Portable solar panel for charging phone while using all day

[Saitama_234]

I was recently injured while doing jujitsu. Someone destroyed my shoulder joint and I needed reconstructive surgery. The surgery went well but I ran into complications and lost my job and apartment because of these complications. Luckily I had about $30,000 saved up and I was able to pay my rent until my lease was up. This didn't leave me with a lot of money left.

Now I'm living out of my car and going to physical therapy to try to get back to normal. I need a way to charge my phone all day while I'm sitting in my car recuperating from physical therapy. Recovering might not be possible at all which is why I applied for permanent disability in January. It really sucks because I went from making a good living writing software to being physically disabled living out of my vehicle.

What kind of power ratings would I need in order to keep my phone plugged in all day and have the panel charge the battery as well. Plugging a fan in at the same time but also be nice. I'm looking for a panel that I don't have to screw into my SUV something I can just lay out on my windshield maybe.

Any help is appreciated! Thank you!

 

[Rednecktek]

The easiest option will be a small Solar Generator from the likes of Jackery/Bluetti/Etc. A cell phone under heavy use might use up 240Wh in a day (2a @ 5v = 10w for 24hr = 240Wh) so really the more Wh you can get for the dollar the better. A folding portable panel you can throw on the roof in the 50-100w range should get you through most weather.

Keeping it behind the windshield is a bad idea, the UV coating on the glass will block most of the usable sunlight and you won't produce jack squat. Apartment people have similar problems.

If you're really lucky you might find a used one on CL that someone else is upgrading from.

 

[Substrate]

We can go even simpler that that, easy to find consumer level stuff.

1) A 28 watt or so folding panel that has a 5v usb output. Easy to find. Many makers.

2) A *quality* li-ion battery to store the energy. Anker makes some good ones. I'd suggest a 10000 to 20000 mah so you don't cycle it to death like you would with a smaller version. There are other makers. I like Anker because it recovers gracefully from temporary shadow drops, and also has a so-called IQ circuit in it's usb connectors to make the most out of any cable you use. Not all usb cables are wired alike! (used to be a bigger problem in the past)

The reason you don't want to directly charge your phone from the panel, but charge it from the battery above, is for two reasons:

1) Heat - generally you don't want to charge your phone in the hot sun. Or even hot shade. With the Anker (or whatever) battery taking any sort of brunt from heat instead of your phone, you can charge whenever necessary. Like at night.

2) Theft - leaving your phone, your lifeline unattended for a moment while your back is turned charging near the panel, makes it an ideal target for theft. Better for someone to steal your panel / battery, than the phone itself.

Pretty simple solution off-the-shelf. With not much engineering necessary, but more practical decisions are guiding the equation.

Forgot about the fan! I myself use an Opolar 9-inch 5v usb fan. Again there are other makers. I charge my phone, and run the fan at night when I'm micro-portable from the Anker battery that has been charging all day in the sun.

Easy consumer level plug-n-play with a minimum of engineering.

 

[pollenface]

A folding portable panel you can throw on the roof in the 50-100w range should get you through most weather.

I agree.

I bought a 10w panel to charge my phone while dirtbike riding it's basically useless unless perfectly positioned in full sun.

 

[Substrate]

Yep - loads of trash out there. Especially if their ads show people camping with one on their back!

Also too, most phones aren't designed to handle shadow drop-outs and require a minimum constant current. Hence my recommendation to get an Anker or higher quality 3rd party storage battery.

So, you *could* have been doing ok off-axis, but the low current from shadow/haze sent the internal phone charger into a failsafe "do not charge" mode requiring phone restarts.

Sometimes phones will react to an initial high current charge, but if interrupted by shadows / haze whatever, will drop back into the slowest charge current mode possible - usually .5A thinking the supply is flaky.

Moral - use a 3rd party battery and do the two-step method. Use a portable foldable panel rated of at least 25 watts or more to account for today's higher-current charge phones which may like 1A, and not the older .5A usb spec. But again, that's not reliable. Charge a "smart" 3rd party li-ion bank instead.

I've had pretty good luck with "Big Blue" panels, (the ones with the built-in current meters were cool) but there are plenty of other makers out there. They aren't lifetime purchases.