Solar only ebike?
- Thread starter patrickza
- Start date
John in CR said:
I've learned to tune out the negativity. Some years ago schools pretty much world wide stopped teaching rhetoric and debate. It's not that people are negative, it's more like they just never learned how to form and present a polite and logical argument. When arguing people now go with what they learned in dysfunctional homes and watching daytime television. At the end of the day it's not pretty.
I believe a hybrid system consisting of a charging trailer with a spare battery and a fold-able solar array would work be functional. The bike would be a pretty traditional efficient e-bike. Schedule the saddle time so you are riding when the sun is the least efficient and sitting still letting your array re-charge your batteries. On the trailer I'd take advantage of it's size and on the top have a small solar device to catch the rays while riding that is charging a small battery.
I'd agree solar only is out. What is needed is an efficient bike , a well though out schedule, and some brainpower to work the charging. Ride when the charging window is not so efficient and charge when it is. Time, patience, and brainpower is all this will take. I'd bring lots of reading material for the charging sessions.
Better to try it and fail miserably then to never try.
Thanks for all the replies so far. As I said earlier, it was only for arguments sake that there would be no battery involved. In reality I realise there are far better ways of doing things.
So let's adjust the rules now and use a few ideas from you guys to imagine what might be possible;
1) A battery pack included, as suggested by many.
2) As suggested by dogman, Tow a trailer with some more panels. Will I gain more than I lose from the drag of the trailer?
3) I quite like drunkskunks idea of charging by day and riding at night. Not sure it's the best idea in africa though, but at the very least I could charge midday and run in the remaining light.
4) As John in CR has suggested, if I could make a lightweight aerodynamic enhancing solar panel that would be ideal. I imagine it would look like half a teardrop, keeping the bottom open for ventilation. It gets hot here!
So if it was you, how would you design the vehicle?
I'm still convinced it needs to be a tadpole trike, but will listen to comments.
What size and voltage in the pack?
Trailer or no trailer?
Which motor?
So let's adjust the rules now and use a few ideas from you guys to imagine what might be possible;
1) A battery pack included, as suggested by many.
2) As suggested by dogman, Tow a trailer with some more panels. Will I gain more than I lose from the drag of the trailer?
3) I quite like drunkskunks idea of charging by day and riding at night. Not sure it's the best idea in africa though, but at the very least I could charge midday and run in the remaining light.
4) As John in CR has suggested, if I could make a lightweight aerodynamic enhancing solar panel that would be ideal. I imagine it would look like half a teardrop, keeping the bottom open for ventilation. It gets hot here!
So if it was you, how would you design the vehicle?
I'm still convinced it needs to be a tadpole trike, but will listen to comments.
What size and voltage in the pack?
Trailer or no trailer?
Which motor?
Ahh... your stubborn-ness is amazing 
More panels = more dead weight to lug around outside of peak sunlight hours.
This is a good idea if you plan on operating this thing only 3 hours a day and are okay with going 5-10mph.
Would be more efficient to walk
More panels = more dead weight to lug around outside of peak sunlight hours.
This is a good idea if you plan on operating this thing only 3 hours a day and are okay with going 5-10mph.
Would be more efficient to walk
John in CR
100 TW
Neptronix seems to be unaware of the World Solar Challenge that is run every year 3000km across the Australian outback, whose competitors have no pedal assist, start the race with a full battery but recharge only using the sun, and speeds started getting so high that the race cars have become more and more limited due to average speeds in excess of 90kph. I'm not suggesting that Patrick build a car like that, but to suggest that a solar assisted tadpole trike is impossible is just silly.
Patrick,
Before getting into design ideas, how about some info first? Are you a cyclist already, so the trip is possible for you even without electric power? Where would you stay for the overnight stops? Is recharging at night possible or do you want to be very strict about solar and leg power only for the trip? How would you picture the typical day of the trip? ie Charge hard and get as much distance each day with short breaks, charge hard for some segments and stop for a day or 2 at the nicer locals, or ride 2-3 hours in the morning with a nice break in the heat of the day and a couple more hours in the afternoon? What is the terrain, mostly flat, lots of rolling hills, mountains to climb?
John
Patrick,
Before getting into design ideas, how about some info first? Are you a cyclist already, so the trip is possible for you even without electric power? Where would you stay for the overnight stops? Is recharging at night possible or do you want to be very strict about solar and leg power only for the trip? How would you picture the typical day of the trip? ie Charge hard and get as much distance each day with short breaks, charge hard for some segments and stop for a day or 2 at the nicer locals, or ride 2-3 hours in the morning with a nice break in the heat of the day and a couple more hours in the afternoon? What is the terrain, mostly flat, lots of rolling hills, mountains to climb?
John
Evoforce
10 kW
If you ran at night you would be using 10-20 additional watts to power your lights every hour. It still is not practical but it's fun. Anyway as long as we are dreaming, we should add more than one set of batteries to our solar trailer. This way our trailer, will constantly be charging a reserve battery (providing that the sun is not obscured).
John in CR said:
The OP is talking about running it with no batteries for very long periods of time. I am aware of these solar powered vehicles, but they always have a battery attached, and these competitions also conveniently occur during peak sunlight hours in the summer, to buffer out the times where sunlight is fading and/or
Solar does work, but with very narrow operating parameters, batteries, and high budgets. Those world solar challenge vehicles are also extremely aerodynamic whereas a bike/trike/tadpole/etc just isn't.
dogman dan
1 PW
Not racing, he could go slow enough to make most of the aerodynamic issues lessen greatly. Weight might be the more important limiting factor when traveling speeds under 15 mph.
This is a fun concept to think about though, what could you do with a smallish panel that could be carried folded during most of the travel time? Say he carried 3 panels of 80 watts, and for 4 hours a day midday, they actually put 80 watts of 36v into a battery even after various charger losses. So you'd have 80 watthours x 4 = 320 watthours in a battery per day. You could actually get somewhere eventually with that. Then suppose you only got about 40 watts of power in 12v when traveling, with just one panel out in the sun for another 4 hours. 13.3 watts of 36v, x 4 hours = 53 more watthours of 36v. The real numbers could only be found out by doing it, but I think 350- 400 watthours of 36v per might be doable in the real world using a set of panels small enough to carry.
So supposing you dragged a 100 pound cargo load for the panels and your baggage, how far could you get with 370 watthours? Assume you used 200 watts of motor, and pedaled another 100, how far and how fast would that get you? I'm pretty sure it could be in the 20-30 miles range, if you traveled nice and slow. You might very well be able to cover 20 miles in the morning, and then spend the rest of the day charging, and angling the panels into the sun till dusk.
I suppose the starting point would be to get a set of those smaller panels from harbor freight, and start seeing how many watthours you could actually put into a battery, starting at say 9 am, and going till dark on a 14 hour summer day.
Of course, on the practical side, you could most likely cover 60 miles a day, just pedaling without all the extra weight. It would be really cool though, for somebody to actually do it, and report how well it works without the usual inflated numbers and hype you see with people that are EV evangelists.
This is a fun concept to think about though, what could you do with a smallish panel that could be carried folded during most of the travel time? Say he carried 3 panels of 80 watts, and for 4 hours a day midday, they actually put 80 watts of 36v into a battery even after various charger losses. So you'd have 80 watthours x 4 = 320 watthours in a battery per day. You could actually get somewhere eventually with that. Then suppose you only got about 40 watts of power in 12v when traveling, with just one panel out in the sun for another 4 hours. 13.3 watts of 36v, x 4 hours = 53 more watthours of 36v. The real numbers could only be found out by doing it, but I think 350- 400 watthours of 36v per might be doable in the real world using a set of panels small enough to carry.
So supposing you dragged a 100 pound cargo load for the panels and your baggage, how far could you get with 370 watthours? Assume you used 200 watts of motor, and pedaled another 100, how far and how fast would that get you? I'm pretty sure it could be in the 20-30 miles range, if you traveled nice and slow. You might very well be able to cover 20 miles in the morning, and then spend the rest of the day charging, and angling the panels into the sun till dusk.
I suppose the starting point would be to get a set of those smaller panels from harbor freight, and start seeing how many watthours you could actually put into a battery, starting at say 9 am, and going till dark on a 14 hour summer day.
Of course, on the practical side, you could most likely cover 60 miles a day, just pedaling without all the extra weight. It would be really cool though, for somebody to actually do it, and report how well it works without the usual inflated numbers and hype you see with people that are EV evangelists.
dogman dan
1 PW
Actually looking at panels at HF, I see 15 watt panels 12" x 36" So 3'x3' gives you 15 watts of 36v. I would think 3' x6' could be carried, but that's only 30 watts of panel, not 80. Not sure what this particular set up weighs. Looks like about as light a frame as would be possible.
The 80 watt panels are roughly 2'x4' . So the concept of carrying a few on a trailer is sound. Again, not sure what they weigh, but anything much over 100 lbs might be like dragging an anchor.
The 80 watt panels are roughly 2'x4' . So the concept of carrying a few on a trailer is sound. Again, not sure what they weigh, but anything much over 100 lbs might be like dragging an anchor.
Evoforce
10 kW
It's 45 watts of panels and they aren't that light. I don't remember what they weigh. But this needs to be kept in perspective. That's 45 watts peak performance and it means it will operate a 45 watt light bulb per hour of good sun at 100% efficiency and OP has not said what voltage they are running to know what inverters or regulators are needed. and none of those run at 100% efficiency...
John in CR
100 TW
Using store bought panels won't make much sense unless he can source some cheap thin film panels, and anyone who can source that we will all want to know about.
Neptronix, the OP already submitted a post accepting that including a battery is a far better approach. We're just waiting for a bit more info from him to be able to make reasonable suggestions.
Neptronix, the OP already submitted a post accepting that including a battery is a far better approach. We're just waiting for a bit more info from him to be able to make reasonable suggestions.
Drunkskunk
100 GW
Evoforce said:
If you set out the pannels were they could get optimum sunlight, perhaps with a portable sun tracker, you wou bee able to catch more energy than you could with one mounted on a moving vehicle, so it should be easier to get the extra power needed for the lights as well. I would think you could carry enough pannels to charge 400-500 watts an hour average for 10 hour day, if they folded up
My thoughts on aerodynamics are less about drag, and more about the size pannel being needed to run 250 watts of motor at 5pm reliably on a cloudy day would be an effective wing in a moderate wind.
Whiplash
1 MW
- Joined
- May 10, 2010
- Messages
- 2,906
I don't know much about solar, but what I do know is Aero is a big deficit to output on any bike, and with that said, a properly designed curved frontal panel could easily gain more efficiency back from the better Aero than you would loose from the weight, no? I mean I have read that MOST of the power required (on flat ground at least) to push a bike forward is due to Aero drag right? So if you use the weight of the panels to your advantage aerodynamically, I would be willing to bet you could easily offset the weight. Not to mention, I don't know about you all, but in Africa (with sun similar to where I live in the desert) I would really like the shade provided by a panel overhead as well, otherwise by the end of the ride you will look like a piece of burnt toast! So truthfully, even IF it does not do a whole lot for you power wise, the gain from Aero and shade alone would be a plus in my book, and there is no doubt it WILL help the question is how much?
Oh an d one other thing, the motor efficiency, can anyone get a hold of one of the motors they use in the solar challenge cars? I watched a video of one and they said the motor was 96% efficient! That is a FAR cry from a Conhis or Golden motor!
Oh an d one other thing, the motor efficiency, can anyone get a hold of one of the motors they use in the solar challenge cars? I watched a video of one and they said the motor was 96% efficient! That is a FAR cry from a Conhis or Golden motor!
Ahh... your stubborn-ness is amazing
Stubbornness is synonymous with determination
As long as you keep trying -different- things, not the same thing over and over, then it's a good thing. patrickza, what you are proposing is essentially a solar car with pedals, and slower speeds. I suggest you look thoroughly into the solar car design over the past two/three decades. The options have been thoroughly explored and I'm sure you would get some really great ideas. From what I remember, it can get expensive really quick. How fast were you hoping on travelling?
The leading teams easily spend millions on their solar arrays (yes, for just one car) but they are using cream of the crop high efficiency cells. Last I heard, multi-junction GaAs were what was being used, with efficiencies above 30%. If you go with a high-quality monocrystaline cell you'd get around 22% efficiency. A car-sized array of this quality costs about $100k. You wouldn't need as large of an array, since you won't be driving across Africa at 60kph.
Also, I think reliability would be a large concern. This of course will also depend on the speed you're going. Solar car race teams bring along a trailer of replacement parts, because they are constantly blowing tires, breaking wheels, spokes, axles, and other miscellaneous parts. There was a thread not too long ago about a group of guys who were fund raising for a third world country that needed reliable power supplies for their computers. They had a tadpole trike with a flat solar panel on the roof and were driving it across North America. I think they blew a couple controllers and had to turn back. I'll find the thread and put it in an edit.
*edit - I stumbled on a similar project while hunting for the link. Hope to see you go through with this!
http://triveloproject.wordpress.com/
http://endless-sphere.com/forums/viewtopic.php?f=28&t=17848&p=260197
thats the one I was thinking of
http://endless-sphere.com/forums/viewtopic.php?f=7&t=14388&p=214687&hilit=suncoaster#p214687
here's something similar
dogman dan
1 PW
To clarify what I was saying about the HF panels I was looking at. The cheap 45 watt kit is three 15 watt 12 v panels. So charging a 36v battery, it would be configured into series. That gives you 15 amps of 36v Eh? I'm pretty dumb, but I think I have that one right. Or you could use the 12v configuration to power a lipo charger that uses 12v. But it wouldn't make the output more watthours.
When I looked into reliably charging a 36v 20 ah pingbattery solar, I came up with about 300 watts of 12v panel would be needed. But that was to have enough even in winter, when insolation would average about 3 hours a day. Too costly to save a dime a day.
I think three of those HF panels of the 80 watt size might get you pretty far each day. Of course, you'd want to lighten up the frames as much as possible, but I don't think there's any steel in em in the first place. So you are talking carbon to make em lighter? It's not a budget project. Dragging a cheap generator on a bob trailer would be the budget route.
A good starting point might be one 80 watt panel, a small buffering 12v battery, and a lipo charger. Then see how fast you can charge 5 ah of lipo with it.
When I looked into reliably charging a 36v 20 ah pingbattery solar, I came up with about 300 watts of 12v panel would be needed. But that was to have enough even in winter, when insolation would average about 3 hours a day. Too costly to save a dime a day.
I think three of those HF panels of the 80 watt size might get you pretty far each day. Of course, you'd want to lighten up the frames as much as possible, but I don't think there's any steel in em in the first place. So you are talking carbon to make em lighter? It's not a budget project. Dragging a cheap generator on a bob trailer would be the budget route.
A good starting point might be one 80 watt panel, a small buffering 12v battery, and a lipo charger. Then see how fast you can charge 5 ah of lipo with it.
Evoforce
10 kW
Well I would keep the system at 12 volt. 12 volt panels, to 12 volt regulator, to 12 volt inverter, inverting to 120 volts, to 120 volt LiFePo4 battery charger for 48 volt or more, to 48 volt or more battery. The reason I would keep it at 12 volt is because it is smaller and cheaper(especially for the inverter) because of the availability of cheap inverters and etc, made for the automotive industry. Also some of the 12 volt regulators have plugins for things like cell phones and other devices. Also I don't know how well lithium batteries would take a charge off a regulator (directly) even if you match panel voltage to battery voltage. I think it would have to go through the 120 volt specialty charger made for the type of batteries being used so you would have to use an inverter to power your charger.
Evoforce
10 kW
You would not be able to pull the weight of 400-500 watts of standard (complete) panels around on your bike like drunkskunk suggests. You would not want to know the cost of non-standard panels.
Whiplash
1 MW
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you could haul a trailer with the HF panels folded up so that only two are getting sun when riding and then when you stop unfold the trailer and voila you have a 4 panel when eating lunch or taking breaks? Seems like that would be the most useful way to do it on the cheap? Also, if you are out in the boonies where it does not matter if the trailer is wide, you could unfold then as well??
Drunkskunk
100 GW
Evoforce said:
I should have been more specific at the time i posted that. By my rough calculations, you would need a rated 1000w worth of pannels to get that 400-500watts reliably. I figure 250lbs of pannels. roughly 5 square meters worth. That should let you charge 3kw worth of battery a day on a good day. I figure 40km distance at night with lights bright enough to be safe would run 1000 - 1500 watts, so you would get enough power to make up for cloudy days, rain, or instances were you spend the entire day going up hill drawing twice the normal power.
I'm roughly basing my figures on pannels like this: http://cgi.ebay.com/ws/eBayISAPI.dl...fd4fc7e&itemid=280425924074&ff4=263602_263622
Whiplash
1 MW
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Seems like those would work ok, a rated 300 watts, which is likely more than that in really good sun, you could put one as a front wind deflector, and one on top for shade, then have a small trailer with the last one. I have to believe that 300 watts of power is worth 60 lbs no? Plus the one on the front will aid aero if done right...
whatever
100 kW
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a few more bits:
encapsulation here ( sylgard: very thin layer required)
http://cgi.ebay.com/Sylgard-184-Sol...ation-Kit-/200509126192?pt=LH_DefaultDomain_0
kapton tape here
http://shop.ebay.com/?_from=R40&_trksid=m570&_nkw=kapton#
basic schematic of how it goes together below
encapsulation here ( sylgard: very thin layer required)
http://cgi.ebay.com/Sylgard-184-Sol...ation-Kit-/200509126192?pt=LH_DefaultDomain_0
kapton tape here
http://shop.ebay.com/?_from=R40&_trksid=m570&_nkw=kapton#
basic schematic of how it goes together below
