DIY Electric Longboard Build (Plan!) - Can you confirm it?

[WeeChumlee]

Check physical size of gears with regards to the wheel size.
If the gear is nearly as big as the wheel it could lead to your belt and/or gear becoming damaged very easily.
60T gear would not work on a small wheel at all I would think.

 

[Njakts]

68mm wheels and the pulleys be like 16/40 on 4S, if i should switch to 6S 16/60

40t diameter should be 63mm for htd 5mm pitch judging by this calculator:
https://sdp-si.com/eStore/CenterDistanceDesigner
add belt thickness x2 - that will be close to ground, but should work.

btw - I have 245kv motor, 15/40 pulleys, 97mm wheels and 6s. Pulls nice and range is around 10-12km.

 

[lemon]

Do you have the shunt resistor for the Ammeter?

no, is that only needed for that ammeter or in general? if so i'll buy one

Why is 60 too much?
this is only 44mm http://www.aliexpress.com/item/High-quality-1pc-60-teeth-Bore-5mm-GT2-Timing-Pulley-fit-width-6mm-of-2GT-timing/32656535008.html
or is a tooth pitch of 2mm not enough?

I have 245kv motor, 15/40 pulleys, 97mm wheels and 6s. Pulls nice and range is around 10-12km.

nice, whats your mAh and top speed?

 

[WeeChumlee]

Shunt is only needed for ammeter.

2mm pitch is to small for the load. Standard here is 5mm pitch. (Although I have tried 3mm, it worked but one had to keep the belt taught or it would slip, particularly on breaking.)
Use a minimum of 9mm belt width.

 

[lemon]

is there any name for 5mm pitch and 9mm belt with? like gt2 or so (i have no clue on pulleys)

Edit: found this http://www.ketten-zahnrad.ch/images/zahnriemenprofile.png

so i should take T5, AT5, 5M or XL, right?

how about this:
http://www.aliexpress.com/item/Aluminum-Alloy-XL-Type-15-Teeth-6mm-Bore-Dia-Double-Flanged-Timing-Pulley/32218789612.html (here i have to drill the hole bigger to 8mm, because the motor shaft is 8mm..)
http://www.aliexpress.com/item/Aluminum-Alloy-XL-Type-40-Teeth-8mm-Pilot-Bore-Screwed-Pulley/32709537708.html

 

[sl33py]

Lemon - i'm pretty sure you are going to set this up poorly and be really dissatisfied.

4s is going to have very little power - especially w/ 270kv motor - it's going to cog/stutter a ton to start. You can kick to get rolling which will help but you are making it difficult for yourself.

Skip the Ammeter - it is what it is (your amp draw). Good to know - sure. Needed - no. Spend the extra $5 on something more critical (like 6s batteries!).

You want HTD5m belts and gears. 9mm at a minimum, but 12 or 15mm wide belts/gears would be preferred. The increased width gives you more contact area which prevents skipping - most common on hard braking w/ 9mm wide belts in a single motor setup.

HTD3m like WeeChumlee mentioned is not a great setup for similar reasons (skipping).

Wheel size - you are going to chip your gears and damage your belts when you only have a mm or 2 clearance. 68mm wheel is tiny, and a 40t pitch wheel gear is 62.5mm.

here's one i've seen used - also a great site to do some research - belt calculator and good technical detail on gears:
http://shop.sdp-si.com/catalog/product/?id=A_6L25M040DF0908

I'd strongly suggest you go w/ a larger wheel - at least the 76mm like flywheel or clone. 83mm is my preferred, but can be a challenge if you don't have wheel clearance on your deck style. Risers help, but nobody wants to ride a 1" riser if you can avoid it.

Disregard or not - best of luck!

 

[lemon]

new wheels would be a big pain in the ass for my budget.
for reference i use some youtube videos i've seen, for example greatscott used 6S with 400kv (15/30 pulleys // ~34km/h topspeed and ~20km range @ 10000mah) and Damir Bijedic (austria) used 4S with 270kv (18/42 pulleys // ~30 km/h topspeed and 10-12km range @ 5000mah)

you all tell me that it wont work, but on videos i can see it works just fine?

so i dont who i shall believe

my biggest problem with 6S is that the board would be to fast, i want it at 20 km/h max..

but hey, as i wrote, if 4S shouldn't satisfy me i send them back and get 6S

So now i went with 15/30 pulleys with 10mm wide belt and 5mm pitch, here's a drawing to make sure that everything fits
https://puu.sh/qxPh0/fbc9b1d39c.JPG
(tomorrow i will make a 3d model of that to be 100% sure everything fits)

 

[WeeChumlee]

The choice is of course yours as to whom you believe or what advice you wish to follow - or not.

What I can say on a pure technical/physical side is:
6S / 400KV / 1:2 gear ratio - Once you have kicked to a good velocity it would then go like snot, until it saw a hill. The initial speed will take it a way but then as the motor slows it will try and keep the speed by drawing more current. The low gear ratio means very little power so it will draw even more current - vicious circle - melted motor or ESC.
4S / 270KV / 1:2.3 ratio - if he says he is getting 30km/h he is bullshitting unless he is going downhill. Even with 97mm wheels (which would sap the power - and there is not much there to begin with) he would not achieve this without a downhill start.

Speed you should regulate with gearing, not voltage.
You need the voltage for the power to be able to get up to speed in the first place.

WIth a 1:3 ratio on the gearing you would have better torque and with 6S / 270KV / 68mm wheels would have a real world speed of about 20km/h.

I agree 100% with what sl33py said before and suggest you rethink before buying/building.
We have done this before and I think we probably all made mistakes in our first build - hell I know I did. I threw away hundreds of pounds due to bad choices, fortunately my budget was not that limited (though I am hardly made of money). All we are trying to do is point you in the right direction while keeping the costs as low as possible while still having a rideable board.

Good luck.

 

[Njakts]

I have 245kv motor, 15/40 pulleys, 97mm wheels and 6s. Pulls nice and range is around 10-12km.

nice, whats your mAh and top speed?

2x3s 5000mah 20c battery
I have not tried max speed but I know I have driven it to 27 kph (gps logged) that felt hella fast and there was still more power left. I am thinking about getting 90mm wheels to reduce top speed and help acceleration a bit.
My theoretical max speed is 37kph. Real life max speed should be around 30kmh

 

[WeeChumlee]

Hi Njakts
May I suggest you do it another way that may well be cheaper and, IMHO, better?
The 97mm wheels are, in my opinion, great. A set of 90mm wheels would be more expensive than changing your wheel gear.
If you made that a bit larger then you would reduce your speed and increase your torque - and still have the rodent squashing wheels.

 

[sl33py]

Hi Njakts
May I suggest you do it another way that may well be cheaper and, IMHO, better?
The 97mm wheels are, in my opinion, great. A set of 90mm wheels would be more expensive than changing your wheel gear.
If you made that a bit larger then you would reduce your speed and increase your torque - and still have the rodent squashing wheels.

@njakts - agree with WC here. I'm building a similar dual setup - 97mm w/ 40t and 13 or 14t motor gear. A couple 8-10$ lower motor gears (don't go 12t on 9mm - skips a lot) and you will have lower speed and better acceleration from lower gearing.

GL!

 

[lemon]

So far so good, ordered everything except the lipos & charger

Which charger could you recommend?
i've seen a lot which dont support 6S, and that wouldnt be that good if i switch to 6S ^^

Is this good? http://www.banggood.com/Wholesale-IMAX-B6-Digital-RC-Lipo-NiMH-battery-Balance-Charger-p-46220.html

 

[WeeChumlee]

Yeah, that charger will be fine.
Don't forget the DC supply to the charger. (Or get one with a 230V input so you can just plug it in without a separate power supply)

 

[lemon]

Like this?
http://www.banggood.com/IMAX-B6-AC-B6AC-Lipo-NiMH-3S-RC-Battery-Balance-Charger-p-908064.html

I know these are fake imax b6's, but as i read they're not that bad

Max power is 50W, so i can charge 4S with 3A and 6S with 2A, right?

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or I just order this: http://www.hobbyking.com/hobbyking/store/__33407__Hobbyking_174_DC_4S_Balance_Charger_Cell_Checker_30w_2s_4s_EU_Warehouse_.html together with the lipos, so in case i use 6S I can send them back together

 

[WeeChumlee]

Yeah, that would be fine I should think.
Charging the battery at under 1C is not a bad thing, prolongs battery life.
Yeah, takes a while but generally I am not in a rush after a ride so would, for me, not be a problem.

 

[lemon]

Ok, anyone tried this? https://www.youtube.com/watch?v=7wj-EB4-71M

 

[WeeChumlee]

As you are only going to do a max of 6S and your charger can do 6S you do not need to parallel charger - if you have a 6S battery.
If you have two 3S batteries then a parallel charger is a good idea. Better still would be to get something like this:
http://www.hobbyking.com/hobbyking/store/__9910__2_x_3S_gt_6S_Splitter_JST_XH_5pcs_bag_.html

 

[lemon]

Ok, uhm i got an old laptop charger with got 19V 2.1A output.

With how much Amps can I charge 4S/6S then with the imax b6?

edit: nevermind just found this bad boy in my cable box: https://puu.sh/qKbrm/f61780a3c8.JPG