Just wondering if its doable - gas to run electric ?



Don't know how I ended up here, I did search for Lifan engine, but I did. Anyway....if anyone is still thinking about this, I have a "semi hybrid" rig that works well. I use a 48 volt hub motor, but instead of using the 80# pounds of 20 amp hour batteries, I used 7 amp hour batteries at maybe 20#. I used a 31cc weed eater motor driving a permanent motor to recharge the batteries. Aside from being lighter than a genset, the neat part is the batteries will start the motor too. I can get about 6-8 miles on just batteries for bikepaths, or unlimited range for longer trips. I also used an unregulated delco alternator, but it was much heavier and larger than the PM motor. One change I am making is to use a 25cc honda 4 stroke to power the motor as soon as it gets here. With the batteries as a buffer, it doesn't take much to keep them charged overall. I can furnish pics and more info if any one is still interested.



And a source where you got your PM motor. Pictures please I would like to see how you set up your bike.


Hang in there guys, it's still raining here, and it's sitting outside. Giving it the moisture test. :rolleyes: That's my story and I'm sticking to it. Actually I've had it set up several ways already. First I set it up as a bike with the motored hub on the front, and the batteries in bags on the back the way the kit reccomends. That was boring, so I put the weedeater charger on the back rack. Well, that worked pretty well, but I couldn't haul anything, so I got a single wheel bob type trailer, and put the power hub on it. I hung the batteries underneath the trailer to keep the center of gravity lower, and put the generator in the back of the trailer. That is the current configuration, and it works well. I found a gx 31 honda on e bay, and that will be the next improvement when it arrives. One little feature that is handy is I put a double pole double throw switch on the handlebars, so I can shut the engine off, or if I engage the motor, the PM motor will start the engine. There is a bike path that cuts about three miles off the trip one way, but they don't allow motorized vehicles, so it is kind of handy. I hope your not looking for anything artistic, because it is kinda in prototype stage yet, lots of duct tape and zip ties. The motor is item #330148415361 on e bay. They still have a bunch for about $20.00. I just set the engine idle screw so it puts out about 60 volts on a 48 volt system. It doesn't seem to bother the batteries as long as I'm moving. It is a 640 watt motor, so it seems to put out plenty juice to keep the batteries up. The 31 cc engine has plenty power too. Speed is a little on the low side....18-20 mph, but it beats pedalling. It definitely does make a difference too. Trying to pedal without the motor gets old real fast, especially if the trailer is loaded. It has been very dependable even with the constant rain, which is surprising for as inexpensive and crude a setup it is. The biggest problem is when I forget to cover the big comfy saddle with the dip in the center, and have to dry off about a half cup of *Juneau Dew* with my a**. Pictures to follow.



I had pondered doing this too--using a gas engine to drive a motor or DC-generator, and use that electrical power to drive an electric hub motor. "The reason why trains use diesel-electric" is exactly the reason--even more so now that I have rode my gas-only bike, and seen how bad it does up hills. The dynamo-electric motor drive would seem to function as a variable-speed transmission.

It would be easy to adapt to any bicycle too, as the front-hub motors are easy to mount, and the gasoline engine/dynamo could be placed anywhere convenient on the bike, but you wouldn't have the range limitations of batteries.


I worked out a system for a Honda 1000W generator.

A few notes on this setup:

The Honda 1000W generator has a voltage regulator that will hold AC voltage at a certain level, for example 120VAC. When a load is added, it powers up the motor to compensate and maintain 120VAC.

I would add that the Honda is an inverter based generator, so it generates DC and then converts it to AC via an internal inverter. There are "paralleling" outputs on the front that transfer an intermediate voltage between two generators; these may output straight high-voltage DC.

In any case, feed either the high voltage DC or the AC output directly into a switchmode supply (they will take either one.) They're cheap and light as well; you can get them at Jameco. Use that to charge the battery.

Actually you can use a simple buck converter if you want since you don't need isolation. They are much more efficient but you'd probably have to roll your own.

Take some plumbers steel strap, wrap it into a circle to make a transformer core, then wrap 14 gauge copper wire for the 120VAC side and 12 gauge or 10 gauge for the low voltage side.

I've built transformers this way, and it takes a LOT of steel to be able to handle 1000 watts! This transformer might well weigh more than the generator.


This is just a thought and I might be completely off key because me and electrics dont get on..

but how about using 2 x 6v dynamos to produce 12 volts then plug that through an inverter to provide 240v... (uk voltage)

that would allow battery charge - power to motors etc. It would also allow a retrofit to any lifan/49/80cc or GEBE/Stanton without all the complications and the use of high performance lighting when under power such as the 100w focussed beam GU10 lights (or their low power cousins) as these run 240v

in conclusion:

system idea

2 x 6v dynamo (hub or standard) giving 12v in series. These can be disengaged when not required
12v to 240v inverter
12v circuit to batteries (if these are 12v)
Circuit to hub motors (front and rear possible with kits such as GEBE) (either powered - gas running, or battery)
240v circuit to GU10 homebrew headlight(s)

Jemma xx
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If you add a little Saran Wrap to the duct tape and zip ties, them I would say you are about where the rest of the lectric are on their builds. I look forward to seeing you build. Some of us here are a little rough around the edges. And this may give me something to do with a 40CC Robin Engine I have iritating my wife. And a hub motor set up would have her asking me what in blazes is that, how much did it cost, and are you ever gonna grow up.


Finally got it to work

Finally got some pics to upload. Kept telling me the files were too big, even thugh the total is less than what it can handle.
Anyway, the good news is that the rain has stopped, the bad news is that it is now snow. Gave me a chance to check out the handling in the white stuff. I anticipated peeling my bruised and bleeding body off the door of a Yugo delivering pizzas under a tight schedule, but it works surprisingly well. I thought the pusher trailer setup would have me sliding around uncontrollably, but it doesn't have enough traction with the weight distribution set up the way it is. I do lose some speed because of the snows resistance though. One thing, I wish I hadn't been quite so polite to all the joggers using the bike path last summer. When their little footie prints freeze. the resulting bone jolting ride tends to reintroduce the Goldwing induced hemmoroid problem. :oops:

As you can see, this is a pretty simple and crude setup at the moment. Just a power hub mounted on the trailer, with 4 7 a/h batteries. Then there is a 31cc trimmer engine driving a 10 amp permanent magnet motor to recharge the batteries, and run a few accessories. (like the 55 watt halogen headlight I have yet to install) I run the engine up till the motor is putting out about 56-60 volts. As long as the biike is using power, it doesn't seem to bother the batteries. The whole generator setup weighs maybe 12-15 lbs. Also I have a dp/dt switch that kills the engine, and discnnects the generator for those instances when I want to glide soundlessly past some one. Flip the switch, and the generator restarts the motor after the situation is past.

I do have some improvements I want to make yet, like a 4 stroke honda for power, the headlight, and a few other things.......maybe a heated cab????



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vanilla ice

Thats neat.

So after you pass the nunnery, a switch flipped, and the gen motor restarts the ICE...