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rusty_tlc

rusty_tlc

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I'm looking for a cell phone/usb recharge battery pack with a built in solar charger. The ability to also charge from a 12V input would also be good.

Anybody have any first hand experience with a product you highly recommend?
Any first hand with products you regret buying?

I'd also be interested in reviews for battery packs that charge from 12V only.
 
Goal Zero? No first hand experience, but seems like a nice product.

http://www.goalzero.com/


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How big? Use? Hiking? Setup at camp?

I'm thinking you likely are wanting one for hiking.

There are some rather large capacity Li-Ion battery packs that may do for extending your cell phone time without the need for a solar panel. This is an example of one of them: http://www.amazon.com/New-Trent-IMP120D-Thunderbolt-Blackberry/dp/B003ZBZ64Q/?tag=ihco-20 but I see it has some troubling reviews. I have no experience with any of them.

Photographers have belt battery packs for supplying power to video gear. Most are 12V Lead-Acid batteries which would be to heavy, but some are made with Li-Ion batteries. Outputs are either the 4 pin XLR or cigarette lighter socket. Also some of the direct camera mount batteries are in that voltage range. Add a cigarette lighter socket and they will power most standard auto chargers. Some auto chargers can't handle over 15 volts input, but others handle it fine. A typical Li-Ion professional video camera battery is usually 14.8V nominal.

A problem I see with many Li-Ion batteries is if the charge voltage isn't regulated very well, they will swell and fail much sooner than they should. That

Years ago I rolled my own somewhat light weight solar charger for charging RC car battery packs. I used 10 E size NiCd batteries in series to provide roughly 12V Nominal. I had a surplus folding 20 Watt solar panel. I made a simple circuit for charging that battery pack and controlling the load. The charge control circuit switched off the solar panel when the battery pack voltage went over so high, and turned it back on when it dropped some. For load control I had it turn off power to the cigarette lighter socket when the voltage went below 10 Volts, then turn it back on when it went back over 12.5 Volts. Both circuits were done with simple op-amp circuits with hysteresis. I also used solid state relays to lower power draw for switching the loads, and to allow switching of the solar panel every few seconds. It would be easy to make one with AA size batteries, and a smaller output solar panel. The batteries allow charger draw currents higher than the solar panel can output. They just require a bit of charging time between uses.
 
http://www.voltaicsystems.com/ Has some interesting stuff that may do.

Edit: I'm liking their 3.4W 6V solar panel. It would be a nice component in a portable solar+battery based system.
 
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I don't think any of the ready made ones are reasonable in price. It's also a low volume market.

At Amazon they have a number of folding solar panels of various capacities. They may provide a starting point.

What devices, voltages, and current draws are you looking for powering?

A problem I see is supplying enough supply current for modern smart phones with just solar. It would take 3 of the 3.4W 6V solar panels to reliably provide 1 Amp @ 5VDC. Then it would still drop out when you go under a tree. I can see using a small solar panel to charge up a battery, then using that battery to charge the smart phone. A small battery could be used in cycles. Let it charge up to around 80%, then charge the smart phone off of it until it drops below 50%. Then the battery is recharged up to 80% again and the cycle repeats. Short cycling a rechargeable battery like this extends it's cycle life allot. A 2 Amp 5VDC step up power supply with on/off control could be used to supply a USB port for charging. It could be supplied by a single 3.7V Li-Polymer battery. When the battery gets to low, an Op-Amp circuit turns off the power supply. When the battery is roughly 80% charged, the Op-Amp circuit turns the power supply back on. Charging the battery could be done with a circuit like the Instructables solar USB charger.

Solar stuff including a Li-Polymer battery charger that can be powered by 6V solar cell, USB, or 5VDC supply.
https://www.adafruit.com/category/67

Note:
Easy to use! Pick up any of our many 3.7V/4.2V LiIon batteries, and a 6V solar panel. Plug the battery into the BATT port using a 2-pin JST cable and the solar panel into the DC jack using a 2.1mm terminal block adapter. Put the solar panel outside (and keep the battery out of the sun, it needs to be kept shaded!) to start charging. You can power another project like a Mintyboost at the same time by connecting to the LOAD output port
Click to expand...
 
I had a solio charger once but it was terrible. I bought it for a camping trip in Sweden last year. I thought I'd make sure it worked well before I left so I tried it out for two weeks in California sun. It went back to rei as soon as I had the chance. It took days to gather and the couldn't even charge my iPod all the way.
 
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