What is the Capacity?

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jerm03
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What is the Capacity?

Looking at USB Power Banks I noticed that a 20,000mAh power bank stated in the Items Specifics section as having a capacity of 8000 mAh. However, the Product Specification indicates a Capacity of 20000mAh.
Is this normal? Does a 20,000 mAh power bank only have a capacity of 8,000 mAh?

http://www.ebay.com/itm/Poweradd-20000mAh-Power-Bank-Battery-Dual-USB-Portable-Charger-for-Cell-Phone-/272699904000?epid=1046458066&hash=item3f7e2e5000:g:MloAAO

Jerry

Lj-_-
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Just an assumption:
20000mah is the “hook you in advertising”
8000mah is probably the real capacity

There are a lot of fake mah claims our there, not saying this one is but seems dubious to me Flat Stare

jerm03
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That is what I think also.

flydiver
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Given the size comparison to the iphone 6 I think it would be a stretch to get 6000 out of it.
20000? Ridiculous.

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everydaysurvivalgear
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I once bought a power bank this size it had about 1000mah battery in it lol. I told Fasttech and they said bad luck!

ZoomieFan
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All power banks have conversion losses.
mAh can’t be compared unless the voltage is the same.

Please look at the fifth picture of this review: http://budgetlightforum.com/node/44933
20,000 mAh 3.6v 12,700 mAh 5.1v
That’s about 63% difference when just looking at the mAh.

20,000 mAh 3.6v = 72,000 mWh 12,700 mAh 5.1v = 64,770 mWh
That’s about 90% when looking at the mWh. -> Very good

Assuming the same voltage thing for your power bank.
20,000 mAh 3.6v = 72,000 mWh 8,000 mAh 5.1v = 40,800 mWh
That’s about 57% -> Very bad

Perhaps a typo? Not uncommon on Chinese sites. 8000 -> 18000
20,000 mAh 3.6v = 72,000 mWh 18,000 mAh 5.1v = 91,800 mWh > That would be magic, so no typo :)

$11 for 8000 mAh isn’t that bad but I would never buy it because I have to carry that weight around all the time.

But as flydive noted the picture doesn’t match the size. I think they just messed up big time.

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pommie
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Why don’t you buy the empty kit and use your own 18650’s that way you know the true capacity Big Smile

Disclaimer, I have not used or even heard about this one, it is just an example Silly

https://www.banggood.com/DIY-USB-Power-Bank-318650-Battery-Charger-Box-Shell-Case-p-971169.html?rmmds=buy

Cheers David

Nothing to see here folks, move along...

jerm03
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pommie wrote:
Why don’t you buy the empty kit and use your own 18650’s that way you know the true capacity Big Smile

Disclaimer, I have not used or even heard about this one, it is just an example Silly

https://www.banggood.com/DIY-USB-Power-Bank-318650-Battery-Charger-Box-Shell-Case-p-971169.html?rmmds=buy

Cheers David

I have a couple of kits, but not enough batteries for any more. When the kits and batteries are purchased you can buy the “ready made” banks cheaper.

I really don’t need any power banks, but just playing to see what is available.

Thanks, Jerry