Duracell Mobile Charger with 4 AA Rechargeable NiMH Batteries, CEF23AU (Australian Plug with US Adapter)

This charger is really good. The quality of the components is very high, very well made.I previously had a cheap charger (Another Duracell, actually...) That charger was a dumb charger, it was timer based, and although it could charge 4 AAA or AA batteries, it had to charge them in pairs... (Another cost issue, the charger had a cheaper transformer because it takes less wire to drop from 120V to 3+ volts than it does to provide 1.5+ volts)And I burned up 4 AA and 4 AAA batteries with that charger in less than a year, because if they weren't completely drained it would constantly over charge them... That's a problem with those time based chargers. That's my theory, anyway... I'm a mechanical engineer, not electrical... :)This one is microprocessor controlled, so if you just want to top off a set of batteries you can do it without issue. (They will last longer if you fully discharge them, but the damage done by topping them off with this guy is much less...)And it is nice if you want to recharge an odd number of batteries (I have a light that uses 3 AA batteries... It always sucked having to charge in pairs) You can charge 1 battery if you want to. My wife has some little fake candles that have I AA rechargeable battery in them to run the LED, and when they quit we can just pop the one battery into this charger...This charger has it all... A car adapter so I can take it on camping trips and recharge things out in the woods... And the USB power feature turned out to be extremely useful; on the same camping trip I realized I didn't have my car charger for my cell phone, but I did have a micro usb cable in the glove compartment. So I plugged the charger in my truck, switched on the USB and recharged my cell phone. Perfect! The charger supplies USB power when it is plugged into a power source, or from the batteries you put in it...I had never seen an Australian plug before, but the adapter plugs in securely and actually helps lift the charger abover the other cords plugged into the power strip where I use it most often. It is secure enough to plug into a wall socket and just let the thing hang out there... The previous charger I had one of the little 2 prong-3 prong adapters in my power strip to accomplish the same thing...I really like this charger, and I am looking forward to using it and my new batteries for a long time...

As a battery charger, it works fine, but as a battery bank, it drains the battery even after the usb is disconnected. This is a design problem.

At least one reviewer said the mode button intermittently works. I had this exact same issue. Sometimes I press it and the USB indicator light would come on, most times it wouldn't. It's not like 50% chance either, maybe 5% of the time it would come on, if even that. After much reluctant testing, I was able to have it provide a charge for my Samsung Galaxy S4, and my Nintendo 3DS (not the XL version). I did not leave either to charge for very long, as I was determined to find out the secret to what I did to actually get it to charge. I was also at one point able to get the USB charge indicator light to come on without any USB cord connected to it, so its not a requirement that a device needs to be connected via USB to enable a "draw". I tried pressing and holding the button, I tried pressing the button quickly. I tried lightly pressing the button, I tried pressing the button with enough pressure to make sure whatever contact behind the button was being made.I suspected maybe the batteries that came with the unit weren't charged enough, so I replaced them with my Sanyo Eneloop fully charged batteries and had the same results. To make sure that my batteries were charged enough, I then got out my digital multi-meter and measured the voltages across the 4 included Duracell batteries as well as my Sanyo Eneloop batteries. The included Duracell batteries each had about 1.2 volts, and my Sanyo Eneloop batteries each had approximately 1.3 volts.Regarding the USA power adapter: I was able to fit the included USA power adapter to the Australia power prongs. Another reviewer mentioned that although the prongs on the device look slanted, they will still fit the vertically slotted adapter and I found this to be true. I was able to plug the device in to an outlet and witnessed all 4 LEDs come on, indicating the supplied Duracell batteries were being charged.My primary purpose of having this device was to be able to utilize AA batteries to provide a charge to my devices (phone/3ds/etc) while not around an outlet. Since it does not reliably perform this function, I will be attempting to return it.I'm sure some reviewers got great units. I may either seek a refund and try another product, or request a replacement.