Using small inverters to keep your stuff charged

Using small inverters to keep your stuff charged

By Dave Helgeson
Traveling with all of today’s modern conveniences like digital cameras, cordless tools, laptops, tablets, electric razors, etc., equates to the need to charge them on a regular basis. If you frequently dry camp for long periods, do you find yourself constantly battling to keep things charged? While some of the items mentioned above can be operated with a 12-volt adapter/charger via a 12-volt outlet in your RV, others cannot.

One solution to this problem is an inexpensive, low wattage inverter. An inverter converts 12 volts DC, which is the primary operating voltage of your RV, tow vehicle and/or dinghy, into 120 volts AC, which is what comes out of your wall outlets in your home and RV when connected to shore power.

In the United States, chargers that plug into a wall outlet require 120 volts AC. When moving between dry camps or out exploring from base camp, plug the inverter into the 12-volt outlet (cigarette lighter, for those of us over 50) of your motorhome or tow vehicle and the items that need recharging into the inverter. When the vehicle is running, the engine’s alternator provides the amps to power the inverter and, in turn, the item that needs recharging. This technique is much more efficient than running a generator to provide the low wattage most items need for a recharge. (Your dry camping neighbors will appreciate the lack of generator noise, too.)

Note about inverters: Ohm’s law tells us that the voltage multiplied by amperage equals wattage. Therefore, if you have an item that requires 120 watts of 120 volt AC power, that equates to 1 amp (120 volts x 1 amp = 120 watts). Conversely that 120-watt item, when operated via a 12-volt inverter, requires 10 amps* (12 volts x 10 amps = 120 watts). For most low-wattage inverters, your standard 12-volt outlet can deliver sufficient amperage. However, if you plan on powering something that requires higher wattage items, make sure you have heavy enough wire on the 12-volt side of the inverter.

*Actually, the amperage will be somewhat higher than this as inverters are not 100% efficient, but for quick calculations this keeps the math simple. [Editor’s note: Inverter “efficiency loss” can be significant, and varies by the inverter itself. Many experts in the field suggest knocking off at least 10 percent for efficiency loss.]