As the old joke goes, “you cannot lose an android phone because it is always near the power socket”. For me this is exactly what I am experiencing with my Acer Liquid E. Whenever I am using it for browsing the Internet via WiFi or 3G, I can discharge it completely in 2 hours.

So right before we went on a bus trip to Norway I decided to find out what are my options to get extended battery life for my phone.

Of course, there are high capacity battery for all normal phones. Unfortunately, not an option for mine.

My wife is also using an Android-based HTC Desire Z, so charging different devices is definitely a plus.

Also, we have cameras that take AA batteries and the ultimate choice would be able to charge external batteries too.

Well, Varta USB Charger from their “professional” line is that ultimate device.

It can:

• Charge USB devices using the power from AA/AAA batteries installed or the power outlet (effectively making this unit a wall outlet USB charger).

• Charge 1-4 AA/AAA batteries from USB devices using a USB-to-5V cable (included)

• Charge those batteries from the wall outlet adapter.

So, your capacity basically depends on what batteries you chose. The unit I purchased came with 4xAA batteries of 2700mAh. I purchased another set as a backup.

It turned out that one set of these batteries can charge a phone and a half completely. Also, we were able to charge 2 phones simultaneously using an USB hub – pure awesomeness!

It is worth noting that when the unit functions as a USB charger from wall outlet, it does not charge the batteries. When functioning as AA/AAA charger it tracks every single battery charge separately.

The only minor issue I found so far is that when the batteries are almost depleted the current converter starts producing a long squeaky sound until it shuts down.