Small motorcycle / moped conversion - General 5 Sachs

[steppe]

Hi there, lurker over here with a project.

I've been meaning to do a build with a small motorcycle/moped with a bit more power to take me around town and do some errand running. I'm based in Mexico, so I can get parts from the USA, China and Canada without much fuss, but locally I'm not always that lucky. I can get industrial parts without problem (wires, connections, switches), but batteries and motors are somewhat limited.

I'm still in the planning phase but I've already got some of the motorcycle components and I'm going over some of the options regarding motor and batteries, and I'd love some help with this. (and a sanity check!)

To sum it all up, I'm looking to make something like riba2233's build (https://endless-sphere.com/forums/memberlist.php?mode=viewprofile&u=33118). riba, if you are reading this, I LOVE your build, I've been lurking your posts for info and analyzing all of your pictures to get all the information I can hahaha. His awesome build at EV Album: http://www.evalbum.com/4966

Another recent build that I like is spata's Honda MT50 conversion: https://endless-sphere.com/forums/viewtopic.php?f=12&t=80785. Love the way the batteries are hidden in the frame.

I'll break everything down into categories to make it easier to explain what I want to do.

GOALS:
As I said I want this to be a small errand runner and maybe a small delivery bike.

Top speed: 30 - 35 MPH / 50 - 55 KPH
Range: Al least around 30 mi / 50 km
Loading weight: Around 265 lb / 120 kg including the rider. I want to be able to attach a case on the back for running errands/delivery.

It should be able to handle a couple of hills here and there, but I'm not expecting crushing performance or destroying tires.

FRAME / MOTORCYCLE / MOPED:
Right now I have a General Sachs 5 Star Moped / Lazer Sport with a junk engine (got it cheap!).

Not my photos:

Most delivery motorcycles around here are Honda CB100s frames with a 125cc (CGL 125) or 150cc (CGL 150) engine or chinese copies with 110/125/150cc engines, so parts for that kind of bike are easy to find.

I want to replace the front forks and rear swingarm with parts from those motorcycles to simplify service and open up tire and brake options. I have a bike mechanic that does quite good work, and I'm not afraid of modifying stuff myself.

My reasoning behind the General/Lazer frame is that mounting the motor should be easy with a plate on the original mount, and the "middle space" can be used for batteries, or modified accordingly.

Tires would be 17" or 18", between 2.50 and 3.00

MOTOR:
EDIT 2016-08-23: [I've since switched over to the Golden Motors 3kW 48V BLDC. Lighter, cheaper and batteries should be easier to find. I'll post a whole lot more about that motor once I get all my info gathered, but I'll leave this here so you can see how this project evolved.]

I've struggled a bit to find options since I don't really know a lot of suppliers. I've checked here on the forums and found some options, but I really want a supplier that can stand behind his product and that could respond if anything happens.

Right now I'm looking into a Golden Motor 5 kW BLDC (http://www.goldenmotor.com/eMotorcycle/frame-emotor.htm look for the 5 kW motor option). I've seen it mentioned a couple of times here and in some more professional builds like the Bolt M-1 (http://www.boltmotorbikes.com/)

I like the size, voltage flexibility and the fact that there's a company behind it.

I've seen Motenergy mentioned a couple of times here, but I'm a bit lost with their BLDCs (http://www.motenergy.com/brdcmo2.html).

Is 5 kW too much? Too little? Too heavy?

I'm still working on the voltage/current I should be running with. 48 V sounds nice and safe (I've had experience with ebikes and no problems there), but I keep finding that 72 V would be more efficient and draw less amps, so I'm still on the fence.

CONTROLLER:
A lot of posts I find here and other forums say to match your motor with a controller from the supplier if you can, so I've really only looked into the controller Golden Motors offers, the VEC300 (http://www.goldenmotor.com/eMotorcycle/frame-emotor.htm just under the 5 kW motor option).

Really no experience or comment here. I like the clean wiring diagrams and connections that they offer, but again, I'm open to opinions/suggestions.

I know about Kelly (http://www.kellycontroller.com/) and Adaptto (http://adaptto.com/Products/Controllers/), but don't really know what to look for here.

As a side note, I've been working on wiring diagrams with the Engineer Dog build over at Instructables. I think it's pretty well explained and very clean, with all of the safety measures it needs: http://www.instructables.com/id/Engineer-Your-Own-Electric-Motorcycle/

BATTERIES:
The big one. I'll break it down with what I've researched so far.

Voltage:
Using the Golden Motor 5 kW as example, it takes 48, 72 or 96 V.

I've worked with 48 V. I've felt pretty good around those batteries and I like that a lot of ebikes run at this voltage or 50 V. (Shout out to Paul at EM3ev, you rock!).

But 48 V draws more current than 72 V, and that takes a toll on battery selection.

From what I understand, the 5 kW motor draws:

1. 48 V: Curve http://www.goldenmotor.com/eCar/HPM48-5000Curve.pdf
* 74 A @ peak efficiency
* 176 A @ peak power

1. 72 V: Curve http://www.goldenmotor.com/eCar/HPM72-5000Curve .pdf
* 50 A @ peak efficiency
* 158 A @ peak power


Which takes me to the next step.

Current draw:
From what I see on the curves, the motor would peak at 180 A @ 48 V or 160 A @ 72 V.

That is a lot more than what my ebike draws.

I've been working on a little excel table to help me decide what works and how big it would be. I'll attach it and if anybody has any use for it, grab it, but please let me know of any error you find!

Range - Ah / Wh:
From my research, 100 Wh/mi seems to be a good estimate for motorcycles. Both the Engineer Dog and 300MPG builds are around that figure, but I'm running a lighter frame.

riba2233s build seems to be around 40 Wh/mi (lighter), and from his cell choice, voltage and C rate I think he is running 48 V @ 60 A with 29E cells. (14S16P). That's 2.8 kW on the motor, and a 2.2 kWh pack.

If I assume around 40 Wh/mi, and run with 48 V (or 50.4 V), I found a couple of interesting choices:

1. Samsung 30Q - 3000 mAh - 15 A:
* If I run the cell @ 10 A, I can get 50.4 V - 90 A in a 14S9P pack
* Up to 4.3 kW constant
* 27 aH - 1.3 kWh for ~34 mi / 54 km
* Paul @ EM3ev sells a pretty similar one for $915: http://em3ev.com/store/index.php?route=product/product&path=35_51&product_id=123 (BMS limited to 40A, but could check if it could be changed)

2. Samsung 25R - 2500 mAh - 20 A:
* If I run the cell @ 10 A, I get 50.4 V - 90 A in a 14S9P pack
* Up to 4.3 kW constant
* 22.5 Ah - 1.1 kWh for ~28 mi / 45 km (I could live with that)
* Paul @ EM3ev has one for $790: http://em3ev.com/store/index.php?route=product/product&path=35_51&product_id=123 (again, BMS limited to 40A)

3. LG MH1 / Panasonic BD - 3200 mAh - 10 A:
* Running @ 10 A, 50.4 V - 90 A in 14S9P
* Up to 4.3 kW constant
* 28.8 Ah - 1.4 kWh for ~36 mi / 58 km
* DIY or no idea where to get one

4. Panasonic GA / LG MJ1 - 3200 mAh - 10 A:
* Same 10 A, 50.4 V - 90 A in 14S9P
* Up to 4.3 kW constant
* 31.5 Ah - 1.5 kW for ~39 mi / 63 km (pretty good!)
* DIY or no idea where to get one

So what do you think? If I could get Paul to switch the BMS in one of those packs could it work? He also has some 14S7P and 14S8P that could work and are a bit cheaper, if I needed to test first or something.

What about running those high amp cells at a lower discharge rate? Better? Am I forgetting something here?

Should I make another post just for my battery questions?

I have no experience with LiFePO batteries, but I've seen some builds here with some of them, and I see Golden Motor sells them. I even added them to my excel to compare them, but still no clue. Any options there?

Also, I have very limited experience with LiPo batteries, but I would prefer to keep with known 18650s or LiFePO if I ever decide to take this to another level, mainly outfitting a couple of bikes for friends or to sell.

Since I know the battery is the most expensive buy here, I've been looking into DIY, but having no experience building packs, I don't know if such a big pack (100+ cells) is a good first project.

EXTRAS:
1. DC/DC converter: I can get an automotive-grade (weather sealed, good heat dissipation) for cheap here.
2. Lights: As I said, the Honda CB100 lights should be pretty easy to find.
3. Contactor.
4. Main battery disconnect.
5. Fuses here and there (full wiring diagram coming up).
6. Charger: Still on the fence if it should be on board or not.
7. Horn: I'd LOVE an attention grabbing horn, but that's for later.
8. Display: No clue what to do here. I'd love something that looks good and is easy to read, but for starters maybe a Cycle Analyst?

BUDGET:
I know it's not cheap, but I'm willing to shell out a bit more for good products and good sellers. Shipping/duties will probably kill me, that's why I'm gonna go junkyard diving for fixing the frame up.

Probably around $2,000 USD for everything, not including the frame that I got for $60. (Tip: Check some mechanic's yard; they're bound to have something interesting just rotting away waiting to get "fixed up" or sold to whoever asks first.)

Right now I want to check what the battery would end up costing to decide how I'm going to allocate resources.

Thanks a lot for reading my wall of text!

 

[Drunkskunk]

*Subscribed*
That motor should be fun. 15 horsepower peak on a super short wheelbase, super light bike will be interesting/suicidal/Fun!
I think your budget will struggle to fund a battery capable of powering that beast of a motor, but you can always de-tune to the limit of the battery. I think your battery issues need their own thread, but you might consider Some of the Tesla cells for this kind of high powered build.



Just before the E-bug bit me and I quit working on gas Mopeds, I had bought a Sasks/General 5 Star frame and a Peugeot 103 swingarm for a race bike I had planned. Apparently, the combo of the frame and the Peugeot's long arm rear suspension makes for a wicked handling monster of a bike. A lot of people have built bikes based on that combo.
For you, it would give you a place to mount the motor near the pivot that would eliminate any chain tension problems, and leave the frame open for battery. Just something to think about.
(not my bike, just a 5 Star/Peugeot hybrid)

 

[grindz145]

Sweet! I motivates me to finally get my Magnum together.

I've shifted gears and decided to just use RC lipo, since it's just kind of a hot-rod. Something to consider.

... and that was after building a complicated, expensive 18650 pack

 

[steppe]

*Subscribed*
That motor should be fun. 15 horsepower peak on a super short wheelbase, super light bike will be interesting/suicidal/Fun!
I think your budget will struggle to fund a battery capable of powering that beast of a motor, but you can always de-tune to the limit of the battery. I think your battery issues need their own thread, but you might consider Some of the Tesla cells for this kind of high powered build.

Hahaha thanks! I'll keep this as my build thread.

I'll definitely de-tune and run lower amps, what I'm working on right now is how much to run, I'm thinking... 40/50 A should be enough.

5 kW IS overkill, I'm thinking maybe 3 to 4 kW is enough, but I'm still doing research while I fix up the bike.

Should I post this on the "Battery Technology" section? https://endless-sphere.com/forums/viewforum.php?f=14 Or maybe on the "E-Bike Technical"? https://endless-sphere.com/forums/viewforum.php?f=2 Since there's a lot more going on there.

Just before the E-bug bit me and I quit working on gas Mopeds, I had bought a Sasks/General 5 Star frame and a Peugeot 103 swingarm for a race bike I had planned. Apparently, the combo of the frame and the Peugeot's long arm rear suspension makes for a wicked handling monster of a bike. A lot of people have built bikes based on that combo.
For you, it would give you a place to mount the motor near the pivot that would eliminate any chain tension problems, and leave the frame open for battery. Just something to think about.
(not my bike, just a 5 Star/Peugeot hybrid)

That is a beautiful bike, that goes to the inspiration folder! My thinking is a quick/fun/cheap(ish) EV that I can run around with a smile for a complete newcomer, and I think this can do it.

I'm looking for a slightly longer swingarm from a 17" or 18" bike, but in a pinch, I can use the original one, it's still in good enough shape. Mid section is perfect for a battery tray, I'm doing some cardboard and foam mock ups to test sizes.

Front forks are bust, there's no saving them.

 

[steppe]

Sweet! I motivates me to finally get my Magnum together.

I've shifted gears and decided to just use RC lipo, since it's just kind of a hot-rod. Something to consider.

... and that was after building a complicated, expensive 18650 pack

That's an awesome build you have there! Yeah your pack does look complicated... that's why I'm looking for vendors that sell something I could use.

I've just used LiPo once and all the warnings and horror stories have steered me away from it, but you are right, if it's just a hot-rod and you care for it that way, it's a good option.

I'll be on the lookout for your build!

 

[steppe]

Sorry about the delay, got caught up with work. Finally got my workshop back together and started looking into the mechanical parts.

Frame / Mechanical parts
Found a small store in my town and the guy is pretty knowledgeable, so that's a huge plus. I'm picking up new shocks (front and rear) and brakes (small drums front and rear) and I'll start cleaning up the frame.

Motor / Controller / Contactors & Fuses / Wiring
I'm still working on what I want from the motor and batteries. Right now I'm looking into the 3 kW Golden Motors HPM3000B (http://www.goldenmotor.com/frame-bldcmotor.htm) with their controller.

I got a quote for around $820 USD for:

• 1. $258 - 3 kW / 48 V BLDC motor
  2. $260 - 48 V / 200 A Sine Wave Controller
  3. $ 20 - Brake Lever (going to need 2, no brake pedal here!)
  4. $ 15 - Twist throttle (expecting a pretty cheap one for the price)
  5. $ 35 - 48 V / 100 A Contactor
  6. $ 80 - Programming kit (probably an overpriced cable, anyone have any input here?)

And $150 for shipping to Mexico. I also inquired about wholesale prices, if anyone is interested I'll dig that info up.

I also contacted Kelly and got a recommendation for a controller. They suggest the KLS4840D (24V-48V 350A Sinusoidal Brushless Motor Controller http://kellycontroller.com/kls4840d24v-48v350asinusoidal-brushless-motor-controller-p-1392.html), but that's $360, versus the $260 from Golden Motors.

I know Kelly is probably a bit better, and programming can be done through RS232, so easier to get. I'll dig around for more info, but if anyone has tried both of them, or can recommend one or the other, I'm open to suggestions.

Kelly also recommended a 48 V / 200 A contactor for $50. I really don't expect to draw more than 80 A from the battery (still working on that). Is the overhead necessary? I'll look more into it.

Their throttle looks as cheap as the Golden Motors one, so I'll get either one, and Kelly has a nice little charge meter (http://kellycontroller.com/meter-led-48volt-state-of-charge-p-205.html) for $10, so if I get anything from them I'll probably get one too.

Battery
So far as the battery goes, I'm still leaning towards a high-power e-bike battery from EM3EV or Luna or someplace like that.

Luna rates their 52 V packs at 50 A continuous and 70 A bursts (BMS limited). Since I scaled back to 3 kW (from my original plan of 5 kW), I can get up to 2.6 kW continuous from those packs, and a max burst of 3.6 kW.

Since this build is all about being light, I'm thinking that power output could be enough, but I haven't really put a lot of thought into it, I'm just throwing these ideas out here.

-----------------------------------------------
I'll try to kept this updated a bit more regularly, and post my calculations and stuff for anyone that could find them helpful.

And keep the suggestions coming, they help a lot!

A couple of builds I found along the way that look pretty interesting:

• Motorhispania Goes Electric (https://endless-sphere.com/forums/viewtopic.php?f=12&t=82158)
  E-Chopper (https://endless-sphere.com/forums/viewtopic.php?t=78569)

Both by Martin "E-Chopper". Pretty interesting stuff and he's using the 3 kW Golden Motor.

Cheers!

 

[steppe]

I posted my battery woes over here: Battery for small motorcycle - Golden Motors 3 kW 48 V, in case somebody has any good ideas on what to do.

Basically, Luna Cycle have some good offers on the 48/52/60V range that could power the 3kW motor with 50A continuous and 80A bursts, but they're a bit expensive for me right now.

I found a local vendor (an hour away from me) that sells these: 6-DZM-20 12V 20Ah Sealed Lead Acid Rechargeable Battery, and they're on pretty good price.

I think the plan right now is going to be to order the 3kW motor and all the stuff from Golden Motors and get those SLA batteries. The guy only sells them as packs, so 6 batteries for around $320 USD, and I could potentially run the motor @ 60V or 72V, if I can fit the batteries in the frame in some not so ugly way.

I'll start on the cleanup and sketching on the weekend, so I hope I can get some pictures up by then.

Cheers!

 

[Chalo]

Those awful SLA batteries are going to cost you a lot more per ride than lithium. I think you should do whatever it takes to get a battery worth having.

 

[steppe]

Those awful SLA batteries are going to cost you a lot more per ride than lithium. I think you should do whatever it takes to get a battery worth having.

Yeah, Life Cycle looks pretty bad... I'll keep researching, maybe get into LiPo, if I can source some.

If not, I'll just sell a kidney and get a pack from Luna Cycle.

 

[steppe]

Hey I'm back with a couple small updates.

First of all, I've never seen a more neglected piece of machinery as this little moped. Dirt, grime, cobwebs, and a less-than-perfect paint job really drive home the kind of life it led.

As you can see, a lot of the motor mount had turned black from oil and two-stroke fumes hitting it constantly. If people who are skeptical about BEVs had to clean little machines like this, they would change their minds in a pinch. After 10 minutes with this you start to feel like your insides are as black as the motor mount!

Anyway, I've talked to some of the guys here at the shop and my mechanic; they all agree that a deep bath in degreaser is called for, so I'll make the arrangements for it. I might blast it with a pressure washer to take some of the horrible paint job off (some parts are just coming off by rubbing it) and assemble a rolling chassis to test brakes and mounts, then I'll think about painting it.

Battery
I've been running the numbers and Chalo is right, SLA would cost me more in the long run, so I'm better off buying something else. Thanks for that Chalo!

I drafted the frame in Solidworks (CAD) and I'm looking into ebike batteries to see what I can do with them. I'll add pictures in another comment to make this one a little less crowded.

SLAs where $320 USD for 72V 20Ah, and cheapest usable ebike pack (already assembled) from Luna Cycle is around $435 USD for 52V 10-11Ah. I know Eric stands by his products so I'll be asking him some questions about them.

I know it's a really small battery, but I could use it for an ebike or something else if I grow tired of it, or I could buy another one and double the range. I'll just have to research more into battery aging. (first guess is, I won't be able to plug a new battery with a slighly used one without harming them, but we'll see)

The small "triangle" area in the frame is ripe for a DIY battery build, from my first measurements and drafts in SW I recon it could fit something like 30Ah if positioned correctly, but I'll start small and scale up from that.

Motor
Pretty much set on the Golden Motors 48V 3kW, I'm just gathering info with local couriers to see if I'll have any problems with importing it. First probes say no, so that's a plus.

Still on the lookout for suggestions on any front.

Cheers!

 

[steppe]

Battery CAD

I mocked up the frame in SolidWorks to get an idea of different battery options. I'll proceed to make some cardboard and foam models to really get an idea of mounting points.

So for LunaCycle's 52V batteries I have:

10Ah - Panasonic GA
This is the smallest pack in size that handles 50A (80+ burst). There's also a Samsung 25R pack (pretty much same size).

12.5Ah - Samsung 25R
There's also an 11.5Ah Panasonic PF pack that is pretty much the same size.

17Ah - Panasonic GA
This is the biggest size that can fit in this orientation.

For all of the above configurations, the packs barely go out of the frame, as seen here from the top view:

If we jump up to 20Ah, we find the "double width" packs.

20Ah - Panasonic PF

The side profile is similar to a 10/12Ah pack, and you can get an idea of how much bigger it is from the top view:

Still looks comfortable enough.

I have no idea just how much you can cram up in that space, I'll probably mock something up in SW and see if I can come up with a number. First guess is something like 30Ah, but I won't be building a battery, it's just a design exercise hahaha.

Anyways, I'll keep working on getting a rolling chassis and the motor/controller mounting points. I'd love to have the controller in the small space behind the battery, along with the other electronic bits, but I have to take heat dissipation and wiring into consideration.

I've also toyed with the idea of making a fiber glass replica of the gas tank to modify as a storage compartment for the charger, or to house more electronics, but that's just an idea.

This is an amazing site, I've learned a lot just by lurking and reading posts, thanks a lot to everyone that shares their wisdom here.

Cheers!

 

[spata]

Hi Steppe,

Spata here: - The guy with the Honda MT50 conversion. I now have some consumption data in my build thread here I do not know if you have seen it but it might help you with your battery sizing.

I am getting around 61 watt hours/mile. Which is more than the 40 watt hours/mile you are basing your calculations on (I think that figure came from riba2233s build data).

I have tried changing gearing, speeds etc, but have not really been able to change that figure. I am using a 2.75 x 19" front tyre and a 3.00 x 16" rear tyre. The consensus seems to be that the additional rolling resistance of these compared to thin moped tyres may be the reason for the high consumption, so you may want to stick to thin section tyres.

I am using 15s x 20ah LIPO batteries (nominal 55.5v) that give me a range of around 15 miles (I charge to 4.1v and discharge to 3.5V). You can get more range if you charge higher and discharge lower, but battery life and balancing may suffer.

If I ride till the BMS first cuts out (ie first time I dip below 3.5v on any cell) and then charge to 4.1v I get 66% of rated capacity ie 13.20ah out of the theoretical 20ah. Most folk work on a maximum of 80% of theoretical capacity for their batteries, which means I have 13% more range I could use - about 2 miles. I figure that I can use this by limping home after the first BMS cutout!!

Godd luck with the build,
- Spata

 

[steppe]

Hi Steppe,

Spata here: - The guy with the Honda MT50 conversion. I now have some consumption data in my build thread here I do not know if you have seen it but it might help you with your battery sizing.

I am getting around 61 watt hours/mile. Which is more than the 40 watt hours/mile you are basing your calculations on (I think that figure came from riba2233s build data).

Hey Spata. Thanks for the heads up, I love your build! I think it's one of the cleanest I've ever seen.

Yeah I've downgraded my expectations to around 50 Wh/mi at most since I've been experimenting with another e-bike and found throttle only on a slightly heavy bike is around 30-35 Wh/mi.

I have tried changing gearing, speeds etc, but have not really been able to change that figure. I am using a 2.75 x 19" front tyre and a 3.00 x 16" rear tyre. The consensus seems to be that the additional rolling resistance of these compared to thin moped tyres may be the reason for the high consumption, so you may want to stick to thin section tyres.

Since all my budget is going towards electronics right now, I'm going to be using the 2.75 x 17" front and rear that came with the bike. I'll try to "upgrade" them to 2.5 (at least on front) a bit further down.

I've read all your posts about gearing and consumption. Maybe making the bike lighter? Drill holes on the frame! :lol:

Jokes aside, lighter components? Or the battery mount (which I love, by the way) could be trimmed a bit? A lot of small gains turn into one big gain.

I am using 15s x 20ah LIPO batteries (nominal 55.5v) that give me a range of around 15 miles (I charge to 4.1v and discharge to 3.5V). You can get more range if you charge higher and discharge lower, but battery life and balancing may suffer.

If I ride till the BMS first cuts out (ie first time I dip below 3.5v on any cell) and then charge to 4.1v I get 66% of rated capacity ie 13.20ah out of the theoretical 20ah. Most folk work on a maximum of 80% of theoretical capacity for their batteries, which means I have 13% more range I could use - about 2 miles. I figure that I can use this by limping home after the first BMS cutout!!

I'm working on the motor mount, but battery selection is still pending.

Really want a 18650 pack with around 20Ah @ 52V, but right now I can only get around 12Ah. Thanks for reminding me about the 80% limit, I've been doing all my numbers with 100% discharge, a sure way to kill the battery.

I'm getting quotes from respectable places, and I think I'll have a battery shipped by the end of the month, just have to squeeze the budget a bit more hahaha.

Godd luck with the build,
- Spata

Thanks! You're a great inspiration and all your findings are really useful.

Steppe.

 

[spata]

I've read all your posts about gearing and consumption. Maybe making the bike lighter? Drill holes on the frame!

Jokes aside, lighter components? Or the battery mount (which I love, by the way) could be trimmed a bit? A lot of small gains turn into one big gain.
spata wrote:

You are absolutely right on this one Steppe ... the lighter you make it the better!!

Here are some figures from my build:

- Original MT50: 89kg kerb weight (dry weight is 78kg)
- Electric MT50: 75.5kg kerb weight
- Original Motor: 20.6kg (all up including covers, magneto, carb, exhaust, mounting bolts + spacers)
- Electric replacement: 7kg (including mounting plates, motor, fan cooling solution, primary and secondary covers + primary drive, sprockets, mounting bolts and spacers)
- Batteries etc: 10.6kg (including 12 off 5s 5ah batteries, 2 contactors and 2 DC- dc converters)

The front battery tray you mentioned is 2.8kg and is indeed heavier than I hoped for. It is all aluminium and the panels are very light and only 1.6mm thick. However I used a lot of angle aluminium in the construction, I initially was going to bend/weld the aluminium but then I looked at the weight of batteries and got worried about fatigue cracks and chickened out.

It looks like the dry weight of your donor bike was only 64kg so you are off to a good start. Your motor weighs 7.3kg so is around the same as my setup. Have you done any weight calculations yet? The one thing that I underestimated was the weight of the wiring and ancillaries.

- Spata