Papa wrote: ↑
Jan 10 2018 3:31am
Would you put solar panel on your electric vehicle?
Not with any of the current, low efficiency PVs on the market. If the on-board battery is designed for the destination distance, why lower you vehicle's overall efficiency by carrying low efficient PVs?
1.) PVs are not cheap.
2.) PVs are easily damaged when not rigidly mounted - not to mention, traffic hazards.
3.) You'll be lucky to see 50% of the PVs rated output by chasing the sun.
4.) And good luck trying to warranty a damaged PV, if the retailer finds out how you use
5.) And just how do you secure it, so no one steals it when your back is turned?
Low efficiency? 20% is where PV is at right now. For comparison, your car also experiences 20% energy efficiency from it's dino juice. I'd say the playing fields are a lot closer than you think.
Solar charging isn't completely necessary for regular distances where you can charge at both point A and B. It's simply convenient to be able to leave the battery on the bike and not have to disconnect it to charge inside. 'What's that thing, is it a battery? Is that a LITHIUM battery? Are those things safe? OMG are you charging that on the wall???' (Regular encounter at the coffee shop, anyone?)
Solar really "shines" when you're
- A) riding to a place with no power, such as a hiking trail, the beach, or a campsite. It's great for charging your bike as well as camping accessories (lamps, stereo, computer, etc) at things like music festivals or over long distance touring.
- B) If you love the idea that your old 20th century 50cc moped's direct replacement (modern e-bike) can perpetually supply its own energy to itself without any need to recharge externally. This is very satisfying to anyone who's ever mixed 2 stroke oil into their dirty old moped that they bought for 'environmental reasons.' You'd better believe that if I lived in Puerto Rico, I would have a solar bike out of pure necessity.
So to recap your questions:
1) Please see above cost modeling that shows how addding a PV system to your bike, even with an expensive-@$$ Genasun controller, delivers more wh per day than a comparable spare battery.
2) Tell that to the crazy Sun Trip people who've made it thousands of miles with the same solar panels. High quality panels, as well as a good mounting strategy are key, but if done properly, your panels will provide years of reliable service. They will usually outlast a lithium battery made of typical 18650's. I've met several individuals, probably more than 10 at this point, who have completed >4,000mile tours with the same PV array. And to your traffic concern: I actually use my solar trailer in heavy traffic at home (Winston-Salem, NC) because I think if I get rear-ended, it'll give me an extra second to bail. I can't verify this sentiment by any measure other than getting hit by a car sucks, I am tired of it, and I would rather destroy their car with the sharp, angry, reflective corners of my PV panels than have a giant car come into contact with my body again.
3) Yes, it's called standard test conditions (STC). I would expect 100% output if I tilted it towards the sun, and rode due west through Arizona while it's a perfect 72 degrees at 2pm in the afternoon. If life were this predictable, I would have bought a couple dozen Bitcoins a few years ago... You 1) take the rating of the panel, 2) multiply by the avg solar irradiance of your area (Boone, NC is 700 w/sq m, so x .7, because STC is 1000w/ sq m) then you multiply by the average sun hours in a day (Boone is 4.5). Example: My 300w solar array, at 70% irradiance, for an avg of 4.5 hours per day, would give me 945 wh on an average day. If my bike gets 16wh/mi, which it does if I'm not challenging cars at green lights, then 945/16 = 59 miles per day. Now, if I start with a full battery, I could easily ride 75-80 miles on an average day. Obviously in January you can slash that number, and in July you can increase the sun hours to, say, 6 per day (100+ miles), but the math stays the same. If I had spent the same amount of money on another battery (as shown above), then I would be getting 518.4 wh per charge, enough to only go a measly 32.4 miles. Add 15 to that, and your daily range is 47+ miles compared to the 75+ miles you would get from PV at the same cost.
4) Simple, either don't tell them, or become a dealer
5) I'm not here to say it won't get stolen, but that it probably won't happen. Chances are if you're riding a labor of love covered in solar panels, you probably park it in the window. You probably tour with at least 3 locks, maybe pepper spray, and possibly a GPS tracking system. You may even have a blog documenting the project on a forum like this. Cedric, the Sun Trip director, told me once that he got out of a really hairy situation in eastern europe by telling the would-be maurauding theives that he was a news reporter who was streaming his whole trip live in France. They got pretty scared of being recorded while trying to illegally blackmail travelers, so after Cedric pointed to the go-pro (that was actually off at the time), they decided to leave and possibly prey on someone less 'special.' Yes, I've heard the story that once an entire solar car, team trailer, and mobile workshop were stolen from a University just minutes after parking outside the CNN center in Atlanta. The thieves easily scored over 1/2 a million dollars in expensive stuff, but do you think they were after a solar car, or just at it to sell whatever was in the trailer? The most stolen car in America is not the Mustang, it's the Honda Accord. If I were the guy who stole the solar car, I'd be pissed, because imagine how hard it is to part out and sell something like that? I would much prefer that the trailer was full of Harleys, or mufflers, or something that would go unnoticed upon resale. I'd say to do such a custom, one off job at your bike that the would-be thief takes one look and ways, 'shit, I'm gonna go rob the liquor store instead, because I have no idea how this ridiculous solar bike even works, let alone who to sell it to.'