Question about 6s E-board

[Dunkirk]

Hello everyone!

New member from Finland here.
I'm going to build a electric longboard. I have knowledge about the rc-world and I understand what everything means, I just don't know anything about e-boards in practice.
I have bunch of 3s 5000mah lipos, 150A Hobbywing 6s car esc and Turnigy 6374 168kv and 6364 245kv motors laying around. I'm a student so I am on a budget. I still want to make everything look fine as possible. I am also a heavier person, 200lbs.

So, I am now wondering how I'm going to execute this project. I think I have two options, single or dual motors. I want speed of 20-30mph and some hill climbing abilities. I do not want to go any higher than 6s. Is it even possible to go 25mph with 6s?

OPTION 1# Single motor
168kv or 245kv?
Gearing? (of course this depends which motor is in use) This is my main worry, what is too much or too little.. 12t:36t?

OPTION 2# Dual
168kv or 245kv Dual? I know that the 168kv motor is way too big to fit two of them. But anyone know does two of the 245kv fit?
Another ESC 150A
Gearing in this case? 15t:32t is it too much? What about the speed?

I know that the option 2# is way better but is it the board goable with single motor?

 

[made_in_the_alps_legacy]

Welcome, not sure if you looked already :
https://endless-sphere.com/forums/viewtopic.php?f=35&t=56375

 

[Dunkirk]

Yes I have already red that topic and I found it very useful. Thank you very much for the writer.

However I'd like to know from people who has a 6s board is the power enough from single motor? Does it require dual motor combination to get me going without feeling that I am really pushing the limits of electronics.

 

[made_in_the_alps_legacy]

you can calculate how much power you can get from your battery knowing its voltage, its capactiy, and its C rating.

I have a 6s single motor board, it goes 25+ mph, it's not lacking of power, see here

if you want to get some confidence on the transmission ratio to order ,
you should do the math knowing your Wheel diameter, motor kV, battery voltage, and desired top speed

 

[sl33py]

Yes I have already red that topic and I found it very useful. Thank you very much for the writer.

However I'd like to know from people who has a 6s board is the power enough from single motor? Does it require dual motor combination to get me going without feeling that I am really pushing the limits of electronics.

I am heavier than you and have a single 6354 200kv setup for my GF. I ride it pretty regularly as well and it works fine. It isn't geared for 20+mph but could be easily. It's not going to be great on hills with only 6s.

Someone feel free to correct me if they disagree, but i see this as two separate issues:

Speed - gearing. This is top speed and usually a compromise or trade-off with startup speed.
Acceleration/torque/hills - Achievable both via lower gearing and more power (8/10/12s).

If you are on a budget i would start with only one motor. You will save on the most expensive components (motor bracket, ESC, gears, etc.).

I would suggest getting a better ESC that is capable of more than 6s. VESC if you can locate one would be my suggestion. If you already have the batteries, using two in series for 6s to start, and then going to 3 in series later for 9s would give you a lot more power for hills even with only one motor.

I would test with both motors on the same gearing if you can. Torque and others has been saying that super low KV motors aren't always the best for hills as they don't seem to get to the best RPM's. So the 168kv motor might be better for general starting and going on the flats, but possibly not on the hills. I'm not sure how that works unless the power requires higher than a certain number of RPMs? If you already have both motors i would try both and let us know!

Gearing gearing gearing! The components needed to determine gearing for the calculator i have are: Wheel size (ex: 83mm), Motor kv, Voltage (ex: 6/8/10s), Motor gear (# teeth), Wheel gear (#t).

So a 83mm, 168kv, 6s, 15/36:

Diameter		Motor KV		Battery S/V		M pully		Hub pulley
								
83		168		6		15		36
								
Speed= KPH	26.2872288							
Speed= MPH	15.83568							
actual speed	13.3019712

Same with 245kv instead:

Diameter		Motor KV		Battery S/V		M pully		Hub pulley
								
83		245		6		15		36
								
Speed= KPH	38.335542							
Speed= MPH	23.0937							
actual speed	19.398708

HTH - GL!

 

[chaka]

Yes I have already red that topic and I found it very useful. Thank you very much for the writer.

However I'd like to know from people who has a 6s board is the power enough from single motor? Does it require dual motor combination to get me going without feeling that I am really pushing the limits of electronics.

I am heavier than you and have a single 6354 200kv setup for my GF. I ride it pretty regularly as well and it works fine. It isn't geared for 20+mph but could be easily. It's not going to be great on hills with only 6s.

Someone feel free to correct me if they disagree, but i see this as two separate issues:

Speed - gearing. This is top speed and usually a compromise or trade-off with startup speed.
Acceleration/torque/hills - Achievable both via lower gearing and more power (8/10/12s).

If you are on a budget i would start with only one motor. You will save on the most expensive components (motor bracket, ESC, gears, etc.).

I would suggest getting a better ESC that is capable of more than 6s. VESC if you can locate one would be my suggestion. If you already have the batteries, using two in series for 6s to start, and then going to 3 in series later for 9s would give you a lot more power for hills even with only one motor.

The power output depends entirely upon the type of motor you are using and is not totally dependent on the diameter of said motor, motor length plays a significant role. An sk3 6374 192kv motor in a single drive configuration will climb anything you throw at it even when geared to hit 25 mph on 6s. The only difference is the amount of heat produced running at lower voltages. Total wattage remains the same, the caveat in a situation such as this is the amp load placed on the battery system can quickly deteriorate even high c rated packs if you are not careful but should not be an issue if you make sure your pack has at least 300Wh of capacity.

 

[sl33py]

Chaka - you had me until the "at least 300Wh" of capacity. Correct me here, but what you are saying effectively is to make sure you have multiple batteries in parallel to lower the overall Amp load (#C) to all the batteries to help extend life?

my simplistic math to figure this out. 6s pack 5000mAh (6*4.2v=25.2v. 25.2v * 5Ah) = 126Wh correct? So you are suggesting a minimum of 6s3p? 3 in parallel would get you over 300Wh (242Ah @ 2p, 3p = 378Wh if my math is correct)

I'm sure it would extend battery life, but man that seems like it would be HEAVY and bulky below the board.

 

[chaka]

Yeah, it adds a bit of weight but it is what works if you want to ride aggressively and not toast your pack by driving the voltage too low. If you use li-ion you can keep it slim and around 4lbs.

 

[haimindo]

Tervetuloa forumille! Fellow Finn here

I have a 6S configuration with APS 275kv motor and it works all right for me (I weigh 65kg/143lbs) in the city. But as we know "hunger grows while eating" and now Im planning dual motor setup for countryside speed runs. The 6S setup can climb almost every hill if I have momentum when approaching the hill. You can check my first setup here http://www.pimio.fi/helectric

Where are you planning to ride your setup? I think single 168kv motor would be good first setup for you, just figure out the right gearing and wheel size. Or just like sl33py said, try both motors Later you can upgrade to VESC and hookup a 12S config.

Cheers!

 

[Dunkirk]

Thank you for everyone your helpful answers.
I'm thinking going with single motor and test which one is better and report to you. I have my dads 70cm long 30 year old vintage skateboard and first I try that out. If it is too short and unstable I think Loaded Vanguard might be good.

And haimindo your helectric board looks awesome!

 

[Dunkirk]

Also I live in the city so the speed of 25mph is not going to be the main point. What you think about gearing 12:36 with 245 motor and 15:36 with 168kv?

 

[sl33py]

i would be cautious of 12t unless running dual motors. Less teeth are engaged and you can have "skipping" during hard acceleration or braking. Unless you go to a wider 15mm belt which would give you better contact area for the force. I would suggest 13t or 14t be your minimum motor gearing for a single motor 9mm width belt setup.

DIYes has the wider belts and gears. With the SK3 motors you aren't likely to be able to run dual rear, so going to a single wider setup now won't impact your ability to run dual diagonal down the road if you want to go to dual motor setup.

The downside to wider belts is a small increase in drag when not under power/accelerating.

GL!

 

[chaka]

If you want a 25mph top speed at 6s a 168kv motor wont do it for you.

Here's a nice calculator to help you out with your decision. Leave the efficiency area blank and it should give you a close approximate top speed. http://toddy616.blogspot.com/2013/07/electric-skateboard-calculator.html

Just remember that you are making a space heater by using low voltage and high amperage to get the power you need. Power draw at 25mph can be as high as 800 watts with sustained burst as high as 1800watts when accelerating hard. You can also easily burn up your system by riding too slow with tall gearing and low voltage/high amp. Things get hot quickly!

 

[cdn]

I totally agree with sl33py on the 12t pulley. No matter what I did as far as belt tightness, the 9mm belt would skip. Really noticeable when climbing a hill or hard braking.

 

[made_in_the_alps_legacy]

If you want a 25mph top speed at 6s a 168kv motor wont do it for you.

weird... why does mine goes 25+mph on 6s w. 150kV w.o heat build up then ? is it because of the Onda 140mm wheels ?

 

[chaka]

Yes , in your case you are using an unconventional wheel size. Technically speaking it isn't a skate wheel.

I should expand on the heat issue at low speed has to do with the ESC heating up.

 

[made_in_the_alps_legacy]

Yes , in your case you are using an unconventional wheel size..

I think it has more to do with the wheel pulley availability : if you could lodge a 1:1,5 transmission ratio on a conventionnal 90mm skateboard Wheel, you could go 25mph on a conventionnal skateboard with that set up.

What is clear is that such ratio is so close to 1 that hubmotor are a logical evolution for skateboard sized wheels.

 

[Dunkirk]

Allright, thank you for your thoughts. Here is what I did:
Hobbywing 150a ESC, 6S
Traxxas RX & TX
13:36 gear Ratio
168kv motor






This is fun, I mean really fun. It is not just transportation it is much better. I managed to travel with two 3s 5000mah lipos about 6km. I tried full speed and it was about 30km/h. It is enough because the board is so short.

I will upgrade my board to bigger one during winter. I also think I need more power.
This board is like prototype. It is ugly and there was no design thoughts putted into. But it works and it is easy to carry.

I was thinking to use 3x3s lipos in paraller with vesc (9s) would that work? 3s lipos are cheap ans flat.

 

[Vulthor]

Sweet! Nice job.

If you go longer deck and Vesc, go 12S, it's more power efficient and recommended by Vedder himself, even if you never go full throttle because of the scary top speed, at least it will extend your range.

 

[astilwell611]

Just FYI 3x3s lipos in parallel do not give you 9s it gives you 3s. You would have to place them in series to obtain 9s. Series connected batteries up voltage, parallel connected batteries up capacity.

 

[Dunkirk]

Sorry my bad, I mixed those two!

 

[Dunkirk]

I have problem with calibrating my Xerun ESC.

I have been using Traxxas TQi radio system. You need to set throttle adjustments to ESC before using it. I changed it to GT2B. Now when i'm trying to do the throttle adjustments the ESC stops with first beep. I remember I needed to calibrate the throttle to the Traxxas TX first by hand because I stucked at the same point. Is there any way to do this to GT2B?

And yes, I Have binded RX and TX

Here is the process:

A) Switch off the ESC, turn on the
transmitter, set the direction of throttle
channel to ”REV”, set the “EPA/ATV”
value of throttle channel to “100%”, and
disable the ABS function of your
transmitter.
B) Hold the “SET” key and then switch on
the ESC, and release the “SET” key as
soon as possible when the red LED
begins to flash.
C) Set the 3 points according to the steps
shown as the pictures on the right side.
1) The neutral point
Move the throttle stick at the neutral point,
and then click the SET key, the green LED HERE IS THE PROBLEM, THERE IS NO FLASH
flashes 1 time.
2) The end point of forward direction
Move the throttle stick at the end point of
forward direction, and then click the SET
key, the green LED flashes 2 times.
3) The end point of backward direction
Move the throttle stick at the end point of
backward direction, and then click the SET
key, the green LED flashes 3 times.
D) Throttle range is calibrated; motor can be
started after 3 seconds.

 

[made_in_the_alps_legacy]

Glad you managed to demonstrate that a 6s system with 168kV can go up to 30 kph

About ur current issue, i would try with different Rx trim pot position and/or switch position like FWD and see what happens…

 

[LEVer]

@Dunkirk.

Check the switch wires, or replace the whole switch. The Xerun's switch is problematic. I've change a few on mine.

 

[Dunkirk]

Thank you all for your reply. I found the issue. The trim was in wrong position.

Current thoughts:

I am balancing between two options:
1. making a sealed enclosure with unswappable batteries and charging batteries directly.
2. making enclosure for easy battery change.

Would this work?



I bought Loaded Vanguard. I also have 3mm ABS for the enclosures. I will vacuum form them to shape.