This is my first time posting in any forum and would like the help from the community to confirm if my math and ideas are correct before I start buying parts and building the electric long board. That being said, Ill list my parts below. The purpose of this post is just to see if all my logic is sound so if you find any errors or irregularities please I am open to criticism.
2 * Electric Skateboard Motor 6374 190KV 3150W
- Max Amps: 80 Amps
- Max Volts: 12S
- 12S 120A-150A
- 150mm silicone 12AWG 5.5mm Gold Bullet Connector Female
3 * 4S 20000mAh (overkill)
- discharge 10c peak 20c
2 * vesc
- 5v BEC
- 8V - 60V
- 50a continuous 240a 5sec
1 * dual motor Mechanical electrical kit
- 63mm spacing
- Rear mount
So with the specs all out of the way I think I’ll start with the batteries. When I started I knew I didn’t want to make an electric skate board just to see if I could do it ( I still don’t). But if I did I’m going to make a darn good one. Which is why I wanted my batteries to last forever. with 20ah I knew the board could go for a long time however I didn’t know all about the technical math side of batteries. I found out that I could reach peak performance if I use 12s to match the cap of the vesc. So I decided to get 3 20ah in series. So instead of 4s1p I would get all three batteries working as one for 12s1p. The Discharge rate was low which I was concerned at first but then I found out that having a big battery meant I could get a big discharge because discharge = 10c * 20ah = 200a discharge per hour. This matched up good because the VESCs has continuous amperage of 50a with a peak of 240a. I could keep the amperage at 50a by configuring the vesc. and at the same time the VESCs limit for voltage was 8v-60v where the batteries in series would mean the voltage would equal 14.8 * 3 = 44.4v. Which would also mean 44.4v * a continous 50a would equal 2220w. Which my motors were 3150w each (that’s if im using the right formula, hence this post).
My next thought was how am I going to charge these since my battery chargers had a limit of 6s charging and in series my batteries are 12s. So I thought I would charge them parallel.
I made a drawing of how this works, (I’m still un sure of myself when it comes to the charging part since I don’t know the proper units of anything to charge the batteries).
After that drawing I decided to learn about gear ratios on the belt. I found that a wider belt is generally better. From the diy electric skateboard website they had either a 36t-13t or 36t-16t. The latter would be faster but the former would have more torque (I think). But then I thought the two motors have enough torques anyway so just go with the 36t-16t anyway. I think I have decided on 36t-16t.
I then started considering what kind of hardware I would need. The batteries use a xt-90 with 5.5mm 10awg cables and JST to connect to the charger. The motor has 12awg cabling but still has 5.5mm cables with bullet connectors on the end. So I think i’m just going to buy a ton of 10awg cable,heat shrinks and xt90 connectors.
The next thing was how am I going to solder everything since I have never done that before. It turns out that a guy on youtube named Barnes’d had some really videos showing him doing a lot of really nice solder work. link below.
As for actually setting up all these things I thought how to connect the to VESC to work together. I found out that it was by a jst cable that run to-and-from eachother. All I had to do was remember to setup them up in Master/Slave mode with all the different peaks for all the different electrical units.
I then started to question if the two motors would actually fit on the mounts because the pictures on diy electric skateboard have to 50mm motors and they look a little too snug. And yet the website says you can get the 63mm motors but it sure doesn’t look like that to me.
With all that I decided to figure out the speed of all these parts if they did indeed work together magically somehow.
with 16t-36t, voltage of 44.4v, 190Kv, tire diameter of 83mm I could travel a speed of 59km/h or 36mph. Holy cheese balls batman.
I started to play with the gear ratios and found out that my 16t-36t wasn’t as fast as a 18t-36t which was 66km/h or 41km/hr. However I don’t know where to get those in canada.
Oh, and this is all going on either a Sector9 Sentinel II or a Loaded vanguard.
I think that’s the end of my rant. If anybody has any critiques please post a reply or comment or something that is constructive. I look forward to hearing from the community.