Converting Derbi Senda to electric

General Discussion about large electric scooters and motorcycles and other things with no pedals.
Post Reply
Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Converting Derbi Senda to electric

Post by Rain » Jan 31 2020 4:03am

Hi everyone!
Not much of a poster but decided to create a blog of current build.
I've been doing it just as a hobby for few years by now. Started with simple bicycle conversion to 350W motor, then took a fat bike and 1.5kW motor, then current kit - Golden Motor HLDC 3kW motor, Kelly KLS-H controller and a bit of battery.
First plan was to use the kit on a Yamaha TZR-125. The e-motor was actually chosen by torque numbers of original motor.
Built it so far that it ran but it looked ridiculous - sportbike looking thing capable of doing about 60km/h.Frame was too heavy too.
tzr125.jpg
tzr125.jpg (37.66 KiB) Viewed 937 times
Then bought a chinese Tmec moped (Jawa Betka). Got it running fine and drove it around entire last summer. Ran fine, top speed around 72km/h.
jawa.jpg
jawa.jpg (81.09 KiB) Viewed 937 times
But as looks and frame was not really what I wanted in the long run, it was now time for another upgrade.

Now looked for biggest moped frame there is and found a year 2000 Derbi Senda R1 50ccm enduro-like thing. It is about 24 cm longer and quite a bit stronger frame while weight is still ok.
derbi1.jpg
derbi1.jpg (17.45 KiB) Viewed 937 times
This photo is from its "good side". Right side has taken some beating, plastics broken and missing.

Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Re: Converting Derbi Senda to electric

Post by Rain » Jan 31 2020 4:12am

Took it to garage and as first thing removed remains of plastics and of course engine.
frame1.jpg
frame1.jpg (61.78 KiB) Viewed 936 times
Quite beefy compared to chinese single tube frame.
frame2.jpg
frame2.jpg (49.51 KiB) Viewed 936 times

Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Re: Converting Derbi Senda to electric

Post by Rain » Feb 02 2020 6:01am

Got the motor mounted.
Aluminium faceplate (6mm) once made for Yamaha is now in use again.
2.jpg
2.jpg (37.58 KiB) Viewed 880 times
Used original mounts with some spacers and long bolts.
5.jpg
5.jpg (44.32 KiB) Viewed 880 times
This motor only has fixing points if front but fabriced a small one to rear side too.
Will see in time if 2+1 fixing points will be enough or will it need more.
Just in case left some room on top of faceplate for additional fixing.

Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Re: Converting Derbi Senda to electric

Post by Rain » Feb 04 2020 2:07am

Found a suitable location for controller
kelly1.jpg
kelly1.jpg (58.78 KiB) Viewed 828 times
Attached through rear mudguard and under the seat, completely hidden but still cooled enough.
Most definitely will need some kind of hard cover on top. Quite happy with it :)

User avatar
tylerwatts   1 mW

1 mW
Posts: 19
Joined: Sep 14 2012 3:10am

Re: Converting Derbi Senda to electric

Post by tylerwatts » Feb 09 2020 5:21am

Looks good. Nice donor choice too. Will you put smaller road wheels on? The Senda came as a supermoto also I believe.

Cheers
Tyler


Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Re: Converting Derbi Senda to electric

Post by Rain » Feb 09 2020 1:58pm

Thanks!
Nope. As I am 190cm I think for me the current look will work just fine.

Some new parts arrived. Some orange stuff.
13.jpg
13.jpg (28.08 KiB) Viewed 712 times
And then battery gauge. Will see if this one works any better.
14.jpg
14.jpg (34.76 KiB) Viewed 712 times

Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Re: Converting Derbi Senda to electric

Post by Rain » Feb 09 2020 2:07pm

Some work progress too.
This is how the controller looks from other side. Cooling should be fine, especially on rainy days :)
11.jpg
11.jpg (37.22 KiB) Viewed 709 times
Most time spent on battery boxes.
12.jpg
12.jpg (48.17 KiB) Viewed 709 times
15.jpg
15.jpg (31.49 KiB) Viewed 709 times
16.jpg
16.jpg (50.86 KiB) Viewed 709 times
Both attached.
19.jpg
19.jpg (41.88 KiB) Viewed 709 times
Also led bulbs for rear arrived. Reflector is in quite bad shape. All the reflecting stuff is gone, resprayed from inside with a silver paint but result is still not too good.
17.jpg
17.jpg (40.38 KiB) Viewed 709 times

User avatar
tylerwatts   1 mW

1 mW
Posts: 19
Joined: Sep 14 2012 3:10am

Re: Converting Derbi Senda to electric

Post by tylerwatts » Feb 10 2020 3:57pm

Interesting how narrow the 2 battery boxes are, what batteries/cells are you using?

Cheers
Tyler


Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Re: Converting Derbi Senda to electric

Post by Rain » Feb 12 2020 1:01am

They really are not that narrow - 8.5cm internal height.
Panasonic NCR18650PF's are used. 112 elements on either side and then enough room for at least 70 more on top.
Plan is to add third pack later, when I can see how much room there will finally be.
21.jpg
21.jpg (43.11 KiB) Viewed 567 times

Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Re: Converting Derbi Senda to electric

Post by Rain » Feb 14 2020 3:14am

Did some wire connecting, everything soldered.
Fuses, blinker relay & step-down in place, also connected startup relay and battery bms.
23.jpg
23.jpg (41.14 KiB) Viewed 484 times
24.jpg
24.jpg (51.64 KiB) Viewed 484 times

As the 48V relay came without holder or any means of fixing - made one myself. Printing will finish in 2 hours...
relee hoidik.png
relee hoidik.png (22.26 KiB) Viewed 484 times

Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Re: Converting Derbi Senda to electric

Post by Rain » Feb 16 2020 8:52am

Connected everything and it is alive.
Only strange thing is that pre-charge resistor now appears to be of too high resistance.
Voltage drops from 50 to 11 volts and Kelly KLS-H is not happy, making whistling sound.
Will try with smaller resistor and see what happens.
As it is the same resistor I had there from day one, it is weird. Resistance measured to 1k as it supposed and all else looks fine.
elektriskeem1.png
elektriskeem1.png (27.08 KiB) Viewed 386 times

Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Re: Converting Derbi Senda to electric

Post by Rain » Feb 16 2020 2:42pm

Figured the pre-charge thing out finally.
I connected the pin 7 - Power - which powers the controller on straight to connectors motor side - so it was powered on when connector was triggered which is fine. What is not fine, is that even through pre-charge it got enough power to attempt powering on.
Moved the pin 7 wire to output line of small relay which switches the 48->12 and all is good again.

Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Re: Converting Derbi Senda to electric

Post by Rain » Feb 18 2020 1:50pm

Two battery halves now connected into one. Plenty of room for one more additional battery.
28.jpg
28.jpg (73.38 KiB) Viewed 309 times
All the wiring is also getting somewhere. All is connected and ready to go.
27.jpg
27.jpg (71.36 KiB) Viewed 309 times
Main contactor (big black thin on the left side) will be replaced soon with a stronger one. Current is actually meant for 12V systems and has 100A switching.
New one coming in soon is a EV200HAANA - switching 500A and up to 900V with 12V coil. Should be enough...

And battery level meter got an fixed.
26.jpg
26.jpg (102.13 KiB) Viewed 309 times
And charging port attached.
29.jpg
29.jpg (26.82 KiB) Viewed 309 times

User avatar
amberwolf   100 GW

100 GW
Posts: 28670
Joined: Aug 17 2009 6:43am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: Converting Derbi Senda to electric

Post by amberwolf » Feb 19 2020 12:09am

Rain wrote:
Feb 09 2020 2:07pm
All the reflecting stuff is gone, resprayed from inside with a silver paint but result is still not too good.
use a matte white instead, over the entire inside surface of the non-transparent parts of the light housing, you'll get a more even lighting of the lens from the led unit.

the reflector was designed to spread/focus the light from one specific small point / line, where the bulb filament is in the incandescent.

the led bulbs don't present light from the same place, so the reflector doesn't really work the way it was meant to anyway.

Rain   1 mW

1 mW
Posts: 12
Joined: Mar 22 2018 2:38am

Re: Converting Derbi Senda to electric

Post by Rain » Feb 19 2020 1:50pm

The white might also work well.
At moment I am happy with it as is. Light is strong enough.

Got the front mask sanded and painted.
30.jpg
30.jpg (26.66 KiB) Viewed 219 times
And also attached and even made first trial.
The result - rear sprocket needs to be replaced with bigger one, as was expected.
Front mudguard is not doing its job at all. Needs either to be lowered a lot or replaced entirely with something attached to front wheel attachment somehow.
At moment I could see the water and dirt flying over the front lip and onto myself, clothes etc.
About 1 km trip result
31.jpg
31.jpg (50.23 KiB) Viewed 219 times
I need something like this..
https://cdn.touratech-usa.com/c/w_1000, ... -20-lg.jpg
Attachments
M05861-20-lg[1].jpg
M05861-20-lg[1].jpg (44.42 KiB) Viewed 217 times

fishbait   1 µW

1 µW
Posts: 1
Joined: Feb 24 2018 1:36am

Re: Converting Derbi Senda to electric

Post by fishbait » Feb 26 2020 11:51am

New rear sprocket arrived, now 69 tooth. Really big thing, almost 29 cm in diameter.
ketiratas.jpg
ketiratas.jpg (92.71 KiB) Viewed 23 times
Also made front fender clips for testing. Got fender lowered quite a bit.
20200226_184551.jpg
20200226_184551.jpg (34.79 KiB) Viewed 23 times
20200226_184600.jpg
20200226_184600.jpg (55.22 KiB) Viewed 23 times

Post Reply