Zone Seeker
1 mW
- Joined
- May 26, 2014
- Messages
- 13
The plan is to build a legal hybrid bicycle that uses a 250w motor (which is the legal limit here in Norway) for propelling the bike forwards and a lightweight generator for charging the battery while driving. The bike must have a speed limited to 25kmh and a pedaling sensor, i want to hook up the sensor to a hidden switch so that i can turn it off and run on only the motor. I hate the idea of having to stop to recharge the battery for hours, i want to be able to ride for as long as i have gasoline! I want to legally be able to ride anywhere and everywhere to boast my urban exploration experience, and also for daily commuting 8)
The reason i'm making a post on this is that i need advice and direction of someone who is experienced with electronics. As my knowledge on that particular field is quite limited. As for now anyways...
And perhaps, if i am successful at this project this can help others do the same. I will post pictures along as i progress.
For the build i will use a lady bicycle as it has more space for the motor and dynamo. (Don't worry, it definitively wont look like a ladies bicycle when i'm done with it) :wink: The first thing i will do is to sand blast the old rusty frame and bicycle parts (I get to do this for free) and then weld on the mounting brackets for the engine and dynamo. I have an almost unlimited supply of old bikes and rusty parts as i live next to a scrap yard. That's also where i found the engine i will be using to drive the dynamo. The engine is an almost unused German two stroke Sachs Stamo 30 from the 1960's, it even has a pulley wheel at the perfect location for a belt drive to the dynamo. The engine is really small, but also very robust, i have reason to believe it will keep on going forever with good maintenance. It weights a total of 4kg, and is able to spin at 7500rpm. If you go to 1:10 in this video you can hear how fast this thing is. Sounds like a jet engine! [youtube]https://www.youtube.com/watch?v=APdbBmY7Bcg[/youtube]
As for the electric motor I've decided to go for a front mounted hub motor. I'm still not certain of which brand to go with yet. I want a hub motor that will never fail or overheat! I have thought of purchasing a Bafang 250w and getting someone to machine steel planetary gears for me (Noise from the gears is not a concern). Then i will either air cool the hub motor or fill it with oil and mount a neodynium magnet somewhere close to the planetary gear to keep tiny metal shaving away from the magnetos in the engine. Perhaps its better to make the gears out of aluminium, brass or titanium if i can afford it. Then shavings sticking to the magnetos in the motor wont be a concern. The oil filling is pretty self explanatory but i have created a sketch of the air cool setup. The "rods" are hollow with a 90° bend at the end to prevent water from dripping on top of the coils in the engine in case of rain. If any water gets inside it will drip out the rods facing downwards. The rods and the mounting holes will be threaded and secured with super glue. When the tire spins the air will be thrown out of the rods and fresh air sucked in to the intake holes, similar to an impeller. Creating this will take a lot more effort than to simply seal the motor off and filling it with oil. Which idea is the best if longevity is my goal?
I would also like a battery that is as small and light as possible. It doesn't really need to hold a lot of charge as the generator generates constant power. Do i even need a battery? Could i mount some kind of regulator to the dynamo to keep the voltage and watts to the specifications of the hub motor?
Here are some specifications of the Sachs ST 30 engine,
Power:
1.5 hp / 1.1 kW at 6,500 rev / min
1.7 hp / 1.3 kW at 7,000 r / min
Operating speed:
(4.000 **) 5000-7500 U / min
Torque:
0.22 kpm at 4,500 rev / min
I would appreciate if someone could help me find a suitable dynamo that would work well with this motor. The dynamo must also have a pulley wheel on it. I'm not exactly sure how fast the pulley wheel on the motor spins as it has a small gearbox. The reduction ratio here is according to the manual either 3.0 or 3.7, i'm not sure exactly which one
Also check out the sketches i made!
The reason i'm making a post on this is that i need advice and direction of someone who is experienced with electronics. As my knowledge on that particular field is quite limited. As for now anyways...
And perhaps, if i am successful at this project this can help others do the same. I will post pictures along as i progress.
For the build i will use a lady bicycle as it has more space for the motor and dynamo. (Don't worry, it definitively wont look like a ladies bicycle when i'm done with it) :wink: The first thing i will do is to sand blast the old rusty frame and bicycle parts (I get to do this for free) and then weld on the mounting brackets for the engine and dynamo. I have an almost unlimited supply of old bikes and rusty parts as i live next to a scrap yard. That's also where i found the engine i will be using to drive the dynamo. The engine is an almost unused German two stroke Sachs Stamo 30 from the 1960's, it even has a pulley wheel at the perfect location for a belt drive to the dynamo. The engine is really small, but also very robust, i have reason to believe it will keep on going forever with good maintenance. It weights a total of 4kg, and is able to spin at 7500rpm. If you go to 1:10 in this video you can hear how fast this thing is. Sounds like a jet engine! [youtube]https://www.youtube.com/watch?v=APdbBmY7Bcg[/youtube]
As for the electric motor I've decided to go for a front mounted hub motor. I'm still not certain of which brand to go with yet. I want a hub motor that will never fail or overheat! I have thought of purchasing a Bafang 250w and getting someone to machine steel planetary gears for me (Noise from the gears is not a concern). Then i will either air cool the hub motor or fill it with oil and mount a neodynium magnet somewhere close to the planetary gear to keep tiny metal shaving away from the magnetos in the engine. Perhaps its better to make the gears out of aluminium, brass or titanium if i can afford it. Then shavings sticking to the magnetos in the motor wont be a concern. The oil filling is pretty self explanatory but i have created a sketch of the air cool setup. The "rods" are hollow with a 90° bend at the end to prevent water from dripping on top of the coils in the engine in case of rain. If any water gets inside it will drip out the rods facing downwards. The rods and the mounting holes will be threaded and secured with super glue. When the tire spins the air will be thrown out of the rods and fresh air sucked in to the intake holes, similar to an impeller. Creating this will take a lot more effort than to simply seal the motor off and filling it with oil. Which idea is the best if longevity is my goal?
I would also like a battery that is as small and light as possible. It doesn't really need to hold a lot of charge as the generator generates constant power. Do i even need a battery? Could i mount some kind of regulator to the dynamo to keep the voltage and watts to the specifications of the hub motor?
Here are some specifications of the Sachs ST 30 engine,
Power:
1.5 hp / 1.1 kW at 6,500 rev / min
1.7 hp / 1.3 kW at 7,000 r / min
Operating speed:
(4.000 **) 5000-7500 U / min
Torque:
0.22 kpm at 4,500 rev / min
I would appreciate if someone could help me find a suitable dynamo that would work well with this motor. The dynamo must also have a pulley wheel on it. I'm not exactly sure how fast the pulley wheel on the motor spins as it has a small gearbox. The reduction ratio here is according to the manual either 3.0 or 3.7, i'm not sure exactly which one
Also check out the sketches i made!