Power banks?

[Yorkshire Andy]

Can anyone explain how the Chineese makers get this magical rating for this:

http://www.dx.com/p/wallet-style-portab ... 5cm-285224


they claim 30,000mah now each 18650 battery is 3.7v and the biggest i have come across is 2500mah



quick look at the arrangement it looks like a very simple parallel all the lives together and all the negatives giving assuming they are 2500mah cells

totaling 15000mah capacity





one of my 18650 (protected version so slightly longer rated at 2500




ok the specs quote this

Nominal Capacity 30000mAh
Battery Actual Capacity 28000mAh
Capacity Range 20000mAh and above


but am i been thick and missing something

somehow they manage to step up the voltage AND get more power out the batteries :s

[Yorkshire Andy]

edit just seen some at 3100mah but they work out at £20 a pair......


not massively bothered the unit was only £10 and a handy thing to have but its either magic electronics or marketing bull excrement which is why im asking

[Jack the Lad]

It's bull

[Yorkshire Andy]

That's what I thought then again have several solar type chargers that won't put one full charge into my smart Phone so far I've done 4 charges and its not dropped a segment on the led power indicator

[daylen]

30,000mAh seems crazy - that would require 5,000mAh cells and I've not come across 5,000mAh cells at all. The most I think I've seen is 3,600mAh but they're really expensive. Certainly not 6 for £10!

I mean, you can get flat, laptop battery style 5,000mAh cells but not as AA style batteries.

I'd be interested to see how many full charges you get out of it though - who knows, there may be some crazy Chinese voodoo going on!

[rik_uk3]

http://www.ebay.co.uk/itm/Universal-500 ... 3393866597

I have several of these and they work very very well indeed. One will keep two smart phones and a ten inch tablet charged for a three night trip and still has power in them. I've a 30000maH that runs a string of LED lights in my shed too.

[daylen]

http://www.ebay.co.uk/itm/Universal-500 ... 3393866597

I have several of these and they work very very well indeed. One will keep two smart phones and a ten inch tablet charged for a three night trip and still has power in them. I've a 30000maH that runs a string of LED lights in my shed too.

They may work well for you and that's great... but... there is no way that they're 50,000 mAh battery packs! That's 50Ah! At 5V that means 250Wh which is like a 20Ah 12V battery which is just silly as those things retail for like £150!

I'm tempted to get one and do a tear down on it!

[Yorkshire Andy]

http://www.ebay.co.uk/itm/Universal-500 ... 3393866597

I have several of these and they work very very well indeed. One will keep two smart phones and a ten inch tablet charged for a three night trip and still has power in them. I've a 30000maH that runs a string of LED lights in my shed too.

They may work well for you and that's great... but... there is no way that they're 50,000 mAh battery packs! That's 50Ah! At 5V that means 250Wh which is like a 20Ah 12V battery which is just silly as those things retail for like £150!

I'm tempted to get one and do a tear down on it!

shame i dont speak russian but this guy has a vid of it opened up

https://www.youtube.com/watch?v=EBo7ocMDRLI

[Hamradioop]

http://www.ebay.co.uk/itm/Universal-500 ... 3393866597

I have several of these and they work very very well indeed. One will keep two smart phones and a ten inch tablet charged for a three night trip and still has power in them. I've a 30000maH that runs a string of LED lights in my shed too.

They may work well for you and that's great... but... there is no way that they're 50,000 mAh battery packs! That's 50Ah! At 5V that means 250Wh which is like a 20Ah 12V battery which is just silly as those things retail for like £150!

I'm tempted to get one and do a tear down on it!

That is bloody expensive, I just bought 2 xYPC14-12 Yuasa Yu-Power Battery 12v 14ah batteries for my wife's Mobility scooter for less than £50 including delivery.

[daylen]

That is bloody expensive, I just bought 2 xYPC14-12 Yuasa Yu-Power Battery 12v 14ah batteries for my wife's Mobility scooter for less than £50 including delivery.

Yes, my post was too ambiguous - The Yuasa batteries you mention are lead acid but I was quoting for branded lithium (LifePo4) batteries. You did make me realise though that the batteries in the backup will be straight lithium polymer rather than LifePo4 and you probably could get those for £50 upwards.

My point really was just that you can't possibly get a 50,000mAh 5V battery backup for £10 or so. Don't get me wrong, the battery bank still probably make sense and seem great value even if they're 8,000mAh.