Recent esc/motor failure, advice on next step.

[StebanJigs]

Hi guys, first off I have to thank all those that post and have created things here for the community at large it's been inspiring seeing what you people can do. I have done some searching on this board for peoples builds and pros and cons regarding the state of esc types at the moment and am in need of some advice after a recent breakdown with my esc/motor.

Specs of the build are/were:
Motor: Turnigy sk3 63mm 260kv (sk3 50mm 275kv last year and no issues)
Bracket: enertion with 36tooth drive gear 14tooth motor (welded aluminum on paris trucks last year)
Wheels: 83mm (90mm last year)
Battery: 4x4s@5000maH 2s2p (2x3s@5000maH 2p last year)
ESC: Turnigy trackstar 200amp 8s (tunigy trackstar 6s 150amp last year and no issues)

With that out of the way I guess I'll explain what happened. Coming back from a 4-5km ride a few nights ago I was accelerating from an intersection (luckily close to home) when it felt like the brake engaged at around 70-80% and I came to a quick stop , again luckily not fast enough to throw me (had a lid on) but could have been bad at the top speeds I am seeing of 40-42kmh(calculations show 45kmh). So after coming to this abrupt halt I quickly flicked the esc switch off and smelt the classic smoke being let out, not at the time I was sure I smelt a slight enamel/winding burn smell from the motor as well. I get it home and take a look at the motor and the only thing I can tell is that there isn't a huge short between my windings since I only have a multimeter to check resistance and not a specialized Lc meter, the only thing that makes me think it is a little shorted possibly is the esc going bonkers and a bit of rotational resistance and a specific point which I made sure was not bearings or the shaft as I disassembled it and it "looked" good.

So next its on to the esc, I opened up the smoking gun and sure enough found a row of burned fets with a few of the leads blasted off. Knowing this I am fairly sure it was a random failure or QC issue since anytime checking it had been running cool along with the motor. My guess is the failure with the esc allowed to much current into the already warm motor windings and allowed a slight short there ontop of the dead esc (fets cost almost as much including shipping for me).

After all that I am wondering what route to go for the rest of the summer months, looking at things as they stand I would like to bump up to dual drive to be able to take on constant inclines and have ensured security of motor temps. Going the enertion mount way it is limiting me to 54-55mm length motors (like the one I am currently on) for dual drive as the spacing is not enough unless I mount them in an angular fashion I would also like feedback/preference from people that have tried both ways. Are there any brands other than the sk3 line for something 8s capable and in the 225-260kv range (for the gear ratio I am at now "2.57") as I am having difficulty sourcing any.

As for the esc I have been looking at alien power systems but their shipping/cost is slightly high to canada and I don't think they have any in stock to get me riding soon, I have also looked at the tourqeboards 12s 120amp unit in either dual singles or the packaged dual setup (sadly only comes "with" motors) and I am unsure the power/speed since it is only 200kv and claculating on a current setup only gets to 36kmh but I guess with going to 90mm wheels and 15tooth motor it could be 42kmh which around what I like as a top speed.

So I guess as a tl:dr I would like suggestions on a currently available dual/dual mono esc and motor combo that works on 8s lipo and achieves 40kmh+ speed.



Thanks in advance to anyone willing to read this and give their input.

Cheers.

 

[torqueboards]

Welcome to ES

Seems like the ESC failed. How, could be a ton of issues. Usually, if an ESC fails it could be a connection problem and/or the setup isn't optimal and causes it to overheat which in return will burn out a motor or esc. Also could be a random failure as you mentioned.

I recommend a dual motor for climbing hills and a semi-high gearing for more torque depending on your weight and how you plan on stressing the motor.

For a great setup, your motors should only get slightly warm.

As for dual rear, you are somewhat limited to 50-55mm motors on the rear for everything to fit at least on 180mm Caliber Trucks. You can almost fit 2x 65mm motors on a 195mm Paris Trucks.

Dual diagonal - You can go ahead and mount 2x 6374 SK3 motors if you wanted too.

We do sell the 12S ESCs without the motors. http://diyelectricskateboard.com/product/torqueboards-12s-120a-car-esc-opto-hv/

10S, Dual Motor 170KV, 90mm Wheels on 16T/36T should get you about 25-28mph or 40-45kph.

The 4S packs are the same price as 6S or 5S packs.

4S - Turnigy 5000mAh 4S 25C Lipo Pack - $32.85
http://hobbyking.com/hobbyking/store/__9179__Turnigy_5000mAh_4S_25C_Lipo_Pack.html

6S - Turnigy 5000mAh 6S 20C Lipo Pack (US Warehouse) - $43.24
http://hobbyking.com/hobbyking/store/__16207__Turnigy_5000mAh_6S_20C_Lipo_Pack_US_Warehouse_.html

 

[StebanJigs]

Thanks for the reply so soon ehh err Mr. Torque

I like what you have suggested, my only issue now going to 10s is that this was a build I did with my brother and he has an identical setup so we have would end up having to purchase 8 new 5s/6s batteries and find something to do with the ones I already have. Although for next year and looking to move up to air tires that is looking to be the idea, we could use the 4s and then as extras get 5s/6s as long as the motor/esc combo as capable. Im just trying to keep this as economical as possible while maxing specs since I am covering a decent portion of his cost.

I guess a key question with regards to cell size and motors with say a turnigy sk3 which is rated at 10s would the only draw back to running it at 8s be a swap in voltage for current with the motor pulling a little more amperage to balance out the watt load? As long as the wattage rating is not exceeded/heat then things should be fine? I was wondering if there was a bit of tracking difference as well in the way a board handled being dual rear vs diagonal driven if you might know.

Also with your single 120amp esc posted is it the same as the dual version just in a single package(I also didn't see a standalone dual unit avail). I ask this because Im not sure how syncing will work with two solo units, I would assume a full throttle on startup then reset similar to multirotor drones, and if so just a y-splitter from the receiver would be necessary. Did you have any on hand to ship?

Thanks again for the info, it's just like being into multirotors 4-5 years ago with there being so many options and ways to go about things like the VESC(another consideration), its a fun and confusing time to say the least.

 

[torqueboards]

Thanks for the reply so soon ehh err Mr. Torque

I like what you have suggested, my only issue now going to 10s is that this was a build I did with my brother and he has an identical setup so we have would end up having to purchase 8 new 5s/6s batteries and find something to do with the ones I already have. Although for next year and looking to move up to air tires that is looking to be the idea, we could use the 4s and then as extras get 5s/6s as long as the motor/esc combo as capable. Im just trying to keep this as economical as possible while maxing specs since I am covering a decent portion of his cost.

Use the other 5S or 6S as a spare pack if you run out of juice on your other.

I guess a key question with regards to cell size and motors with say a turnigy sk3 which is rated at 10s would the only draw back to running it at 8s be a swap in voltage for current with the motor pulling a little more amperage to balance out the watt load? As long as the wattage rating is not exceeded/heat then things should be fine? I was wondering if there was a bit of tracking difference as well in the way a board handled being dual rear vs diagonal driven if you might know.

While this is somewhat true. We don't actually use anywhere near what we could use so this wouldn't matter too much. You'll start up easier because of the high voltage, you'll be less on the throttle because of the higher voltage.

As far as dual diagonal. IMO I prefer Dual Diagonal for a dual motor setup especially climbing hills and a city with potholes and cracks.

The reason why is simple. There is pull from both the front and rear of your board.

Occasionally, you may come across an uneven pavement. If you have traction on the front but none on the back. The front wheels will still pull you out of the rut and vice versa.

If your dual rear wheel setup get's stuck on the back. Your board will stop and you'll have to kick out to get out of it.

Although, this will only happen if you are trying to ride on uneven areas. This was actually a curb which I got stuck on.

Your board would be better with (2) 6374 192kv motors on a dual diagonal setup vs (2) 5055 motors on a dual rear.

However, your board will be heavier and will you use all the extra power? Most likely, not.

Both setups are great it's just preference. I prefer dual diagonal however when climbing hills. I do use (2) 5065 because (2) 6374 192KV are just too heavy.

Also with your single 120amp esc posted is it the same as the dual version just in a single package(I also didn't see a standalone dual unit avail). I ask this because Im not sure how syncing will work with two solo units, I would assume a full throttle on startup then reset similar to multirotor drones, and if so just a y-splitter from the receiver would be necessary. Did you have any on hand to ship?

Thanks again for the info, it's just like being into multirotors 4-5 years ago with there being so many options and ways to go about things like the VESC(another consideration), its a fun and confusing time to say the least.

For the dual, I automatically include Y connectors for discharge wires + ferrite rings. I do have them in stock. You will also need a 12S UBEC and the ESC Programmer Card.

The units work well together and both start up and run the exact same. In the beginning on start-up when you throttle it. One is faster than the other but in about 2 seconds they are both the same.

Haha yeah tons of options..I wanted an ebike but decided to just buy one instead of getting into an entirely different hobby. Lol

 

[StebanJigs]

Thanks again for being so quick.

What you say about diagonal seems to make sense since 4wd is a dream splitting the motors on each side front and back should maximize the contact patch with bumps and wobble. Well with that being said I believe for the time being I will be content going for a second enertion bracket and dual mono 12s 120A esc units from you (lookout for an incoming order with HVswitches). Although this is a bit pricey it allows me to use the batteries I have now as well as upgrading them to 5s/6s in the future for range and speed.

Thanks for the advice, it's a fast growing industry here and your helping with eliminating the confusion.