Modern Vespa

Hello all

I'm new to this forum but found some good info about doing an electric conversion on a retro scooter so I thought I'd post the project here.

As you probably know, the Genuine Stella 2T is a PX150/LML Star under the hood. I bought this as a barely running project scooter and did a full teardown and overhaul of the ICE. When it was back together it ran great but I did something wrong with the gear stack. It slipped and just was unsettled, so the project has sat for a year.



I've decided I wanted to convert this to a hub motor and get rid of all the oil everywhere that you need to keep these going! I also have a 2007 Genuine Buddy 125 that runs very well, so this electric would be kind of a novelty short hop scooter.

Here is what I very tentatively have in mind for the basics of the project:

72V 4000W hub motor
72V battery pack 17-25 AH

Pics so far

Pulling the fuel and mix oil tanks



Creating a cardboard mock-up of the 25AH triangle battery pack


Fits into the tank void pretty well


More to come, but just getting a thread started!

Darn that's a nice Stella I want it if you decide and change your mind please let me know I want to buy the Stella.

I was away from this project for a few months but I'm back on it pretty seriously. As others have mentioned, the swing arm fabrication is the hardest part - pretty much everything else is off the shelf. While I'm working on getting the swing arm done, I've started dissecting the 12V sub systems and getting them mapped out one by one.

I'll be using a QS Motor 4KW hub motor





LED Lights everywhere


Pulled all of the old wiring harness out




I won't be moving at the pace of @JimVonBaden, but he has inspired me to continue on with the project. I also receive great wisdom from @resistor. They have blazed the trail!

I have a complete and fully functional Stella 2T engine that I need to sell. PM me if interested.

I have been planning to build the battery pack myself out of LG MJ1 18650 cells. They are getting harder to source at the moment and I think I can have a more energy dense battery made for me from 21700 cells for the same cost.

I'll see. I'd like to make it, just for the experience of it. I have the hex cell holders and a small spot welder, so I'm ready to do it. I've only purchased a small number of 18650 cells so I can still change paths and feel OK about it.

Very cool! Yours is a way better start than mine. I look forward to seeing your progress!

I found someone who will help fabricate the swing arm for my project. He's a local guy who has a shop building custom electric hot rods and classics. He dropped a Tesla S motor into a 1957 Chevy Apache Truck. His truck was a big inspiration for my project overall and for building a sleeper without much cosmetic improvement.

Here is his badass truck:


I'm still awaiting small parts and pieces but am working on the 12V side things. For the rear cowl turn signals, the original bulb housing is grounded to the frame, ultimately via the top cowl spring. Although not entirely necessary, I have an objective in my re-wiring to remove all frame grounds and run them back to the battery. Therefore these turn signal bulb housings aren't plug and play for new LEDs and I have to forego using the weird pin connector setup on the cowl.

I bought some simple bulb sockets and cut the old bulb holder off. Then I opened up the hole to accommodate the new socket. I ran the new wires under the cowl tabs and will have a waterproof disconnect when I need to take the cowl off.








I love the LEDs, they are so BRIGHT!


I also found these nice butt connectors that combine shrink tubing and low temp solder. They work very well.


It has been very cold here lately and my little garage heater hasn't kept up, so I fiddled with creating some badging for the cowls. I looked up the Italian word for "electric" and liked the masculine form because the "o" at the end looked better. It was only after printing it that I recalled the Vespa electric model is called the "Elettrica", the feminine form. So I don't know if I'll use this, but it is fun to play around with. The paint needs some touch up and I may add some color.

Finished the front-end 12V wiring - installed fuse box, LED turn signals with adjustable relay, headlight, all of the cluster lighting.

New wiring for everything



I also replaced the front brake master cylinder, as the old one had stripped out screws and had been left unmaintained.

The left shifter tube fit the new grip and I will screw it into place so it no longer moves. The throttle tube wouldn't fit into the Domino potentiometer throttle housing, so I had to use a 7/8" steel pipe which I'll shim up to fit the 24mm holders. Otherwise the Domino will fit great. I went with a potentiometer rather than a typical hall throttle.



The hub motor I purchased has a disc brake on the rear and that kit came with a brake lever for the left handle, but I didn't want to cut the shifter housing apart and didn't really like the way that looked. I found a rear brake foot pedal master cylinder on SIP, which arrived this week. Looks very well made and I'm happy to be able to keep the foot stomping rear brake vibe! Unit looks really well made and I'm excited to get it installed.



I also decided to simplify my cowl badging, so this is what I came up with from the 3D printer and some spray paint:



At this point I'm 2-3 weeks out on the battery pack. I decided not to build it myself and leave it someone with some expertise. I'll definitely build a smaller pack out of 18650 cells, but not for this just yet.

This is Lola, my garage beast. She loves hanging out while I fart around.

Battery pack builder got this turned around quickly and its on its way. We played around with a number of configurations and cell options.

For my needs I was more focused on performance vs. range. I live less than 2 miles from work and everything I typically do on a scooter is within 5 miles of my house. There are lots of hills in my area so I wanted a lot of grunt and speed.

I ended up choosing Samsung 30Q 18650 cells for a 20S10P pack (200 cells). That gives me 72V and 30Ah, with a constant power output of 150A with a peak of 250A. For a 20% decrease in range I get a 50% increase in power potential by choosing that particular cell.





Still buttoning up the 12V wiring harness but it is all coming together nicely. It's been fun so far. Yes that's an old 5A laptop charger serving as my 12V battery for the moment.

Very rad! Nice job tackling a project like this. What's your expected top speed? 35-40?

Thanks MJ! It has been so much fun and I'm learning as I go. The 4kw motor in theory can run up to 90-100KPH, so 55-60MPH, at 72V. I expect I'll start with working toward 40-45MPH and see how it feels.

I installed the rear brake pedal master cylinder and it plugs right in. Very well made. Excited to have dual disc brakes.

Great job on the signals. I used the stock bulb holders, but added a ground to them. I like yours better.

As for the badge, I like your 3D print. I want one for the legshield that says VespaLectri, to match my decals for the cowls.

Looking great! I am jealous of your dual disc set-up. The rest is looking great too!

I managed 52mph today on mine, but think 60 is easily possible once I start tweaking the controller. Now it is set as the factory set it.

It is great seeing you get yours on the road. Amazing job. I can make a leg shield badge for you if you want, and you can use it or not. The 3D printed badges aren't nearly as nice as a molded and chromed real badge, but they look pretty cool. Take a pic of your decals and I can try to match the style.

Been a few weeks since I posted an update. Yesterday I performed the angle identification procedure with the QS motor and Kelly controller. I had an old Kindle Fire and was able to get the Kelly controller app loaded onto it and it works great with the bluetooth controller adapter. I wanted to do this off-bike (plus I'm still working on the swingarm) so I made a simple wood mount and set it up on sawhorses.




After the photo above, I wired in the contactor and keyed ignition switch. Just hearing the contactor clunk to life with the key was exciting.


I couldn't get the Domino throttle to spin the motor, but I was getting throttle input in the app and I could see the hall sensor values changing as I spun the wheel manually. Many thanks to @Resistor for helping during this process and with frustrating troubleshooting. Eventually I pulled and reconnected the wires for the Domino and it all started working! Seeing the wheel spin with the throttle and hearing that motor noise was a big deal.

From there I took it all apart and made a mounting plate for the controller, attaching it to the old spare tire mount in the left cowl area. I used some angled aluminum to mount the contactor and the shunt for the battery monitor. I'm not sure if that will ultimately work with the heavy gage wiring, but I'll see. Easy enough to come up with something else.




As I've mentioned before, this project isn't going to win any concours prizes! I did another fitment of the battery after making a bracket underneath the battery. You can see the ground bus bar on the right and 72V to 12V converter mounted in the back.



All of the motor/controller pin plugs will connect and sit nicely under the battery bracket and will be easy to access. I re-mounted the Domino throttle on the throttle tube and I think it's going to be a nice clean install.



Next I'll be finalizing wiring runs and cleaning them up and wrapping them. I'll wire in the 12V converter and make sure all of the 12V side still works. Then I wait until the swing arm is completed and fire it up. I should have swing arm parts back this week and I can test fit some things.

I also purchased an upgraded rear shock upper mount that has two attachment bolts instead of one. It is much beefier than the stock mount and I'm waiting to install it until I have the swingarm in place as I think it will give me some latitude to tweak the rear shock placement if needed.



Lastly, as I was drilling the holes into the scooter body for the battery shelf - I drilled a hole into my index finger. I thought my hand was clear but the drill bit came through much faster than I had expected. Idiot moment. I won't post a pic but it drilled a perfect circle about 1/2" into my finger and just spun everything around. Ouch. Be careful with those power tools, kids.

I don't think I can embed video, so here is a link to it if you want to see/hear the spinning motor:

https://imgur.com/UzzDou6

I haven't updated this post in a while, but thought I'd close it out. I completed the conversion about 2 months ago and I'm very happy with the end result. Performance is beyond what I had expected and the Stella is much better-balanced now than it was with the big ICE hanging out the ride side.

I spent quite a bit of time riding around with a tablet, tweaking controller parameters as I rode, to see what the real world effect was with them. At one point I got kind of greedy (stupid) and allowed too much current to pass to the contactor. My battery pack can peak at 250A for up to a minute and my contactor was rated at 72V/200A. I managed to fry it, but boy it was quite a ride for that 45 seconds or so. Wheelies on a steel scooter is white knuckle territory. I pushed it home and ordered a 400A contactor.

That took a few weeks to arrive and as I was installing it, I broke one of the wires on the contactor relay and had to order some of those from China. That took over a month to arrive. So that's the main reason I haven't updated anything....I was waiting on logistics from China. But the resistors arrived yesterday and I was able to get back on the road quickly.

Today I have been finalizing controller parameters and beginning to measure performance and battery life/range. The scooter will very easily do 50MPH and based on what I'm seeing after using up half of the battery power, I'd expect to have a 40 mile range. I spec'd the battery pack for max performance and not long range, so this is exactly what I had planned and hoped for. When I looked back on 15 years of urban scootering, I realized I pretty much ride as fast as I can go for a few miles at a time.

Here are some final pics and if I get around to it, I'll post a riding video. It is so different to ride through a neighborhood with only the rattles and dim whine of the motor. Overall I'm very happy and proud of this project. I knew almost nothing about how to go about this. I messed lots of things up and purchased little bits I didn't need or weren't correct. I would do it again in a heartbeat, and probably will. Cheers - Michael












I didn't spend much time or money at gas stations with the ICE, but I still find great pleasure in plugging it in and filling up the tank!

EmVeeTee,

What a great project! Congratulations on completing it! I'm sure there were a lot of challenges, as there are with any resto-mod, but it looks like you overcame them all. It really did turn out great and I applaud your perseverance in dealing with the quirks of building an electric.

As you get more riding experience, perhaps you can update us on the real-world performance that you are experiencing. At this point, I think people aren't surprised about your speed performance, but I sense that there is quite a bit of range anxiety amongst those who might try this if range performance was better. Keep us posted if you have a minute.

Once again, a fantastic product and congratulations on the outcome!

Thanks @resistor! Many many thanks to you for your moral and technical support. There were a few times I was ready to throw in the towel and you played a big part in not letting that happen. Cheers

That was a great project!
Like many of us who think electric is the future, you took action and completed something anyone would be proud off, congratulations to you!

Very nice work. I'm in the process of getting an unwanted Stella back on the road as an electric as well.

For those who know this stuff, why is it not a good idea to remove the 2T engine from the transfer case and connect a drive motor there? ( I've seen some janky Indian videos on youtube of dudes sawing off half the crank shaft and spot welding the DC motor shaft straight on, which I would not EVER actually consider doing).

Seems to me to be a more elegant notion. ie replace the ICE powerplant with an electric one, keeping the 4 speed tranny, the swing arm, the tires and the original electrics.

I seem to remember seeing some DC motors that have "similar" performance specs to the 2T engine, and the existing transmission would do the rest.

I'll take a crack at this question. The short answer is that it is very possible to do as you are suggesting. In fact, there used to be a commercial offering from a company called SoundSpeed Scooters that was using a drive train like you describe. Unfortunately, they are no longer in business. Since their demise, there has been a tremendous advances in battery technology and other components for converting ICE vehicles to EV's. I think they were just a little ahead of their time. But if you are clever enough to engineer a plate to hold the motor and bolt on the engine case as in the attached MV post, then this solution should work a treat.

In my case, I used a hub motor because it is simple and virtually maintenance free. If you use a hub motor paired with a 72V battery, then speeds of between 55-60 mph are possible. Of course, you would have to design a swing arm, and there are some limitations of hub motors. One of the more notable limitations is RPM--you can only spin a magnet so fast. When attached to a 10 inch wheel, you can be speed limited. Bigger wheels or tires will mitigate some of this, but having gears as you propose would certainly reduce this limitation.

The only other commercial offering for Vintage Vespa electrification is a company called Retrospective Scooters in the UK, and they use a hub motor in their scooters. And, as with battery technology, hub motors are getting better all the time. And they are space efficient as they only take up the space of a rear wheel, while the bolt on solution will occupy a lot the space formerly taken up by the engine under the right side cowl. But if the bolt on solution results in more speed, then count me in!

As more people become interested in conversions, I think we'll see a lot of interesting solutions and builds. And I can't wait to see yours!

Oops, my link didn't work. This is the MV thread I thought I was posting: Would you convert a classic Vespa to electric? (Page 2)

Resistor, thats sort of what I was hoping to hear and from one of the guys I was hoping to hear it from.

I've seen scooter and VW conversions of ICE to electric, leaving the trannys in place. Each said "just keep it in 3rd". So it looks like to get maximum benefit and bowl watering speed, tranny gearing will need to be addressed. But thats for next year.

This year is 1) get dead bike, 2) get steel plate plasma cut to fit over transfer case, 3) select appropriate DC motor. I already have a line on #1, and a gasket kit will allow a machinist to make something that fits just right.

This is brilliant! I've sent you a PM for more info.

Thank you for taking the time to post all this.

After looking about I believe that the Retrospective Scooter conversion kit maybe the way to go. I'm wishing the hub motor they use was a little bigger, but the potential range and max speed of 55 mph is acceptable at this time. Any thoughts on this from interested readers?

I believe MV member Charlieman22 actually rode a small frame conversion in the UK back in 2019, so you may wish to PM and get his thoughts.

Absent any actual experience with their conversion kit, the Pro's would be 1) the swing arm, which is the hardest part of the conversion process, is already done; 2) they have made their kit with minimal frame mods in case you want to go back to ICE; 3) a removable battery is a nice feature; and 4) having it all in a kit with instructions will shorten your learning curve.

The con's are: 1) the 3K motor (you can push a 4K motor a little harder without risk of damage); and 2) this setup uses a drum brake where a disc would ensure better stopping power. Your Stella has a front disc, so you have plenty of braking for a 50+mph stop.

So, almost all kits have a compromise somewhere. If you have resources to make a swing arm, you can get some better drive components for less money. You'd have to source a battery also, but we can help with that. However, if you just want to dive in to the EV world, and you have the cash, this is probably the fastest way to make that happen.

After speaking with Retrospective, I think I'm going to stick with the ICE replacement idea vs. hub motor. Their design philosophy is all about motoring about town and plugging in where ever they happen to park. I'm sure thats the correct way to go about it inside a major city.

However, I live in Florida, and everything is 30 miles from everything else. So I need more range than they were comfortable dealing with. I also need to get onto US 1 for everything, so 45-50 mph is the absolute bare minimum SAFE speed, with 55-60 a much better idea.

So, here is my $600 Stella 2t. Bought and paid for.


2009 Stella 2t wrecked. Bent front fender, chewed up chrome trim, not started in 4 years. Fuel and oil still in the tank.

Resistor, that thread was one I had seen before. Its 12 years old, so both electric motors AND batteries have come light years since then. I think it will be possible to do what I want today, even if it wasn't in 2010.

I would like some advice on motor selection (plus all the fiddly bits). I think 72v is the way to go right now tho Retrospective seems to like 60v on their Vespa conversions.

Oh, and the bike came with an Alligator Skin seat

Very nice starting point! And the alligator seat will show very well at Bike Week in Daytona next year. It's right down the road from you in St Augustine. Now the real work begins!

I think your assessment of battery voltage of 72V is right on, and I've never been totally convinced that Retrospective Scooters can hit their advertised speed at 60V. Plus, a margin of safety is a good idea for all electrical systems. I bought a battery from a supplier called EM3EV, and they don't make that battery anymore. So, I'll ask JimVonBaden and EmVeeTee who they bought theirs from, as they both seem happy with their end product.

As for the bits--motors, contactors, 12V converters, volt/amp meters, etc, I'll PM you with options and field your questions. This will be a fun ride when you are finished, and I can't wait to see it go!

I too doubt that they can hit 55-60mph. My specs are much higher and the top speed I have made is 62 mph. Endurance is another issue. I have pushed 250 amps at top speed through my QS205 4KW motor, roughly 14KW. Granted I am near 300 pounds. Someone lighter may do even better. I have done over 40 miles on a charge keeping my wrist calm, and not hard accelerating. My bet is 60 miles with a 150 pound rider taking it easy in the city.

My battery builder is this guy. https://eonlithium.com/?fbclid=IwAR1lw5Py7rbePtBCr1rSIW0rM3wt3uWCwgEvXvJQwzV8luXz-HIlBMf5wvA Raymond Yu is pretty well known for good batteries and his customer service is very good. My 38ah battery, including BMS, was $1000. Another $80 for a 5 amp 110V charger.