I recently got a new rechargeable battery pack to play with. It's a 10400mAh Li-on "power bank" and I wanted to use it for Raspberry Pi experiments and charging my mobile phone and tablet while on holiday.

It is made by RAVPower and they produce a range of portable charging and power accessories. The RP-PB07 is the largest device in their range and provides a massive 10400mAh. That's probably 4 to 5 times the capacity of your Smartphone!

Here are the specifications :
- 10400mAh capacity (Samsung cells)
- 1 USB output (1A)
- 1 USB output (2A)
- 1 MicroUSB input
- On/Off button

Using my own measurements the dimensions are 70x22x115mm and the main unit weighs 230g.

Here are the items I received in the box :

- 10400mAh power bank
- 2 MicroUSB cables (coiled)
- 1 Carry bag
- 1 User manual

The box clearly shows the manufacturers details as well as the company responsible for importing it. This is something so often missing from generic items on eBay.

The unit itself is made with black gloss plastic with a silver band running around the sides. Overall it feels well made, compact and solid. The switch and status LEDs are mounted on the top surface with all three USB ports on the front surface. A label is stuck to the underside and identifies the model number and capacity.

As with most Li-on batteries it came half charged so the first thing I did was to plug in one of my HTC MicroUSB chargers. I left it one charge until all the blue LEDs were lit and prepared to use it for the first time.

The first application I found for this battery pack was running a Raspberry Pi mini-computer. The full details of that test can be found over at RaspberryPi-Spy.co.uk. It performed well in that test and gave me high level of confidence that this product would help support my smartphone and tablet when out-and-about.

All my devices use MicroUSB so I can connect them using the supplied cables. If you have a device that doesn't use MicroUSB connectors then you will need to use the USB cable that came with that device. This is most likely to include phones using MiniUSB or Apple iPhones, iPads and iPods.

Although the product has an On/Off switch plugging in a device will automatically activate the battery. You can choose which of the two ports to use but it's best to plug the bigger device into the 2A port if you are charging a phone and a tablet at the same time.

A conventional USB port may only provide 0.5A (500mA) of current so either of the RAVPower's USB ports should out perform a standard PC or laptop USB port.

The blue LEDs give a good, clear indication of remaining capacity. It's a minor point but on these type of products I wish they had more LEDs. This would give you a more accurate measure of remaining capacity rather than only showing 25% chunks.

It's difficult to predict how many times you can charge your phone or tablet on one full charge of the RP-PB07. There is such a wide variety of mobile devices out there. A good guess is to divide 10400mAh by the capcity of your device's battery. My HTC One S has a 1650mAh battery which implies I could get 6 charges. In reality this won't be the case as some energy is always lost in the charging process. A more realistic figure is 4 but it gives you a rough estimate.

At the time of writing the Amazon description mentions a free wall charger but the product does not come with this charger. This didn't matter to me because I've already got a growing collection of 5V MicroUSB chargers. In most cases I actually prefer not to have chargers included with products as they are easy to buy if you need one and a waste of plastic if you already have plenty in your drawer.

A nice touch is the inclusion of a soft pouch which you can use to carry the unit around in. Some people don't worry but I hate things getting scratched, especially gloss black plastic. I like being able to pop it into the bag and put it in my rucksack knowing it is safe from scratches. The black gloss plastic attracts fingerprints but it is easy to clean with a soft cloth.

These days my household has got more mobile devices and they are more power-hungry than ever. A portable power source really is a useful thing to have available so you aren't ever faced with a dead phone.

The RP-PB07 is available from Amazon alongside RAVPower's range of other portable Li-on power banks. There are also other customer reviews available so be sure to browse through those and see what other users have to say.

Click to view the RAVPower 10400mAh Power Bank on Amazon UK or Amazon US.

Here are some more photos :