10S custom skate ESC: testers wanted!

austindavid said:
Hey guys-

Vedder posted a video describing how all this works in plain language: https://www.youtube.com/watch?v=RXJKdh1KZ0w
Click to expand...

Nice video... lol

austindavid said:
re: "round in circles," that thread didn't seem to conclude with an ESC anyone could use. I saw a schematic, but no PCB, no code, no parts list, and -- most importantly -- no working skateboards. Maybe the market has changed, who knows.
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Yeah, the thread is dead. Nothing use-able. Thankfully, Ben is around :mrgreen:
 
I have smoked 2 mamba monsters 150 A, 1 Toro 150 A and a Turnigy 200 A 8S so it would have been great to have some leverage in the specs and thermal protection. It costs more in the long run to buy new escs.
 
If you've trashed that many ESC's I'd take another look at your setup. You are either geared wrong or abusing it somehow. People have hundreds of miles on their esc's without issue.

I liked the video. I'll have people watch that next time I'm trying to explain something to them.. :lol:
 
Hook a wattmeter up and tell us your wattage and amps. The spikes are what kills the escs. I'm curious how high you've gotten your amps. That is the weak point in RC escs. They won't do current limiting, it will just blow. Easy on the throttle there. :lol:
 
austindavid said:
made_in_the_alps_legacy said:
vedder said:
the price is about 80€ for every ESC when I solder everything by myself. .
Click to expand...
Would you start selling "soldier your own / bag of parts" ESC kit for 80E ? seems fine to me :wink:
Click to expand...

Surface mount. If you seriously want to save like $20 of $100 or so I'm sure we could help you, but quality is much harder to control for that. Very easy to screw up on accident.

Really we need to get the first few made and see how it goes.
Click to expand...

Yes, I do like "soldier your own" option (I soldiered my wiireciever during spare time at work, so I earn money while soldering :mrgreen: )
I was reading vedder specs again, so 10s and 50A continuous means 2100W continuous - is that the basis for the specs ? (1300W on 6s)
 
I was reading vedder specs again, so 10s and 50A continuous means 2100W continuous - is that the basis for the specs ? (1300W on 6s)
Click to expand...
Yes, something like that. That is for the current version of the PCB I have though without heatsinks. We might add heatsinks and/or a fan to the final version to run at higher currents.

Regarding the voltage, 12s should be fine too. A fully charged 12s pack is 4.2 * 12 = 50.4V, so there is still some margin left. Running at 14s, which fully charged is at 58.8V, is pushing it a bit, but I wouldn't say that it is impossible. What I have tested for a long time is a 10s setup, because that is what I happened to have on the board I was borrowing.

When running on 6s, the output power is lower. Heating losses in the ESC only depend on current, not on voltage. So running at a voltage close to the rated one with a low kv motor will generate the least amount of heat in the ESC. One thing that could be done for 6s setups would be to use different MOSFETs. Lower voltage FETs in the same package tend to have lower ON-resistance, so then the current can be higher. There are several FETs with different voltage ratings in the the same package, so we could make a few different versions of the ESC for low voltage/high current and high voltage/low current. You can expect a higher power output for the higher voltage versions though, because handling high currents also generates heat in wires, PCB-traces, shunts etc.
 
OK, thxs, agreed that running at higher voltage makes less losses for a given power output
As per the "batery range" topic, I think +1000W continuous is fine
http://endless-sphere.com/forums/viewtopic.php?f=35&t=58661&start=25
281395ESEboardevalI.jpg
 
Glad you like it, the more data provided, the sweeter the graph is :
so feel free to post (in the battery range topic) "average speed" and "average consumption" in Wh and you will show up in that graph.
(it's not really clear yet what we ultimatly get out of that evaluation, some e-board rider drag coefficient? some rolling resistance discrepencies when using inflated wheels? some transmission resistance evaluation? ... so keep feeding it and we see if there is some trend, i think so far the "kind of trend" showing up is the aerodynamic resistance and inflated versus hard wheels)
 
Some updates on the project, with the longboard kit I got from Austin and Dexter. I have posted the youtube video description below for convenience.

[youtube]-4hbnewUonw[/youtube]

I got an electric longboard kit from http://diyelectricskateboard.com/ today. Dexter from diyelectricskateboard and Austin David, who developed wiiceiver, sent it to me for free to support the development of my open source ESC (http://vedder.se/2014/01/a-custom-bld...). Thank you guys for the support!

After I got home from work I assembled it and put on the electronics using some duct tape, for the first test drive. I spent a few minutes using the latest version of my BLDCTool GUI to configure the ESC for this motor and PPM input signal from wiiceiver ( without having to recompile the code this time :) ).

Since the longboard only has a single motor and a gear ratio of 1:2 that at full RPM using a 8s lipo battery would run almost 70 km/h, the sensorless startup without pushing is a big challenge; but is seems to work quite well anyway. However, with only one motor, I would prefer to have a gear ratio of at least 1:4 with this wheel diameter. Otherwise, the motor will run very hot uphill and have insufficient torque - after all I was using 60 amps during acceleration in this video and barely got away. With the other longboard I posted a video about with two motors and a gear ratio for a top speed of 35 km/h, I would have fallen of right away by pushing 60A into each motor. This single motor setup, a 10 or 12s lipo and 1:5 gear ratio would be ideal. Then the top speed would be around 35 km/h and I could go up any hill without problems.
 
So awesome. We sent you that setup specifically because it should be a challenge for an ESC. if you can make *that* work well, then anything will work well.

The fact that your ESC worked immediately is a pretty solid testament to the work you've done already. We're looking at lower kV motors for 8S, and you've noted the lower gearing of interest. 10-12S seems to be a little challenging for off-the-shelf LiPo packs, but as we look at manufactured batteries with onboard BMS & custom chargers, the higher voltage may make more sense. The commercial boards all seem to be in the 10S range, apparently they've figured something out :)

I'm really glad to hear everything arrived and works so well initially. I found more problems with the flier -- or, I was able to confirm previously-suspected problems -- and am totally ready to receive a few prototypes from a proper ESC :D
 
just for the amp database...
ran the destroyer at a max speed of 47 kph with a max amp rating of 36.2 amps... at 48.1v on my new 12s battery pack... been a while since i went that fast... and it actually felt a lot faster... guess im getting old...(or smart)

MIght go for a 50kph sprint on sunday and check the max amps....
 
I'm not sure what flier did.... all the previous ESC from them where rock solid... last batch definatley some issues.... if they don't get there shit together I'll be looking for a new supplier....

Ill buy 20 of these if they are the goods....

I'm also in the process of building a eboard-centric bench dyno so I can quickly/easily test different ESC's, ESC settings, motors, motor RPM, temp, volts, amps, watts, gearing ratios.....

So suppose the question is how quickly can you make these ESC?

And how can I get one to test?
 
@Vedder. So i gather your fairly keen on higher voltage, low KV motors....

Is the primary goal to limit peak current draw through your setup? Can you discuss in more detail what you belive to be the best setup for eboards and why?

Don't get me wrong....More voltage sounds great to me... higher RPM.... more reduction....less load on motor. however eventually you will be limited by motor KV & the diameter of the pulleys that can fit on a skate wheel.

many respected ES ebike guys claim high voltage. High RPM motors. Big reduction.. offers the best efficiency. Lower peak current draw. Cooler motors Etc.

I'll be testing 3mm HTD pulleys to see if they can handle the RPM & torqué required for eboards.

If it proves to be functional it really opens up the door for the reduction you are wanting to use. 4:1 is easily possible on a 83mm wheel. Maybe 4.5:1

Only other issue with 8S.... 10S.... is the physical size of the battery and making enough room for it on the deck.... whilst still having large capacity... I'm working on 20AH super slim options.

I look forward to reading your thoughts.
 
I think it's less heat generated by running on higher voltage which would end up running at less amps. You can run at 6S but your amps are higher which result in more heat.

Pretty much the same as you mentioned with ES ebike guys. Dual motor seems ideal if you are running your setup hard. I think 63mm would be better versus 50mm setup. 50mm should mainly be used for flat ground and/or you need to up the torque to put less stress on the motors. 63mm are definitely a better feel to it than 50mm. However, it also adds 1-2 lbs to your setup. If you aren't climbing any steep hills then it probably wouldn't matter much.

I really don't think 3mm HTD would fix any of your issues. The depth of the 3mm is just way too small IMO could be wrong. Let me us know if it works out. I'm definitely interested. I think GT2 5mm would be more ideal with 15mm width belts. You also could fix everything by going chains. The keyway also definitely helps. I would add it to your kits. I could only imagine the stress we put on set screws going up steep hills or riding the throttle hard. The pulley also gets mangled and tore up on the motor shaft and is hard to remove a few times. I assume this is due to the torque and a keyway would definitely help with it.

Chains are the easy way of fixing it and/or 15mm width belts. Chains are also an easier way of reaching a better gearing ratio. 10T Pulley doesn't seem to hold much while a 10T chain is probably more then sufficient. They do have some crazy belt setups on motorcycles. Haven't read what they use yet.

Batteries - As much as everyone would like to have 20ah on a board. That's a ton of weight. Not sure, how much weight you calculated but you'll end up easily being a 20+ lb board or so. 48ah 20ah might be around 8-10lbs?

In the end - the question seems more broad than anything. It's kind of tough to have 1 specific setup for an eboard to be lightweight 10-12 lbs, powerful 30+ mph, hill climber (20% steep hills), distance runner (12-15miles). It's more along the lines -- what do you need? Why do you need? Do you have the money?

Supposedly, highest output for power that we need while keeping the heat to a minimum?

@Vedder - Still want to hear what you have to say :)
 
just watched one of your other eboard test videos vedder.... it looks like you have 3mm pitch pulley in use already.
 
onloop said:
just watched one of your other eboard test videos vedder.... it looks like you have 3mm pitch pulley in use already.
Click to expand...

on 15mm :) I wouldn't try it on 9mm. Boosted runs 3mm or 2mm on 15mm width. 15mm would probably work well. You can reach those more unreachable gearing ratios with the 3mm belts. Let us know.
 
@torque the 20Ah 6S LIPO is 4.9pounds.. Or 2232 grams. YES ITS HEAVY.... but how cool would it be to ride for 2hrs on one charge!

there are other "better" areas to save weight
> 3mm pulleys are substantially lighter than 5mm due to the ability to make them smaller with the same qty of teeth.
> wood is also heavy.
> Components housings.

my dual drive all terrain build that i'm working on atm is under 21.69pounds with 20AH & 5 inch pneumatic wheels.
 
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