Solar Chargers

A Soleo solar charger left of a smaller and cheaper off-brandEven with our reduced electrical usage, installing enough solar panels to meet our average needs just isn’t cost-effective for us yet. Photovoltaic (PV) prices have dropped a lot in recent years so even though we can’t afford a big system, there are a couple of cheaper options for trying out solar energy on a small scale.

Before our first big train trip last year, I bought a small (and cheap!) solar charger for my cell phone. It’s about the size of a box of cards and has two suction cups so that it can be placed directly onto a window. Despite costing less than $30, the solar panel has a battery behind it so that you can charge the battery first and then hook up your phone later. That turns out to be a really good thing because it takes over a week to charge fully!

Something that I didn’t realize before getting this solar charger is that most solar panels require direct sunlight. When I put the charger on a south-facing window, it didn’t charge at all, despite getting indirect sunlight for most of the day. I had to place it on our east-facing window, where it got 1-2 hours of direct morning sunlight, for it to charge.

More recently, we won a much nicer (and more expensive–$90 or so) Soleo charger as part of the SIREN Energy Challenge. This solar charger has a built-in battery with three panels attached, each a bit larger than the first charger I got. When it’s open, the charger looks a bit like a tilted flower, with solar panels for petals (you put a pencil, included, through the center to keep it upright). The advantage of this charger is that you can rotate it so that it gets direct sunlight throughout the day. The drawback is that you do have to rotate it. This one only takes 2-3 sunny days to charge (or a little less than a week if you don’t rotate it) plus it has a larger battery (more capacity).

Both chargers have a bunch of adapters for changing a variety of cell phones. The Soleo also includes a USB adapter so that it can charge or run a USB-powered device. It can also be charged by USB if need be.

We have three different devices that we’ve tried with the charges: a normal cell phone, an iPhone, and an e-reader. Neither charger has a very accurate charge indicator, so it’s hard to know exactly how well they work, but the cheap charger would charge the cell phone fully and have some juice left over or charge the iPhone by half to three-quarters. It couldn’t charge the e-reader because it doesn’t have a USB adapter. The Soleo can charge the phone about five times from full or the iPhone once or twice. It can charge the e-reader about as well as it can charge the iPhone.

Are we saving any money? Not really. Cell phones, even power-hungry ones like the iPhone, and e-readers just don’t draw that much power. Over the course of a year, each phone probably uses less than a kWH each, so even if we charged all of them by solar, we’d be saving well less than a dollar a year. And, unfortunately, we can’t charge them by solar all of the time because they run out of power faster than the solar cells charge their batteries (especially during those cloudy winter days we’ve been having).

On the other hand, the chargers provide a lot of convenience under certain circumstances. On our latest trip, Maggie forgot her phone’s power cord but was able to charge it using the solar panel. I can also leave one of the solar chargers in my bag in case I need to use my phone more than normal. The cheaper one especially could be left in a car window to charge and you’d have it handy if you needed to quickly recharge a small electronic device.

The real issue is that most of the things we use draw a LOT of power compared to the amount of electricity a small solar panel can provide, even on a sunny day. If we were willing to keep our phones off more often or to use only small LEDs for lights, a small solar charger like these two would be enough to make a significant dent in our use. When compared to the amount of electricity a television or computer uses, the difference amounts to a rounding error.

I’d recommend getting a small solar panel to most people so that they can play with it, figure out the benefits and drawbacks of solar without a huge investment, and get a better sense of how much power a kilowatt-hour actually is!

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3 Responses so far »

  1. 1

    Andy said,

    March 28, 2011 @ 1:13 pm

    I’ve always seen these types of devices as toys. If they only produce a kWh in a year, than the $30-90 cost obviously isn’t going to save any money, and unfortunately the electronics and plastics that went into making them have an impact as well. The only time they do seem like the right tool, is for extended traveling when access to power isn’t regular. Like you say though, it would be more efficient just to turn off some devices more often than you get a trickle solar charge over a week to keep it powered.

    On my bike, I have a generator hub inside a wheel that creates power with no noticeable drag on the wheel that powers my headlight. While I could run batteries instead, it’s so much more convenient to use this tiny generator so that I always have light anytime that the bike is moving, instead of plugging in the batteries every few days to recharge. But I don’t do it for the energy savings since that amount is so low; it’s really just for the convenience.

  2. 2

    Will said,

    April 11, 2011 @ 9:51 am

    Yeah, you’re right. It’s definitely more about convenience than anything else. The only time they would be really useful would be if you were away from the grid and away from a car, but still wanted power something in an emergency.

  3. 3

    Stephanie said,

    April 6, 2014 @ 7:12 pm

    The solar power devices are useful only if you do not have access to electricity. Family members have used such devices at hunting shacks or edges of large properties, where it doesn’t make economical sense to run a line from the nearest transformer (which could be miles away) since the wildlife often chew them. My BIL has run a solar powering device for about 6 years now to charge cell phones. He gets just enough juice to power up one Iphone and a small light. Since he and his buddies are in their 70s, family members insist that they have some way of contacting the outside world, and the Iphone turned out to be the only one that gets cell service there.

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