C.Crane 11-in-1 Solar Battery Charger

I bought two of these recently. They do what they are supposed to do. I've used them to recharge Sanyo Eneloop batteries after I drained them in my Kodak digital camera. This battery charger works quite well. It uses sunlight to generate a current that charges pairs of batteries in sizes AAA, AA, C, or D. It will also charge gum batteries. Sanyo Eneloop AA Battery 4 pack Precharged Use Up to 1500 Times Kodak EasyShare C182 Digital Camera (Blue) However, it will not recharge 9-volt batteries. The voltage from the solar panel isn't high enough. If you want to charge a 9V battery, the product you need is AA and 9 volt battery charger with 3, 6, 9, and 12 volt power supply The only thing the Crane charger's dial really indicates is current. The time shown on the dial is an estimate based on the assumption that the battery was drained until its pole potential difference was about one volt. It isn't the amount of time remaining. You still have to check the batteries from time to time with a voltmeter, until they're just over 1.4 volts each when you measure them with a voltmeter 30 minutes after taking them out of the charger. (The battery voltage usually falls off by 0.01V to 0.03V during the first half hour after removal.)Not all of these chargers are equals. Some of them generate a higher charging voltage than others do. I tested mine with a voltmeter and found that one of them has a maximum voltage (full sun on perpendicular panel) of 5.4 volts, while the other shows 4.8 volts. As the result, the charger that creates the higher voltage charges pairs of batteries faster than the other one does. But both of them do charge pairs of NiMH batteries.Added 21 April 2011. I bought a third charger. The voltage in full sun with panel normal is 5.2 volts.Will a solar battery charger pay for itself? It depends on how you look at it. Versus buying lots of single-use alkaline or lithium batteries, definitely it will. Versus recharging batteries with a cheaper house-current powered charger, probably not. In 1500 rechargings of a pair of Eneloop batteries, you'll be lucky to get a dollar's worth of electricity out of them, at the present price of utility supplied electricity.E = total energyB = number of batteries = 2R = number of rechargings = 1500P = electric powerT = timeV = average battery voltage = 1.25VE = BRPT = BR(IV)T = BR(IT)VIT = 2000 mAh = 7200 amp-secE = (2 batteries)(1500 rechargings)(7200 amp-seconds)(1.25 volts)E = 2.7e7 Joules = 7.5 kWhCost = 7.5 kWh ($0.1/kWh) = 75 cents.Consider a solar battery charger to be a way to hedge your battery investment against the possibility that you might not have house current someday.Added 21 April 2011. The maximum charging voltage for my best Crane charger is 5.42V. Once it has enough light intensity to reach this maximum voltage, further increases in light intensity no longer raise the voltage, but will raise the current flow. In full sun, with panel normal, the highest current flow I noticed was 0.180 amps. So the power being put into the batteries, at most, by the Crane charger is about 0.976 watts. This energy transfer rate will slow to about 0.457 watts as the two batteries, upon being charged, oppose their own voltage to that from the solar panel, assuming that the sunlight remains at a constant intensity and that the panel remains normal to the sun's direction during that time. If I approximate the average energy transfer rate by averaging the extremes of net voltage, it would take about 7 hours to fully recharge a pair of 2000 mAh AA batteries that had been completely discharged before recharging. In actual practice, you don't really fully discharge the batteries; you recharge them when their voltage has dropped so low (but not to zero) that they can't make anything work anymore, so it doesn't take as long as seven hours to top them off again.Added 21 April 2011. Contrary to some of the reviews here, this charger will charge a pair of AAA, AA, C, or D size NiMH batteries on a cloudy day. The voltage from the solar panel on a cloudy day remains high enough to do the job. However, because the current can be under 30mA under heavily overcast skies, the charging rate would be very, very slow.Added 24 April 2011.Assuming 1 volt potential difference across the poles of the battery.Full sun: (5.4V-1.0V) x 180 mA = 0.79 WSunny w/ hazy sky: (5.0V-1.0V) x 150 mA = 0.60 WOvercast by small cloud: (4.8V-1.0V) x 80 mA = 0.30 WStrong overcast: (4.3V-1.0V) x 20 mA = 0.07 WThe charger works about 11 times faster on a clear day than it does on a strongly overcast day.There's no need to weep and gnash your teeth in the outer darkness. With rechargeable low-self-discharge batteries and these solar battery chargers, you'll have power for your flashlights and digital cameras far into the die-off period of the Apocalypse. So stock up!

I got it for my sister in PR because a hurricane. Electric out for months. She let it out on the sun by the window that got all day light. She said it worked great. But if you can change it with a outlet first it charges better. But that was not the case with her. And it still changed all her rechargeable batteries. She keeps it in storage. And when the lights go off she takes it out and recharge her batteries. Loves the convinced of having one. She keeps extra batteries. So it gives her time to charge the rechargeable ones. It takes about 8 plus hrs depending on the sun for her batteries to recharge.

I have quite a few devices that require AA and AAA batteries, so I'm investing in this charger and rechargeable batteries for long-term savings.It does work on my window sill on a sunny day (it works much better if the window is open). The instructions tell you to reclose the solar panel cover once you load the batteries, but I find that propping it up with a pencil at a 45-degree angle to the sun works better.The built-in meter will give you an estimation of how long it will take to charge your batteries according to how much sun it is getting at any given moment, so the needle fluctuates with the clouds., making it difficult to determine how much real time they need.The makers could have added a little tweak to use the same needle to measure how full the batteries actually are, but they didn't do that. Fortunately, I do have a gadget that can test the batteries (which I keep numbered so I can tell them apart).I intend to review the battery performance when I start using them.

Hard to tell how to read this thing, but it does charge batteries. Quite a multitude of different sizes will fit in there.

Fast shipping and great packing. The charger works great and I love the meter on it. The better the light, the quicker it will charge. Just get the good rechargable batteries if you are going to really do this. It can hold multiple batteries at the same time. The AA and AAA fit in the same spot, so you can't do both. Same goes for the C and D batteries. I charge AA and D at the same time and it works great. The only down side is that you can only charge two of any kind at a time, so if you need three or four, you have to do them in batches. I'm think of getting a second one, just so I can charge more.

Bought it so I could charge C & D batteries. The wall outlet charger doesn’t charge those. Set it up in the sun. The needle moved to indicate it was beginning to charge. From there, the needle never moved again. Up or down. Not for 10 days. Didn’t seem to mind where I set it or if I tapped it, the needle didn’t budge. As I don’t drive or have access to easy transportation (that’s why I shop Amazon) I had no way to return this nonfunctional solar charger. Gave it to the neighborhood fix-it guy to see if he can do any thing with it. So far? Nothing! The charger that plugs into an outlet? Still working great. Just doesn’t charge C or D batteries.

I have read the reviews from other users at Amazon.com, and lot of them gave 2 stars or less. I don't know what they're trying to accomplish, but the product actually did as advertised. Even under a hazy sun, the meter was reading 160mA, all I had to do was tilt the solar panel towards the sun. If you want this product to charge under a dimmer condition, you can always upgrade the solar cells.

This is a really awesome and cool product just a little on the pricey side, that a side I will tell you the pros and cons of this product. Pros: when there is a full sun blazing with no clouds your batteries will charge no problem and in a decent amount of time, i been using this for a lot of different brands but mostly just for AA and AAA type batteries. Cons: you can only charge two AA or AAA batteries at a time along with two D size batteries or two C size and two D size but not AA or AAA, and of course the more batteries the longer to charge them all at once. It has a solar panel meter but no "your batteries are charged" meter, no indication at all. The solar power meter does give you an idea like AA batteries at full solar power will be 3 hrs and AAA 2 hrs and so on. The last con is.. and it could just be my batteries but it does not seem to charge up to 100% my batteries are always around 80% even if leave them in longer. Overall this is a neat product and idea and it works for me but keep in mind you do have to trace the sun, morning its here mid day its there then its over there so I was moving it around to get the most solar power I could.

I am now set should the world plunge into no power again.

I charged a couple of AAA's, and the meter read well. When I opened the cover after an hour in the sun the batteries were so dam hot. I would only recommend using this product with the cover open to let some of the heat out. Black may have been a bad choice. I am sure it works great in the snow though.

Works