Can You Recharge an E-Bike With Solar?
In every campground in the U.S. and Canada, we’ve seen RVers with e-bikes! People of all ages are using e-bikes for exercise and as an alternative transportation while their RV is set-up at the campsite. It’s exciting to see this trend that not only gets people out of their vehicles and into the outdoors, but also helps reduce car traffic and pollution in and around popular campgrounds and national parks! All U.S. national parks allow e-bikes, though some have restrictions on the class of bike and the areas / trails in which they are allowed to be ridden. It's always a good idea to check the regulations at each park before you ride.
But, e-bikes have their downsides, they need to be recharged frequently. Recently, we’ve seen signs popping up in campground bathrooms explicitly banning the charging of bikes at the bathroom electrical outlets. Why? E-bike batteries are large, expensive, and take a lot of energy! I mean, who wants to have to share a small bathroom with a charging bike? So, how can you stay off-grid and keep your e-bike battery charged and ready to go?
First, let’s get our heads around a typical e-bike battery as they are more powerful and energy dense than most other portable electronics that we carry around. There are many variations between manufacturers, and battery technology is constantly improving, so check your own battery specs. If you are new to e-bikes, here’s a great resource that explains some terminology. With that said, most e-bike batteries…
are lithium-ion which can provide 500-1,000 watt hours (Wh) of energy.
operate between 36V-52V in order to increase the amount of time a person can ride, and provide more power/control to the pedals.
draw around 15-20A while recharging and can usually fully recharge overnight (an important stat for those of us with inverters).
range widely in style, quality, longevity, miles per charge, and price.
can be charged in a standard 20A AC wall outlet.
come with a 12V DC charger, which means you can plug it into almost anything with a compatible receiver (12V utility outlet), such as a portable power station, a portable solar panel, your car/truck*, etc.
*Note: This is best to do while driving to avoid the risk of a dead starting battery! It simply doesn’t make good environmental sense to let your car idle at a campground just to charge up your e-bike – that’s a bit counterintuitive, environmentally unethical, and rude to your campground neighbors.
Let’s play out a typical scenario….
You arrive at an off-grid campground with your e-bike batteries charged up – either at home or while you are driving using the previously mentioned 12V outlet. You go out for a 20-30 mile ride around the area each day for a couple of days and you’ve drawn the batteries down to their safe depth of discharge (usually 80% depth of discharge [DOD] or 20% state of charge [SOC] is as low as you want to drop your batteries to extend their performance lifetime). How do you charge these hefty e-bike batteries without having to idle the car engine or run a gas powered generator?
Your best bet is to build a robust enough solar powered system in your RV to accommodate all of your electrical needs, including recharging your e-bike batteries. Use this Solar System Sizing Worksheet to calculate your average daily watt hours and explore the components you’ll need to power your entire RV lifestyle off-grid.
If you already have a solar system installed, just focus specifically on what you’ll need to upgrade to accommodate your e-bike(s). To calculate your e-bike battery capacity, you need to multiply the battery Voltage (V) x Amp hours (Ah). For example, if you have an 36V e-bike battery with 15Ah capacity, it’ll be: 36V x 15Ah = 540Wh (Watt hours)
Thus, recharging one 36V e-bike battery (approximately 540Wh) will use a bit more than half of one 12V-100Ah PRO Lithium Iron Phosphate battery’s capacity at 1024Wh (using a safe depth of discharge of 80%). 12.8V x 100Ah = 1280 Wh; 1280Wh x .80 Safe DOD = 1024Wh.
If you have two e-bike batteries that need to be charged, plan on dedicating an entire 12V-100Ah PRO LiFePO4 battery to e-bike charging, especially if you plan to use the bikes regularly. Remember…all e-bike batteries and chargers are a bit different, so always check the specs of your model!
Also be sure that the size of your inverter is large enough to handle the extra draw from the e-bike chargers. Again you can find resources to help you size an inverter using our Solar System Sizing worksheet.
Charging an E-Bike Battery with DC Power
If you’ve maxed out your space for extra batteries in your rig, another slick and easy way to accomplish this is to set-up a dedicated LiFePO4 battery bank (at the appropriate battery voltage) in your tow vehicle and use a DC to DC charger with Solar MPPT to charge that battery bank – either while driving using the engine’s power or with a portable solar panel while at the campground. Then, with a simple DC outlet connected to the battery bank, you can trickle charge the e-bike batteries using this set-up overnight. When the sun comes up the next day and you are out riding, you can recharge this LFP battery bank in your tow vehicle with a portable solar panel. Then, when you return to camp, the battery bank will be all charged up and ready to recharge your e-bike batteries again overnight.
We have a similar set-up in the back of our truck that runs our ICECO 12V fridge/freezer, and it’s worked seamlessly for many years! An added bonus with this system is that when the fridge battery is good and topped up, and we are driving during a low solar day or at night, we can switch the energy being produced by the DC to DC charger to recharge our RV battery bank. We are always making great use of that extra trickle charge coming from the alternator while driving!
Charging an E-bike Battery with AC Power Using an Inverter
Most e-bike manufacturers recommend recharging their batteries using the provided charger, which typically plugs into a household outlet. So, if you want to follow their suggestion and use your off-grid power, you’re going to need an inverter.
Typically, a 1000W battery inverter will be sufficient to charge a single e-bike battery. This inverter can be installed in your tow vehicle near the set-up described above. Since some e-bike batteries are slightly larger capacity, or if you want to be able to charge 2 batteries at once, it’s important to install an inverter with an appropriate wattage capacity to accommodate the load. Need help with appropriately sizing an inverter to meet your energy demands? Check out this blog.
Another reason you may want to get a larger inverter than you need now is that you never know if/when you’ll upgrade the e-bike’s battery. Battery technology is constantly improving, so when it’s time to replace it, you may want to go bigger, thus you will need a larger inverter (e.g., 2000W or 3000W). One note of caution – the larger the inverter itself, the more power it uses to run itself, so don’t buy too big, or you will simply eat up your battery bank’s energy by running the inverter.
Charging an E-Bike Battery Directly with Solar Panels
If you want to by-pass the need for a battery bank and/or inverter, you’ll want to make sure the wattage produced by the panel (or array) is higher than the e-bike’s battery wattage and/or use a charge controller which can boost the voltage as shown in this video. This allows the system to still produces much voltage as the e-bike battery requires for charging, even when there are passing clouds. For instance, if your e-bike battery operates at 36V, you’ll need a solar array (or portable panel) that can produce 40V or more such as a 400W Portable Solar Suitcase combined with a Rover 60A or Rover 100A Charge Controller. If you are seeking an even smaller, more portable set-up, try the 220W Portable Panel combined with a 36V/48V MPPT Rover Boost 10A Charge Controller to boost the voltage up to what is required by your e-bike battery. Finally, if you are interested in charging while riding on a multi-day bikepacking trip, check out this cool video for some great ideas!
Regardless of how you recharge those e-bike batteries, enjoy the opportunity to see your public lands from the seat of a more sustainable form of transportation!
☝Don't forget to use our Solar System Sizing Worksheet to determine your energy needs, learn more about the components you need to build out a system, and even put together an order with all the wiring, fuses, monitor, and accessories you need. It's a super helpful tool to simplify this complex process. Remember to use our link AND promo code CANLIFE at checkout to save a bundle on Renogy components! And, of course, holler back with questions. We love to help!
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