electric/solar bicycle

[oriol]

Hi there!


I am a recumbent bicycle builder enthusiast. After having build several tricycle protoypes I am considering trying an hybrid electric solar pedal set up. The option of installing an electric solar panel to charge the batteries, to avoid having to depend on the electrical grid, seems feasible and attractive since it will allow me to travel long distances away from urban areas.

Although I have not performed an exhaustive search about solar panels I have enough information to make some preliminary calculations.
I have found a solar panel that weights 18 kg, with a 1,5 m^2 surface that is capable to deliver a maximum output of 250 watts.

Since I am considering to follow the rules scrupulously to avoid any trouble with the authorities.
The maximum speed that I can achieve is 25 km/h (17 mph) and the maximum power I can use is 500 watts.

Given the extra weight that will represent the solar panel + batteries + other extras compared to a conventional bicycle, I am considering using a recycled motorcycle fork and swing arm.
Apart form the poetry of recycling a junkyard motorbike it also allows me to save some bucks in lathe work but forces me to look away from hub bicycle motors.

The rear wheel will be something close to a sandard bicycle 26" wheel.
I understand that this will require an engine that runs to at least 200 rpm aprox to achieve the maximum legal speed, but that can also turn at very low speeds giving the maximum possible output for going uphill if needed.

Is the BAFANG mid motor engine below the most straighforward solution or are there any other better alternative within the same price?
http://www.szbaf.com/en/components/component/motor/mm-g330250.html

Regarding the batteries a local guy who uses a bottom bracket BAFANG told me that someone connected for him multiple cell phone batteries within the shape of his bicycle frame. According to him it was not expensive.

Does any of you have build or have heard from someome who has build a solar powered bicycle?
Is there anything important according to you that I am missing?


I am currently very busy working on another recumbent bicycle with full suspension frame. I realize that I will not be able to start this project anytime soon, however I would like to solve the technical issues on paper beforehand.


Any suggestions or any input will be extremely welcome!
Thanks!


Oriol

 

[flat tire]

Forget the solar panel idea unless they're sitting on someone's roof where you stop to charge. You will get almost no use out of a solar panel on your bicycle.

Put your money into a good battery, and you can ride that recumbent surprisingly long distances. Also, electric bikes can go fast and be very fun, the law notwithstanding--as a cyclist it's your duty to be extremely aware of your surroundings so as an extension of this you can keep eyes out for police and slow to the legal speed if you see them. My last bike, built on a budget for under $1500 USD, went 56 MPH (90 KPH) and was serious fun to ride.

The motor type will depend on how you ride the bike. Are there hills?

 

[amberwolf]

There's quite a lot of posts about solar bikes, including some builds, if you read around. Parajared has a trike that runs entirely off solar, IIRC. Ddk has charged his from solar, too, and there are others.

Not all the threads below are relevant, but you can guess from the titles which might be what you're after.

https://endless-sphere.com/forums/search.php?keywords=solar&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search

 

[oriol]

Thanks flattire for your comments,


Although I understand a solar panel has many limitations as the only source to charge the batteries, I think it is a concept worth experimenting.
For the time being I am not interested in achieving high speeds. However since it is just a protoype if the concept works, I might consider to build another more powerful prototype and register it as a motorbike.

I will like to climb hills so if you have any suggestion for a motor better than the BAFANG I am all ear?


Thanks for the link amberwolf,

There is plenty of info on the forum that I have to dig in!


Oriol

 

[MadRhino]

Using a motorcycle fork and/or other components, will only add weight and tax efficiency. If you stand a chance to run on solar power, it is with strict weight concern. Yet, even with a system that works, there are many days that will not be sunny enough to power your trike. For this, there is a minimum battery capacity that will be required. You need to plan optimal use of solar power, and this has to be with accumulation when you are not riding. You will also need to build some means of practical orientation adjustment for your solar panels to optimize the efficiency, even on fully sunny days.

 

[craneplaneguy]

I just use my permanently installed grid tied solar system at home to charge my bikes. The idea of packing enough PV around on my ride to make a meaningful difference doesn't appeal to me at all! Yes it can be done, but that doesn't mean it necessarily should.

 

[oriol]

Thanks MadRhino and craneplaneguy for your inputs!


In were I live most of the year we enjoy sunny days, the idea is to have the battery located flat on the roof, acting as a canopy to shield the rider/s from the sun. However in case the battery gets discharged the rider/s has to be able to move the bicycle by itself without electric assistance. The electric motor is to make life easier but it is not compulsory to use it to make the machine move.

I am not considering running using directly the energy from the solar panel, the energy from the panel serves to charge the battery. The idea is to be able to travel long journeys away form urban areas and thus without the need to rely on the electric grid.

The recumbent bicycle I have in mind is actuallly a tandem quadracycle with the riders seating side by side around the chassis of the motorbike. There will be two litlle fixed wheels on each side; like in Jim Bede´s Litestar. The Quadracycle is similar in size to a small car, nothing that can be comparable to a conventional bicycle.

This vehicle is neither intented for urban commuting nor to compete in performances with a Tesla car.

Of course at this early stages there are plenty of issues and trade offs to address yet on the paper before I start cutting and welding.


Oriol

 

[parajared]

Forget the solar panel idea unless they're sitting on someone's roof where you stop to charge. You will get almost no use out of a solar panel on your bicycle

.

I am inclined to agree with you. I can get a good three hours of riding in with much less cumbersome 800 watthour battery and don't see a need for a solar panel for those shorter rides (I rode for three hours yesterday and consumed 342 watt hours). The OP didn’t really mention what he intends to do with the solar panel but my suspicions are that he wants some "cool factor" but the sad reality is that a recumbent just makes you look like a bit of a dork and a solar panel makes you a mega dork. They work great for XC though. If you intend to do some cross-country trips with that trike I think you should go for it. I much prefer charging at the camp-site out in the woods to hanging out at the gas station like a homeless person tapping electricity off the soda machine power outlet.

electric motor is to make life easier but it is not compulsory use it to make the machine move.

With a motorcycle fork and a few hundred watts of solar on your roof you sure as heck are going to need the motor to help you move that bike… unless you have some mutant beast legs or something.

Here is a link to my solar recumbent trike build if you need inspiration on how to build these: I wouldn't recommend building your roof rack out of floppy PVC pipe like I did and I sure wouldn't recommend using a charge controller.
https://endless-sphere.com/forums/viewtopic.php?f=3&t=80117&p=1181184#p1181184

 

[craneplaneguy]

Using solar to offset your ebike's energy use is a super seductive idea, but a large part of what I do as a solar professional is talk people down from over enthusiastic expectations. Sure, you can do it, but it may not be worth the hassle, as compared to packing extra batteries. IF those extra batteries are charged via a home based PV system (whether permanent grid tied or a more temporary system) you still get a warm fuzzy feeling. Today I drove the Prius 135 miles to get to a ride along a high canyon by a raging river, (complete with several hundred feet high waterfalls, very cool) and could have topped off my battery off the onboard inverter that works of the car's main battery. BUT, I charged it the night before off my home solar system, so today's ride was all "solar powered." Tomorrow's ride will be in town on the multi use trail, and again I have the battery charged off of the home PV system rather then mooching off the car's. Doing it this way I for sure have the bragging rights of saying my bike is solar powered, PLUS I don't have to pack them along, just a thought.

 

[Wheazel]

If I were to pursue a solar build, that would be due to factors like:
- Want to experiment and learn
- I will be going places where charging a battery won't happen

Furthermore the build would be strict in terms of weight, as you can not expect to have meaningful solar help at all times.
That is why the bike need to be rideable without solar or with minor solar input.

With a mindset along these lines I can see a solar build being reasonable.
For riding around town or commuting to work, not so much.

 

[oriol]

The OP didn’t really mention what he intends to do with the solar panel but my suspicions are that he wants some "cool factor" but the sad reality is that a recumbent just makes you look like a bit of a dork and a solar panel makes you a mega dork.

Parajared Sorry if I my explanations were vague.

To put a bit of context I build a couple of recumbent tricycles intended for urban commuting but had some nasty experiences with cars, despite riding in the bicycle lanes. This prompted me to build a sort of recumbent buggy in were the rider is enclosed by a tubular structure.

Although I am not obsessed with reaching high speeds and I enjoy riding slowly. I do realize that the extraweight of the tubular structure surrounding the pilot will be a major drawback, particularly if I am forced to share the road with cars.

This has led me to explore the possibility of adding an electric engine or even a solar/electric set up for this protype or the next one; that I described in my first post and is supposed to be a two seater.

It is true that some people might look at recumbents bicycles with disdain but according to my experience it is quite the opposite in most cases. Those below are the two recumbent tricycles I have build so far.

The proto I am working on now looks much more striking than those above, I sure would not go unnoticed riding on the street once it will be on wheels. Adding some solar panels to the proto will not seem odd at least to me.

With a motorcycle fork and a few hundred watts of solar on your roof you sure as heck are going to need the motor to help you move that bike… unless you have some mutant beast legs or something.

You are right. The proto is only sketched and morphing, I decided to make some radical changes but still it would be much more heavy than any conventional bike.

Parajared I love your solar recumbent trike and the pvc structure is very clever!

Using solar to offset your ebike's energy use is a super seductive idea, but a large part of what I do as a solar professional is talk people down from over enthusiastic expectations.

Thanks for your advice craneplaneguy!

I understand that charging a battery is clearly the most straighforward way to go. However I am not considering the solar/electric set up for everyday commuting to work etc. The idea is to be able to make small holiday journeys away form urban areas or campings; and thus get the benefit of being able to recharge the batteries without having to relay on the electric grid.

If I were to pursue a solar build, that would be due to factors like:
- Want to experiment and learn
- I will be going places where charging a battery won't happen

Indeed!

 

[AF7JA]

I have a solar powered trike and it works out well. The battery is almost always topped off and I have a sun shade overhead. For extended touring I keep the speeds down to about 12mph, but that is a decent touring bike speed. In town there are not the same concerns because so much time is spent stopped.

One thing to keep in mind is this forum is focused on over powered e-bike. If you stick to the legal limits, solar can work.

a bit of information about it here http://www.bikeforums.net/electric-bikes/1077306-solar-trike-build-thread.html

 

[craneplaneguy]

Looks like about the most practical way to pack a fairly significant amount of PV around. and I like the way you have a "table" when parked!

 

[dogman dan]

Parajed's solar trike sure is cool, as are others.

I sort of like though, the idea of a bit less panel, a bit more battery. But for sure, at a minimum, 100w of panel seems to make sense. Range extension using just 100w of panel makes a lot of sense to me. If you are cruising at 300w, and making close to 100, you should be able to milk out about 50-60 miles from a single 48v 20 ah. It would though, take all day to recharge from empty, so you might need to go fishing or camera stalking wildlife for a day before riding on to the next camp.

I love the idea of the solar charged bike camping, but personally, I'm about done roughing it. Car camping with a small generator to charge the bikes has worked good for me. But if I had my dream, it would be a 35 foot RV waiting for me at a camp every 50 miles. Not very eco,, but I never got into this for the planet. It's all about fun for me, and helping out my health. A slow ride across the west would be sweet for me.

I doubt I'll get my dream, but If I get a van,, I want to put about 400w of panel on the roof. Then I won't need to listen to generators run so much, unless I'm inside enjoying the air conditioning.

 

[AF7JA]

Looks like about the most practical way to pack a fairly significant amount of PV around. and I like the way you have a "table" when parked!

It's not just a table when parked, it is also a sun-shade while underway.

 

[dogman dan]

A table when out camping is one handy thing. You miss it big time if you go backpacking. Bike camping, I loved the back deck of the cargo bike for a table. Set up the stove there waist high, vs on the ground kicking dirt into your food. My busted up bones just can't sleep on a thin camping pad any more. So three days and I'm dying to get a real bed.

But my dream, its still having a table, full kitchen, soft bed, shower, and AC for the afternoon siesta after a hard morning ride. Never going to happen, even If I get the RV, I'll still need a driver. The wife sees weeks in an RV with me as some kind of hell.

I'd love to just ride motel to motel too, but out here in the west that means 70 mile days. So you end up carrying camp gear and huge batteries. I built a trailer to carry a better camp, but it ended up too heavy if I carried a good bed, plus what 200w solar would weigh. So back to the car camping idea for me at this point. The drawback of that is you have to ride each section of road twice.

 

[parajared]

Never going to happen, even If I get the RV, I'll still need a driver

I am starting to think that Endless-Sphere feels incomplete without a electric-converted Dogman Dan cross-country cruiser that falls outside of NMDOT regulations.

 

[oriol]

Sorry for the delay on the my replay!

If you stick to the legal limits, solar can work.

Thanks for sharing your project AF7JA, it is very helpful to learn from the previous experience of others!

It is good to know that a solar panel suffices to provide the energy required to charge the batteries if touring at low speeds.
On the other hand a solar panel acting as a roof like in parajared´s and your tricycles is a must for protecting the recumbent rider from the sun.

At the current stages I am focused on solving the transmission issues. I understand that an internal gear hub would be much better than a typical derailleur gear. The ideal set up would be to install an electric 250W motor on the crankset and then a hub gear on the rear wheel like you did.

The proto I am working on has a conventional derailleur, the first road test will be only using my legs. As I further advance with the project I might buy an internal gear hub and an electric motor. I bet that the assistance of an electric motor will be a great advantage when climbing uphill.

I love the idea of the solar charged bike camping, but personally, I'm about done roughing it. Car camping with a small generator to charge the bikes has worked good for me. But if I had my dream, it would be a 35 foot RV waiting for me at a camp every 50 miles. Not very eco,, but I never got into this for the planet. It's all about fun for me, and helping out my health. A slow ride across the west would be sweet for me.

There are some really nice and inspiring homebuilt bike camps on the net.
It would be great to add some panels to the structure and have a comfortable small palace on wheels in where to rest after a long journey of pedalling adventures.

Of course it is all a matter of pros and cons but the idea is appealing.


Oriol

 

[Cephalotus]

Maybe you can get into this guy shown in the pictures (not the guy that started the thread)

http://www.pedelecforum.de/forum/index.php?threads/mit-solaranh%C3%A4nger-rundtour-durch-spanien.40611/

He has been riding with his solar bike in Spain.

Read about Thesuntrip 2013 and Thesuntrip 2015.

Those people have experience with many thousands of km driven including luggage and without a single recharge allowed during the race...

https://www.thesuntrip.com/

Noone uses glas PV panels, because they are too heavy. Most of them use "semiflexible" moduls with sunpower cells.

I strongly(!!!) advice not to use cheap PET cover, because it is highly reflective and dangaerous rinding with it in public traffic (ETFE is much, much better and will also last much longer) and I strongly(!!!) advice to built a very solid understructure, because those sunpower cells crack very easily. you will not notice that imediatly, but the moduls will devlop hotspots and get very, very hot.
I see many flawed design around...

Here is one of my 50W panels brand new from China. (they weight 1,1kg each) Notice the broken cells that you can see only with an infrared camera... "Semiflexible" does not(!9 mean that you can use them flexible swinging around. Bend them once and fix them in that position. Many "reviewers" on youtube bending them this way and that way obviously have no idea what those moduls can do and what not...

View attachment 2





You also need a good solar charger, otherwise you will waste large amounts of potential solar energy. Genasun chargers are expensive but good. They have been design for such an application with quick MPP tracking which is very important if you have some shade on your moduls that move while you ride...

 

[rojitor]

[youtube]k6RLA0abmF8 [/youtube]
Es member named nobuo did a solar vehicle time ago.
https://endless-sphere.com/forums/viewtopic.php?f=34&t=73080
I personally find it interesting

 

[reptilian]

I am also planning on using solar power to assist with charging my trike. I would like to have a large camping trailer that I can equip with solar panels, but I think I will probably start with a solar canopy first.
Here is the charging controller I was looking at getting:
http://www.ebay.com/itm/141943518483
I don't have any idea if it is good or not, but it's affordable and charges to 60v which is where I want my 15s battery to be topped off.

 

[AF7JA]

I am also planning on using solar power to assist with charging my trike. I would like to have a large camping trailer that I can equip with solar panels, but I think I will probably start with a solar canopy first.
Here is the charging controller I was looking at getting:
http://www.ebay.com/itm/141943518483
I don't have any idea if it is good or not, but it's affordable and charges to 60v which is where I want my 15s battery to be topped off.

If I were doing this again, I think I would start with a Surley or bikes at work, long trailer. In fact, that is my plan for V.2.

I want to make it openable so that I have ready sleeping space. Also, by openeing it, I can collect more morning sun as I am getting ready to head out.

 

[oriol]

Maybe you can get into this guy shown in the pictures (not the guy that started the thread)

http://www.pedelecforum.de/forum/index. ... ien.40611/

He has been riding with his solar bike in Spain.

Hi Cephalotus!

I have many interesting routes in mind in where to get lost with my next project in Spain or Catalonia!
The logistical problems of the travel can be considered minor issues, compared with the titanic task of finishing the prototype I am working on.
I am looking forward to add some floats and convert the bicycle in a pedalo and do part of the journey going slow down a river, definitely away from cars but not completely from civilization.

Read about Thesuntrip 2013 and Thesuntrip 2015.

No one uses glas PV panels, because they are too heavy. Most of them use "semiflexible" moduls with sunpower cells.

I strongly(!!!) advice not to use cheap PET cover, because it is highly reflective and dangaerous rinding with it in public traffic (ETFE is much, much better and will also last much longer) and I strongly(!!!) advice to built a very solid understructure, because those sunpower cells crack very easily. you will not notice that imediatly, but the moduls will devlop hotspots and get very, very hot.
I see many flawed design around...

You also need a good solar charger, otherwise you will waste large amounts of potential solar energy. Genasun chargers are expensive but good. They have been design for such an application with quick MPP tracking which is very important if you have some shade on your moduls that move while you ride...

Thanks a lot for sharing all those interesting details, I take good note!

I understand that the price difference is justified and it is worth to save the necessary money to buy the components you suggest.

Es member named nobuo did a solar vehicle time ago.
https://endless-sphere.com/forums/viewtopic.php?f=34&t=73080
I personally find it interesting

Hola Rojitor!

Nobuo´s vehicle and video is awesome!

It seems that Nobuo has eliminated the pedals of the original vehicle. Although there might be a reason to do so, I believe that it is worth to keep them since that way the vehicle is considered an electric bicycle which makes it street legal.
Although electric mopeds are sold in Spain they are not considered street legal and many owners are afraid to use theirs because of the expensive fines.

I am also planning on using solar power to assist with charging my trike. I would like to have a large camping trailer that I can equip with solar panels, but I think I will probably start with a solar canopy first.

If I were doing this again, I think I would start with a Surley or bikes at work, long trailer. In fact, that is my plan for V.2.
I want to make it openable so that I have ready sleeping space. Also, by openeing it, I can collect more morning sun as I am getting ready to head out.

To use an existing bicycle and build a nice and simple plywood trailer, covered with solar panels and enough room to sleep in, seems like a very interesting and affordable project.


Oriol

 

[amberwolf]

Notice the broken cells that you can see only with an infrared camera...

Took a while to find this post.

I recently ran across information that you can apply power across a solar cell, and use a near-IR camera to image it for defects (as the broken-away segments won't pass current and so won't light up).

Is that how you imaged this cell, or was it simply using the near-IR camera to pickup reflected light from the panel?