5 Questions for Pocket Solar Chargers

I've been seeing a huge number of 'gadget' solar chargers on the market this year. Everything from keychain size up to devices larger than your hand. Personally, I think this is fantastic, and am glad to see so many alternative energy products making it into the retail realm.

However, I do know that many of these products are not built very well, and many manufacturers cut corners. And if a Chinese factory cannot secure an OEM contract with a recognized North American brand name, they tend to dump their wares on Amazon. A pretty picture, and statements about charging digital cameras & phones, should not always be trusted.

So, how can you spot the good ones?
Well, apart from always checking ModernOutpost.com, use the following 5 questions to guide you...

1. Is the solar panel the thin-film variety?
Thin film doesn't require direct sunlight, while crystalline does. So thin film solar cells will provide a charge in most weather conditions. A thin film solar panel will outperform a crystalline panel of the same power rating any day of the week. Less efficient, but far more effective!
If they don't tell you, it will be the cheapest form of crystalline, and not worth buying.

2. Solar Panel Power?
Pocket chargers like to quote the capacity of their battery pack, or confuse you by telling you that they can pump out 2100 mAH from their USB port. All very good, but how quickly they charge from the sun is the key spec they don't always tell you.
Look for a panel of at least 2 Watts... this is large enough to cover 50% of a smartphone battery April-Sept.

3. Battery Capacity?
Look for at least 4,000 mAHr, or you won't get even 1 full charge on a Samsung Galaxy or iPhone 6.

4. Pass-Through Charging?
Pass-Through charging means that your solar gadget is able to charge your phone or camera while it is charging itself. This seems like an obvious point, but a huge number of USB batteries & solar gadgets don't do it. Imagine having to wait until your solar charger gadget is almost full before charging your phone, and while charging your phone, not being able to collect the sun's energy (or even use the USB port)! This is a must-have feature!

5. Apple Compatible?
You might not have an Apple product, but you should care if your solar gadget supports Apple.
Why?
Because if the manufacturer has taken the time to ensure that the USB port is fully functional, and able to support the fussiest of personal electronics, it is far more likely to be a product that you can rely on to charge any USB device.

Send me a note if you want my opinion on any particular product you see online.
Cheers!

Solar Trickle Charging Stored Vehicle Batteries During Canadian Winters

Need to store an RV, car, boat, SeaDoo, or ATV for the winter?
Here's a quick look at your solar options for keeping your vehicle battery maintained through our Canadian winter, and avoid the cost of a ruined battery in the spring.

How much power do you need?

A typical flooded lead-acid battery will self-discharge at approx 40% per year. Doing the math, this means that for a typical group 27 or group 31 battery, you will need to offset at least 1 Watt-Hour per day. Sounds easy enough.

But, before you run out and purchase one of those little dashboard solar panels, there are a few things to consider...

1. What sunlight exposure are you likely to get?

2. Are you wanting to charge through a window?

3. Are there any 'mystery loads' on the battery?

4. What solar cell chemistry will be used?

5. Do you need a charge controller?

I'll deal with each of these quickly...

1. Sunlight Exposure

Winter in Canada. Need I say more?

Even if you get a string of sunny days, if you can't get a sunburn, then neither can the solar panel!

Check for obstructions like trees. Shading will drastically cut your solar charger's output.

So, considering only our latitude & weather, solar radiation for most Canadian locations can fall from a summer high of 5-6 peak-sun hours per day to less than 2. In the case of Vancouver, it falls to less than 1 in December!

This means that for most Canadian locales, you will need at least a 2W panel to deliver your desired 1 Watt-Hour Per Day of power (for the smaller group 27 & 31 battery formats).

If you have trees shading your property for part of the day (hopefully not the middle of the day), then double this estimate.

2. Charging Through A Window

Window glass absorbs a lot of UV. So much so, that any solar panel charging through a window will lose as much as 50% of its power output because most of its power is generated from UV light.

So, if you plan to use a dashboard-mounted solar panel, you'd better double your original estimate for power needs. That 2W panel is now up to 4-5 Watts with a window in the way.

3. Mystery Loads?

Clocks, meters, and stand-by control circuits all work to drain your battery power without you noticing. If you can disconnect them all for the winter, great!

If you can't disconnect them all, you'd better make an allowance for the power lost, which can be at least as much as the natural self-discharge rate of the battery.

Poof! We are now up to 8 Watts of solar to keep our single battery maintained.

4. Solar Cell Chemistry

Some solar cells are more sensitive than others. For Canadian latitudes & climate, we will want the most sensitive so that we can collect the most power in any daylight conditions. It just so happens that the most sensitive is NOT crystalline silicone cells like the ones you see on rooftop systems. Crystalline Silicone panels are the most efficient, and therefore produce the most power per square inch "In Direct Sunlight".

The solar cells most recommended for low-light & partial shade conditions are the amorphous silicone or "Thin-Film" solar panels. These have a very flat appearance, and do not have the little rectangular or hexagonal wafers wired together under the glass.

The other advantage of thin film panels is that they can be produced in foldable or rollable format for easy storage, and are very light weight.

5. Is A Charge Controller Needed?

The usual answer is 'YES', however if the panel is only being used for trickle charging, offers less than 1% of the battery's capacity in Amp-Hours, and operates in the 15-16V range under load, then you can safely forgo the charge controller.

That being said, I advise getting one just to be certain your batteries are being cared for during peak sun seasons.

Products To Check Out...

Here are a few solar panels that can help you in keeping your vehicle batteries charged over the winter months...

Powerfilm R7

Powerfilm R14

Powerfilm R21

& a couple of handy traditional crystalline panels designed for all types of vehicles...

SunCharger 5

SunCharger 10

Let me know if you need any help determining how to keep your boat, RV, ATV, SeaDoo, or other vehicle battery maintained over the winter.

Avoid Solar Disappointment This Holiday Season

I just completed an important comment on a review I read of the Bushnell SolarWrap Mini on Trailspace. The review lacked performance numbers & prompted me to write a bit more about pocket solar chargers. Here is a link to the review (my comment follows)...
Bushnell SolarWrap Mini Review

The Problem With Pocket Solar Chargers...

In attempting to reduce size, weight, & cost, manufacturers are prone to eliminating performance to any reasonable level.

In brief, I don't recommend any solar charger under 2 Watts (solar cell peak power), and all solar/back-up battery packs should be at least 2500 mAHr.
And, if the product doesn't state these specs clearly, you should smell a rat.

The Explanation...

The typical electronics-equipped trekker is taking a smartphone & camera into the wild. Often, the camera is a dSLR with a larger battery pack than the iPhone. Sometimes there is a need to charge AA or AAA batteries for headlamps or GPS receivers.
Let's run a scenario with the basics: iPhone & dSLR.

The Smartphone's power budget...

The iPhone 6 now packs a battery size of 1800mAHr (up from the iPhone 5's 1500mAhr). The iPhone 6 'plus' is up to the 2900mAHr range. The Samsung Galaxy S5 packs a battery in the 2,800mAHr range these days.
What does this mean?
It will take at least 9 Watt-Hours of power to fully recharge the iPhone 5, and at least 15 Watt-Hours to sully recharge the latest iPhone 6 or Samsung Galaxy S5.

Now the camera...

Most point & shoot camera batteries are in the 1,000 mAHr range, while the bigger dSLR batteries are in the 1800-2000mAHr range. Let's take the case of the popular Canon LP-E6 battery which is used in the 5D, 60D, 7D camera models.
The LP-E6 battery is 1800mAHr @ 7.4V which means it will take at least 18 Watt-Hours to fully charge it.

The other issue is the battery's voltage. Charging a 7.4V battery from a 5V USB source requires a special charger. 12V charger cradles are available, but let's keep the cost & size of the system down by choosing to stay in the USB realm.

Total Power Budget...

Let's assume that you are taking your Canon 5D Mark II camera, and your fancy new iPhone 6 into the bush for a week of trekking. You are planning to drain both the camera each day, but the iPhone should last 2 days.
By the numbers, you will need to replace 18 + 8 = 26 Watt-Hours of power each day. 18 for a full LP-E6, and half of the iPhone 6's 15 WHrs.

Attaching a solar charger to a backpack means less than ideal exposure to the sky (except during stops), so allowing for that, plus occasional tree cover, you would need a solar panel of at least 10 Watts to keep up with your power needs.

A solar storage battery should ideally be twice your anticipated demand, which puts us at 52 Watt-Hours in our example (or 14,000mAHr in a USB battery).

Your Options...

If you look around the market, you'll see PowerMonkey products in the 3-4W range, and Goal Zero in the 3-7 Watt range. These will not keep up with the demands of our scenario. And you can certainly forget the little chinese clamshell chargers in the 0.5-1.5 Watt range!

Look for the components you need...
Waterproof solar panels for kayaking & canoeing. Sensitive thinfilm panels if you are going north or expect tree cover or questionable weather, or crystalline panels if you are at altitude or tropical latitudes. You're not going to purchase a separate system for each (probably), so consider what trekking you plan to do most.
The battery should be thin & light, and able to support all your electronics. Keep it safe & dry. Please don't believe that you can trek properly with an AC inverter... too much added weight, cost, & complexity. Stick to USB or 12V.

What About Just The Smartphone?

If you're considering a gift of solar this holiday season, stick to solar chargers that have a solar panel of at least 2 Watts. This will give you up to 50% of a typical smartphone charge each summer day. That is a level of performance most people can live with. Combine that with an internal boost battery in the same range as the smartphone (2500 mAHr or more), and you will have a satisfied trekker!

Need Any Help?

Send me a note! I can help evaluate any products you are interested in.

Poweradd Apollo review on Trailspace

I just wrote a quick review of the Poweradd Apollo on Trailspace. You can read the review here...
http://www.trailspace.com/gear/other/poweradd-apollo/?review=32193
The issues raised are consistent for any of these small, gimmick solar chargers. They are typically just a back-up battery with a solar panel slapped on it. They are always underpowered.

Solar Charger vs More Camera Batteries

The question almost always comes up... do I really need a solar charger for my upcoming wilderness trek, or should I just buy a bunch of camera batteries?
Knowing that you will be away from power for days, weeks, or even months, what is the best way to keep your camera charged?

The decision comes down to the following: how long the trip is, and how many other devices you need to keep charged (GPS, headlamps, phones, radios, etc), and how well you are able to budget power.

Remember... If you only pack camera batteries, then once you are out, you are out!

Let's look at your options for cameras first, and then we will consider your other gear...

1. Extra Camera Batteries

Most people who take their cameras on their adventures find that they get anywhere from 1-3 days per battery. Anyone sensible will be taking a spare, so with two or even three batteries, you will be able to power through 3-9 days (if nothing goes wrong!). So, for weekend trips, take a couple of batteries with you, and you will be fine.
dSLR camera are a lot more power hungry than the smaller point & shoots, and most serious photographers I talk to seem to want to budget 1 day per battery.

A quick look at the current price of dSLR batteries will quickly make you look for alternatives for longer time frames. At anywhere from $80-$120 per battery, the 2 or 3 batteries you probably already have in your camera bag will suffice if you are looking at a trip of 7 days or less. But, you will need to control your shutterbug urges and stick to a power budget!
Because when your batteries are drained... you are done with the camera.

2. Solar Storage Battery = 3 dSLR batteries

Going for longer than 1 week?
Consider the advantages of using a solar storage battery to pack the extra power you will need. Cheaper than a complete solar kit, and cheaper than buying more camera batteries.

A solar storage battery is the equivalent of 3-4 camera batteries, but when you consider that the price tag is not much more than a new Canon LP-E6 battery, the economics is obvious. Combined with your 2-3 back-up batteries, you now have the ability to go up to 2 weeks, or even 3 weeks for the smaller point-and-shoot cameras.

The advantages of using a solar storage battery...
1. Economy - saving money over buying more camera batteries.
2. Expandability - being able to add a solar panel later if you ever want to.
3. Versatility - works with any camera brand/model. There's nothing worse than having a bag full of model x batteries @ $70each, only to decide to buy a new camera a year later.

What does a solar storage battery look like?
Here's a current top seller... Voltaic V60

How would you get the power from the storage battery into your camera?
Use the solar storage battery to drive a universal battery charger or DC car charger for your particular camera model. The AC charger that came with your camera is not designed for this job.
examples: Ansmann Vario or DC LP-E6 charger.

3. Complete Solar Power Kit

This is for serious trekkers... this is the power system that generates power continuously. You will never run out of power as long as the sun comes up each day. The power varies with the strength of sunlight (latitude and weather), but we take all that into account when we recommend equipment for you.
So, if your trip is longer than 1-2 weeks, and/or you would rather not take chances with getting your power budget correct, using a complete solar kit is your best option.

solar panel -> storage battery -> battery charger -> camera battery

How does it work?

Plug the solar storage battery into the solar panel to start collecting charge.

Whenever you need to top-off a camera battery, simply fit it into the camera charger and plug the charger into the universal battery. Just like you plug it into the wall at home (except we use DC instead of AC power when we're packing it on our backs).

There are many ways to design the solar kit. From fully integrated packs, to custom plug-n-play sets of equipment. Be sure to get information about several options that fit your mode of transport, weight restrictions, and power needs.

What about other electronics?

It is a fairly simple matter to add all sorts of other devices to the mix, and have everything charged from the same power system. We budget for power consumption in things like GPS receivers, headlamp batteries, phones, and even laptops. A good solar storage battery like the V60 is able to provide the voltages needed to support all this gear, and many times you still only need one charger cradle to support them all.

Discover Your Options...

Want to know what I would recommend for you to have a completely independent power system that works everywhere?

... Just let me know where you are going, for how long, what time of year, and what camera(s) & other gear you want to pack, and I will let you know what equipment will serve you best.

Click Here : I look forward to your email!