ReviewsTech Toys

Anker Astro Mini 2600mAh External Battery: Yet Another Gadget to Test

My other new toy is a respectable 3 and a half inches long.


To go with the Contour Roam I recently purchased, I got an external USB battery pack for charging on the go. The Roam doesn’t have a user-replacable Li-Ion battery pack and shooting 720p on it will deplete the battery in 3.5 hours (theoretically). 1080p will drain the built-in battery faster still, so in order to get through a full day of (anticipated) shooting, I needed a way to top off its battery during breaks and such.

There are a couple other choices in the $20 range if you’re looking for an external battery, most notably a smaller capacity Duracell pack, but I decided to give this smaller-brand battery found on Amazon a try. The reviews seemed promising, and the form-factor and construction looked like it would survive being tossed around in a backpack fairly well.


The assortment of adapters for various USB devices is a nice touch. Note: Since these adapters plug into a coaxial jack, the charging cable will not carry data.

Using It
The Astro Mini has two ports and a single on-button. Input and output are rated at 5V @ 0.8A, which is better than the USB 2.0 spec’s half amp but not nearly as much as what a modern motherboard can push through (1+ A), and won’t hold a candle to a high-power AC adapter. While charging the Astro Mini pack from my Macbook, it remained cool to the touch.


The Astro Mini only has an on-button. If no current draw is detected it shuts off after about 30 seconds. It blinks red when it’s charging, and green when it’s discharging.

Anker states up front that the conversion circuitry in its battery pack eats up 30% of the rated capacity. I’m not sure if they’re stepping a single cell Li-Ion from 3.7V to 5V, or regulating a 7.4V pack but it doesn’t really matter. This thing can charge an iPhone (~1400 mAh) with a little juice left over. Theoretically. (For reference, a ContourROAM has a 1300 mAh capacity so this should be plenty.)

I ran down my iPhone 4S to around 6% on a video call, before letting the phone coast to its pre-programmed demise. I then charged it while completely off for a period of time before turning it on with Airplane Mode enabled and screen brightness set to minimum so I could observe the recharge rate. I then repeated the test to see how much juice was left in the Astro Mini.

First Charge:
25 minutes - 20% Charged
70 minutes - 50% Charged
120 minutes - 80% Charged
160 minutes - 97% Charged
175 minutes - 100% Charged


The first charge was almost textbook, really. The charge-rate slowed down appropriately as the iPhone reached saturation. I drained my phone again and charged it until the Astro Mini no longer turned on. It restored the battery by 24%.

A rough calculation gives the total electrical transfer at 1775 mAh, or 68% of the Astro Mini’s capacity. This is almost perfectly in line with Anker’s claim that 30% is lost in conversion so everything checks out.

Overall, I’m pretty pleased with the output of this little battery. It’s about the size and heft of a pair of C cells (if you still remember them), and the design seems well thought out. The metal outer shell and thoughtful assortment of adapters inspire confidence that it will last a little longer than the usual fare of Chinese knockoffs.

However, we will see how the Anker Astro Mini holds up through repeated charge cycles. I’ll report back to you after I put this thing through its paces in the streets of Copenhagen.

… Oh, did I mention I was going to Copenhagen this summer?

4 thoughts on “Anker Astro Mini 2600mAh External Battery: Yet Another Gadget to Test

  1. hi, i have the roam 2 & a 3000 mAh Anker but when i connected them together for maybe 10 mins my contour wouldn’t respond for maybe 2 hours (thought it was broke) it was like the Anker reset the contour roam..? have you had this issue at all? cheers

  2. hi, yeah its works no probs on other devices like iPhone, iPad etc… i was thinking maybe the roam was trying to connect to the anker thinking it was a computer & this caused it to temp shut down..? strange one.

Leave a Reply