Para's LED lantern thread has me wondering, what is the best portable solar panel setup for rechargeable batteries?

I'm looking beyond Goal Zero's stuff, unless that is the only option.

I saw something like this for backpackers. The solar panels were flexible and designed to recharge while walking/hanging from a pack. Look at REI or LL Bean.

You will need a larger one than you would want to carry on a backpack. You would also need at least a small 12V battery. I use Zamp solar 240 watt connected to a RV deep cycle (group 24). Of course this is more than what is needed. I have a small panel with built in battery, wont even charge my phone in full sunlight. It is a cheep model though, mabey there is better chargers out there.

I use a Topray briefcase solar panel. 13 watt. Around $70. I can easily charge rechargeable batteries, power packs, or the devices themselves. Fully charged a full-sized iPad in 12 hours.

quote:

Originally posted by kkina:
I use a Topray briefcase solar panel. 13 watt. Around $70. I can easily charge rechargeable batteries, power packs, or the devices themselves. Fully charged a full-sized iPad in 12 hours.

Is this the Harbor Freight model?

https://www.harborfreight.com/...r-charger-68750.html

I wonder if a few could be connected together?

quote:

Originally posted by deepocean:

quote:

Originally posted by kkina:
I use a Topray briefcase solar panel. 13 watt. Around $70. I can easily charge rechargeable batteries, power packs, or the devices themselves. Fully charged a full-sized iPad in 12 hours.

Is this the Harbor Freight model?

https://www.harborfreight.com/...r-charger-68750.html

I wonder if a few could be connected together?

That has a different brand name, but it sure looks somewhat similar. I bought mine over eBay. Have no idea if they can be connected together in any way.

The Anker 21 watt solar panel gets the best reviews at $64 from Amazon.

https://www.amazon.com/Anker-C...ds=anker+solar+power

Something funny about the Anker, they say 3 Amps x 5 Volts which is 15 Watts, not 21??

quote:

Originally posted by kkina:
Something funny about the Anker, they say 3 Amps x 5 Volts which is 15 Watts, not 21??

The charge voltage has to be higher than the component to be charged or you would have little current output.

The 21 watts is telling you that the output voltage from the charger is around 7 volts. It will drop when the current output exceeds 3 amperes. Think of it as a water hose and the more water flowing results in a pressure drop.

Check a voltage charger sometime and you will see 17 volts to charge a 12 volt battery.

Given the amount of time it takes to recharge a device or three via these little solar kits, in terms of hours of good sunlight, and the size of the kits themselves, you're better off carrying small rechargeable batteries / power packs instead, unless of course you're worried about being out there for days upon days without grid power. Because for overnight / weekend trips, I don't think they're worth it / quick enough / useful enough. One little tiny battery pack the size of a single cigar can recharge two phones much more quickly. And you could carry ten of them in the same space as many of these kits, and last I checked - none of the solar kits worked well enough or fast enough to just be able to clip one on your backpack while dorking around and end up charging much very quickly.

My ten cents... maybe it's changed in the last several months, but I doubt it.

Thanks for starting the thread. I had intended to create a thread on this subject. It just makes sense for disaster preparedness.

I have a Goal Zero Nomad with the charger for AAA and AA. I am planning to try one of the Harbor Freight kits for the house to charge 12 volt batteries and use for the Ham Shack. I may upgrade one day to a Sherpa.

Good point 46n2. I've had great success matching the two together.

I have the 21W Anker solar panels matched with a lumsing 10400mah external battery.

2 vacations ago I took the panels and battery to mexico and did not use any of the resorts electricity. I kept 2 note 3's charged, a kindle paperwhite, an Ipad, and cobra walkie talkies for 10 days with no issues. Now to be fair the sun in cancun is pretty strong and we only used wifi and the phones to play music/games. But id bet theres a few folks in hurricane slammed places that woulda liked this.

I have also used this on a 3 day camping trip for myself in November which kept my note 3 charged and also Fenix 900lumen usb flashlight charged as well using it 3 nights in a row. I always take these items when I go on vacation now.

Solar panels are all math. Add up your battery size mah, then findout how much mah ur panels can put out in 4 hours. You also want more watts then it takes to charge your items because you wont always get full sun and you lose power when charging due to transfer loss.

For those wondering I just drop all this but the flash light in my carryon to make sure the panels dont get jacked up. Also bring some paracord cause it makes it easy to hang the panels if you need to.

Lumsing - https://www.amazon.com/Lumsing...r-Bank/dp/B00IP1MQNK

Usb chargeable flashlight - https://www.fenix-store.com/fe...able-led-flashlight/

for those wandering size of the items I mentioned. those are 9mm boxes

This message has been edited. Last edited by: Deqlyn,

I researched this a while back, and I have no idea if 1) I'm remembering correctly; and 2) it's still true.

You start out in bright sunlight, the charge level is at max. It gets cloudy, charge level declines. Sun comes back out,charge level stays low.

Better ones (Goal Zero) have electronics to control this. Cheap ones don't.

As stated, I could be wrong. It's happened before.

ETA: Confirmation! See about 1/4 of the way down in this article:

http://thewirecutter.com/revie...-solar-battery-pack/

^^ same review i read in selecting my panels. Thats why the the more panels the better!

Deqlyn and I are basically the same person.

I have the Anker 21W as well. Use it for camping.

OK, I guess I don't have to seriously research this anymore, thanks Deqlyn! Just put those 2 items on my Amazon wish list.

quote:

Originally posted by Aeteocles:
Deqlyn and I are basically the same person.

I have the Anker 21W as well. Use it for camping.

I think you helped me narrow down my choices 4 years ago Aeteocles and even did the math for me. The confusing part is Watts to maH.

Additional info for those watching is the solar map. So take for example Alabama. You get a maximum of "perfect sun" for 4 hours. Assumes no cloud cover etc...

So the anker panels at 21 Watts at 5 volts will charge at around 4200 mAh an hour. A Note sized phone/iphone 6s is 3300mAh battery. So technically it could be charged in an hour...

But assume you don't get perfect sun half the time and of course transfer loss(sometimes around 25%!) that makes 2100 mAh an hour or less. Now you are looking at a potential of two days to charge your phone fully. Which is why its best to go as many watts as possible on whatever system you're buying.

If you bought an 11 Watt solar panel system, you'd get 2200 mAh per hour. Again,if you half that for non-perfect sun, it could take 3 days plus to charge your phone if you had perfect sun half the time. Throw ina cloudy day or two and you are up a creek.

Buy the bigger one. Match it with the battery pack and keep the battery pack charged so you don't need to camp on your panels all day with your phone.

I think I am remembering my math right here. someone double check.

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So the anker panels at 21 Watts at 5 volts will charge at around 4200 mAh an hour. A Note sized phone/iphone 6s is 3300mAh battery. So technically it could be charged in an hour...

Nope...the maximum output current is stated at 2.4 amp per port or 3.0 amp total using two ports under direct sunlight.

So lets say the 3300 mAH battery is discharged to 300 mAH or less. So you need 3000 mAH battery charged by 2400 mAH or 1 1/4 hour plus in direct sunlight or probably twice as long in poor sunlight conditions.

quote:

Originally posted by 41:

quote:

Originally posted by kkina:
Something funny about the Anker, they say 3 Amps x 5 Volts which is 15 Watts, not 21??

The charge voltage has to be higher than the component to be charged or you would have little current output.

The 21 watts is telling you that the output voltage from the charger is around 7 volts. It will drop when the current output exceeds 3 amperes. Think of it as a water hose and the more water flowing results in a pressure drop.

Check a voltage charger sometime and you will see 17 volts to charge a 12 volt battery.

You're theory is correct. Your numbers are wrong. You cannot charge a 12 volt battery at more than 14.1 volts or it will grenade...Most battery chargers will charge at 13.5 volts and alternators may go as high as 14 volts (for a 12 volt lead acid battery)..about 15% over operating voltage is what batteries are charged at. Different battery technologies require different charging voltages for example GEL 12 volt batteries will only take around 13.2 volts.