If you've ever thought that the rider platform of an electric scooter is just crying out for a solar panel, you're not alone. California renewable energy veterans Mike Donnell and Tony VanMeeteren have spent the last four years working on some PV-panel-packing, adult-sized, emission-free electric scooters called SES, and are now moving toward mass production.
Donnell and VanMeeteren have both been in the renewable energy industry since the early 1980s and, after being given an old scooter, they began designing a practical solar version.
"We started with a 24-volt system that was on the old scooter chain drive and bought all new parts and added a solar in order to charge it," VanMeeteren told Gizmag. "It worked fine. Now we had to make it cool and we needed to add range. We went with a hub motor and 36 volts."
The team was expanded to include an electrical engineer, to help integrate the most efficient PV panel possible. After that, it was time to build a prototype with the help of Killer Off Road in Simi Valley.
The result is a pretty cool-looking, emission-free short haul vehicle called the Solar Electric Scooter. Riders stand on a deck that's actually a 13.5 by 32 inch (34 x 81 cm), 37-watt/0.88 amp PV panel sporting 4-mm thick glass that's been laminated and made skid-resistant. According to VanMeeteren, the riding platform has been "designed to hold up to 350 lb (159 kg), however we suggest a limit of 250 lb."
There are three ways to top up the scooter's 36 V/15 Ah Li-ion battery pack. The first, and perhaps easiest, is just to kick the stand and park it in bright sunlight. Every hour left in the baking sun gives the battery enough juice for about a mile of travel. The SES also has a built-in 4-ft (1.2-m) pull-out charging cord connected to the included 2-amp charger that can be plugged into any standard power outlet. Lastly, the battery pack can be removed and hooked up to a 3-amp external charger. When the status light shows green (full), the battery offers a range of up to 20 miles (32 km) per charge, depending on rider style.
The 350-watt brushless hub motor is reported capable of taking the e-scooter from a standing start to its top speed of 15 mph (24 km/h) in just 3.7 seconds, which will probably make you appreciate the inclusion of disc braking front and rear. The 12.5 x 2.5-inch stainless steel rim at the front, and 10 x 2-inch at the back, are home to pneumatic tires. There's also safety lighting front and rear, and the goose-neck handlebars collapse down and lock for ease of storage or transport.
To get the scooter into the hands of consumers, Donnell and VanMeeteren have launched on the When You Wish fundraising platform. Lower pledge levels are rewarded with solar-powered torches or lunch with the developers combined with a test drive of the SES, but to get your hands on a production SES in a choice of five different colors, you'll need to stump up US$1,500 for one of the first 50. The next 50 are offered at $1,700, and then the pledge level rises to $1,900 (which is still $200 less than the proposed retail price).
The developers say that the SES is street legal (though you're advised to check local regulations before diving in), and is not really designed for use in hilly areas. Production versions will benefit from superior lighting, a new throttle/hand grip design, improved inner tube and stem to help guard against flats, and better handlebars. Though a cable or chain and lock are the usual methods of securing the SES, the designers told us that a tracking device may be added to help in the event of theft.
For every scooter purchased through the When You Wish site, $50 will be donated by team SES to charities like Friends of the Earth and Erase Poverty. A $100,000 funding target has been set, and everyone who pledges at an appropriate level will receive a Solar Electric Scooter at the close of the campaign on May 22, even if the funding goal is not reached.
You can see the SES in action in the promo video below.
Sources: SES, When You Wish
In my experience, they should have stuck with 24 volts. I searched the internet for a week trying to find a regulator which would handle 36 volts, but unsuccessfully. Initially I had my trike solar charged, but without a regulator, if I didn't ride it regularly (or forgot to disconnect the solar panel), the battery boiled dry. But at 24 volts, there were regulators galore. Now I can safely leave my vehicle in the sun for days.
The motor is 350 watts, the panel nominally generates 37 watts - in reality closer to 20 watts. Any recharge, even at 37 watts is going to be fairly minimal.
This is a one ride wonder. You go for a ride, the battery gets discharged and you have to walk home pushing to have it recharge, or you "scoot" it home, don't get a charge and plug it in to the wall. And that's probably the last time you'll ride it.
Just because you could not find a 36v regulator does not mean that they can not build one. The scooter has a built in 2-amp charger with a four foot cord. Anybody who takes it for ride beyond what the batteries and solar collector can be expected to deliver deserve what they get.
Joe Blake, 1. good idea putting the solar panel behind you, but this is a scooter not a tricycle - where the hell else are you going to put it that is both convenient for a user and robust in design?. 2. This is a commercial product not a home DIY project, so 24V vs 36V doesn't really matter at all, I'm not sure why you would bring that up.
And slowburn, that would be terrible for aerodynamics and I am sure that the tradeoff for a bit of dirt or some scuff marks on the panel would not be worth it.