When you are using an iPhone or iPad and you do not have convenient access to a power outlet — perhaps you are out of the home or office, or perhaps you are just in a room where you need to use your device and you are not seated near an outlet — it is incredibly useful to have an external battery for when you need to recharge your device. Lots of companies make external batteries, but I've been very impressed with the Lumsing Harmonica Style Power Bank that I reviewed back in 2014. That one is a 10,400 mAh battery in a nicely styled case that can charge two devices at once. Lumsing recently sent me a free review unit of a similar device with even more capacity called, and yes this is a mouthful, the Lumsing Most Compact Grand A1 Plus 13400mAh Portable Charger External Battery Power. The device currently costs only $27 on Amazon. I've been testing it for about six weeks and I can definitely recommend it.
Design
I like the way that Lumsing designs its chargers. Like the Harmonia Style device that I reviewed last year, this one has curved sides so it feels good in your hand and doesn't have any rough edges to scratch anything else in your briefcase or purse.
There are two USB outlets on one end, and unlike the battery I reviewed last year, you can use either USB outlet to give an iPad the full 2.4 amps of power that will charge it most quickly. The device can sense what you are charging, so it sends the right amount of power — more for an iPad, less for an iPhone. The device can output a total of 3 amps of power at a time, so you can charge two iPhones at the maximum speed. If you charge both an iPad and an iPhone at the same time you get a little less than maximum charging speed, but it is still more than enough to get the job done, albeit a little more slowly than just charging one at a time.
The input for the device is a Micro USB cable (included). It takes about eight hours to fully charge the device, so when it is empty you'll want to charge it overnight.
You can press a button on the side to see one to four blue lights depending upon whether you have 25%, 50%, 75% or 100% charge. Or if you hold down that button for a few seconds, a small flashlight turns on. It's not very bright so I doubt I'll ever use the flashlight, but I suppose there is no harm in it being there.
The device weighs 9.3 ounces. That's slightly more than the Harmonica Style battery from Lumsing that I reviewed last year (which was 8.35 oz). I found that the weight of this device is heavy enough that I can tell that it was in my briefcase, but light enough that it hasn't bothered me to keep it in there all the time. On the other hand, I wouldn't want to carry it in a pocket.
The size is almost 4 inches long (98mm), about 3 1/4 inches wide (79mm), and just over 3/4 of an inch tall (21mm).
The unit sent to me is silver with blue highlights. There is also a black model with orange highlights and a gold model with white highlights.
Capacity
As the name tells you, the battery has a 13,400 mAh capacity. Lumsing says that is enough to charge an iPhone 6 five times or an iPad Air more than once. From my tests, that seems about right. I haven't yet tried to charge my iPad Pro from zero to 100% using this charger, but I believe that the iPad Pro has a 10,307 battery so this charger should be able to give you at least one full charge.
Utility
Putting aside the numbers, in my real life experience, this battery has given me all of the extra power that I need. I've never had to recharge my iPhone more than a few times before I had access to a power outlet, nor have I ever had to recharge my iPad more than once in a day. I've used this charger on trips that I have taken where I put heavy use on my devices but didn't have easy access to a wall charger. I've used the charger in depositions where my iPad was getting heavy use but no outlet was near me and I also needed to charge my iPhone because its cellular connection was being shared with my iPad. I've shared this charger when I was charging my iPhone and someone next to me needed to charge his iPhone too. This charger has always been up to the task. So whenever this charger was with me, suffice it to say that I always had all of the power I needed.
It is really useful that there are two USB ports on this device. Often I need to just charge one device at a time, but sometimes near the end of a long day I'll want to recharge both my iPhone and my iPad at the same time, such as when I am waiting for a plane to head home, and I want a charged iPad to use on the plane and a charged iPhone to use when I land. This device can do that, without my needing to locate one of the rare seats in the waiting area that has an outlet nearby.
Conclusion
I usually carry two batteries in my briefcase: a small battery that can recharge an iPhone and that is small and light enough that I can carry it in a pocket, plus a large battery. For that small battery, I continue to like the Powerocks Super Magicstick that I reviewed in early 2014 and which I see is now selling for only $13 on Amazon. But for a larger battery that can charge an iPad, or even an iPad and an iPhone at the same time, I've been very satisfied with this Lumsing device. The retail price is $56.99, but you can get it on Amazon for only $26.99.