Young and lost... but excited to learn! (EBoard checking in)

Lightweight / Folding / Portable EVs - seats optional

Young and lost... but excited to learn! (EBoard checking in)

Postby sk8gineer » Sat Apr 27, 2013 11:45 am

Hi there! I just found this forum while doing a little research on a work on EV for my university (I am in my 2nd year of Electrical Engineering and I just realised that I haven't learned many things about the real world...)

Here's what I'd like to create:

-Electric Board
-Powered by a single BLDC motor
-30km/h of average speed (without stress on the motor)
-45km/h max
-8km at average speed will be more than fine
-6kg maximum wheight (13.2 Ib)

I want it as a substitute for my car in a daily commute of less than 4km (2+2).

I'd like to control it with something like the wii nunchuck (any tips on this, right now I am pretty lost!)

First of all i'd like to buy the motor, ESC (what kind?), batteries to see if I can make em work... so please, I need tips on, given my necesities, I can base the criteria to pick the stuff.

*Motor - 30km/h as average speed without burning it
*Batteries - 4km distance
*ESC - Compatible with the aforementione and is it connected with the controller (R/C or wii in this case?)
*Other stuff you think I'd need for prepearing the setup off the board


What else do I need to see if I am capable of controlling (with switching it on I'd be satisfied ahaha) the motor? I don't have anything right now so... the motor, battery pack, ESC, controller (wii nunchuck?) and a charger?

I feel kind of bad for coming here and asking all this (below)entry-level stuff, but I've been exploring the forum for some days and I feel overwhelmed by the amount of info and things you have to take into consideration :( but sooner or later I know I'll be able to put it into practice!

Sorry for the brick, hope I'll be able to open a new thread soon and show you my progress, I am really lookiing forward to enjoying my new creation! Thank you for your suggestions beforehand!
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Re: Young and lost... but excited to learn! (EBoard checking

Postby sk8norcal » Sat Apr 27, 2013 1:22 pm

just take your time and read some more,
read through other's build threads, you will pick up a lot of stuff there,
good luck.

this is a good resource.
http://www.instructables.com/id/The-New ... /?ALLSTEPS

this one too,
http://recumbents.com/wisil/e-bent/rc_d ... torial.htm

http://wackyboards.blogspot.com/2012/02 ... board.html
http://wackyboards.blogspot.com/search/ ... c%20boards
Last edited by sk8norcal on Sun May 12, 2013 5:43 pm, edited 1 time in total. View post history.
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Re: Young and lost... but excited to learn! (EBoard checking

Postby hmin7186 » Sun Apr 28, 2013 7:42 pm

i'm planning on building a electric board with similar requirements except i'm going boosted boards style with 2 bldc motors.

Here is my plan so far

1. Board
- Landyachtz Tomahawk 2012 40'
- 10' Caliber Trucks
- ABEC11 90mm Flywheels (trying to go with big wheels as i've got some rough roads in my path.. may change that to some rubber later)

2. Motor
- 2 x Turnigy Aerodrive SK3 - 5055-320kv
- going to run it on 6S battery which would bring maximum RPM to 7104 and with 3:1 gear ratio my top speed will be 40km/h
- its two 1630W motors so i assume running 25~35km/h on average will be okay

3. ESC
- 2 x Turnigy TrackStar 150A 1/8th Scale Brushless Car ESC
- this is where i'm having a hard time to make a decision. this ESC seems too much for my motor (max current on motor is only 65A) but i can't find other ESC smaller that would run on 6S

4. Timing pulleys and motor brackets
- these would have to be machined and i'm in the middle of finding shops to get this done.
- as for pulleys keyless timing pulleys from Misumi will be perfect but it is expensive... ($80 for one pulley), any suggestions would be nice.. i need 60teeth, S3M (or 3mm HTD) keyless pulley

5. BAttery
- 10Ah LiPo 6S battery would be sufficient i think?

My board is going to arrive sometime this week, and i'm going to measure out the dimensions to make sure i can use the components above.
Will post pictures as i go..

If you are going single motor check out many posts around here. Many of them are using Turnigy Aerodrive SK3 series motors with same ESC as the one i'm going to use.

if anyone else out there have any comments about my setup idea please let me know as i'm new to this too and i'm not 100% sure this is going to work out.
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Re: Young and lost... but excited to learn! (EBoard checking

Postby sk8gineer » Mon Apr 29, 2013 3:55 pm

Yaay!

Thank you sk8norcal for those links, I actually have learned a whole lot of new things! I still have to revise some of the basic concepts but you helped to clear my mind, a lot!

I am not going for the 2 bldc motors because first, it means more money + customizing the board and second because it's my first project so I prefer to go step by step :) But I guess that 2bldc motors is the way to go. Also, is the same controlling one motor or two?

Are you attaching em to both rear wheels or one in the front and one in the back?

Thank you for your responses, I am enjoying this forum more everyday :D there's lots of interesting projects going on in the sphere!
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Re: Young and lost... but excited to learn! (EBoard checking

Postby hmin7186 » Mon Apr 29, 2013 6:53 pm

It's good to see another beginner having the same interests as i am.. i'm new at this too and make me feel a little less intimidated.. haha

anyway i'm new at this too but going to go with 2 bldc motors because i don't wanna have to make another board later.. but it does cost a lot... almost twice as much for electronics and pulleys but i hope it's worth it..
oh.. i'm going to drive two rear wheels by the way... i think this will give a good ride and good dynamics when carving around..
and i'm planning dong having two ESCs driving two motors.. so one ESC for each motor... I heard this is the proper way to go and it's the reason that brings the price up.

please share your interest and progress as you continue on with your project. I will do the same as all my parts arrive

good luck!!
Last edited by hmin7186 on Mon Apr 29, 2013 6:55 pm, edited 1 time in total. View post history.
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Any must EV books to read?

Postby sk8gineer » Tue Apr 30, 2013 5:32 pm

Hi there!

I recently discovered this forum due to a univesity project on EVs, what an incredible place! I'm learning more about the real world in a couple of afternoons here than in my years at the Engineering school! :oops:

To cut a long story short, I came across with the "Who Killed the Electric Car?" and "The Revenge of the Electric Car" documentaries and I am quite interested in the topic and would enjoy reading on it.

Any interesting books to get stared?

I guess somebody has already asked this... but I found lots of threads which sadly didn't got me any answers. Thank you beforehand!
Last edited by sk8gineer on Tue Apr 30, 2013 5:33 pm, edited 1 time in total. View post history.
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Re: Young and lost... but excited to learn! (EBoard checking

Postby Murfix » Fri May 03, 2013 10:10 am

Well in that case... I'll jump on that boat as well!

I'm a 24 year old electro-mechanical engineer from Belgium and this is all new for me.

I've been studying these forums for a few weeks now and I really want to build a 2wd board. I want to be able to get around 30km/h, but I need a longer range, so I'm counting on a 20Ah LiPo pack (7s4p) with which I hope to get to 25/30 km.

I already got my board (found it online 2nd hand).
- Battery: Zippy Compact: 7s4p, which means 4 packs of 5Ah = 25.9V and 20Ah (cost around 260$ for 4)
- Motor: 2 x Turnigy Aerodrive SK3 5065 275kv (fit for 6s-10s lipo batteries), 65A and 2050W of power (price: 57$ each)

When calculating, using 5:1 reduction, 9" wheels and 65% of total efficiency (incl. motor, chain, frictions, controllers, ...) I get to a speed of around 40km/h!

Now I'm reading up on motor controllers (ESC). I want to be using regenerative breaking and a wireless controller.

I've also got some questions:
- If I calculate my speed based on these specs, am I calculating top speed, or avg speed? (The wheels, gearing and efficiency doesn't change (much), so with a constant kv and counting on the full 25.9V, I would say that's the continuous speed which is decreasing slowly when the batteries deplete.
- Would regen. breaking and/or wireless control involve (alot of) extra programming? This is not my strongest suit.
- For a 2wd setup, I'm thinking that you can just hook the 2 ESC's (one for each motor) up to the 1 battery controller? (like in parallel) Would this be correct, or is there more to it?
- When a motor's specs rate the max voltage to be 37V (10s LiPo) for example, does this mean you're throwing away the good stuff when hooking up a 25.9V system?

I hope we can share our experiences while building our projects!

Kind regards,
Memo to myself: Screw it, just do it!
1 Apr 2013 - Start pre-engineering my first EV build!
6 Aug 2013 - Ordered all parts for my Emtb 8s 2x2kW 270kv Alien ESC setup.
3 Sept 2013 - All parts have arrived: on to the build!
23 Sept 2013 - First test ride: AWESOME!
7 Feb 2014 - Upgrade finished: 3kW motors, 12S Alien ESC, entire new drivetrain and LED's!
Build topic: viewtopic.php?f=35&t=52390
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Re: Young and lost... but excited to learn! (EBoard checking

Postby sleepsLikeNinja » Sun May 05, 2013 11:11 pm

hey all,
I am also new to this. This forum is amazing! so much info and help.
Im still doing my home work before I start my build. I was wondering: if I hit cruising speed and let go of the throttle, would the electromagnetic field created by the motor slow me down? Aside from friction in the motor, gears and belt, would the setup have an affect on the cruising speed of the board at all?
thanks and best,
Tim
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Re: Young and lost... but excited to learn! (EBoard checking

Postby hmin7186 » Tue May 07, 2013 7:27 am

I have just receive my longboard and figured i can't fit two 5055 motors side by side... with caliber trucks and 90mm wheels, there's just not enough room. So I've decided to go one motor front and one motor rear. and i think i'm going to go with NTM Prop Drive 50-60 270kv motor since this have more power and 8mm shaft.

I have just ordered my electronics and now i have to figure out drive pulleys and motor mount... I think this will be the difficult part. I did not think about calculating in the efficiency when calculating speed. 90mm wheels with 270kv motor 6S(22.2V) battery is what i'm going to use. What do you think my gear ratio should be to have enough torque during startup and enough top speed?
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Re: Young and lost... but excited to learn! (EBoard checking

Postby Murfix » Tue May 07, 2013 11:40 am

Don't worry, I've seen builds with this motor setup (front and rear). Just be sure to put the motors on the opposite side (left/right) ;-)

About the speed: what I did is calculate for the speed I wanted and use a common motor for these builds. Here is how I calculated it (I'm using the metric system):

Suppose (using your values):
- Tires: 90mm = 0.090m
- Efficiency = 0.7 (I've seen on the forum about formulas a graph that showed that 70% is realistic)
- kv = 270 rpm/V
- Battery: 22.2 V
- You want a speed of 40 km/h

Circumference of the wheel: diameter * Pi = 0.090* 3.14 = 0.283m = "1 round" (You will be making larger errors than just rounding off Pi ;-) )
speed when putting the motor directly on the wheel and no losses = (270 rpm * 0.283m)/60 * 22.2V = 28.27 m/s = 101.78 km/h
speed with losses = 101.78 * 0.7 = 71.24 km/h
Gear ratio = 71.24 / 40 = 1.78 ==> 2 (use a ratio you can find... I used 2 here as an example)
Actual speed = 71.24 / 2 = 35.62 km/h

You can tweak these parameters as you like, but remember that the higher speed you want, the less torque you will have.
This is how I did it, please correct me if I'm wrong.

Now, for torque:
I didn't calculate this, but I'm trusting that for a commonly used motor, with a likewise top speed, the torque will be sufficient.
Before I'm ordering my motor, though, I will probably calculate it something like this:
- Total weight to be pushed = your weight + board weight
- Friction: look up friction values for tires on asphalt or something
- With these 2 parameters, calculate the force the wheels will have to put on the ground to get you going: F = N*µ with N = total weight * 9.81 N/kg and µ: the friction value
- With the radius of the wheel, calculate the torque on the axis (with 2 motors, divide this torque by 2): Torque = radius of the wheel * force(F)
- look up the ki value of the motor (similar to kv, now it is: Nm/A)
- A = Nm/ki = amps your motor will need for this.
- I don't know about these losses, but they are there! (wheels on ground, chain, motor, ...) I suppose 0.7 will do.
- To be completely sure your motor is strong enough, you should be using the friction value for the worst case scenario you will be using it in)
- The amount of amps you have calculated is the absolute minimum to get you started!

I hope this was useful. I haven't tried calculating the torque yet, so feel free to point out any errors or give advice!

Good luck!
Memo to myself: Screw it, just do it!
1 Apr 2013 - Start pre-engineering my first EV build!
6 Aug 2013 - Ordered all parts for my Emtb 8s 2x2kW 270kv Alien ESC setup.
3 Sept 2013 - All parts have arrived: on to the build!
23 Sept 2013 - First test ride: AWESOME!
7 Feb 2014 - Upgrade finished: 3kW motors, 12S Alien ESC, entire new drivetrain and LED's!
Build topic: viewtopic.php?f=35&t=52390
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Re: Young and lost... but excited to learn! (EBoard checking

Postby sk8norcal » Tue May 07, 2013 3:10 pm

caliber 185mm hanger
how about paris 195?
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Re: Young and lost... but excited to learn! (EBoard checking

Postby hmin7186 » Tue May 07, 2013 6:12 pm

Thank you Murfix!! That was very helpful.. according your calculation I should have gotten motors with higher kv value... i was designing the drive system with 3:1 ratio.. well since i already purchased the motors i guess i will have to find me some new pulleys.
Does anyone know where i can find these pulleys for cheap price? Since i have to attach the drive pulley to the wheel i was thinking if keyless pulleys from Misumi but they are expensive(90 dollars each). Cant find one that will just fit on my wheels
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Re: Young and lost... but excited to learn! (EBoard checking

Postby Murfix » Wed May 08, 2013 4:37 am

You're welcome :-)

For everyone's convenience, I'll share the excel sheet I've made for myself. It can be downloaded here:
https://dl.dropboxusercontent.com/u/318 ... tions.xlsx

If you don't feel safe about downloading it, you can watch it with an online viewer (paste the URL above on this page): https://sheet.zoho.com/excelviewer

I made it to be able to play with my parameters and watch the resulting speed using the filters in the column headers. It's also useful to compare certain builds.
Remark: I noticed I forgot to add the value of 7s LiPo batteries, 25.9V in the upper table, but it's in the calculations.
Last edited by Murfix on Wed May 15, 2013 7:51 am, edited 2 times in total. View post history.
Memo to myself: Screw it, just do it!
1 Apr 2013 - Start pre-engineering my first EV build!
6 Aug 2013 - Ordered all parts for my Emtb 8s 2x2kW 270kv Alien ESC setup.
3 Sept 2013 - All parts have arrived: on to the build!
23 Sept 2013 - First test ride: AWESOME!
7 Feb 2014 - Upgrade finished: 3kW motors, 12S Alien ESC, entire new drivetrain and LED's!
Build topic: viewtopic.php?f=35&t=52390
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Re: Young and lost... but excited to learn! (EBoard checking

Postby Murfix » Wed May 15, 2013 7:53 am

One thing I don't find alot of info about: the ESC!

1. When you order for example a car ESC from HK, is it usable out of the box? I expect there will be some custom programming involved? I've never done this. What can I expect? Will I always need a programming card for the ESC?
2. I would really like to be able to use regenerative breaking. I think only the ESC has to be fit for it, or are there some other extra's you have to foresee?
3. Will any 'switch regulator' do, if you check the input voltage? I suppose this is only used for powering the ESC?
4. with the rc controller I've seen everywhere on this forum (http://www.hobbyking.com/hobbyking/stor ... aff=326255), is it possible to have the 3 options accelerate/coast/brake? When releasing the throttle, I want to coast, not brake. Anything special I would need for that?

Another thing I find quite shocking:

From the instructable everyone is recommending: http://www.instructables.com/id/The-New ... /?ALLSTEPS
2. The internal resistance of the motor, also known as winding resistance, terminal resistance, etc. It will generally be a low number (less than 1) ohms . Given this value and your system voltage, you can calculate the maximum current draw the system can theoretically see based on Ohm's Law, I = V / R . Real current draw will be less (but not much less) than this value due to the inherent resistance of copper wire, semiconductors, switch contacts, etc. But again, a ballpark figure.


For this hobbyking Turnigy aerodrive SK3 outrunner: http://hobbyking.com/hobbyking/store/__ ... arch=192kv
* R = 0.016 Ohm
* Suppose V = 44V (as specified by the max motor voltage)

I = U/R = 44/0.016 = 2750A --> What the hell????

Thanks!
Last edited by Murfix on Wed May 15, 2013 8:45 am, edited 1 time in total. View post history.
Memo to myself: Screw it, just do it!
1 Apr 2013 - Start pre-engineering my first EV build!
6 Aug 2013 - Ordered all parts for my Emtb 8s 2x2kW 270kv Alien ESC setup.
3 Sept 2013 - All parts have arrived: on to the build!
23 Sept 2013 - First test ride: AWESOME!
7 Feb 2014 - Upgrade finished: 3kW motors, 12S Alien ESC, entire new drivetrain and LED's!
Build topic: viewtopic.php?f=35&t=52390
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Re: Young and lost... but excited to learn! (EBoard checking

Postby sn0wchyld » Wed May 15, 2013 8:26 pm

1. pretty much, yes. however, its a good idea to add a few (2 - 5, or even more) low esr caps in parallel with your batteries, as close as possible to the ESC to help with voltage spikes. The longer your wire between your batteries and your esc, the more caps you should have.
Programming card is not essentual, but makes life really easy. The main setting you need is to put it into 'high timing' - otherwise the ESC will have allot of trouble staying in sinc with the motor, resulting in power loss/damage to controller/heatnig of motor.
2.
Regen wont happen on a normal car ESC, but you could look up alien escs, they might have it - a few have used them on ES with good results. typically regen requires a sensored motor setup, though there are exceptions to this.
3.
not sure what you mean by 'switch regulator'...
4.
yep, exactly what im using. setting up the accelerate/coast/brake is just a matter of setting up the controller. again, programming cards make this easier.

as to that instructable, its more than a tad misleading. your average lipo will have an IR of about 5mOhms or there abouts, so a 10s pack will have a total R of about 50mOhms to add to your current 16mOhms. Then there's your wires, the IR of your controller, and even the inductance of your motor to take account of... so the simple i=v/r calc with r only equal to your motor winding resistance is more than a little misleading. You may see breif peaks of a few hundred amps, but that's only with the motor standing still and very high loads. On my Elec mountainboard I've only seen peaks of ~100A for less than a second, and then only when flooring it from about 1km'h (and its bloody hard to not flip over backwards, im leaning so far forward when doing this im almost falling over). It quickly drops to about 70-80 as the back emf of the motor comes into play.



Murfix wrote:One thing I don't find alot of info about: the ESC!

1. When you order for example a car ESC from HK, is it usable out of the box? I expect there will be some custom programming involved? I've never done this. What can I expect? Will I always need a programming card for the ESC?
2. I would really like to be able to use regenerative breaking. I think only the ESC has to be fit for it, or are there some other extra's you have to foresee?
3. Will any 'switch regulator' do, if you check the input voltage? I suppose this is only used for powering the ESC?
4. with the rc controller I've seen everywhere on this forum (http://www.hobbyking.com/hobbyking/stor ... aff=326255), is it possible to have the 3 options accelerate/coast/brake? When releasing the throttle, I want to coast, not brake. Anything special I would need for that?

Another thing I find quite shocking:

From the instructable everyone is recommending: http://www.instructables.com/id/The-New ... /?ALLSTEPS
2. The internal resistance of the motor, also known as winding resistance, terminal resistance, etc. It will generally be a low number (less than 1) ohms . Given this value and your system voltage, you can calculate the maximum current draw the system can theoretically see based on Ohm's Law, I = V / R . Real current draw will be less (but not much less) than this value due to the inherent resistance of copper wire, semiconductors, switch contacts, etc. But again, a ballpark figure.


For this hobbyking Turnigy aerodrive SK3 outrunner: http://hobbyking.com/hobbyking/store/__ ... arch=192kv
* R = 0.016 Ohm
* Suppose V = 44V (as specified by the max motor voltage)

I = U/R = 44/0.016 = 2750A --> What the hell????

Thanks!
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Re: Young and lost... but excited to learn! (EBoard checking

Postby sn0wchyld » Wed May 15, 2013 8:35 pm

sleepsLikeNinja wrote:hey all,
I am also new to this. This forum is amazing! so much info and help.
Im still doing my home work before I start my build. I was wondering: if I hit cruising speed and let go of the throttle, would the electromagnetic field created by the motor slow me down? Aside from friction in the motor, gears and belt, would the setup have an affect on the cruising speed of the board at all?
thanks and best,
Tim


yes, but not massively. infact the motor drag can be really useful, on my mointainboard (which has more rolling resistance than a scatebaord) the drag will hold me at about 30-40km'h on a light hill. a longboard will probably roll a little faster, and a touch of throttle will eliminate almost all of the motors rolling resistance, and only take 4-5 amps to do so.
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Re: Young and lost... but excited to learn! (EBoard checking

Postby Murfix » Thu May 16, 2013 6:59 am

sn0wchyld wrote:
--> Some Awesome things!
1 + 2 + 4: thanks a million! This is really helpful information! I'll be getting that programming card for sure.
3: never mind the 'switch regulator', this seems to be just another type of ESC, not fit for this application.

About the kazillion amp calculation: I'll just overdimension the ESC by 150% of the max motor amp spec (at least 150A), since there seems to be no way to accurately and quickly calculate this which would be worth doing.

I've been looking at an alien system, but I'm not willing to pay that much.

I'm still worried about the ESC though:
regarding the information on the same instructable (http://www.instructables.com/id/The-New ... /?ALLSTEPS):
1. You don't want to invoke soft start (or governor control) as it would increase your chance on cogging. Although, I'm reading everywhere that you really need that soft start to be able to start from standstill without torturing the ESC. What is done in practice?
2. Timing control (or vector control) is a big plus. Is this the same as Hobbyking's "motor timing" spec?
And also
3. I want to be using a HV 150+A car ESC with regen braking, but sn0wchyld indicated that these are hard to find (if at all).
4. Is a sensored motor a MUST to be able to drive (mainly start) smoothly? My plan was to start with a sensorless motor and add sensors myself later on, when everything works (this will be hard enough to start with). Is this doable with 1 set of electronics (regarding the other specs I'd want)?

Anyone with an ESC with specs like these? I really can't find one.
Extra: I'm currently looking for an ESC for a 10s LiPo pack.

Thanks for reading
Last edited by Murfix on Thu May 16, 2013 7:38 am, edited 2 times in total. View post history.
Memo to myself: Screw it, just do it!
1 Apr 2013 - Start pre-engineering my first EV build!
6 Aug 2013 - Ordered all parts for my Emtb 8s 2x2kW 270kv Alien ESC setup.
3 Sept 2013 - All parts have arrived: on to the build!
23 Sept 2013 - First test ride: AWESOME!
7 Feb 2014 - Upgrade finished: 3kW motors, 12S Alien ESC, entire new drivetrain and LED's!
Build topic: viewtopic.php?f=35&t=52390
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Re: Young and lost... but excited to learn! (EBoard checking

Postby sn0wchyld » Thu May 16, 2013 7:44 am

Murfix wrote:
sn0wchyld wrote:
--> Some Awesome things!
1 + 2 + 4: thanks a million! This is really helpful information! I'll be getting that programming card for sure.
3: never mind the 'switch regulator', this seems to be just another type of ESC, not fit for this application.

About the kazillion amp calculation: I'll just overdimension the ESC by 150% of the max motor amp spec (at least 150A), since there seems to be no way to accurately and quickly calculate this which would be worth doing.

I've been looking at an alien system, but I'm not willing to pay that much.

I'm still worried about the ESC though:
regarding the information on the same instructable (http://www.instructables.com/id/The-New ... /?ALLSTEPS):
1. You don't want to invoke soft start (or governor control) as it would increase your chance on cogging. Although, I'm reading everywhere that you really need that soft start to be able to start from standstill without torturing the ESC. What is done in practice?
2. Timing control (or vector control) is a big plus. Is this the same as Hobbyking's "motor timing" spec?
And also
3. I want to be using a HV 150+A car ESC with regen braking, but sn0wchyld indicated that these are hard to find (if at all).
4. Is a sensored motor a MUST to be able to drive (mainly start) smoothly? My plan was to start with a sensorless motor and add sensors myself later on, when everything works (this will be hard enough to start with). Is this doable with 1 set of electronics (regarding the other specs I'd want)?

Anyone with an ESC with specs like these? I really can't find one.
Extra: I'm currently looking for an ESC for a 10s LiPo pack.

Thanks for reading


1.
use a medium level. any more and you're liable to throw yourself off the board... these controllers can be savage! ive been using 2 on a scale of 1 to 6, 6 being the 'hardest' start, no probs so far
2.
i believe so
3.
regen is hard to find, yes... but just braking is easy. get the hobbyking 150a esc (check my build thread if your not sure which one) they work well. I'm testing out the 200A 8s esc from HK at the moment, but so far it seems to work well too. for 10s im not sure... why so high a voltage?
4.
not a must, but defiantly a 'plus' for taking off. they tend to not be as good once they are going though, as (not sure on this point) even a small error in the positioning of the sensors can cause significant power loss/motor heating etc etc. for a skateboard where you can push yourself to at least get rolling, you wont have a problem. its not a big problem on my mountainboard either, so long as im not trying to go uphill/start in deep grass.
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Re: Young and lost... but excited to learn! (EBoard checking

Postby Murfix » Thu May 16, 2013 8:19 am

sn0wchyld wrote:1.
use a medium level. any more and you're liable to throw yourself off the board... these controllers can be savage! ive been using 2 on a scale of 1 to 6, 6 being the 'hardest' start, no probs so far
2.
i believe so
3.
regen is hard to find, yes... but just braking is easy. get the hobbyking 150a esc (check my build thread if your not sure which one) they work well. I'm testing out the 200A 8s esc from HK at the moment, but so far it seems to work well too. for 10s im not sure... why so high a voltage?
4.
not a must, but defiantly a 'plus' for taking off. they tend to not be as good once they are going though, as (not sure on this point) even a small error in the positioning of the sensors can cause significant power loss/motor heating etc etc. for a skateboard where you can push yourself to at least get rolling, you wont have a problem. its not a big problem on my mountainboard either, so long as im not trying to go uphill/start in deep grass.


Thanks again!
sounds like I should be having a bit more faith in the components

3. I'll probably have to do without regen braking then, maybe I can find something for this later (much later). I've read that it's just regenerating a couple of % of the generated power into the batteries anyway, so maybe it's not worth the pain.

Why 37V (10s)?
I've found a quite cheap Turnigy setup for 10s3p for 216$ (http://hobbyking.com/hobbyking/store/__9174__Turnigy_5000mAh_5S_20C_Lipo_Pack.html?strSearch=turnigy%205000%205s) with 37V and 15Ah.
Initially, I wanted 25.9V (7s) and 20Ah, but this would cost me aroud 260$. Now I found 37V and 15Ah for 216$, so I thought 'why not?'

But, if this is all the trouble for it, I should be going for a lower voltage...
Originally I wanted a range of 30km on the road (home-work-home = 26km, I'd rather not bring the charger to work). I figured I needed at least 20Ah for that, when comparing other people's builds and facts. It seems Ah's are more expensive than V's thought =/.
I could make a 6s4p (20Ah) setup for under 200$, but would 6s be enough on a mountainboard with air inflated tires (for both on/off road)?

4. True, and I don't have a problem with 'setting off with a kick', although a start from 0 would be cool.
Memo to myself: Screw it, just do it!
1 Apr 2013 - Start pre-engineering my first EV build!
6 Aug 2013 - Ordered all parts for my Emtb 8s 2x2kW 270kv Alien ESC setup.
3 Sept 2013 - All parts have arrived: on to the build!
23 Sept 2013 - First test ride: AWESOME!
7 Feb 2014 - Upgrade finished: 3kW motors, 12S Alien ESC, entire new drivetrain and LED's!
Build topic: viewtopic.php?f=35&t=52390
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Re: Young and lost... but excited to learn! (EBoard checking

Postby sn0wchyld » Thu May 16, 2013 10:10 am

Murfix wrote:
sn0wchyld wrote:1.
use a medium level. any more and you're liable to throw yourself off the board... these controllers can be savage! ive been using 2 on a scale of 1 to 6, 6 being the 'hardest' start, no probs so far
2.
i believe so
3.
regen is hard to find, yes... but just braking is easy. get the hobbyking 150a esc (check my build thread if your not sure which one) they work well. I'm testing out the 200A 8s esc from HK at the moment, but so far it seems to work well too. for 10s im not sure... why so high a voltage?
4.
not a must, but defiantly a 'plus' for taking off. they tend to not be as good once they are going though, as (not sure on this point) even a small error in the positioning of the sensors can cause significant power loss/motor heating etc etc. for a skateboard where you can push yourself to at least get rolling, you wont have a problem. its not a big problem on my mountainboard either, so long as im not trying to go uphill/start in deep grass.


Thanks again!
sounds like I should be having a bit more faith in the components

3. I'll probably have to do without regen braking then, maybe I can find something for this later (much later). I've read that it's just regenerating a couple of % of the generated power into the batteries anyway, so maybe it's not worth the pain.

Why 37V (10s)?
I've found a quite cheap Turnigy setup for 10s3p for 216$ (http://hobbyking.com/hobbyking/store/__9174__Turnigy_5000mAh_5S_20C_Lipo_Pack.html?strSearch=turnigy%205000%205s) with 37V and 15Ah.
Initially, I wanted 25.9V (7s) and 20Ah, but this would cost me aroud 260$. Now I found 37V and 15Ah for 216$, so I thought 'why not?'

But, if this is all the trouble for it, I should be going for a lower voltage...
Originally I wanted a range of 30km on the road (home-work-home = 26km, I'd rather not bring the charger to work). I figured I needed at least 20Ah for that, when comparing other people's builds and facts. It seems Ah's are more expensive than V's thought =/.
I could make a 6s4p (20Ah) setup for under 200$, but would 6s be enough on a mountainboard with air inflated tires (for both on/off road)?

4. True, and I don't have a problem with 'setting off with a kick', although a start from 0 would be cool.


im running 5s at the moment (4 of the packs you just linked too) in parrallel for 20ah. eventually going to switch to 8s 20-30ah for the mountainboard, and 5s 20ah for the longboard.

watt hours is all that counts for range. a 100v 1ah pack will get you just as far as a 1v 100ah pack, they both have the same amount of energy stored in them.
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Re: Young and lost... but excited to learn! (EBoard checking

Postby Murfix » Thu May 16, 2013 1:50 pm

sn0wchyld wrote:im running 5s at the moment (4 of the packs you just linked too) in parrallel for 20ah. eventually going to switch to 8s 20-30ah for the mountainboard, and 5s 20ah for the longboard.
watt hours is all that counts for range. a 100v 1ah pack will get you just as far as a 1v 100ah pack, they both have the same amount of energy stored in them.


True but a 1Ah pack wouldn't even get you started since it can't deliver enough Amps while the top speed of a 1V is next to nothing.
So it's either 37V and 15Ah or 25.9V and 20Ah.
37V: 555 Wh
25.9V: 518 Wh

So actually the 10s3p is (alot) cheaper and has a longer range than a 7s4p pack !?! Prices are roughly 216$ for 10s3p and 260$ for 7s4p.

The downside is finding a suitable ESC and the bigger gear reduction for the 10s3p pack...

Any thoughts?
Memo to myself: Screw it, just do it!
1 Apr 2013 - Start pre-engineering my first EV build!
6 Aug 2013 - Ordered all parts for my Emtb 8s 2x2kW 270kv Alien ESC setup.
3 Sept 2013 - All parts have arrived: on to the build!
23 Sept 2013 - First test ride: AWESOME!
7 Feb 2014 - Upgrade finished: 3kW motors, 12S Alien ESC, entire new drivetrain and LED's!
Build topic: viewtopic.php?f=35&t=52390
Murfix
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Re: Young and lost... but excited to learn! (EBoard checking

Postby sk8norcal » Thu May 16, 2013 2:57 pm

Murfix wrote:So actually the 10s3p is (alot) cheaper and has a longer range than a 7s4p pack !?! Prices are roughly 216$ for 10s3p and 260$ for 7s4p.


you are not buying 10s packs, but 5s packs
its cheaper because those 5s/6s packs are more popular
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Re: Young and lost... but excited to learn! (EBoard checking

Postby Murfix » Fri May 17, 2013 9:51 am

So actually, I'll be wanting the 10s3p configuration.

The problem is still... the ESC.

There is 1 HV, non-OPTO ESC I can find on hobbyking, but the amp-rating is not sufficient... (100A cont, 110A burst)

Is no1 running a board with these specs?
Memo to myself: Screw it, just do it!
1 Apr 2013 - Start pre-engineering my first EV build!
6 Aug 2013 - Ordered all parts for my Emtb 8s 2x2kW 270kv Alien ESC setup.
3 Sept 2013 - All parts have arrived: on to the build!
23 Sept 2013 - First test ride: AWESOME!
7 Feb 2014 - Upgrade finished: 3kW motors, 12S Alien ESC, entire new drivetrain and LED's!
Build topic: viewtopic.php?f=35&t=52390
Murfix
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Re: Young and lost... but excited to learn! (EBoard checking

Postby sn0wchyld » Fri May 17, 2013 8:18 pm

Murfix wrote:So actually, I'll be wanting the 10s3p configuration.

The problem is still... the ESC.

There is 1 HV, non-OPTO ESC I can find on hobbyking, but the amp-rating is not sufficient... (100A cont, 110A burst)

Is no1 running a board with these specs?


you'd want to use a car esc, as they're better setup for the kinds of loads seen on a board... and there are no car esc's that i know of that can handle 10s for less than about $250. 8s can be had for about $110, or 6s for $65, and 5s will work fine for what you want to do, so why not go with that? 10s is just gonna make gearing it down harder too...
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