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Customer Review

62 of 75 people found the following review helpful
3.0 out of 5 stars False advertising - only 7400 mAh at 5v, 27 Feb. 2013
Verified Purchase(What is this?)
This review is from: Anker 2nd Gen Astro E3 10000mAh Portable Charger External Battery Power Bank with PowerIQ Technology for iPhone 6 Plus 5S 5C 5 4S, iPad Air 2 Mini 3, Samsung Galaxy S6 S5 S4 Note Tab, Nexus, HTC, Motorola, Nokia, PS Vita, Gopro, more Phones and Tablets () (Wireless Phone Accessory)
This is a good product, it's not bad value for money, and having bought it I intend to keep it.

It's advertised under false pretences though, and here's why:

This charger operates at 5v (because USB power is 5v). But the batteries inside the device are only 3.7v... and there's some booster circuit inside which boosts that voltage up to 5.

When the manufacturer says 10,000mAh, they mean 10,000mAh at 3.7v. This is confirmed, as they say they use 37Wh of battery. Trouble is, when you have to boost this voltage up, your 'mAh' rating drops by the same amount.

So the device is only really a 7400mAh at 5v unit. The 10,000mAh is pure marketing, because really the customer shouldn't have to know or care about the voltages of the internal batteries!!

It's not bad value for a 7400mAh unit - but buyer beware!
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Tracked by 1 customer

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Showing 1-6 of 6 posts in this discussion
Initial post: 2 Mar 2013 05:34:04 GMT
ANKER says:
Dear tarangere,

Thank you for taking time to leave us the review and sharing your experience.

Kindly please be advised the battery requires 30% of this capacity to run and convert voltage. Since similar competing devices by other manufacturers also require a similar percentage of capacity to function, 10000 mAh is a fair comparison figure. May your understand.

This battery has 18 months warranty, if there is any problem on it within the warranty, please email us at with your Amazon order #, we will replace it for you at no cost (if we have available stock) or issue full refund to you per your preference.

Welcome to order Anker products and experience our service!

AnkerDirect Customer Service Team
Mon-Fri 9am to 5pm(pst)

Posted on 22 Mar 2013 23:39:49 GMT
Bigfeller says:
Well spotted! Thanks for sharing this.
As much as I sympathise with Anker that once another manufacturer makes a misleading advert, they are at a disadvantage, I think they need to be clear and honest in their descriptions. There is no way of knowing what cell configuration is used. I naturally assumed the 10Ah applied to the 5V output. Perhaps a milliwatt hour figure should be given instead.
It's a great product and deserves to do well.

Posted on 18 Sep 2013 11:38:16 BDT
Charging a battery from another battery isn't as simple as the raw capacity figure of the source, so being pedantic even your "correct" capacity @5V doesn't tell you enough.

You're not going to get all the performance figures you really need, but more importantly everyone else markets their products in the same way, so you're still comparing apples with apples!

Don't get me wrong, I'd prefer it if manufacturers gave truthful information too- I've just accepted the way of the world and adjust my own expectations!

Posted on 26 Oct 2013 00:15:01 BDT
Edmond says:
While you're technically correct, all battery manufacturers are advertising with it's internal capacity combined, simply by adding all the mAh values of individual cells together.
While it might be misleading to consumers but when everyone is using the same internal voltage cell then it's still a fair comparison between different products.
Of course the better option would be for everyone to go for watt-hours.

Posted on 13 Nov 2013 12:36:28 GMT
newway says:
Thanks for this. I always suspect the definition of the mAh capacity varies. I do hope all manufacturers will add a note to watt-hour figures, this is because, despite differences in "converting voltage", the difference between 10000mAh/2v cell and 10000mAh/4v cell is quite substantial.

Posted on 3 Aug 2014 10:53:25 BDT
Sarasa says:
Many thanks for the information. As you say, it looks as though the manufacturer is intentionally misleading their customers. There is a big difference between the published 10,000mAh and the actual 7400mAh -approximately 25%. I will not be buying this product as a result.
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