Connecting Your Equipment to the PedalPC

There are two types of electricity, alternating current (AC) and direct current (DC). AC is the type supplied to your home by your electric utility. It best suited for large loads like electric motors and heaters.

DC is the type stored in batteries. Most consumer electronics like laptops, monitors, and phone chargers run on DC, using a power adapter to convert household AC to the DC they need.

Anytime electricity is converted from AC to DC or vice-versa, some power is lost. For a large generator used by an electric utility, this loss are a tiny fraction of the total power generated. But for a small power generator like the PedalPC, it can add up to a significant fraction of its output.

Since most of the equipment you will be powering requires DC anyway, the PedalPC has DC power outlets instead of household AC power outlets. This prevents any unnecessary DC-to-AC and AC-to-DC power conversions, reducing power loss and allowing you to power more and larger electronic equipment.

Equally important to the type of electricity (AC or DC) a device requires is it’s input voltage and power jack dimensions. The PedalPC can supply 5 and 12 Volts DC (VDC) through its USB and automotive power sockets, respectively. (There is also a built-in 3-pin header reserved for powering a 12 V DC fan.)

If your device doesn’t have a power cord to fit either of these sockets, or it requires a different input voltage, you will need an adapter to connect it to the PedalPC.

There are multiple adapters available. What follows is a description of how to determine what kind of adapter you need.

Determing Input Voltage

The input voltage required by a device is usually shown on its label. Here are some sample labels from a laptop and a small battery charger:

a laptop label with its input voltage highlighted

this laptop runs on 19V DC

a battery charger label with its input voltage highlighted

this battery charger requires 12V DC

If there is no label on the equipment, you can use the output voltage from the device’s power adapter label, since the device’s input voltage must match it’s adapter’s output voltage to work properly.

label of power adapter showing output voltage

this power adapter produces 12V DC

If neither is available (e.g., you are shopping for a new piece of equipment), you can usually find the voltage listed on the product web site or in the product manual under “Specifications”.

You can also tell a device’s voltage requirements by the type of power socket it has. All devices charged by a micro-USB cable, for instance, use 5V DC.

Choosing the Right Adapter

5V DC / USB Devices

Standard USB 2.0 power sockets supply 5V DC. The PedalPC has four such sockets built into the machine, one of which is used to power the PedalPC’s computer. You can use the other three to recharge a phone, tablet, or any similar device that requires 5V DC.

2 port USB power outlet built into PedalPC

Two of the four USB power outlet on PedalPC

If you need to power additional USB devices, use a 12V-to-USB car adapter.

a 12V DC to USB car adapter

a 5-port 12V DC-to-USB car adapter

Each socket of a USB adapter can supply either 1 or 2.1 amps of current, depending on how it is designed. I recommend choosing adapters where all sockets supply 2.1 A, as they can power a broader range of devices and recharge devices more quickly.

12V DC Devices

Most monitors, small battery chargers, modems, routers, and some small computers require 12V DC. You can power these devices directly from one of the PedalPC’s power sockets. Each device will need a 12V DC car power cord with a automotive plug on one end and a barrel plug on the other. Barrel plugs come in a few different sizes; be sure to choose a cord with a plug that fits your device.

12V DC power cord with barrel connector

typical 12V DC power cord with barrel plug

Devices Requiring > 12V DC

Other small computers and most laptops require a higher DC voltage, usualy between 16V and 24V DC. The best way to power these is using a DC-to-DC laptop car adapter. You can purchase adapters made specifically for your model of laptop, or universal adapters with selectable output voltage and power plugs that fit a variety of laptops.

a universal car laptop adapter with a colleciton of tips

universal car laptop adapter

AC Devices

Finally, some devices (e.g., most HP inkjet printers) have no extenal power adapter and will require a 12V DC-to-110V AC inverter. Inverters waste power (especially if they have a fan) and should be avoided if possible. The most efficient inexpensive inverters I have found are single-outlet, 75 W passively-cooled models like the one show below.

small passive inverter

small 75W passive inverter

It consumes about 2.5 W with nothing plugged in.