1500W DIY Solar Powered Electric Bike Beats a Car for Kids Traveling and Grocery Shopping
Last month we featured a great DIY solar cargo trailer that a Electrek reader built for his electric bike. Just in case you need more proof that our readers are some of the most practical and smart eco-do-it-yourselfers on the planet, we’ve got another awesome solar-powered e-bike to show you. This time, it makes dual use of a school drop-off vehicle for the kids and a grocer.
This construction comes from Electrek reader Luke, who built this project during the pandemic with the goal of replacing a family car with a high-utility e-bike. He did this by extensively modifying his Rad Power Bikes RadWagon 4 electric cargo bike.
While this bike is already an impressive cargo e-bike with plenty of utility, Luke made a number of upgrades to help the bike better perform the heavy daily use it needed.
Before we even get to the solar addition, here’s a list of all the upgrades Luke made.
First he replaced the stock controller with one with double the power. The new 1500W controller is mounted under a varnished plywood platform he built for the midframe. Above this platform is a 200W DC-DC converter to provide a 12V outlet for any accessories Luke wishes to run from the bike. He also painted it white to prevent it from getting so hot in the sun. Next to it is the solar charge controller, which we’ll get to in a minute. He used sealed SAE connectors for all connections to make the system as water resistant as reasonably possible.
It should be noted that doubling the power of the controller, which essentially doubles the power drawn from the battery and supplied to the motor, almost certainly voids the bike’s warranty. With Luke’s level of handling, I’m not sure he really needs the warranty.
From experience I can also tell you that overheating your motor with an overpowered controller can eventually burn out the motor, especially if you push it too hard uphill or in other high horsepower scenarios. Luke pays attention to his power delivery to keep this in check, and explained that if he ever cooks the engine, he’ll just replace it.
Then he replaced mechanical disc brakes with hydraulic ones, which he says was a big improvement in reducing the need to adjust and set the brakes. Hydraulic brakes don’t suffer from cable stretch, which can be exacerbated on heavy-haul e-bikes that make lots of stops while loaded with kiddos and gear. He also added a suspension dropper post to the saddle, helping to improve the ride on the hard-framed bike.
Finally, he added a solar installation, consisting of a 50W SunPower solar panel mounted on a custom lightweight plywood frame. It used foam door gaskets to reduce vibration and captive threaded inserts instead of nuts for a clean-looking installation.
The frame was connected to the Rad Power Bikes Conestoga accessory, mounted with Rad’s solar cover shade.
The solar panel powers a GenaSun MPPT boost charge controller to recharge the e-bike battery directly from the panel.
The 50W solar panel trickle charges the battery, and a full day of sunshine would probably put about 50% of the battery charge back there. In other words, as long as Luke is using around 50% or less of the battery per day, he’ll probably never need to plug the bike into an outlet to charge it.
This is a distinct possibility, since the bike is used for two main tasks: dropping the kids off at school and running errands for the family. For the first, the kids sit in the back (and Luke added gorilla tape to the floorboards so the wood isn’t as slippery when wet). The front basket holds their backpacks on the way to school.
The Rad Power Bikes Conestoga accessory on which the solar panel is mounted includes a waterproof enclosure for the rear passengers. To keep himself dry, Luke used one of those Chinese scooter waterproof canopies. He didn’t have a photo of it in action, but explained that the bike “looks like a bright blue rickshaw when set up.” He explained that he only takes it out for heavy rain, but it works well and can even handle speeds of up to 35 km/h (22 mph) when properly tensioned at the front.
For grocery shopping, Luke puts a corrugated plastic box in the child carrier and can fit about four bags of groceries in it.
It’s a nifty solution that shows just how effectively e-bikes can replace cars, even for more cargo-intensive tasks like running errands or carrying multiple passengers.
This project involved much larger modifications than most people would need, but it also meant that Luke ended up with a one-of-a-kind e-bike that was perfect for his exact needs.
In the past, we’ve seen other simplified solar e-bike charging setups (which I’ve also recreated myself) and even learned of cases where other riders have saved tens of thousands of dollars over several years by abandoning their car in favor of electric bikes. .
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