Sunday, November 13, 2011

Affordable Emergency Solar Charger

Since I moved into the woods, and after hurricane Irene, I started researching to get something solar, but affordable in place. The idea is being able to have some electric energy during a power outage and/or if the roads are blocked due to a blizzard. A solar panel gets charge even when is cloudy. Smartphones and other gadgets will lose charge fast needing to be recharged often. So we must plan ahead before another emergency hit.

First, I must say is that this advice should be taken as given, without any guarantees. I’m sharing what I did to have a solar charger backup in case of another electric outage due to bad weather, but I don’t intent to replace the advice of a licensed electrician..

Solar energy usually is expensive, but for the purpose of this article, I chose the least expensive and best quality components I could find.

The basic parts of a solar kit are:

Solar panel to convert solar energy into electricity.

Solar panel charge controller to avoid overcharging the battery. Said charge controller usually includes a blocking diode to keep current from flowing back to the solar panel at night and a fuse to protect the solar panel, the battery and regulate any overload.

A battery to storage the solar panel’s energy. I prefer Sealed Lead-acid or absorbed glass matte (AGM) batteries, which are better because under regular conditions they don’t leak acid or fumes. The AGM are more expensive and have a shorter life span too.

A power inverter to convert the DC (direct current) from the battery into AC (electric current).

Most inverters can be connected to a car’s battery too. Now, my idea is to have silent, and fumes free energy. So I chose a Sealed Lead-acid, 12 Volt / 8 Ah battery rechargeable by a solar panel. My first kit is small, because I wanted to see how it works, before increasing watts on everything.

The higher the voltage the more complicated the installation becomes. For example, if one wish to get a 1100 Watt inverter, one needs to have a fuse between the positive wire going to the inverter and the battery, in case of an accidental short circuit to avoid a wire meltdown or fire. And the inverter must be grounded too. The 400 watts inverter and 8 amps battery I picked doesn’t need any of this, but it won’t power a higher demanding appliance either.

The goal of my solar set up is to keep the charge of cell phones, laptops and provide safe and free long hours of light, good enough for reading.

So this is my basic affordable solar charger kit. At the end of this article I link to every component individually from where I bought it. I made a video because I thought it was easier to see than pictures. I tested these components for more than a month.

The kit should be tested before an emergency comes. I’m using mine to recharge my cell phone daily, and occasionally use the led light to read at night. I bought two led lights, two inverters and two batteries, so one battery gets charge while the other is in use. The ideal place for the solar panel is outside in the sun, but from the sunny window it produces enough energy to keep the charge in the batteries if they are not used.

The cables between the inverter and the battery should be short in order to avoid power loss and cables getting too hot. It’s better to use an electric extension from the inverter AC outlets to the appliances. Or a USB extension with the inverter that comes with a USB outlet like mine. Always be certain that the power cable terminal connections run Negative (-) to Negative (-) and Positive (+) to Positive (+). Usually red is positive and black is negative.

Connecting inverter terminals to the battery positive connectors may cause a spark because of the electric current flowing to the capacitors within the inverter. This is a normal event which occurs usually the first time one connects a full charge battery.

All these components are only for reference.  One can get the equivalent or similar in different brands or/and higher voltages.


  1. This is a great post! I would love to do this. You did a wonderful job with the video too.

  2. I'm glad you liked it, thanks for telling me.