"the dolphin" electric bobber

damirsky · Sep 1, 2018

bought a new rear wheel:

i have finally chosen 420 chain and sprockets for this bike so i've bought a new small sprocket and got a new aluminium rear sprocket from waterjet:

comparison of the sprockets, old one made of steel:

after installing of the rear wheel we've found that the rear sprocket's plane is pretty far from the frame:

it seems that we need to shift a motor for approx 20 mm to the right side but we decided to make long shaft as a temporary solution:

and welded small sprocket to it:

EbikeAus · Sep 1, 2018

Looking really nice! Great build so far

Bernel · Sep 2, 2018

Wow, very impressive. I have followed this from the start. Can’t wait to see the end product.

Good job.

Bernel

damirsky · Sep 21, 2018

for a last few days i was building a battery.
made 4 pcs of pins and insulated them:

drilled a little back side of the battery's front panel and installed nuts:
View attachment 5
and then the process of battery's assembly has started..
View attachment 4

View attachment 2
weight measuring (no bms and wires):
View attachment 1
chassis weight measuring (no battery, controller, covers, chain etc):

to be continued..

trazor · Sep 21, 2018

Your build skills keep me impressing every post. Nice work.
I would like to ask which pouch cells are you using. Model, manufacturer, seller, etc.

TUNA0026 · Sep 21, 2018

hello I congratulate you on your bike it's beautiful ... I never saw that battery ... where did you get it? Are they more efficient than circular batteries? regards

damirsky · Sep 21, 2018

thank you guys for very kind words.

i bought my cells few years ago from russia. it was announced that the capacity is 35ah, rated current is 170-180a, max current is 350a. as i mentioned the seller beleives they made for nissan leaf by aesc. if you look at leaf's cells these cells look pretty similar.

my cells:

nissan leaf cells:

in my opinoin my cells are lipo made in china. if they die i can try to buy used nissan leaf cells.

icherouveim · Sep 21, 2018

damirsky said:
thank you guys for very kind words.

i bought my cells few years ago from russia. it was announced that the capacity is 35ah, rated current is 170-180a, max current is 350a. as i mentioned the seller beleives they made for nissan leaf by aesc. if you look at leaf's cells these cells look pretty similar.

my cells:
new35AH.jpg

nissan leaf cells:

in my opinoin my cells are lipo made in china. if they die i can try to buy used nissan leaf cells.

Good morning and congratulations for the nice hand made project!

Do you have a pic from the battery tabs to see how exactly they connect to each other ?

I like pouch cells, If they are good quality it's always a better and simpler solution compare to 18650 cells (less sag voltage, more reliable, brutal acceleration, longer cycle life).

I have made two battery packs with Westart cells and they are still work fine after lot of abuse and cycles. I don't have to sacrifice capacity by not fully charge them every time. 3V to 4.2V

The only penalty is the additional weight and size so they are suitable only for big frames likes yours.

What the final weight will be ? 120 kilos ?

damirsky · Sep 22, 2018

icherouveim said:
Good morning and congratulations for the nice hand made project!

Do you have a pic from the battery tabs to see how exactly they connect to each other ?

I like pouch cells, If they are good quality it's always a better and simpler solution compare to 18650 cells (less sag voltage, more reliable, brutal acceleration, longer cycle life).

I have made two battery packs with Westart cells and they are still work fine after lot of abuse and cycles. I don't have to sacrifice capacity by not fully charge them every time. 3V to 4.2V

The only penalty is the additional weight and size so they are suitable only for big frames likes yours.

What the final weight will be ? 120 kilos ?

thank you.

unfortunately i didn't make a photos during assembly i only have photos from my first try with wrong sized front panel:

so as you can see cells connected to each other by bending the contact plates to each other and then press it to the front panel by srewed bars.
and oops!
View attachment 1

i have already ordered the fabrication of three versions of front panel and all because of wrong measurements. :oops:

icherouveim · Sep 22, 2018

Thanks for the Photos! Now I understand how you've connected the battery tabs.

damirsky · Sep 22, 2018

icherouveim said:
What the final weight will be ? 120 kilos ?

sorry i didn't answer you before. i guess that weight will be about 95-100 kg.

damirsky · Sep 24, 2018

hello everybody.

today i've opened the motor for installiing of thermal sensor.
View attachment 4
as you can see hexahedron tool clings to the rotor.

this is not good.. any ideas how to imrove this? may be cover the rotor by additional iron jacket?
i was also disappointed by lamination tickness.
View attachment 2

so the lamination tickness is 0.5 mm. i don't know why but i had a thought that it should be 0.35 so that's why i preffered to purchase rv-120pro instead of rv-120. i've checked with revolt website and it is written that lamination at rv-120pro is 0.5 mm. it sucks..
the fill by copper is also not the best..

we will anyway install this motor in the bike and check how it works but i'm gonna order qs3000w 138 70h middrive motor. i guess that 138 means diameter of rotor and 70h means height of magnets in mm. so we will see which motor is better for this bike..

macribs · Sep 24, 2018

Best of luck with the revolt, you might need it.
Consensus on the forum seems to be that the revolt was a good idea, and it kind of stopped at the good idea. Can't remember one revolt thread here where the builder was pleased with the revolt. You can use the search function to see for your self. Magnetic leakage from the can, low copper fill, and even magnet problems are all common it seems. Also the hall sensors are often "out of whack"so it might lead to problems with smooth take offs, to much heat, too little power etc. Personally I would plain an simple ditch the motor and be done with it. I don't think you will ever be happy with it.

What about looking at the sur ron motor? It spins faster but it got a build in reduction in the motor housing. I wrote about it here, and there are links to read more about it. Motor comes in various versions, including a dual motor, and can even be paired with a controller. Don't know the price but as cheap as Sur Ron bike's are maybe the parts are low priced as well? https://endless-sphere.com/forums/viewtopic.php?f=30&t=91144&p=1413388#p1412910

damirsky · Sep 25, 2018

macribs said:
What about looking at the sur ron motor? It spins faster but it got a build in reduction in the motor housing. I wrote about it here, and there are links to read more about it. Motor comes in various versions, including a dual motor, and can even be paired with a controller. Don't know the price but as cheap as Sur Ron bike's are maybe the parts are low priced as well? https://endless-sphere.com/forums/viewtopic.php?f=30&t=91144&p=1413388#p1412910

i was looking at them and the denzel motors either. i finally plan to order qs motor because of their well known reputation, i red some feedbacks from russian guys who have experience with qsmotor 3000w mid. finally qsmotor factory store at aliexpress have pretty attractive offer - i can buy motor+foc controller+delivery for about $500.

QS-3000W-138-70H-mid-drive-motor-with-EM150S-controller-max-speed-100kph.jpg

if i knew about this proposal couple of years before i would definetly buy this one before buying revolt+adaptto.

but what's done is done so i only have a way to continue getting of a new experience. :lol: another thing is that if i change controller i need to purchase bms and display too. it's not a huge deal but i need to research it before buy.

macribs · Sep 25, 2018

I think you make a good choice ditching the Revolt. Don't know anything about the QS motor, but as you said it is QS and we know they do good things with their hubs so surely they have put that know how into their mid drive as well.

spinningmagnets · Sep 25, 2018

I am no motor expert, but I think there is a chance that you may need a little more airspace between the spinning shell of the outrunner and the metal parts in the frame. It would not take much to ensure there are no eddy-current issues.

These outrunners are typically using a thin section of "back iron" as the steel shell, in order to save weight, since their main customers for RC models are sensitive to grams of weight between one motor and the next.

I am surprised that they still carry any motor model with 0.50mm thick laminations. The extra cost to use the thinner 0.35mm is very minimal, and quite affordable.

damirsky · Sep 28, 2018

spinningmagnets said:
I am no motor expert, but I think there is a chance that you may need a little more airspace between the spinning shell of the outrunner and the metal parts in the frame. It would not take much to ensure there are no eddy-current issues.

These outrunners are typically using a thin section of "back iron" as the steel shell, in order to save weight, since their main customers for RC models are sensitive to grams of weight between one motor and the next.

I am surprised that they still carry any motor model with 0.50mm thick laminations. The extra cost to use the thinner 0.35mm is very minimal, and quite affordable.

yes, you are right. the metal near the rotor is not a good idea. i'm gonna work on this.

damirsky · Sep 28, 2018

hi everybody.

got the fiberglass covers from outsource..

View attachment 4

..and immediately tried fitting..
View attachment 3
View attachment 2
View attachment 1

https://youtu.be/ZSV_2dw_1MU

p.s. sorry for the mess at the backstage

macribs · Sep 28, 2018

Oh man that thing is coming along nicely. She is a beauty.

damirsky · Oct 5, 2018

hello my dear colleagues!
glad to inform you that we continue building of the electric motorcycle..
last days i was soldering the bms wires:

fabricated some covers from acryllic glass:
View attachment 3
installed the bms board:
View attachment 2
unfortunately i couldn't find jst-xh connectors here locally so i've bought this kind of connector:

and made connectors myself:

some cats:

have a nice time and to be continued..

damirsky · Oct 6, 2018

hi everybody.
today i was soldering the bms connectors to wires:

and then started screwing wires to contact plates:

and finally connected wires to bms:

to be continued...

sjofels · Oct 29, 2018

Love the project, keep up the good work!

TilmanBaumann · Oct 29, 2018

I have to say the stand-off screw going right through the side of the battery pouches makes me a bit nervous.
At least with some manufacturers, the inner liner layers are conductive and connected to battery potential.
I would perhaps wrap the screw in some kapton tape or some other insulating material.

Ah, and FANTASTIC looking bike. This is going to be a sweet sweet bike taking full advantage of the artistic flexibility of electric drivetrains.

damirsky · Nov 6, 2018

dear friends, thank you for your kind words, it is really motivating.

TilmanBaumann said:
I have to say the stand-off screw going right through the side of the battery pouches makes me a bit nervous.
At least with some manufacturers, the inner liner layers are conductive and connected to battery potential.
I would perhaps wrap the screw in some kapton tape or some other insulating material.

you mean those threaded rods:

?
if so they are already insulated by heat-shrink tubing. you can see it at the right rod and at some of the battery's picrures. i found that the holes can be conductive during first assembly of battery. :mrgreen:

then i made new thinner rods and insulated them.
the battery is working now and i even could connect it all together and make a first motor run in wye:
https://youtu.be/oyWOh-WEUSo

TilmanBaumann · Nov 6, 2018

:wink:

"the dolphin" electric bobber

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