Gas conversion to electric

[Alistair]

I already know this will be a long term project but I'm wanting to convert a Honda 2002 Metropolitan scooter from a gas engine to electric. It's sat for a long time but only has 39 miles on it. I know nothing about taking apart an engine but don't mind admitting to it and am more than willing to learn. Does anyone know if it is just outright impossible to do this because of this model? My daily drive to work is 8.6 miles per way so I don't need much of an engine to support the drive. Is there a kit or maybe suggestions on how to go about doing this. I also want to build a side car for storage or my dog and I was thinking it might double as an undercarriage for a large enough battery bank if I need it for that model. I have no desire to get rid of the scooter and wanted to give it new life since it just sits around.

This is the wiki page for the type of scooter if you don't know what I mean. https://en.m.wikipedia.org/wiki/Honda_CHF50 Any advice is really appreciated.

 

[motomech]

You are in the wrong section, you should post in the Electric Scooter section. There are very few conversions of the type you are mentioning because they are complicated.
The few that I have looked at remove the cylinder and piston and machine a flat surface on the crankcases to mount an electric motor.
I suspect that is beyond your skill set and that doesn't even begin to cover all the wiring and fabrcating the electrics.
Do yourself a big favor, get your nice Honda running, sell it and buy an Electric scooter.

 

[dogman dan]

I'd seriously look into getting that Honda fixed, unless it has a blown motor because it ran 39 miles with no oil in it.

 

[Sunder]

That kind of conversion is not really a weekend project.

However, circular motion is circular motion, regardless of whether it's coming from the main crank of a petrol motor, or the spindle of an electric motor, so it's not by any means impossible.

There are a few ways you could do this:

1. Put a hub motor in the wheel, and rip out both the engine and the transmission. This is the "Easy" way of doing things, but it's still by no means easy, as most hub motors are designed for bikes, not scooters, so you will need to manufacture a custom mount. The down side is that you won't get gearing, though with a strong enough motor, you won't need it. In essence, you are just keeping the "rolling chassis" (wheels and frame), and gutting everything else.

2. Look at how the motor and the gearbox interface, and see if you can get someone to machine up a mount for your motor, and an adapter to make it fit. The up side is you can keep the gearing, but it will be an extremely complex piece of custom work. This is the process that Motomech just described.

In either case, the batteries usually get fitted to where the gas tank was, and the wiring can usually be cleverly routed neatly where chains and fuel lines used to be.

There is no way I would recommend a conversion like this, but it has been done by those with too much time and money on their hands. It'd probably be cheaper to buy a Zero DSR, have a wild weekend of drugs and booze, crash the DSR, pay the hospital bill and get a second one, than to convert your scooter. (Unless you're a machinist and mechanic by trade. Then it might be cheaper to convert your scooter. Just.)

 

[Sunder]

Forgot to post a picture of a Zero DSR:

0-100km/h in 3.3 seconds

 

[macribs]

1. Put a hub motor in the wheel, and rip out both the engine and the transmission. This is the "Easy" way of doing things, but it's still by no means easy, as most hub motors are designed for bikes, not scooters, so you will need to manufacture a custom mount. The down side is that you won't get gearing, though with a strong enough motor, you won't need it. In essence, you are just keeping the "rolling chassis" (wheels and frame), and gutting everything else.

Well it could be really easy if you get a hubmotor made for electric scooters. They come with axle, rim, and if you like even disc rotor and tire. These puppies don't need gearing. The hub/wheel low outside diameter is their gearing. Ensuring you plenty of torque and if you overvolt you can top out > 110 km/h.

Take a look at this 8kw e-scooter hub from QS motor, it will peak beyond 16 kw for sure. For a 500$ price tag. Serious motor with plenty of power and torque. The end price tag does not need to sky rocket either. A custom build swing arm locally made probably around 2-300 $. Now the battery can be a lot. Depending on your need for range. If you don't need long range a 600-1200 $ lipo pack can get you started, great for noodling around in the city. If you need hi speed for a long distance your battery cost will be the most costly.

If you fear lack of power you can even find a QS 17" e-scooter hub/rim combo boosting a whopping 16 kw and will peak north of 30 kw. Twice the power but quadruple the price tag



Make a custom swing arm and you bob is your uncle.

 

[mistercrash]

If it's a GY6 engine, the easiest way is to get it off and have a swing arm made that uses the same pivot point as the engine did. Unless you are an engineer and can design a monoshock swing arm, you might need to have a second bracket welded to the chassis to have a second shock absorber on the opposite side of the one you already have. Like it was said, QS Motors make good hub motors for scooters. Yours seems to use 10'' rims. You can get a 4KW hub motor in a 10 inch rim from QS Motors that will give the appropriate power for what you want to do with the scooter. Going bigger than 10'' on the size of the rim results in a lot of fitment issues and the tire rubbing when the road is bumpy. I know as I fit a 12'' rim on a scooter the same size as yours and have a second project converting a Yamaha Vino with a 13'' rim. QS Motors can also suggest a good controller to pair with the hub motor, either Kelly or APT make good power. Kellys are more compact and easier to fit but are more expensive. APT is a lot cheaper and powerful but a big honkin' controller that is tough to hide inside the scooter's body. Running 74V will get you a good top speed and good torque with a 4KW motor, something close to 65 km/h(maybe more if you are a feather weight) but running at 51.8V makes for a smaller battery that will be easier to fit in the chassis. Either way, the storage space under the seat will be lost to house the battery and other stuff like some sort of battery management, relays, contactor, DC/DC converter, fuse, etc. Don't use wires for power, use cables. Big ones.
Finally, batteries. What to use... Most of your money will be spent on that. Opinions will differ but this is not a bicycle, it's a small motorcycle so why not go with something made for the automotive industry.

Other things to check out, can it be registered and licensed when converted? Can it be insured once converted?

 

[macribs]

Considering how big the electric conversion of scooters are in both India and China I would be surprised if you could not find a ready made conversion kit for your scooter. A complete kit with motor, swing arm etc. Have you tried to browser the usual China webshops?