Latest, Lightest Solar Charges?

I have a folding 12W solar array and use a 12V automotive-plug-to-USB adapter (the 5V, 2.1A kind). I noted that it would charge my iPhone 5 directly, unless a cloud passed by, which would kick it into the mode of telling me that this was not the correct kind of charger. Unplugging and replugging it got it charging again until the next cloud.

Just wondering if once it starts charging, if I then shut it down, will it continue to charge but without the discriminatory circuitry that keeps stopping the charging when the direct sun is interrupted?

The reason I ask is this same panel seems to charge my MacBook Pro when it's asleep, even though the wattage is well below the 65W provided by its power supply…

>"which would kick it into the mode of telling me that this was not the correct kind of charger."

I get that with various marginal chargers, loose connections, and having too many apps running for some chargers to support.

Could there be an app that would clear that fault and let the phone try again to be charged? The only solution I've found is to unplug and replug the cord?

>"Just wondering if once it starts charging, if I then shut it down, will it continue to charge but without the discriminatory circuitry that keeps stopping the charging when the direct sun is interrupted?"

For some of my marginal chargers, I need to do that. If the iThing is off, it turns on when I connect the charging cord and often, quickly goes into "charging not supported with this accessory". I've had better luck having the iThing on, shutting down all apps, connecting the cord, and then quickly powering off the unit (just the quick, one-button push. Not the long-hold then thumb-slide shut down). Sometimes it still stops the charging before reaching 100%, but the above procedure gets me much further than leaving the unit on. So the discriminatory circuit still seems engaged, but by reducing the power draw of the unit, charging is supported for longer periods.

Interesting; thanks, David. I tested my phone last night by plugging it into a USB port, then doing the complete shutdown (holding down the top button until I can use the red slidey thing at the top of the screen to shutdown).

Of course, now I can't tell how quickly it's charging, but it would see that there's essentially no current draw in this mode and that it might consistently charge, even on a partly cloudy day.

I will try to set up this experiment; I would think this would be great if it eliminates the need for a buffering battery intermediary…

I actually work at a Solar Company that makes roof top module, but no device chargers. I don't have solar module design experience, so I asked someone savvy today. He had a printer letter size module that is thin. Our product is a flexible laminate where silicon based solar is rigid and brittle, so our stuff can be a lot lighter and durable. The design is a nominal 5 volts and he said that with the performance of the cells, its possible to charge without any extra electronics.

Yet, its still to big and heavy compared to a little 35g battery that I have. I'n not sure what the power is, but I think it could be downsized. I would not want anything bigger than a postcard.

I think all I need is the battery for 6 day trips. I'm going backpacking, I don't need to be playing with electronics for a 5 day trip. Maybe for a 10 day trip next year.

"Our product is a flexible laminate where silicon based solar is rigid and brittle, so our stuff can be a lot lighter and durable."

If your product is not silicon-based, then what is it?

The current types of solar chargers use either single-crystalline silicon (for high efficiency) or else amorphous silicon (for flexibility).

–B.G.–

Bob, I'm talking about CIGS.

So, what commercially viable solar charger products are there using this?

–B.G.–

This one is down 112 g, but still fairly big.
http://www.globalsolar.com/products/retail/sunlinq-1

2 watts maximum output (400mA) is rather anemic.

For most backpackers the technology isn’t there yet. Over the past 10 years I have spent nearly 1,000 days off the grid utilizing solar in my tent trailers, so I have a little bit of experience.

You might find this interesting. Solar for backpacking?

For thoughts on charging strategies and system sizing read this. RV Solar Systems

Keep in mind, I am not an advocate for things electronic when backpacking. But if I were, spare batteries or a battery pack would be my solution, given the current state of technology.

I used a Brunton Ember on my last trip. Charged my phone very fast. Weighs 142gm. Major downside is that it lacks any attachment points. It would be nice to have it on my pack charging while I'm hiking. Otherwise very simple use.

"2 watts maximum output (400mA) is rather anemic. "

A USB only charges at 500mA. Of course if you are hiking, the panel is not going to be directly facing the sun(as mentioned in your link), but if you are carrying solar weight, it better be put to use on your pack all day when you don't have a full charge.

In the link the solar charger was used was 360g. I never play with that many electronics to want to carry 360g of solar charger. For that weight, I could carry enough battery's to charge 10 iPhones.

The Brunton Ember charged your phone fast because it is a big battery. The solar is only good for 100mA max. I would call that anemic.

Maybe solar works best if it charges a battery at whatever current it produces.

Then, use that battery to charge your device at the current required.

"Maybe solar works best if it charges a battery at whatever current it produces."

Not exactly. For most rechargeable batteries, there is an optimum charge current, and that is generally in the ballpark of one-tenth of the maximum available output current of the battery, but for ten times the time period. This varies from one battery chemistry to another.

Solar panels work best in charging batteries if you use a charge controller.

–B.G.–

+1 Jerry!

In particular most smartphones need something in the range of 7.5v to charge, when they don't get that they disconnect. Solar panels fluctuate the voltage output depending on how much sun they are getting. Charging a battery that has an integrated controller is the answer, charge the battery during the day, use the battery to charge the phone at night.

Goal Zero is one company that seems to really have solar figured out.

I have been very impressed with my Suntactics Charger as it has been very reliable, and definitely feels like it will hold up as the construction feels solid. I apologize for not having more detailed voltage and amperage information, but I have found Suntactics claims of charging an iphone 5 in 2 hours to be reasonably accurate with consistent direct sunlight. Additionally just taking the panel, 8.5oz is pretty reasonable for the right trips.

http://www.suntactics.com/shop/usb-scharger-5/

Perhaps that is because you don't understand the usage model: Deliver a lot of juice when you need it and then slowly recharge during the day when you don't.