No matter how much range your electric bicycle has, eventually you’re going to have to charge it. It’s the achilles heel of every ebike, being tied to its charger like a junkie needing his next fix.
If your ebike has a removable battery then the process isn’t so bad – simply slide out the battery and bring it to your charger. But if your battery is fixed to your ebike, on the other hand, charging can be a real pain. A potential solution is to mount an ebike charger “on-board”, which has a number of advantages and disadvantages.
Why mount an onboard charger?
An onboard charger makes it much more convenient to charge your ebike’s battery, especially when the battery isn’t removable. Instead of trying to snake the charger or extension cord through a window or around your house, you can use a smaller extension cord to go straight from the outlet to your ebike, no matter where you’ve parked.
An on-board charger also gives you the freedom to charge anywhere you can find an outlet. One of the biggest problems with electric cars is “range anxiety” which is the act of worrying about always being within range of a charging station. By mounting your charger on-board, all you need to charge your ebike is an extension cord and an outlet. Suddenly any coffee shop, book store, or restaurant is a charging station. Your city just got a hundred thousand ebike charging stations! Just remember to as you ask if you can plug in your extension cord first – not everybody’s outlet is a public charging station.
An extension cord is easier to hide in a bag or basket than a bulky ebike charger, giving you more freedom when you’re out on a ride. And if you ever forget to bring an extension cord but still need a charge, many places will already have one that you can use for a quick top-off charge. Service stations and gas stations are a great option for a quick charge, just ask if they’d mind you borrowing a cord and plugging in for a few minutes.
Onboard charger disadvantages
But an on-board charger isn’t without its disadvantages as well. Chargers get hot while they operate, especially higher power chargers. If the charger is hidden in a bag or other enclosure on your ebike it could begin to overheat, causing problems and even posing a potential fire hazard. This risk can be mitigated by making sure the charger has room to breathe.
On-board chargers also pose the risk of debris and other foreign objects entering the charger through the vent ports. One of the biggest issues is the potential for road salt, used during the winter in cold areas, to enter the charger and destroy the components inside. I’ve seen this exact problem happen multiple times.
One way around it is to install a flap of material over the air ports on your charger. While riding, the flap will remain down and cover the exhaust port. During charging, the air exiting the charger will lift the flap up and out of the way. Just make sure to use a light enough material that the exhaust air can still lift it. And don’t cover the air intake, which could cause the charger to overheat.
The best method is to point the exhaust port forward, that way the intake is pointing to the rear and less likely to pick up foreign objects. Of course you can also look for a lower power ebike charger to use instead. Low power ebike chargers don’t require a fan and are completely sealed. These chargers are great for on-board chargers but will take a little longer to charge your ebike.
Another issue with onboard chargers is battery drain. Leaving the charger connected to the battery all the time can slowly drain the battery. There are two ways to solve this problem. The first method is to unplug the charger from the battery when not in use. Depending on where you’ve mounted the charger, this option can be less appealing. Also, one of the advantages of having an on-board charger is not needing to repeatedly connect and disconnect it from the battery, so this method totally removes that advantage.
A better method is to install a switch between the ebike’s battery and charger. The switch will open the circuit to the charger any time you aren’t charging the bike. When you are ready to start charging, simply plug in your extension cord and flip the switch. When you’ve finished, turn the switch to its “off” position and unplug your extension cord.
Lastly, you need to consider the extra vibration the charger will be experiencing. electric bicycle chargers weren’t generally meant to take the bouncing around and shock forces of daily riding the way your other ebike parts can, so you’ll want to mount it accordingly. It is important to mount the charger in a way that allows for some form of shock absorption.
I like to mount a thin piece of foam between the charger and the frame. If you go with foam, just make sure not to completely surround the charger – it still needs room to breathe! Another option is to use a bag to hold the charger, since the bag will absorb most of the forces during riding.
On-board chargers come with a series of issues that need to be addressed, most importantly heat dissipation and battery drain. When you take of these issues though, an on-board ebike charger can be an elegant solution to increase your range and make charging a much more pleasant process.