MYATU X7 Electric Mountain Bike 26" (hobbyking)

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dr_frost_dk
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MYATU X7 Electric Mountain Bike 26" (hobbyking)

Post by dr_frost_dk » Oct 19, 2016 11:05 am

Link to EU warehouse http://www.hobbyking.com/hobbyking/stor ... ouse_.html
It will take some days to do this write up and i have a lot of mods i want to do, like voltmeter to get an accurate battery %, and i have an extra battery from my previous bikes/mopeds i want to add to this.

Stock Bike
Image
"Modded" bike so far
Image
To begin with ill talk about assembly of the bike.
It comes very complete, all that needs doing is:
Front Wheel
Fenders/Front Light
Handlebars
Pedels
Battery holder needs tightening up
The front fender was a BIG hassle to get on with the light, had to get creative to get it to fit.

Pros:
* 350W motor, pulls nicely but of course nothing vs my DIY 3000W friction drive bike
* Good Frame, nothing seems to thin or flimsy.
* It has a HORN
* Has a throttle and can be driven on throttle on Level 0

Cons:
* 8.8Ah battery, tested to 7.5Ah, this might be where the low price comes in
* Built in Light, very cheaply made lamp that will blind on comers as it just throws without any "cutoff"
* PAS slow to react, but maybe it can be setup better in the MANY options in the computer
* Rear Fender is just crap, very little help from the elements
* Crank bearing seems "loose", will get it checked out

I did however have to mod the battery holder as it was loose and the battery would barely be held in place, this could cause the battery to come of in a big bump, so that is a -, any maybe im the only one that will have this problem, i will do some more on this with pictures.

So far im VERY impressed by the quality of this 730$ (shipped) bike, it does come with a "normal" seat so i changed it to my GEL-Seat very quickly

Rear Motor:
20161111_001.jpg
20161111_001.jpg (62.17 KiB) Viewed 2121 times
This is all i can see, and can't find anything about it

Controller:
20161113_003.jpg
20161113_003.jpg (120.41 KiB) Viewed 2121 times
Also no info on this on the inet....

Display/Computer - Key-Disp KD21C:
Im really impressed by all the settings in this computer, have been used to just having a Motor & ESC with a few settings, but on this computer you can do all kind of things, and instead of me going through all things i will just post the manuel here instead.
Key-Disp-KD21C.pdf
(1.04 MiB) Downloaded 63 times
Some Data so far:
* 7Km run (city) = battery at 38.6V, manuel says this battery needs 4 cycles to be "run in" and it should perform better, battery has a cutoff at 27.5V! (2.75V pr cell), looking at other 18650 they can actually go down to 2.5V, but i stil don't like pushing battery's to that level, also under 3.15V the capacity is VERY low, as can be seen in Post #3, from 3.26 to 3.16 only gained 0.1 Ah.
Another user on hobbyking got 16km in a hilly area till battery cut off, so that does not inspire confidence.
My run was pretty much on FULL power at 27km/h, pretty much no pedaling.
* A little battery update for me is changing from Li-Po to Li-ion and the much lower V pr cell where there is still power, normally i am use to the lowest voltage of 3.6V and this battery goes to 3.15V, so a longer run is required to get the full range city and "country", testing will go on when the weather is better, right now it is just raining all the time.
* 8.9km run (city) = Battery at 37.35V (65%), giving me a max range of about 25km, battery is now on 3 cycle
* 12.8km ("country") = Battery at 36.09V (45%), giving me a max range of about 24km (This run was with the bags and into the wind on a windy day)
* 12.8km ("country") = Battery at 37.03V (61%), giving me a max range of about 33km (This run was with the bags and with the wind on a windy day)
EDIT: corrected % left after many data points on last discharge, now i know my battery better

Estimated Consumption: (more data needed)
* City Driving = 10.6 wh/km
* Country Driving = 10.1 wh/km
* Extra battery (1110Wh) (Still needs more data)
* City Driving = 13 wh/km (max)
* Country Driving = 12wh/km (max)

More to come.
Attachments
MYATO-X7.jpg
MYATO-X7.jpg (207.79 KiB) Viewed 543 times
MYATO-X7_Mod2.jpg
Last edited by dr_frost_dk on Sep 24, 2017 8:02 am, edited 19 times in total.

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dr_frost_dk
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Re: MYATU X7 Electric Mountain Bike 26" (hobbyking)

Post by dr_frost_dk » Oct 19, 2016 11:06 am

POST #2 reserved for MODS, Tweaks and Upgrades

Mods that ill like to do:
* Change front chainring as it is almost impossible to help the bike when speed is 22+km/t as you have to pedel VERY fast. This does require changing the whole pedal as this bike has a fixed chainring.
* Make a PROPER rear fender, today i was in the rain and my pants was just soaked.
* Various Alarms etc.

Critical MOD:
Have to make a small drain hole in the battery holder as it can accumulate water, not good for the battery
20161023_003.jpg
20161023_003.jpg (213.47 KiB) Viewed 2151 times
Rear Fender "upgrade"
Well had some Acrylic laying around so after the soaking i got today i just made a Quick Fender
20161023_002.jpg
20161023_002.jpg (136.01 KiB) Viewed 543 times
Just tested the fender by hitting a lot of puddles on a 9Km trip round the city, and my pants are dry :)

Cargo Rack
I did not know if i could get my E-Bike Cargo Rack to fit this bike, but as it turned out it was very easy :), future addon is maybe paint it black to match
I can put my entire weight on it and it is rock solid :)
20161024_002.jpg
Battery Mod:
20161124_007.jpg
20161124_007.jpg (241.71 KiB) Viewed 543 times
Changed the 4 LED indicator for this Voltmeter, only problem with this voltmeter is that it is off by 1.0V, so the 42.8V is actually 41.8V, ordered 2x of these voltmeters and this is sadly the best one....
And yes it is not pretty but will get the job done :)
Last edited by dr_frost_dk on Mar 17, 2017 9:54 am, edited 11 times in total.

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dr_frost_dk
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Re: MYATU X7 Electric Mountain Bike 26" (hobbyking)

Post by dr_frost_dk » Oct 20, 2016 3:33 pm

Ill add this post #3 just for the included battery.

Im testing it right now with a Watt meter and inductive load of 40-60W
Testing in Progress:
Well looks better then feared, so far: (random checks)
5.6Ah at 35.0V
6.6Ah at 34.1V
7.1Ah at 33.5V
7.4Ah at 32.6V
7.5Ah at 31.6V
So now i know i can set the battery display to show low at 32V, i have been to used to using Li-Po at 3.6V "dead" and the battery's here go to 3.2V "dead", found a test
at http://lygte-info.dk/info/BatteryCharge ... %20UK.html
Image
And the graph that has the same kind of percent to voltage is the last panasonic battery

Test 2016/10/21 - 40-60W discharge:
41.3V - 31.6V
7.5Ah - 271Wh
Test 2016/10/26 - 40-60W discharge: (Charger is not the best for a "Precise" test)
41.3V - 31.6V
7.46Ah - 268Wh
This test is only for very little help from the motor, not for going 25km/h with no pedal assistant
Now with both tests the capacity is the same within margin of error, so the 4 charge cycles claimed are hereby shot down, next task will be to take battery apart to see what kind of cells are in the battery, should be able to find the time in the next week

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dr_frost_dk
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Re: MYATU X7 Electric Mountain Bike 26" (hobbyking)

Post by dr_frost_dk » Nov 10, 2016 2:32 pm

well not even 1 month and i have a flat tire, the valve got some pressure from my lock as i forgot to take it of, and i only went a few CM/Inch before the lock held it back but the valve broke...., i will get some pictures in this post in the next hours.
Oh and of course it had to be the rear tire.... but at least now i can add controller with picture in post #1

So another upgrade to do on this bike is to get some schwalbe tubes instead of these CHEAP Chadyang tubes, man they are just crap
20161110_004.jpg
Last edited by dr_frost_dk on Mar 17, 2017 9:51 am, edited 3 times in total.

hemo
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Re: MYATU X7 Electric Mountain Bike 26" (hobbyking)

Post by hemo » Mar 15, 2017 12:32 pm

Do you know which Xiongda hub is fitted is it the 2 speed version ?

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