I read this week that a lawn light charger actually charges a aa battery as its power source. ( the $3 size) Am investigating...

Many do, some are AAA, some smaller. They are a simple trickle charger so you will want a good charger that can refresh/ recondition your batteries every so often.

If you actually want to charge something significantly, you need a fairly big solarpanel. I have seen plenty of small panels, which might be strong enough to power a few low powered LED's but not much more.

I haven't had good luck with AA "emergency" chargers or AA Solar Chargers at all. The 2xAA emergency Cell Phone chargers get really got when I try to charge my Android phone. I have a 4000mah Solar/Lithium Charger that's 4.5 x 3.3 x .5. It can charge my Android up from empty 4 to 5 times, and will charge my IPAD from empty to around 50% without melting down.

It does have a built in Solar Cell, but it would have to sit out in the direct sun all day long to get any type of usable charge. It does work well for "topping" off the battery in the unit however.

The device is made by Opteka, It's model BP-SC4000. Unfortunately, it doesn't charge AA/AAA batteries directly. But it's light enough that it works well for most all my other EDC electronics that I carry. It's about $25.

If the manufacturer is saying that it is a lithium battery, it is most likely lithium-phosphate. That is different chemistry than "standard" lithiums. The battery form-factor is a bit undersized from a regular AA. IIRC

found the link

solar light/ battery chargers

I have experimented with this a little.

For the units with AA NiCads, the first thing to note is that they are low capacity cells, typically 600 mAh. You can plunk a NiMH battery in there, it doesn't have to be a NiCad. But if you plunk a high-capacity NiMH in there (most good ones are in the 2000-2500 mAh range), you're going to be disappointed. You will get better results with cheapo, low-capacity NiMH cell. I get mine for a buck apiece at the local dollar store (Dollarama in my case, 800 mAh and claim to be low self-discharge).

The other thing is that (at least on the units I've messed with), the direct output voltage of the solar panel is higher than the voltage that the circuit pumps to the battery. Maybe that extends the cell life in the original intended use, but it slows charging. So I direct wire the cell to the battery contacts. The kicker is that the batt should be removed at night; some panels have enough leakage that they will discharge your cell when they're not charging. Of course adding a 5-cent diode in series would solve that problem.

I haven't tested this over a long period, but I found that cycling a few cells back and forth with a modest 1-AA LED flashlight was enough to keep me "lit up" for several nights.

Hope this helps.

The main thing with those is that its a trickle (dumb) charger. So if you leave the battery connected all the time it will overcharge. Typically they are slow enough that it doesn't greatly affect the batteries but it does shorten the lifetime. I get 10+ years out of NiCad or NiMH using a decent charger, you may get 3 using a trickle charger.

Yeah, I wouldn't use a dumb trickle charger for any length of time. It's a short-term expedient when no better option is available. Still, it's a useful trick to have up your sleeve.

I have had one of the $3 units sitting on my front lawn for a couple of years now. It has provided nice illumination and it obviously would come in handy in an emergency.

I have upgraded to a Goal Zero guide 10 Plus unit, which will allow me to recharge my Eneloops. I have just been playing around with it so far, but it seems workable. I should be able to keep lights and cell phone humming when the grid crashes.

Does anyone have comments or experience with GZ and their products? It looks appropriate for a Luddite like me.