Monday, December 3, 2012

Top 5 Solar Gadgets for Christmas

As the holidays approach, I thought it fitting to write a brief note about solar gadgets. I want you to avoid giving (or receiving) a solar charger that doesn't do the job. I will assume that you are looking for a solar charger that really works, not just a novelty gift.

So, without further introduction, here are the solar toys that actually work well...

Fuse by Voltaic Systems
This nifty little solar charger case packs a solar panel & solar storage battery in a rugged zippered case that can attach to any backpack or bike panier rack. It has room to store your iPod, iPhone, GPS, or other small USB device safely inside. Best of all, Voltaic didn't skip on performance... this package has 8-12 times the power of typical solar chargers.

Fuse 10 by Voltaic Systems
This is the larger Fuse model, capable of supporting everything up to & including laptops. Like it's little brother, the webbing on the back of this case enables it to be easily attached to backpacks, paniers, and more. Lots of power & onboard storage for up to 2 hours of laptop use per summer day.

Amp by Voltaic Systems
The smallest of the Voltaic cases, but not lacking in performance. Like all Voltaic cases, the materials used are second to none. Rugged, yet easy to use. The Amp is a great choice for phones, iPods, & eReaders.

Restore by Brunton
This is the toughest little 1-Watt charger around. Rugged rubberized shell, snap-shut solar panel, integrated charging cable, easy attachment points, and on-board power storage. Performance will offset 50% of most GPS & smartphones during summer months.

Guide10+ Mobile Kit by Goal Zero
A modular kit comprised of a rugged, and highly efficient compact folding solar panel, and a battery storage & power pack based on NiMh rechargeable batteries. Aimed at the adventurous backpacker who needs to keep their point & shoot camera, GPS, headlamp, and other small devices running.

So, why these 5?
First, I've used them all, and they work great.
Second, apart from the Brunton Restore, I typically don't like solar chargers under 1 Watt. The reason is that a common device like a smart phone will take approx 8 Watt-Hours to fully charge from dead (try not to do this by the way... not good for the battery). So a 1Watt solar panel in summer months might only get you 50% of your charge (if you drain your smartphone daily). This is workable, but you'll get only 25% in the shoulder seasons, and if you have other devices to charge, you will find such a small charger just won't keep up. Look for devices with at least 2 watts of solar, and at least 8 Watt-Hours of on-board solar power storage.

That's it for this edition.
But, before I sign-off, I will offer you this gift...
Please let me know if you see a cool product and want my opinion on how it should perform for you, and I will reply as fast as I can.
There are a lot of 'deals' this time of year that don't turn out to be deals in the end. I'd like to help you if I can.

Cheers everybody!

Sunday, September 30, 2012

Reality Check : Solar Charging an iPhone

iPhones, Blackberries, and other smartphones are a common solar charging question. So here is a summary of what you need to know to avoid frustration and choose the solar charger that will do the job for you.

USB Port Compatibility

The first thing you need to know is that as smartphones have evolved, their power requirements seem to be getting fussier & fussier. An iPhone has become the laptop computer of the USB set. So, while the iPhone and others are still "USB devices", they need specific performance from the USB ports they connect to. Anyone with an iPhone 3 or iPhone 4 will be aware of this issue. Not every USB port is acceptable to an iPhone. I'm sure the iPhone 5 will be just as particular. An iPhone requires a full-function USB port, with specific characteristics, so it is important to choose only those solar chargers that specifically state that their USB port is Apple iPhone compatible. I try to test every USB port in our catalog to determine if it is Apple-compatible, and have noted the results on each web pages.
Beware of cheap chargers... if it doesn't say iPhone compatible, it won't be

USB Port Power Output

As iPhones have evolved, their minimum power requirements have increased. No longer will an iPhone accept a low-power USB port, even if it was once deemed Apple-Compatible. This means you need to choose a solar charger that is capable of at least 500mA output. Check the solar charger's specifications to know for sure.
What this means is that for a solar panel to be able to charge an iPhone directly, it has to be producing at least 2.5 Watts for even the smallest amount of charge to flow. The alternative is to store solar power in a battery pack that can in turn deliver what an iPhone is wanting. This is almost always the preferred solution, as this frees you from moment-to-moment solar conditions.
Special Note: if your iPhone is 'Off' it's power requirements are lower. But 'Off' is not usually the way people use an iPhone.
Beware of cheap chargers... they often lack the output power to handle iPhones

iPhone Battery Capacity

The iPhone 4 & 5 are similar in battery capacity, at just over 5 Watt-Hours (1400mAHr @ 3.7V). Given losses in the charging process, it will take approx 6.5 Watt-Hours to fully charge a current model iPhone.
What does this mean?
I'll hide the math & suggest that if you drain your iPhone battery easily in a day, you will need a solar charger of at least 2 Watts, and have it exposed to sunlight for most of the day (summer, for most North American locations).
But, like I said in the previous section, the iPhone will likely ignore panels producing less than 2.5 Watts, so you need to use a solar storage battery pack between the panel & the iPhone.
Below are links to several popular solar chargers for the iPhone, along with their performance.
Beware of cheap chargers... they use poor-grade battery cells

iPhone Connection to Solar

This part is easy.
Use the USB cable that came with your iPhone. The iPhone 5 has a new connector, so your old sync cable will not work with it.

Recommended All-In-One Solutions (for all iPhone models)...

#1 : Voltaic Fuse
4 Watts in peak sun (up to 2 full iPhones per summer day)
11 Watt-Hour on-board storage (almost 2 full iPhones)
Easily attached to backpacks etc
Click here to see the Fuse

#2 : Voltaic Amp
4 Watts in peak sun (2 Watts per side) (up to 2 full iPhones per summer day)
11 Watt-Hour on-board storage (almost 2 full iPhones)
Handy zipper case format
Click here to see the Amp

#3 : PowerFilm USB+AA
1.4 Watts in full sun (approx 75% of a full iPhone per summer day)
5.75 Watt-Hour on-board storage (approx 75% of a full iPhone)
Lightweight, sensitive in shade/overcast, uses/charges AA rechargeable batteries
Click here to see the Powerfilm

#4 : Brunton Restore
1 Watt in peak sun (approx 50% of an iPhone per summer day)
8 Watt-Hour on-board storage (slightly more than 1 full iPhone)
Rugged pocket format, easily attached to packs
Click here to see the Restore

#5 : Brunton Freedom
0.5 Watt in peak sun (approx 25% of an iPhone per summer day)
8 Watt-Hour on-board storage (slightly more than 1 full iPhone)
Rugged pocket format, easily attached to packs, great back-up battery
Click here to see the Freedom

Beyond The iPhone

Bundled solutions, comprised of a larger USB solar panel like the Brunton Explorer or Goal Zero Nomad 7 can be combined with a USB storage battery like the Voltaic V11, V39, Brunton ReSync, Inspire, or Guide10 Plus, to create your own higher power USB solar station. Such systems can support tablets & iPads if the storage battery says it can, but that is a topic for an upcoming post.

Let me know your questions or comments!

Tuesday, August 28, 2012

Battery-Free vs Free-Of-Batteries

I'm getting a little tired of misleading semantics when it comes to self-powered flashlights & radios. So here's the scoop...
When a flashlight or radio says that it is powered by solar or hand crank and there are no batteries to worry about, they are mincing words. Truth is, the power from either charging system is stored somewhere, and that somewhere is a rechargeable battery pack. It's on-board. Inside the casing. Usually where you can't see or touch it. So, when they say that the flashlight or radio doesn't need batteries, what they really mean is that you don't have to put actual batteries into the device.
Well, that's good right?
Yes it is.
But, realize that the device DOES have a battery on-board. If you stick to a name brand like Freeplay, Kaito, or Eton/Grundig, it will operate properly for years. All bets are off if you go with a cheap, generic brand.
Can this internal battery be replaced?
Yes. Even if you have to take the flashlight or radio apart, the battery is usually easy to replace. Or have someone who knows how to splice wires replace it for you. Kaito's newest radios, like the KA600 & KA500 have the rechargeable battery pack accessible through the main battery compartment and connected just like a cordless phone battery, so they are very easy to replace.
Is there such thing as a device that doesn't use batteries of any kind?
Not in radios due to the power draw, but AIT makes a line of flashlights powered by a super-capacitor instead of a battery. These are the only devices that can be said to be "free of batteries". If you've ever seen a proper magnetic shake flashlight, then you're familiar with at least one model.

Pros of a capacitor-based flashlight...
+ No finite lifetime
+ Reliability
+ Small & lightweight
Cons...
- shorter run time
- doesn't hold a charge for more than a couple of hours

So, when you decide to purchase a self-powered flashlight or radio, remember that what you are getting is a low-maintenance device that will be ready when you need it. But, you are advised to take care of the internal battery pack, and do what you can to keep it in a charged state.