The Off the Wall Pro and Off the Wall stand are pedal power generators that produce AC (alternating current) similar to wall power used around to world and can directly power many devices. The voltage and frequency will vary with the speed of the pedaling.
Most devices will require a switching power supply (often include with the device).
How do I tell if my device has a switching power supply? If you look at the back it will read “INPUT: 100 – 240V” on the back of the device, as seen below. Examples include most newer chargers and power cords for laptops, cell phones, tablets, and many other devices. If the device only has a single input such as “120v ” it will not be compatible.
Not all devices are compatible.
Many power strips have surge protection circuitry that is not compatible with the variable voltage and frequency range of the Off the Wall. Instead use power splitters when you want to add extra devices.
Devices with brushed motors that require AC power will likely not work. Many fans, vacuums, blenders, and drills need a particular frequency (60HZ) in order to spin. However DC motor devices can be powered with a separate power supply.
Some fluorescent and led light bulbs have circuitry that is only rated for 120v and can burn out.
DON’T plug in any device that is irreplaceable. A perfect example would be a vintage guitar amplifier. Why risk it?
We now include an over-voltage protection circuit, but it only protects devices that are rated to input up to 240 volts. When the voltage reaches around 230v the circuit will drop the voltage down back to around 110v. This will not protect devices that need a specific input of 120v or need a stable frequency rating of 60 hertz. Some devices can be damaged by receiving variable voltages or frequency. This includes power strips that are designed to protect against surges. Higher voltages happen when people pedal really fast, and this is more likely to happen if the bike is in too hard of a gear. In our experience, pedaling too fast is not something you will ever do by accident. It only happens when a pedaler gets on and wants to see what happens when they pedal like crazy. The over-voltage protection circuit helps to keep many devices safe in the case of fast pedaling.
Pedal Power should be an attended activity. We do not recommend leaving your Off The Wall unattended for several reasons. 1) People could plug in the wrong kind of devices, ruining them and possibly risking electrical fire. 2) Any time people get on and off a bike there’s a chance your help will be needed to make that safe and easy. 3) Any time a bike is unattended there’s a higher chance people will get on and pedal really fast, which can cause damage to some devices.
When using the Off the Wall stand with your own bike, choose a bike with gears. Select a medium-hard gear, probably not the hardest gear on the bike. If your bike has 3 speeds in the front, you probably want to be in the middle group, and then choose the hardest or 2nd hardest gear in the back. Once you determine what the best gear is for pedaling, DO NOT let your pedalers change the gear. You may want to tape the shifter or use the limit screws of the derailleur to lock the gear. You will know you need to be in a harder gear if your device turns off even when you are consistently pedaling. You will know you need to be in an easier gear if it feels too hard! You will know you are in the right gear IF, when you plug in a 60 Watt device, such as a laptop computer, pedaling feels like biking around town. You can use a watt meter, voltage tester or purchase our Comparator display to help with this test. Keep in mind a laptop that is fully charged already will consume no power. Best to allow your laptop to drop to 50% charge or lower before trying the test.
Add a Comparator display so that you can see wattage, voltage, current, and watt hours generated. Highly educational!
Given all these warnings, you may be wondering what ideal usage is. Here are some examples:
- Charging a laptop. All recently made laptops have Switching Power Supplies. This is a 50-60W effort, perfect for learning about how much effort it takes to power up this common item. Great for getting a workout and using your energy.
- Powering a USB hub that charges 10 cell phones (or iPads, etc). We have a USB brick available for $100.
- Doing a lightbulb comparison station (LED vs. Incandescent). For maximum effect, we recommend using 2 60W incandescent lightbulbs vs. 2 equivalent LED lightbulbs. Use our Comparator or power splitters and switched sockets to go between the two modes. If you use too few incandescent bulbs they will burn out by being overpowered. Some LED and Fluorescent bulbs have circuitry that is not compatible and will burn out.
- Loudspeakers. Many newer powered speakers have a switching power supply. You can look at the writing near the plug to know for sure. Use the volume and a watt meter to demonstrate that louder music requires more power. Feel the difference in your legs. Careful blasting people with loud music! Not every speaker is compatible. To prevent damaging speakers, we recommend using one we’ve tested. We’ve tested and love the Mackie DRM series including the DRM215. And we’ve also tested and approve the less expensive EV ZLX series.