/8 of the full speed. After that, the motor current will be more and more limited the faster you go.

 

[elkick]

Thanks Benjamin for the explanation, makes it easier to understand the dependencies. I'll change the settings on both boards to your recommended values.

 

[onloop]

That battery pack isn't compatible with hub motors, I wouldn't go higher than 6s for your battery system if you are using pediglides hubs.

Thanks mate! Really Appreciate it... NOT please check the facts first next time...

I don't recommend the alien esc. It doesn't have current limiting.

I suggest the VESC, it is the most advanced ESC available and has some really awesome functions. Like the start-up boost control & Current limiting is also one of them too! It also has rpm limits too which might be useful for a 149kv hub motor on 10s.

For hubs I think it is a wise choice. Especially non-sensored hubs.

Basically you can program it to perform exactly how you need it to perform. Also...It's not that hard to program.

Combining the VESC with S.P.A.C.E cell gives you the most advanced, user friendly, safe, reliable, slim, customizable power system for a DIY build...

Maybe Not the cheapest combination of products but I think you will struggle to better it in terms of quality & function. I also back our products up with full warranty and support too....

I also offer 300 days money back guarantee, so if you don't like what you get from us send it back for full refund.

 

[nickkapoor]

That battery pack isn't compatible with hub motors, I wouldn't go higher than 6s for your battery system if you are using pediglides hubs.

Thanks mate! Really Appreciate it... NOT please check the facts first next time...

I don't recommend the alien esc. It doesn't have current limiting.

I suggest the VESC, it is the most advanced ESC available and has some really awesome functions. Like the start-up boost control & Current limiting is also one of them too! It also has rpm limits too which might be useful for a 149kv hub motor on 10s.

For hubs I think it is a wise choice. Especially non-sensored hubs.

Basically you can program it to perform exactly how you need it to perform. Also...It's not that hard to program.

Combining the VESC with S.P.A.C.E cell gives you the most advanced, user friendly, safe, reliable, slim, customizable power system for a DIY build...

Maybe Not the cheapest combination of products but I think you will struggle to better it in terms of quality & function. I also back our products up with full warranty and support too....

I also offer 300 days money back guarantee, so if you don't like what you get from us send it back for full refund.

Any news of when you will be releasing your larger space cell? Would be very interested in that. And i will definitely be using dual vescs.

 

[onloop]

Will have the sample when I get back home from my holidays... just need time to test it.... ill be busy packing 3 weeks of orders first..

It will be 10s4p with a newly developed BMS that supports continuous 50 amp draw with 100 amp peak for a few seconds.

It will be about the same length as the space cell. Slightly thicker. It will still fit inside the enertion CF deck cavity.

 

[nickkapoor]

Will have the sample when I get back home from my holidays... just need time to test it.... ill be busy packing 3 weeks of orders first..

It will be 10s4p with a newly developed BMS that supports continuous 50 amp draw with 100 amp peak for a few seconds.

It will be about the same length as the space cell. Slightly thicker. It will still fit inside the enertion CF deck cavity.

Sign me up for one when your done testing.

 

[nickkapoor]

Will have the sample when I get back home from my holidays... just need time to test it.... ill be busy packing 3 weeks of orders first..

It will be 10s4p with a newly developed BMS that supports continuous 50 amp draw with 100 amp peak for a few seconds.

It will be about the same length as the space cell. Slightly thicker. It will still fit inside the enertion CF deck cavity.

Also, can the cf deck house two vescs?

 

[onloop]

Yes. 2 vesc & a 10s4p will fit inside.

 

[nickkapoor]

Yes. 2 vesc & a 10s4p will fit inside.

Cool!

 

[dashimsta]

ONLOOP,

I have one of your spacecells and 2 VESC's now, with 12:36 ratio on kegels. I understand we have limited output current capabilities with the SPACE cell so how should I configure my VESC's so that I dont encounter issues or damage your pretty slim battery, LOL!

I figure since this is the setup you're advertising you have recommendations,

Thanks! can't wait to get my new board running, i put your battery inside the deck, waterjetted out motor mounts that are fixed, but have a bearing belt tensioner to keep proper tooth engagement while having less belt tension overall. It also lets me wrap the belt 3/4 around the smaller pulley and even more on the bigger pulley!

Not In this picture are the stainless connecting rods between the 2 mounts that also serve to protect the motor from curbs speedbumps ect, sorry for the crappy pic

 

[whitepony]

very cool mounts, could you post a few more pictures of those?

 

[onloop]

ONLOOP,

I have one of your spacecells and 2 VESC's now, with 12:36 ratio on kegels. I understand we have limited output current capabilities with the SPACE cell so how should I configure my VESC's so that I dont encounter issues

The space cell BMS is happy continuously outputting 30A with Peaks of 60A for a few seconds.

To be 100% safe and never blow a fuse you should limit the battery current in each VESC to 15A.

However you will realise if you do some experiments that you can increase this higher without blowing the 30A fuse. 30A fuses can allow peaks much higher for a few seconds.

I think the default in the vesc is 60A battery current. When testing the space cell I used the default settings and never damaged the BMS. Meaning that the motors current draw never exceeded the BMS abilities.

As vedder mention you can set higher motor current and lower battery current.

I would say try 30A battery current in each vesc & 60 or 80A motor current limits.. See if you have any fuse blowing when going up the steepest hill in your area.

 

[dashimsta]

Thanks OnLoop!

and heres a screenshot from my CAD package, by using a belt tensioner like i have it allows the driving pulley to tension the belt on the top side just enough.

For my mount I felt a machined mount was too expensive for the given purpose and the needed accuracy. Instead i designed it specifically to be waterjet. After waterjet one hole needs to be drilled in a drill press and 2 holes need to be tapped 1/4-20 in a hand drill real quick. The first one i made was 1/2" thick 6061 and was great but beefier than it needed to be, so in my 2nd and third iteration i made it out of 3/8" 6061 and this is what im still using. For the dual board im building now i had to machine an 1/8" off the motor area on both mounts to enable the C clips to work and position the pulley as OnLoops mounts are 6mm thick.

The bearings are 1/2 OD 1/4 ID ball bearings abec 5 (not by choice just all that fit the size) I use 3 side by side to form a tensioner that doesnt add rolling friction on the belt.