Decent solar chargers that won't break the bank?

[JustAGuy]

Decent solar chargers that won\'t break the bank?

I was thinking about getting a solar battery charger because, um, it just seems like a cool thing to have and it might even be useful if the power goes out for a while. Does anyone have any recommendations? I'm just thinking about using it for flashlight-type batteries.

I did a forum search, and didn't spot anything that knocked my socks off. I don't think I want some big solar panel conversion kit, just something simple that will do the job in a reasonable time (10 hours?? I don't really know).

Also, the chargers I read about were all for AA batteries. Is there something with a little more versatility?

Thanks for any suggestions.

 

[K A]

Re: Decent solar chargers that won\'t break the bank?

Originally posted by JustAGuy:
I was thinking about getting a solar battery charger because, um, it just seems like a cool thing to have and it might even be useful if the power goes out for a while. Does anyone have any recommendations? I'm just thinking about using it for flashlight-type batteries.

I did a forum search, and didn't spot anything that knocked my socks off. I don't think I want some big solar panel conversion kit, just something simple that will do the job in a reasonable time (10 hours?? I don't really know).

Also, the chargers I read about were all for AA batteries. Is there something with a little more versatility?

Thanks for any suggestions.

<font size="2" face="Verdana, Arial">Yes there is. CCrane makes one here. It can do everything but 9volt batteries. Do you REALLY need one though? You would have to leave the thing out in FULL sunlight ALL day to be able to charge anything decently in one day... Meaning you would have to keep repositioning the thing all day to stay in direct sunlight. And if you're looking at charging any D cells.. I hope you got a week to wait, because thats probably how long it would take to charge them.

If you only need AAA or AA's then a better solution would be to get the MaHa 401FS with the car 12volt adapter.

Or you can get one of those car power converters which plug into the cars cigeratte lighter and converts the 12v to 110v for your choice of charger.

 

[JustAGuy]

Re: Decent solar chargers that won\'t break the bank?

KA, thanks, that's the kind of thing I had in mind. And at that price, there's no reason not to get two or three.

I do, however, have a little bone to pick with you.

Do you realize what you asked me?? I will quote: "Do you REALLY need one though?"

Well, no. I also don't need more flashlights, more guns, more knives, more camping gear, more coins, more fishing gear, or a new car. But I really don't expect that question except from my wife.

And don't worry, she WILL ask, I will give some lame answer, she'll roll her eyes, and I'll notice a new pair of shoes in a day or two. Which she doesn't need either.

I sincerely appreciate your suggestion, and I hope you understand I'm just kidding you about "the question."

 

[ledfanfromjuno]

Re: Decent solar chargers that won\'t break the bank?

I know this is out of your price range, but I want to open your eyes to this possibility in case in the future you decide you want MORE in a solar charger. I believe the best solar charger is:

the maha c401fs 100 minute cool charger which will fully charge 4 whole 2000 mah nimh AA batteries in about 100 minutes. That's at least 7 times faster than the speed the rapid chargers that can do D and C cells charge at. This really makes solar charging practical because you only need a very short amount of sunlight.

to power the charger I would use one of two DURABLE solar panels:
1. Unsisolar's flexible 11 watt panel, 2 of them actually connected together with a simple y extension adapter cord for a total of 22 watts with an alligator clipped female cigarette lighter receptacle. Cheap $111 each. Very Durable, maybe strongest at any price. 3 times larger than unipac and heavier. Maybe 4or 5 times when 2 panels are considerred but still very portable.

2. Unisolar's unipac30watt panel. Very compact. Not as durable but durable. alligator clipped female ligter receptacle. Expensive $700 as it is very compact and folds really small, made for military and filming crews when in say tibet.

3. a voltage regulator could be used? It's up to you. I believe the charger could live without it to save money. But? It's your call.

I have all these systems myself. For real wilderness useage. You'll die trying to use the cheap solar charger you bought. For fun, it's fine and good. It just takes forever, the sun'll set before it finishes 2 batteries.
Links:
30 watt unipac
http://www.aapspower.com/un30watfolfl.html
11 watt flexible
http://www.aapspower.com/us103watflex.html
Yadapter for SAE to two SAE
http://www.powerletproducts.com/products/cables.html
voltage regulator
http://www.nescobatteries.com/Products.html
female receptacle
http://www.marinco2.com/showProduct.asp?p=12VXC

 

[Wits' End]

Re: Decent solar chargers that won\'t break the bank?

You mentioned you would want to use it when you have a power failure. If I may point out power failures usually happen in bad weather

. The sun may come out tomorow (thanks Annie) but it may not. For emergency use have a good supply of alkalines that you rotate out occasionally or Lithiums that you rotate out every 5 years or so.
On the other hand I won't repeat KA's error and it would be nice to have one for camping Etc, it is never cloudy when you camp...R-i-ght

 

[K A]

Re: Decent solar chargers that won\'t break the bank?

Originally posted by Wits' End:
You mentioned you would want to use it when you have a power failure. If I may point out power failures usually happen in bad weather

. The sun may come out tomorow (thanks Annie) but it may not. For emergency use have a good supply of alkalines that you rotate out occasionally or Lithiums that you rotate out every 5 years or so.
On the other hand I won't repeat KA's error and it would be nice to have one for camping Etc, it is never cloudy when you camp...R-i-ght

<font size="2" face="Verdana, Arial">

Ok ok so I used a bad choice of words.

 

[JustAGuy]

Re: Decent solar chargers that won\'t break the bank?

If I kept a couple flashlights shining on the solar cells, wouldn't that speed up the charge?

 

[ikendu]

Re: Decent solar chargers that won\'t break the bank?

I have a compact solar battery charger. It has about 25 square inches of panel.

4 AA compact solar charger $18

It takes several days to charge 4 high capacity NiMH AAs (like 1600 mah). It is so slow, it is basically worthless for this purpose. I'm really sorry I got it.

If you really want to charge batteries, you need either a large surface area or good surface area and pretty efficient solar cells (they vary quite a bit in efficiency).

You can get a UniSolar 11 watt panel for about $120 that will put out .6 amps at 16v (peak output). My Maha MH-C204F charger needs .5 amps at 12v to charge 4 NiMH AAs in 2.5 hours.

This 11 watt panel is 19" by 15" (285 sq.in.) so that should give you some idea of the surface area needed for a decent charge rate. In order to sustain that rate, you'd be moving the panel every half hour or so to keep it aimed optimally at the sun. So...you'd have to move it about 5 times before your batteries are charged. This is all under optimum conditions, not overcast.

Even so, you can see that you need about 10 times the surface area of one of these small chargers to get any kind of decent charge time.

Regarding efficiency, here is a Kyocera 50 watt solar panel $215 that is about 530 sq.in. That is 4.5 times the solar power at only about 2 times the area of solar cells. So...efficiency matters when it comes to size (and price!).

 

[Darkaway]

Re: Decent solar chargers that won\'t break the bank?

I have a solar charger similar to the CCrane mentioned above. Everything said above about the small trickle of current from the miniscule panel is 100% true. I have a 300W array with a charge controller that charges a 12v battery bank, which in turn provides me with 110 volts AC through an inverter. I use this to power my Maha chargers, pond pump and lights/games/TV in my kid's playhouse. The whole setup cost me over a grand and will never pay for itself in saved electricity costs, but it was fun to build and I have the satisfaction of using clean, free power.

All that being said, the small solar charger has its place. I use it to maintain a charge in batteries that I have topped off with the Mahas. I simply leave them in the charger until they are needed. I figure the small charge rate of the solar charger, even when not in direct sun all day, at least equals or slightly exceeds the self discharge rate of my NiMH AA's. I don't think there's any danger of overcharging in that pathetic little charger.

Two words of caution. (1)Make sure you use a solar charger with a blocking diode (sort of a one way valve for electricity) so you don't lose power back into the panel at night.(2) Don't leave the charger in direct sun at midday during the summer. It(and the batteries) get REALLY hot!!!!