THE TRUTH ABOUT SOLAR GENERATORS
Ready-made versions may require a lot of charging for not much usable power
Portable, off-grid electric power generated without noise or fumes, this is the promise of solar generators. They’re an up-andcoming energy technology that has been getting a lot of press lately. But if you want to avoid disappointment, there are things you need to know before you get your hopes up.
The technology behind solar generators is not new. For decades we’ve had the ability to convert sunlight into electric power, then store that power in a battery for use later. What is new is the variety, reliability, economy and sophistication of components that allow portable solar power generation to happen more easily. These advances made portable solar generators possible, with more and more manufacturers offering these products.
Whatever you do, don’t fall for the sometimes-slippery marketing messages you’ll find around solar generators. Every model needs to be assessed by answering three key questions.
HOW LONG WILL IT RUN?
Short run time is the typical reason people are disappointed with ready-made solar generators. Imagine it’s night or cloudy. Your solar generator isn’t actually generating any new power, it only has what’s stored in the battery.
So how long will that battery keep lights working? A toaster oven operating? To understand this you need to understand how solar generators work. Every model is a combination of the same main components.
Photovoltaic panels convert light into electricity. This electricity runs through a device called a charge controller that delivers just the right amount of power to charge the battery. Power from this battery runs through an inverter that converts the electricity to a form that plug-in appliances can use. The run time of any solar generator is how long it can operate on battery power alone, and this is a function of the size and type of battery that’s part of the system, and the electrical load you’re demanding.
Most factory-built solar generators have a rating that shows how much power they store.
The units of this stored power rating is watt-hours (Wh). Every electrical device that uses power has its power consumption listed on a name plate somewhere. This is the number you need so you can determine how long a solar generator can deliver power. Divide the total watt-hour (Wh) capacity of a solar generator by the wattage of the item you have in mind. The result is the maximum run time in hours. A 1,000-Wh solar generator powering a 1,000-watt toaster oven will operate for one hour before the battery is dead and needs recharging.
HOW LONG TO RECHARGE?
Recharge speed is a function of solar panel size and the intensity of the sun. Some ready-made solar generators come with a panel, but many need to have one or more panels added by the operator. Assuming a 100-watt solar panel and an 85-amp-hour (Ah) battery, a 100-watt panel would require 10 hours of full sun for a full charge. That’s a lot of recharge time just to operate a toaster oven for an hour, but it’s typical of many ready-made solar generators.
HOW MUCH POWER?
Duration of run time is one thing, but how much maximum power output a solar generator can deliver at any given moment is another. This is what you call peak power and it’s measured in watts (not watt-hours).
Different solar generator models can have max wattage output of 500 watts, 1,500 or even 2,000 watts. Pay attention to product description and don’t demand more than 80 per cent of the maximum solar generator output at any given time.
Portable solar generators can’t deliver the quantity of power offered by even a medium-sized gas-powered generator, but they can keep on delivering power indefinitely with no need for fuel.
To learn more about solar generators, including the buildit-yourself option, visit baileylineroad.com/38892.
Steve Maxwell has been helping people figure out solar energy for decades. Visit him online at BaileyLineRoad.com and learn some hands-on skills in a Canadian context.