Does anyone know of a solar charger that can do 5V and 12V?

As the title says, i’m looking for a solar charger that provide the right voltage for my Li-ion chargers. The most reviewed and acclaimed solar chargers on Amazon and eBay do either 5V or 18V. Don’t see myself charging up quickly on the go without my Lii-500. Has anyone any idea?

18v is the 12v

18v = open no load
12v = under load

or close enough with PV power sources (they fluctuate constantly)

so all those 2.1 x 2.5 dc cables that run 12v that also fit the 18v for a reason.

I have done it with my Lii-500 so know worries.

2 amps x 12v = 24 watts (but since you need to apply the Chinese fudge factor of 50% realized) look for something closer to 45w or 60w.

or maybe don’t try to use all 4 bays at 1 amp each. either fewer cells of lower charge.

If you running powerfilm panels then you only need to bump it 10%

thanks. why don’t they rate the 5V port the same way though? This sounds strange.

Which solar chargers do you have by the way, and which would you recommend? Right now, QC issues highlighted by reviewers point me to the allpowers, although the bigblue 28W sure seemed nice, and the iNice supposedly has a qc 3.0 port.

The only panels that I know of that comes with true auto-restart function are the choetech and ravpower. The new blitzwolf 28W panel is supposed to include auto restart but we will have to wait for the reviews.

I have tried many brand name panels in the past with superb reviews and while they claim to be 20W I can hardly get 10W out of it under full sun, so I think I’m going to hold until newer/better stuff comes out or wait for when I truly need it. A high capacity powerbank can give you ~100Wh worth of energy which translates into at least a week of power under moderated usage.

I would recommend using a powerbank or two and have them connected to the solar panel instead of connecting your phone, you lose some efficiency, but powerbanks can charge at a faster and more steady rate than a phone.

never thought of those panels. do you think they all were made at the same factory, or perhaps are just renames? Everything about them externally just looks so similar.

I’m incidentally considering buying powerbanks like the TOMO that i can feed spare li-ions into but their efficiency apparently isn’t too good, or they die after some time.

Would you recommend the allpowers 21 or 28W?

I did some reviews on how solar chargers self-restart… search the forum for ‘cloud restart test’

yes i remember reading your posts months back. very informative! that’s the reason why i wanted to go with the allpowers but they don’t ship their 4 port version with the 8000mAh battery to certain countries…

USB is as you know a “standard”. I have observed the USB portion of solar panels to be 4.8-5.2

Work in solar and have had over a dozen different MFG of panels.

Assuming we are not talking about Poly, all the Chinese claim “Sunpower Mono cells” So when it comes to solar panels (using same tech) size aka area matters, for obvious physical reasons, more area=more juice. for USB style I Like the Aukey 28W the best. The Big Blue is hit and miss (all other 28w panels are smaller then the Aukey 28w).

The Ravpower looks good also and performs great considering it has three outlets.

As far as tech the CIGS and Thin Film have advantages over Monocrystalline which has advantages over Polycrystalline and as mentioned Powerfilm (and licensees) work great if you have the $$$.

The OP started off asking about running is Lii-500 this can be done from an 18v panel with a 2.1 x 2.5 DC cord. Please note that unless running thru a boost circuit you can not run one from a 5v USB. But as you know, you can run the 5v USB from the Lii-500.

Also remember that solar panels divide their power over the outlet so the optimum is one outlet per, and to use different panels for different voltage requirements. Sure there are combination panels but just be aware they are compromises.

Ok… so i tested out my recently received Allpowers with a 3000 lumen flashlight as light source. Only volts, no amps. Reading other similar accounts points out some possible causes, although i’m not sure i understand them. I had my phone plugged into the port before awakening the charger with the light, but it looks like it might be blind and unenlightened!

Have i just received a lemon?

My guess is that you aren’t giving your panel nearly enough light, for the load of a phone.

If your flashlight delivers a real 3000 lumens and has, say 100lumen/w efficiency, and all of it falls evenly on the active areas of the panel, that’s 30W. Assuming 20% conversion efficiency, thats 6w. That should be enough, but in a crude, real world test setup, I’d guess you’ll get, at best, 50% of the light on the panel, so that takes you down to 3W. Say another 10% loss in the 5v converter, that’s 2.7W…

A peak sun-hour, specifically, is an hour during which the intensity of sunlight is 1,000 watts per square meter. Plus by definition its FULL spectrum light.

So trying to run small folding Chinese solar panels from a flashlight might be interesting, but it is a total waste of time.

Using the solar panels to charge a battery bank (Ill-500 18650 is just fine) is really the way to go we don’t want to cook out electronics. batteries are cheap and are meant to be used up.

ok, so i just gotta wait out the gloomy weather that’s just set in. perfect timing!

@Ronin42 when you say “cook out electronics”, do you mean that solar panel charging batteries may not be done in a 100% beneficial manner to the batteries? Has that something to do with the varying amperage or voltage during the normal course of charging under changeable light conditions?

wow, turned out better than what most people have said about it. the way it shot up to 2.05A, and probably would do the same for both ports simultaneously if the light shines my way.

To charge Liion cells you only need a protection circuit to prevent over charge.
The actual voltage of the solar panel is the same as the cell, because solar panels have quite a high Ri.
The important thing is the charging current.
So if you have 2 panels of approximately 6 Volts, you can connect them in parallel for more current for charging 1 battery or more in parallel, and if you need 12 volts you connect them in series.

Thing is, every bit of electronics you put in between the panel and the cell eats power, which you want to use for charging, not for hardly necessary regulations and what not.
That is, if you want things to be portable.

If you’re worried about the max current being too high, you can use a couple of 7135 .

please correct me if i’m wrong though, my experience may be outdated.