Gas and Electric Power Bike

[aaronjohn_9]

I have been looking around on the internet to see if anyone has create or produced an electric and gas powered bike,or dual powered. I have a friend that just finished putting a gas powered 2 cycle engine on his rear hub of his bike. It works great, it gets over 100 mpg and top speed right about 30mph. He was looking into putting a electric conversion wheel on the front of the bike. So the bike would have an electric front wheel, going about 13-15 mph, and a 2 cycle motor on the rear wheel. I thought for sure, someone would have already done such a task, but non that I could find. My friend overall whats a bike that 30 mph for longer commuting, and something that operates unassisted under 10 mph for congested traffic and easier maneuvering. Is this project even feasible or possible? What does everyone think the outcome would be?

 

[markz]

There have been people who have done it here on E.S.
I am unsure if they completed it, but if I remember correctly, there was a MXUS 3KW electric motor user on here with a gasser on a fat cruiser type. Black/Red.

Its a good idea for those who ride pathways where gassers are too loud and you'd get busted fairly quickly and ticketed. But also do a lot of riding on city streets.
For long rides, across country, I would really see no need for electric, buts its common. I'd just go gasser and try to silence the engine as much as possible. I'd do that too, to try and ride city pathways. The only idea I have come up with is a enclosed box system, and perhaps some vents with fans in them for air cooled engines. For liquid cooled, I think those are too expensive but ideal for enclosed gasser setup. Its on my ideas list for sure.

I have thought about it myself, I am about a couple grand into this electric bike hobby already. I havent ridden a lot, dunno why as I am not broke broke.
I think ever since my LiPo's exploded and made some fireworks, I've been more cautious and researching more on batteries and their chemistries. Another thing is I procrastinate and havent boughten Riba's tab welder yet. I will soon, once I make a order of 18650 batteries. Dunno if I want capacity or discharge. Discharge for sure for the mxus, but capacity for my geared bike. I myself kind of looked into dual drive electric/gas, but I'd just get a 3rd bike and make it completely a big engine gasser, or small gasser with electric as a grocery getter. I got pinched awhile ago, so I can still rent cars but I think without a revelation and some of "Gods" Handiwork, I'm in the deep. Luckily things have been going in my favor, but once the Gavel is banged, it is what it.

I never went the gasser route because of the noise.

 

[dogman dan]

No reason it won't work. But for most of us, we have other reasons we don't want a gas bike at all. We prefer the silent operation, lack of vibration, etc of the electric bike. So we just ante up for enough battery to go longer distances.

1500 watt hours can get you as far as 80 miles, but not at 30 mph. That's 48v 30 ah, and though expensive, it can be affordable enough. And it will go close to 30 miles, at 25-30 mph.

One thing is true though, a gas bike gets refilled a lot faster on a really long trip. I'd still like a very quiet, micro generator. Something really small and light, 250w or so. Right now 600w or so is the smallest, and they are still pretty heavy.

 

[aaronjohn_9]

How fast will the 1500 w get up to? How long does a charge last and how long does it take to recharge? Are the batteries removable for easier ability to charge? how much weight is being added? Is there even room on the frame for a gas motor and battery packs? Will a 4 stroke engine be quieter?

 

[markz]

Depending on motor wind (the lower the faster, higher the slower) I'd say 45-55kph. About an hour or 2 depending on your charger. Removable, yes.
Weight, depending on Ah, ~5lbs.

Room, who knows, I dont. You can get a triangle bag for the frame, but thats where the motor goes. Maybe handlebar bag for batteries, maybe rear rack for batteries. BMSBattery has a slide in battery into the rack. 4 stroke is quieter, but bigger and wider. There are some ~30cc motors that are quite small, I've seen them mounted near the rear wheel hub, seen them mounted on the rear rack under the seat, seen them mounted above the Bottom Bracket. Most 4 strokes are rear rack, or above BB.

 

[dogman dan]

I wasn't talking about 1500 watts. I was talking about 1500 watt hours. If the battery is a 48v pack, that means 30 ah of it.

48v 15 ah fits in most bikes frame triangle, then the rest would have to go someplace else. Panniers, saddle bags, whatever. 20 to 30 pounds weight for 30 ah.

Charge time for 30 ah is just a function of how many amps your charger has. for example. If you have two 48v 15 ah packs, a 5 amps charger will get it 95% full in three hours. At a rate of 5 amps, it puts out 5 ah in one hour. Two such chargers fills both in 3 hours. But it may take 4 hours to get 100% full, since charging slows to a fraction of an amp as the battery gets fuller.

To go a long distance, like 60 miles, with 1500wh, you cannot be riding 30 mph/48kph. At that speed you might be pulling 60 watt hours per mile, or more if hilly. So range could be only 25 -30 miles at that speed To get 60 miles range, you need to travel at 25 watt hours per mile. Typically, this is 20 mph or less.

Lastly, when you calculate the distance you can go, don't forget that a label on your battery that says 15 ah, does not mean you are guaranteed 15 ah. I have a 20 ah pack that only puts out 18 ah. and my 13 ah pack puts out 11.5 ah. So carrying both, I really only have 29.5 ah. But it's still very close to 1500wh, and I can go 60 miles with it, at a speed of about 18 mph.

 

[Nehmo]

... the bike would have an electric front wheel, going about 13-15 mph, and a 2 cycle motor on the rear wheel...

It's a fine idea. -- except 2-strokes are emission monsters and are prone to hard starting. Harbor Freight has a small 4-stroke engine that can be adapted to a bike. It's heavier than a comparable 2-stroke, but at least you can be confident it will start.
If I were doing the project, I'd make sure to have regenerative braking, which is a negligible advantage in a regular ebike.