I've bought some solar products through the years- and some were decent, and some were just plain bad.
I had two identical Solio's that one still works to this day, and another one which developed a temperamental power switch within a week. Such is the nature of technology, where only a few years ago, that every phone manufacturer had their own chargers. We now have new and improved choices.
Without getting too deep into the tech parts of the solar industry, Here is a quick run down:
polycrystalline solar (lower power output, cheaper price) (cheaper solar implementations, found in garden pathway lights, etc but has its own advantage during certain partly cloudy conditions)
Mono crystalline solar (highest power output per inch, most expensive, most fragile) (found in Goal Zero, long history of commerical/residential applications)
Thin film amorphous silicon (lower cost, durable) (found in Powerfilm products, some RV equipment, also applied to glass panels for cost effective solar apps)
Copper indium gallium (di)selenide (CIGS) (mostly used for polycrystalline thin film tech) (Brunton's higher wattage panels)
There's many products at many price points which you'll have to decide on. How rugged, durable, and bomb proof do you need your gear to be, and how long you want it to last. For example, Amorphous silicon doesn't have a long service life. Usually by 3 years, the power output drops off below 80 percent. CIGS panels don't like to be stored dark and hot- they may not produce power for a little while until things cool down a bit and get light soaked.
Why I Chose the Goal Zero Nomad 7
and what I still don't like about it)
Its compact. Its like a small book. Version 2 now has the storage pouch on the outside, so that the panels face each other and are protected. It will fit charge cables, the Guide 10, and your cell phone/mp3 player (at the same time!)
It has a lot of lashing points- good to attach to your backpack or tent. I've even used it outside my window of my car by clipping it to the glass.
Appears durable and well made.
The nomad 7 was able to fully charge my Galaxy Nexus from 20% to full in about 3 hours, on a flat surface. That was surprisingly good. It still generates power (although kinda low), but enough to register charging status, even by a window indoors. It has a 12v cigarette lighter socket for maximum flexibility, to charge camera batteries, etc.
Now to the bad parts: I wish it didn't come in black. A tan would have made more sense. Perhaps not as "cool" looking, but since a solar panels output drops with heat, why make it hotter than it needs to be? anyone who has worn a dark t shirt in the summer knows that dark=hot!
I also don't like the rating system that Goal Zero uses. Don't advertise a 7w panel, if you don't have 7w available for use. Straight from their PDF:
USB port 5V, 1.0A max (5W), linear regulated
12V port 13-15V, 0.2A max (3W), boost regulated
Solar port 6-6.5V, 1.0A max (6W), not regulated
I feel a little cheated here. Brunton Solar Marine 7 Solar Panel specs are 12 volts at 0.4A. On paper that is nearly double the output. (it would calculate out to be 4.8 watt for 12v @.4A, where as the Goal Zero would be 12*.2A=2.4 watts) Maybe this is industry standard? I don't know... at least the non regulated port should give me full power (as it does on *some* of goal zero's panels).
Performance otherwise has been quite stellar. Its heavier than it looks, and they do a great job of protecting the relatively fragile solar panels. Which brings me to another issue. With the cells touching directly on each other, the surface of the solar panels will scratch up. How much this affects output, I am not sure, but I can be sure, that there will be some loss. I've resorted to using a thin piece of packing material fluff to prevent this, although a charge cable tucked in there (without the ends) also does a good job. Otherwise, it can take a good beating, perhaps not as good as the thin film stuff (say tossed off a cliff), but still good. It could theoretically only loose .5% efficiency for every full year in the sun, so that means potentially 20 years to drop 10% in power output. Im not certain the other parts will last that long (nylon outer) being in the sun all that time.
Guide 10 Plus:
If the Nomad 7 is pretty good... what makes it stand out from the pack is the Guide 10 Plus. If it wasn't for this feature, there are other panels which are lighter weight, and equally well built and useful.
Mobile solar charging is not exactly an exact science. Hit some trees, an underpass, some clouds.. the power output drops off, if not completely off. Your devices will stop charging. Some devices won't even start charging again even when solar power resumes.
The Guide 10 acts like a buffer-it has power stored, and will recharge your devices. This is no different than any other power pack. In fact, I have used the Nomad 7 with a Brunton Lithium pack for several weeks now. There is however two key differences:
1. The Guide 10 can interface using the largest power source the Nomad 7 can deliver, with the ability to utilize 6 watts of power, vs only the 5 watts via USB.
2. The Guide 10 can be operated in "pass through" mode. Its not documented very well, but the guide 10 can both take incoming power and send power to the USB output at the same time. Another forum user answered this question for me. However, while trouble shooting some strange sound and smells...(more on that later).
The three position switch (off, usb output on, LED light) is rather intuitive, and clearly marked. The variations however, really need to be better documented.
The troubles: when I received my unit, I decided to test a function, which is to charge the 4 batteries via USB, similar to what we would do while we are driving, or sitting at our computer. I started to hear all sorts of high pitched noises, and smelled that ever crazy smell of solder on electronics. I stopped. I then proceeded to take the batteries out, and try some fully charged AAA's, (with adapter) out of my Vanson speedy box charger. (its a good micro processor controlled charger). Again, plugging it into the USB charge port, the indicator lights became a christmas tree! I stopped.
The USB output still put out power, so I tried charging my phone. The AAA's were low capacity, 2 800's, 2 650's. I was able to get about 30-40 min of charging out of them before the guide 10 plus turned red, and no longer had output. Very decent. I then took the Goal zero 2300Mah AA batteries and put them into the Vanson, and set them for a discharge/charge cycle. Two were discharged and charging way sooner than the other two. Intriguing.
Still the USB charging boggled me. The instructions are vague to say the least. So here are MY instructions (subject to change!).
1.Use only the same set of like rated batteries. Do not combine capacities! (but you can- apparently the Guide 10 uses different charging features when powered from solar vs USB!).
2.Try to only charge similar discharged batteries together. (in otherwords, don't stick two drained batteries with two charged ones) The usb charger does not like this at all! (But the solar doesn't complain as badly).
3.You must charge 4 batteries at once
4.You can apparently charge the Goal 10 via usb and your phone... at the same time.. in the off position. :Wow1: im still researching this one myself. It appears power can flow through the port, even when it is physically switched off. Im not certain if this is a function or not. I will have to test tomorrow under the sun to see if this happens. If it works in this condition, it would mean that you can set the priority for the solar to charge your phone while the secondary power goes to charge the batteries. (aka, no power wasted).
In a weird twist, its the sparsely documented features that make the Goal Zero solution more robust. However there are some other issues:
Even with 4 batteries, freshly discharged, then fully topped off in the Vanson, the Guide 10 Plus, when plugged into the USB, took about 10 minutes of slow blinking to fast blinking and then finally a solid green. It spends a huge amount of time in evaluation mode, and has great difficulty dealing with even a single mis matched cell. It leads me to believe that the circuitry inside can only register the combined voltage of 4 cells (4.8-6v) and so it tries to to either juice it up to the specific voltage, even if the batteries are already full. there must be some step up converter inside, as it can step up 5v usb power to charge the battery pack (and a weak one at that.. hence 8 hour charge times, as listed), and it most likely uses a regulated output (5v at 1A) for the output.
If your doing this the optimal way, use a volt meter, or a load test, and match the fully charged batteries with other batteries that perform the same. This way the charger can cope with all 4 batteries together.
I had two identical Solio's that one still works to this day, and another one which developed a temperamental power switch within a week. Such is the nature of technology, where only a few years ago, that every phone manufacturer had their own chargers. We now have new and improved choices.
Without getting too deep into the tech parts of the solar industry, Here is a quick run down:
polycrystalline solar (lower power output, cheaper price) (cheaper solar implementations, found in garden pathway lights, etc but has its own advantage during certain partly cloudy conditions)
Mono crystalline solar (highest power output per inch, most expensive, most fragile) (found in Goal Zero, long history of commerical/residential applications)
Thin film amorphous silicon (lower cost, durable) (found in Powerfilm products, some RV equipment, also applied to glass panels for cost effective solar apps)
Copper indium gallium (di)selenide (CIGS) (mostly used for polycrystalline thin film tech) (Brunton's higher wattage panels)
There's many products at many price points which you'll have to decide on. How rugged, durable, and bomb proof do you need your gear to be, and how long you want it to last. For example, Amorphous silicon doesn't have a long service life. Usually by 3 years, the power output drops off below 80 percent. CIGS panels don't like to be stored dark and hot- they may not produce power for a little while until things cool down a bit and get light soaked.
Why I Chose the Goal Zero Nomad 7
and what I still don't like about it)Its compact. Its like a small book. Version 2 now has the storage pouch on the outside, so that the panels face each other and are protected. It will fit charge cables, the Guide 10, and your cell phone/mp3 player (at the same time!)
It has a lot of lashing points- good to attach to your backpack or tent. I've even used it outside my window of my car by clipping it to the glass.
Appears durable and well made.
The nomad 7 was able to fully charge my Galaxy Nexus from 20% to full in about 3 hours, on a flat surface. That was surprisingly good. It still generates power (although kinda low), but enough to register charging status, even by a window indoors. It has a 12v cigarette lighter socket for maximum flexibility, to charge camera batteries, etc.
Now to the bad parts: I wish it didn't come in black. A tan would have made more sense. Perhaps not as "cool" looking, but since a solar panels output drops with heat, why make it hotter than it needs to be? anyone who has worn a dark t shirt in the summer knows that dark=hot!
I also don't like the rating system that Goal Zero uses. Don't advertise a 7w panel, if you don't have 7w available for use. Straight from their PDF:
USB port 5V, 1.0A max (5W), linear regulated
12V port 13-15V, 0.2A max (3W), boost regulated
Solar port 6-6.5V, 1.0A max (6W), not regulated
I feel a little cheated here. Brunton Solar Marine 7 Solar Panel specs are 12 volts at 0.4A. On paper that is nearly double the output. (it would calculate out to be 4.8 watt for 12v @.4A, where as the Goal Zero would be 12*.2A=2.4 watts) Maybe this is industry standard? I don't know... at least the non regulated port should give me full power (as it does on *some* of goal zero's panels).
Performance otherwise has been quite stellar. Its heavier than it looks, and they do a great job of protecting the relatively fragile solar panels. Which brings me to another issue. With the cells touching directly on each other, the surface of the solar panels will scratch up. How much this affects output, I am not sure, but I can be sure, that there will be some loss. I've resorted to using a thin piece of packing material fluff to prevent this, although a charge cable tucked in there (without the ends) also does a good job. Otherwise, it can take a good beating, perhaps not as good as the thin film stuff (say tossed off a cliff), but still good. It could theoretically only loose .5% efficiency for every full year in the sun, so that means potentially 20 years to drop 10% in power output. Im not certain the other parts will last that long (nylon outer) being in the sun all that time.
Guide 10 Plus:
If the Nomad 7 is pretty good... what makes it stand out from the pack is the Guide 10 Plus. If it wasn't for this feature, there are other panels which are lighter weight, and equally well built and useful.
Mobile solar charging is not exactly an exact science. Hit some trees, an underpass, some clouds.. the power output drops off, if not completely off. Your devices will stop charging. Some devices won't even start charging again even when solar power resumes.
The Guide 10 acts like a buffer-it has power stored, and will recharge your devices. This is no different than any other power pack. In fact, I have used the Nomad 7 with a Brunton Lithium pack for several weeks now. There is however two key differences:
1. The Guide 10 can interface using the largest power source the Nomad 7 can deliver, with the ability to utilize 6 watts of power, vs only the 5 watts via USB.
2. The Guide 10 can be operated in "pass through" mode. Its not documented very well, but the guide 10 can both take incoming power and send power to the USB output at the same time. Another forum user answered this question for me. However, while trouble shooting some strange sound and smells...(more on that later).
The three position switch (off, usb output on, LED light) is rather intuitive, and clearly marked. The variations however, really need to be better documented.
The troubles: when I received my unit, I decided to test a function, which is to charge the 4 batteries via USB, similar to what we would do while we are driving, or sitting at our computer. I started to hear all sorts of high pitched noises, and smelled that ever crazy smell of solder on electronics. I stopped. I then proceeded to take the batteries out, and try some fully charged AAA's, (with adapter) out of my Vanson speedy box charger. (its a good micro processor controlled charger). Again, plugging it into the USB charge port, the indicator lights became a christmas tree! I stopped.
The USB output still put out power, so I tried charging my phone. The AAA's were low capacity, 2 800's, 2 650's. I was able to get about 30-40 min of charging out of them before the guide 10 plus turned red, and no longer had output. Very decent. I then took the Goal zero 2300Mah AA batteries and put them into the Vanson, and set them for a discharge/charge cycle. Two were discharged and charging way sooner than the other two. Intriguing.
Still the USB charging boggled me. The instructions are vague to say the least. So here are MY instructions (subject to change!).
1.Use only the same set of like rated batteries. Do not combine capacities! (but you can- apparently the Guide 10 uses different charging features when powered from solar vs USB!).
2.Try to only charge similar discharged batteries together. (in otherwords, don't stick two drained batteries with two charged ones) The usb charger does not like this at all! (But the solar doesn't complain as badly).
3.You must charge 4 batteries at once
4.You can apparently charge the Goal 10 via usb and your phone... at the same time.. in the off position. :Wow1: im still researching this one myself. It appears power can flow through the port, even when it is physically switched off. Im not certain if this is a function or not. I will have to test tomorrow under the sun to see if this happens. If it works in this condition, it would mean that you can set the priority for the solar to charge your phone while the secondary power goes to charge the batteries. (aka, no power wasted).
In a weird twist, its the sparsely documented features that make the Goal Zero solution more robust. However there are some other issues:
Even with 4 batteries, freshly discharged, then fully topped off in the Vanson, the Guide 10 Plus, when plugged into the USB, took about 10 minutes of slow blinking to fast blinking and then finally a solid green. It spends a huge amount of time in evaluation mode, and has great difficulty dealing with even a single mis matched cell. It leads me to believe that the circuitry inside can only register the combined voltage of 4 cells (4.8-6v) and so it tries to to either juice it up to the specific voltage, even if the batteries are already full. there must be some step up converter inside, as it can step up 5v usb power to charge the battery pack (and a weak one at that.. hence 8 hour charge times, as listed), and it most likely uses a regulated output (5v at 1A) for the output.
If your doing this the optimal way, use a volt meter, or a load test, and match the fully charged batteries with other batteries that perform the same. This way the charger can cope with all 4 batteries together.