Yeah finding a decent 12s BMS was a lot harder than 10s or even 13s since so many ebikes use those. Here’s a 12s BMS that I’ve used before in a previous build that I’m satisfied with.
2 Likes
Is this right? I can’t remember where I read it but is it possible that the VESC can upscale the current when PWM is less than 100%. For example the PWM to the motor is 50% and the battery is outputting 60A, would the current to the motor (without any limitations in place) be 120A? (similar to how a transformer works)
Also I saw a build where the battery pack is 2500W and there are two motors which combined are 7000W. It seems like a lot of wasted potential from the motors. Is there a ratio for what works best that I can use to select a lower power motor?
bat amps not motor amps. you can draw 10A from the battery and your motors get 20A for example.
But as input power is (more or less) output power your voltage on the motors will drop.
1 Like
Regarding Vesc tool and regenerative braking:
The standard value for maximum input voltage value in the vesc tool is set to 57V, does this mean if I do regenerative braking the Vesc produces up to 57V and supplies the battery (in my case 10s) with that? How does this not damage the 10s battery (max. voltage is 42V)? Isn’t that triggering internal shorts due to overvoltage?
1 Like
No regent is normally set to 10-12 amps
1 Like
Hi everyone, I am writing from Italy, I am a super noob in the skate world and even more in that of esk8.
From the first day I saw a mountain esk8 on youtube I was kidnapped and I can’t think of anything else! So here I am to expose those millions of doubts that run through my head.
I gathered more information than I could on the forum before writing because I didn’t want to be too heavy for you, but I got to the point of being too confused to learn for myself …
My idea of Mountain esk8 that I would like to build is similar to this:
H2C 2 x 800 W Brushless Motors Electric Skateboard
Main features:
● Powerful dual 2 x 800 W motors, maximum speed 38 km / h, gradient can be overcome up to 25 degrees
● 11000 mAh battery (included in the package), 20 km max
● Remote control to adjust speed (beginner speed and expert speed)
● 8-inch solid rubber wheel, wear-resistant and durable to use on different terrain
● The motor cover has better heat dissipation and plays a dust-proof role, the use of the brushless external rotor motor
● 8-layer maple and 2-layer bamboo edge with non-slip design, durable and safe for outdoor use
● Remote control power supply: 200 mAh lithium ion battery (included in the product), the control range is 14 km and the recharge time is 1.5 hours
Battery: Lithium ion battery
Mileage (depending on the road and weight of the driver): 15-20km
Maximum mileage: 20 km
Max Payload: 200kg
Battery Capacity: 11000mAh
Battery Voltage: 36V
Rated Motor Power: 2 x 800W
Input Voltage: 100-240V AC
Charging time: 6 hours
Rubber Diameter: 8 inches
Clearance Pedal Earth (There is no weight bearing): 14 centimeters
Youtube video where I saw it:
The price of this esk8 is very good (I think), today it costs € 540 for flash sales but honestly I really want to build it myself. My fear is that building it from me costs much more, do you think it is?
Now I come to my doubts about the construction, starting with what I know.
The components:
-
Board . (this I believe will be the last thing I will think about but I gladly accept advice)
-
Engines . I thought I would put two 800W motors like the model above, with belt drive, do you have any suggestions? Where can I buy them? Are there stores where they are cheaper? It is convenient to buy more powerful engines in case you want to increase the battery and I also believe the ESC?
-
Esc (or Vesc). On this subject I am really ignorant. I don’t know how to choose it. I think I understood that the parameters are the maximum voltage and maximum amperage that can be supplied. But I don’t know how many models exist, what are the best models. Is it the Esc that eventually deals with managing the two speeds (beginner and expert)? Are it hard to set? Does Vesc handle sending battery charge data? And finally, is Vesc managing the transmission system between the radio control and the esk8?
-
Batteries . . I thought of using LiPo batteries because I know them little but better than the Li-Ion (even if in commercial esk8 I always seem to find Li-Ion (why?). If I used LiPo batteries, how many cells do you advise me to put in series and how many groups in parallel? A 10s3P or 12s2p or what else? What grade C do you recommend (the minimum value, I know that the higher it is the better it is for batteries) But the biggest doubt about batteries is the balancing connector for charging. Where should all balancer connectors be connected? Perhaps to a BMS?
One more thing about batteries, I saw that some built the LiPo battery pack from a cell without a balancer connector (https://hobbyking.com/it_it/turnigy-5000mah-1s-40c-lipoly-single-cell.html) , how will they load the package without blowing up the esk8?
-
BMS . I do not know what a BMS really does, is there a dedicated threed on the forum? I read (I don’t remember exactly where) that with LiPo batteries it’s not necessary but it’s useful, what does it mean? Perhaps, if the LiPo balance connectors go to him, does it allow the charge and discharge by balancing the cells? Is the BMS or Vesc to protect the batteries from excessive discharge?
-
Trucks . I really like those with springs (I apologize for ignorance, I know I will make people laugh for how I express myself). I’ve seen them in a video (https://youtu.be/jSxdPojJ0ow min 5:07) and call them Matrix Trucks, but I don’t know which ones fit to mount and if the axes section will be fine for mechanical parts for belt drive. Can anyone recommend a mix of Trucks, mechanical parts for belt drive and wheels (from Mountainboard, 8 inc credo) that are compatible with each other?
-
Remote control . Do you have advice on a remote control and receiver? Should it be suitable for the Vesc I will choose or are they universal?
-
Vesc protection circuit . On the forum I read an article that showed a protection circuit for the Esc (https://www.electric-skateboard.builders/t/3d-printed-boosted-board-killer/88803/3), do you use it?
Surely I have a thousand other questions to do but I think they are too many for the moment …
If you have useful links both for information and for the eventual purchase of the material I need, please write to me.
Thank you so much for your patience
Andrea
2 Likes
Here is a really great topic to start with.
If you buy that board I can almost guarantee you that you will want more and have a hard time finding compatible upgrades. You will want to improve the battery, then you will want a VESC controller, then better trucks, then a better deck, etc.
It will be cheaper only in the short run. Diy is intimidating with all the knowledge spread out but you will end up with a much better machine and a ton of useful knowledge.
I almost bought that same board when I started this journey!
Here I am now, with a second build almost finished
7 Likes
Yeah I second that, those are one of the most unappealing specs ive seen
whats the minimum balance wire gauge that is acceptable for a cheap BMS? Its one of the old AnnPower 10s BMSes that is no longer in production so I don’t know the balancing rate. Is 26awg acceptable or will it melt?
https://www.amazon.com/Pitch-Single-Female-Adapter-connector/dp/B075ZZM2G8
If you aren’t putting the whole charging current through it, 26AWG won’t melt, assuming you’re certain the charge current isn’t going through it. (only the balance current which is typically <200mA) However, also remember that thinner wire is more prone to physically breaking after many thousands of miles/kilometers of extreme vibration.
I would use 22AWG or 20AWG – and 24AWG at a minimum.
26AWG - 2.2A max continuous
24AWG - 3.5A max continuous
22AWG - 7A max continuous
20AWG - 11A max continuous
2 Likes
Anywhere you know has one with better wires and can do fast shipping? Most places are like $9 for a single wire or take weeks to ship
The ones that come with Bestech BMS are 22AWG (but are 10-pin, without B0). I’d check digikey.
Any eSk8.builder forum vinyl stickers out there?
The logo is much better 
It can increase amps, but not watts. Most builds, especially duals, run considerably less battery current than motor current. At low RPM (and thus low PWM), the ESC can act as a buck converter, converting the (for example) 40V and 40A from the battery to 20V and 80A for the motor.
It doesn’t really matter if the motor power rating is greater than that of your battery or ESC, because the motor is a dumb lump of copper, iron and neodymium, governed by the simple laws of thermodynamics. It’d be very bad to try to draw 4KW from a battery that can only safely deliver 2, but running a motor at less than its rated maximum just gives you more safety margin, and can actually improve the efficiency a little.
2 Likes
I’m down for that too!
1 Like
Does anyone know what capacitors the DIYElectric skateboards VESC uses?
Perhaps @JohnnyMeduse Knows?
Sorry, I really don’t know.
3 Likes
damn, I tried to look for them nothing matches them.
By any chance is there a common one all VESC use?
I contact DIY via there website and they had no clue, mabye @torqueboards