Amazon.com: Customer Reviews: NEEWER Portable AA Battery Powered Emergency Charger with Flashlight - Black - For Apple iPhone 4
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on July 4, 2010
I don't review often, but I felt compelled to write a review for this because there weren't many and because this is an excellent device at a great deal. I bought this with the intention of using rechargeable AA batteries to recharge my iPod Touch 2G when away from other power sources. It works great for this.

After a little bit of testing, I found that this will consistently charge my iPod Touch from completely drained to 100% in about 3 hours from 2 fully charged AA rechargeable batteries. One full charge completely drains the AA batteries. It will get to 80% in about 1.5 hours. (I tested Energizer, Everlast, and Eneloop rechargeable batteries with this, and all produced about the same results). Interestingly, I also tested Rayovac AA alkaline batteries, which only produced a 45% charge before they were completely drained.

I also used this with an HTC Incredible, for which it produced about half a charge before the AA batteries were drained.

Overall, it works very well for what I bought it for, and at a very reasonable price for something like this.
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on April 23, 2011
Pros: Cheap, provides consistent voltage, good current, and easy to use.
Cons: Cover very difficult to get off, LED is almost useless (super dim, although can be used as a battery life indicator), Switch can easily be turned on while in pockets, device does not handle high currents very well (creates noxious, burning plastic smell in charging currents >500mA), conversion is 5V is inefficient (loses much of the energy to heat).

Other thoughts: The D+ and D- on the USB port is shorted so that some devices (e.g. mobile phones) charges more quickly using higher currents than ordinary chargers. When the device is switched on, it provides a constant 4.98V on the USB port, even when the batteries themselves approach 1.0V. While the device is off, the voltage will slowly go down from 4.98V to the voltage of the installed batteries (possibly due to capacitance?).

Overall, this is a good device for its price. However, I would not really use it as your ordinary backup charger because it has a serious design flaw. Depending on what you are planning to charge using this device, it might work for you. However, as stated on the package itself, this device is only designed for an 500mA output. That being said, since D+/D- is shorted, many phones recognize this as an AC source and draws currents up to 1A. This is a huge problem since the internal circuits get so hot that it essentially melts something (plastic?) inside (you will soon notice a burning plastic smell if you plug this in a high current drawing device like an iPhone). Also with this great amount of heat generated, many of of battery's stored energy is lost to heat rather than charging your device (to be expected since you are upconverting ~2.5V to 5V). Using a freshly charged set of 2100mAh NiMHs, I was able to charge my LG Optimus S ~24% (3.7V Li-Ion, 1500mAh) before the batteries themselves die completely. That gives an overall charging efficiency of just ~25% (again expected since there is so much conversion inefficiencies in the process...)
Overall, good for emergencies, although not very efficient at all (gives out heat and burning plastic smell)... If you don't mind those, then this is a good deal. :)
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on September 26, 2011
I googled here when tried to find out why my charger (the same, but from another retailer) became burning hot when I tried to charge Samsung Galaxy S using AA NiMH batteries. Reviews here clearly show that this charges is recognized as a standalone dedicated power source, not a USB-compliant charger. 2 USB data pins are responsible for that - if they're shortened, the device sees this charger as the one capable of delivering up to 1.8 amps, which at 5 volts results in 9 Watts, and given that we use AAs it means that the current of more than 3 amps (closer to 4 in fact) may be drawn. 3..4 amps is way too much for the batteries and for the step-up converter making 5 volts out of 2x1.2, and that's why they (batteries and the circuit inside the charger) become really hot.

I modded the charger a little bit. Do on your own risk, no special skills required.

I just used tweezers to break away one of the data pins inside the USB port on this charger. If you look at the port, you'll see 4 pins. Two outer ones are power, two in the middle - data (no actual data of course in case of a charger). As I said, I broke off one of the data pins (first pry it up to release the outer end, than sway it from side to side until it breaks at the base). Then I carefully removed all bits and pieces from the port, made sure that under no circumstances the remaining stub will get in contact with the corresponding pin on the USB cable, and here we go: now it charges my Galaxy S all right, because the phone don't anymore think it's a powerful charger and don't try to draw higher current than allowed by USB specs (5V, 0.5A). Charger is lukewarm (just cool compared to how hot it was before). The phone says "USB connected" now when I connect the charger... before the mod it did not say anything just started to suck the juice rapidly, overheating the charger. It works fine while I'm writing this.

I could not pry open the charger itself without damaging the case, so I could not just use the soldering iron to mod the charger in a more civilized way.

Good luck !
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on November 11, 2011
I previously reviewed this product 4 of 5 stars because it worked well after I removed one of the center pins to trick it to charge slower. This allowed it to charge my smart phone about half way on 2 rechargeable Eneloop batteries. I gave that one to a friend and bought another one. This time after removing a pin it got hotter than before and would charge a bit some of the time, but most of the time it would just get hot and my phone would not charge and eventually the charging light would flash. I've never seen my charging light flash before this. I never tried the 2nd one before removing the pin. The switch on the 2nd one I bought had a textured surface which makes me think it's a different design. Anyway the one that worked was bought October 2011 from seller ACC Stop. The one that didn't work was bought September 2012 from seller Tidbits and Pieces.
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on April 19, 2011
I inserted freshly charged batteries, and turned the unit on and connected it to my cell phone. At first, the phone started charging. However, within 5 minutes, I smelled smoke and noticed the phone was not charging. The charger was extremely hot. I must have got a defective unit.
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on May 18, 2011
The last batch of these I received was updated from the original. The battery cover is much easier to remove and the switch on the side is smaller to reduce chances of accidental turn on in a pocket or bag. This charger features the smallest footprint you can get out of a 2xAA charger, works great with rechargeable batteries, and is cheap. I get about 50% of a charge for the average smartphone off of 2 Sanyo Eneloops. One of the recurring scenarios I find myself using this is at the end of the day when I am heading into a restaurant and find my phone dead or almost dead. It's easy to hook this charger up with a 1ft USB cable and put it in my pocket. It says it's for the iphone, but this will work for any USB charging application.
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on May 27, 2011
The charger does indeed provide a charge for USB devices. It did a good job charging my iPod shuffle. Unfortunately, when charging my iPhone 4, it became extremely hot to the point that I felt the batteries might rupture. I have no doubt that the charger performs as intended, but the current draw on 2 AA's is simply too much when charging an iPhone.

Bottom line: It works, but I wouldn't recommend it for charging a current-hungry device like an iPhone.
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on July 19, 2010
I have never before reviewed a product, but this product MUST be commented on!

I purchased this little charger to charge my iPhone while camping. I could not find any other reasonably priced products that would accomplish the task so figured I had little to lose if it did not work...

The product DOES work and works well. I recommend bringing lots of AA batteries if you will be gone for a while since it goes through the batteries after about two full charges, but it is compact and even has a pen light we used in the tent!

For the price, this is probably the greatest charger you can buy.
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on July 11, 2011
It was a mistake to buy this. I tried it because it was cheap, but the price is about a dollar and shipping is $5 to discourage returns (that should have been a tipoff). Instead of the cell phone version I ordered, they sent the iPod version, but their support said they were the same. No cables are included, so you will have to buy those separately. That will add about $10 or so from Radio Shack. There were no instructions included. The real problem with this is that it doesn't work. The light will go on, it will get warm, but it didn't charge my phone. I tried 2 times with fresh batteries. Left it running for 2 hours. Nothing. Instead of this, buy the Duracell one. It includes instructions, batteries, and cables. Also, it actually works, which is nice.

Buy this one instead: Duracell 852-0217 MyPocket Charger for Cell Phones
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on December 14, 2011
First lets understand the limitations of this neat little inexpensive USB Powering/Recharging device. The Listing Title for this Charger is totally miss-leading. It's is NOT "...For Anything Powered Via USB". It only holds two AA batteries so it cannot recharge your power hungry iPhone/Android or iPad, but it can temporarily power them for a graceful shut-down in emergencies. It is designed to recharge/power less power-hungry devices like standard cellphones, ipods, etc, myriad of small USB powered devices. In addition, don't expect it to recharge devices as quickly as you can from an AC wall charger. It can take double the time. If you leave it connected to larger devices unattended it cannot fully charge, it will eventually drain both itself and devices batteries, as well as possible over-heat itself.

To extend its capability to larger device, carry two with you (they're small and cheap) and switch them out during recharges (red charging light dims out when discharged), or get a larger higher capacity Charger like the four AA battery combination recharger and AA Battery Charger like Tekkeon's MP1580. The 1580 is a newer 1Amp version of the Tekkeon MP1550, where most user comments are found. The trade-off of higher capacity chargers is size to carry around, but if you need more power you cannot get it from just one of these 2X AA devices.

PROS:
*Small pants pocket size.
*Uses both replaceable Rechargeable AA or readily available Alkaline
*Will completely recharge smaller non-hungry USB devices.
*Will power more hungry devices for a short period before heating up.
*Life not limited to internal non-replaceable battery life.
*Very inexpensive.

CONS:
*Cannot completely recharge more complex gadgets with larger batteries.
*Has about useless one-LED Flashlight.
*Switch to turn on USB or Flashlight power is too easily moved causing potential accidental drainage.
*Users note more mfg quality problems than normal. But for cost, still good value/risk.

I have had great success with the two I bought. It is key to understand its design limitations/applications as noted above in order to be satisfied with this great value. This product is not alone in failure to specify and/or note its limitations, ie, what it CANNOT do. This is a result of a highly competitive capitalistic system that seems to reward product sales over satisfaction. Amazon's user Reviews, seller Rating, and seller-paid postage returns goes a long way to even the odds in consumers favor.

Here are some tips I found for correcting some of its limitations and extending its usefulness:
*Use high capacity, 2000mah or larger, name brand rechargeable batteries. This will allow you to recharge
and power more of your devices while saving gobs of money and waste.

*Use Precharged (low-self discharge) batteries so you don't end up with self-drained batteries in 3 to 6
months. This is especially important for back-up emergency devices like this one, and remember to top up
their charge every approx 6 months to maximize recharge power available. Sanyo's Eneloop or GP's Recylo are
good choices.

*Pretest recharging of each USB device you plan to use this with by draining their batteries from use first,
then attaching Charger with your device's power off. Attend the recharging session until your device
either indicates "Charged or red light on Charger dims to off. Some devices may need to have devices power
left ON to display battery 'Charged" indicator. If so, see if it will recharge fully when device is left
powered ON. If it will not, see if it will recharge fully with device power OFF by recharging until
Charger's red Power light dims out. Disconnect Charger and power your device ON to check its battery
Meter/Indicator to see if it is fully charged. The goal here is to determine which of your devices you
can leave Charger attached unattended and which you cannot because Charger cannot fully charge it. Devices
Charger cannot fully charge may drain both itself and your device's battery over time.

*You must disconnect the Charger from a device the Charger cannot fully charge, or can no longer supply power
to, as indicated by Chargers red Power light dimming to out. Charger Power light out means power/volts from
Charger batts is equal to power/volts it has transferred to devices batt and can no longer help or prolong
your devices use. In fact, if you leave Charger attached beyond this point, your device may begin to take
power from your devices battery, eventually draining both completely. NOT GOOD!

*Pretest all your USB devices during charging/powering of a fully or partially drained battery to check for
over-heating of Charger. This is possible due to over-current draw from Charger attached to devices with
high-capacity batteries. The goal here is to determine which of your devices you cannot leave Charger
attached unattended due to heat buildup. Over-heating not only shortens life/capacity of rechargeable
batteries, but can permanently damage you Charger. It will not damage your device or its battery in any
case.

*Consider buying more that one of these small device so you have backup power for larger devices, as well as
a storage place for extra rechargeable batteries. Even pre-charged (low self-discharge) rechargeable
batteries begin to gradually lose their power overtime, albeit at a much slower rate, than non-precharged.
Since this device is an emergency backup power device that will not get used that often, it is even more
important to have backup of the backup, use best low-discharge rate batteries, and remember to top up their
charge every 3 to 6 months.

Understand this Charger's limitation and design intent, use it right, and it is a great must-have value.
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