Solar Powered Bike / Trike

[sdelgad8]

I am a student in a Mechanical Engineering Technology program. As my groups senior project we are trying to make a solar powered bike/trike. Just wondering if anyone had any ideas on how we should make this work. Here is an idea of what we have. We are still in the research phase so any suggestions would be appreciated.


-Custom tricycle frame to support equipment
-500-750 watt direct drive hub motor
-36 Volt Lithium Battery 15ah
- Solar Panels in research now

We are looking ways to get the most energy and power. We are at the early stages of research, so any thing helps.

Thanks!!!

[Sunking]

Well if you are going to use lithium, then you are going to have to custom design a charge controller. No solar charge controllers exist for lithium batteries yet as Lithium cost are way to high for energy storage. At the end of the day what you will discover it is much cheaper to buy power than make it.

First thing to work out is the battery to wheel efficiency in terms of Wh/mile or Wh/Km. For example something like the Nissan Leaf gets around 400 wh/mile. A Golf Cart around 150 wh/mile. An E-bike I can only guess and say maybe 50 wh/mile. So with a 36 volt 15 AH battery discharged to 80% DOD gives you [36 volts x 15 AH x .8] / 50 wh/mile = 8.6 mile range.

[Sunny Solar]

There are many problems with attempting to use a solar panel/s while bike in motion.
I.its almost impossible to keep the panel/s pointing towards the sun
1,very little room on a trike for panel/s
3.keeping building and tree shadows off the panels.
4, A 100w panel at 48v? would be about the max size you could carry. And you be lucky if you get while bike moving more than 60w average.

[Sunking]

John based on an earkier post the solar will be stationary using a 360 watt panel.

[sdelgad8]

Well if you are going to use lithium, then you are going to have to custom design a charge controller. No solar charge controllers exist for lithium batteries yet as Lithium cost are way to high for energy storage. At the end of the day what you will discover it is much cheaper to buy power than make it.

First thing to work out is the battery to wheel efficiency in terms of Wh/mile or Wh/Km. For example something like the Nissan Leaf gets around 400 wh/mile. A Golf Cart around 150 wh/mile. An E-bike I can only guess and say maybe 50 wh/mile. So with a 36 volt 15 AH battery discharged to 80% DOD gives you [36 volts x 15 AH x .8] / 50 wh/mile = 8.6 mile range.

The motor and battery listed in the start of the post are standard equipment for E-bikes. They get about 15 to 40 mile range depending on all factors. As for the solar charge controller I am looking into it now. Our challenge is really just to find a way to charge the battery using solar power so the solar controller is going to very important.

[sdelgad8]

There are many problems with attempting to use a solar panel/s while bike in motion.
I.its almost impossible to keep the panel/s pointing towards the sun
1,very little room on a trike for panel/s
3.keeping building and tree shadows off the panels.
4, A 100w panel at 48v? would be about the max size you could carry. And you be lucky if you get while bike moving more than 60w average.

We are going to build a custom frame to support the solar panels. I have been researching panels, and I am starting to see that we are going to need some of the more efficient solar panels to make this possible. I also was looking at different flexible solar panels but none of them seem to be very powerful. We are still in the research phase so I am exploring different ideas.

Thanks for your response!

[Sunking]

Th eissue you are going to run into the efficient panels are very rigid in frames and heavy. Physics is going to bite you in the butt.

[russ]

There are 40% plus cells out there - only a small problem that you can't afford them unless your name is Bill Gates.

[sdelgad8]

Yes I am realizing that the more research I do. I am going to an E-bike rental company to get some real data . While I continue my solar panel research. Solar panels are all new to me but Its coming along. I have some ideas but first I need to find some solar panels that are powerful at a reasonable cost,so I can base my design off the solar panel. This seems to be the biggest constraint, so I would like to find the panels and work backwards. We have raised some money already and we are working on getting more funding. Any suggestions on brands ?

[russ]

You can charge batteries in a stationary solar setup and charge your bikes from there. To try to charge on the go is not gonna happen in a successful manner. Only problem with this is efficiencies keep piling up.

Just think of the solar car runs across Australia and other places - a very big surface and a very, very light car.

[Sunking]

Like I said physics is going to bite you in the butt, and economics do not work. For any vehicle it has to be as light and aerodynamic as possible which solar will rob you blind. Economically power cost in TX 9 cents per Kwh. A 36 volt 15 AH battery only holds .5 Kwh or 5 cents worth of energy.

How do you intend to keep the panels tracking the sun on a vehicle? How much weight will that be? How much wind resistance will that add? Cross wind, head wind, down wind. Simple physics tells you why no one does it other than an experiment or concept. Commercially it has no market.

[Sunking]

Now that I beat you down let me offer a concept that can work and has application in Military and Civil communications. A flying wing pressurized with helium or hydrogen with graphite for the structure support that can carry a communications radio package to high altitude and orbit a strategic area like a city indefinitely. It is possible with tech we have today. Military would love such a product or Civil search and rescue operations where there is not cell phone over 70% of the USA land mass. That you can sell.

[SunEagle]

Now that I beat you down let me offer a concept that can work and has application in Military and Civil communications. A flying wing pressurized with helium or hydrogen with graphite for the structure support that can carry a communications radio package to high altitude and orbit a strategic area like a city indefinitely. It is possible with tech we have today. Military would love such a product or Civil search and rescue operations where there is not cell phone over 70% of the USA land mass. That you can sell.

That would be a great tool for search and rescue or during natural disasters.

The biggest obstacle would be to get the FAA to allow you to test fly it. That has been a problem for a lot of manufacturers of non piloted flying machines or an sUAV.

[Sunking]

The biggest obstacle would be to get the FAA to allow you to test fly it. That has been a problem for a lot of manufacturers of non piloted flying machines or an sUAV.

Well FWIW the military already has a aircraft very similar to it, it just uses fuel and a turbine engine. It is a big glider. They take it high altitude, cut the engine and let if glide a few hours, restart and climb again. repeat until fuel is exhausted.

NASA built such a craft but it crashed in the Pacific. But I have a slightly different idea.

Build a flying wing with with carbon fiber framing. Stretch thin film across the top of the wing and seal it to the lower skin. Use hydrogen to pressurize the wing and lighten the aircraft. For deployment use a weather balloon to get to high altitude initially and quickly, then orbit the tactical. When the sun rises turn on the electric motor to climb and recharge the battery, then glide at night and the radio equipment runs off battery. It can be done with the tech we have now.

[russ]

Helium would be a better choice.