I’m debating getting another USB power bank and what size. What I started wondering was what I could use it for other than for charging my phone or tablet.
It makes a nice tiny lamp using my Xiaomi USB light. Should I get a 20,000 mAH? 10,000 or 5000? What are some other interesting things I can do with it?
I charge my micro quadcopter batteries from one when on the go. My wife loves the fan.
I have the Xiaomi fan that I use with mine and it great.
If you can power an ebike with xiaomi powerbanks in series i would buy that guide
The ultimate…. use USB power banks to charge USB power banks… Free Electricity
I have the ENB triple power bank: https://www.fasttech.com/products/0/10002784/1381305-enb-enb-tri18650-1a-3-18650-battery-usb-emergency (sold out or no longer available).
I have a compact sound bar that is USB powered; I’ll use my power bank to power the speaker when I have it connected to my cell phone/tablet/gaming device. (unfortunately, the speaker isn’t available any longer: http://www.dx.com/p/usb-powered-sound-bar-speaker-for-laptop-notebook-black-105312)
I also have and occasionally play my old PSP 3000. This model has a hidden fourth screen brightness setting that is only available when connected to a power source. I’ll connect a very small 1x 18650-sized power bank to force the higher brightness mode.
I also have a USB-rechargeable Bluetooth audio receiver; I’ll connect the power bank to maintain power to the device for extended play times as the battery life is very poor.
Take your power banks to work with you… Charge them from your office PC… take the electricity home… Free Electricity!
I charger AA/AAA sized Ni-MH batteries with it, useful when traveling and there is no power outlet.
This might seem crazy but anyone experimented with combining a few packs and using an inverter for AC output?
I like those powerpacks with 12v and AC inverter output but they’re only made with sealed lead acid batteries. Large bulky and heavy in comparison to these sleek lithium packs.
You can charge your toothbrush with it.
Most “DC to Mains Current” inverters are rather innefficient. The ones that aren’t cost a bundle.
Charging at the office for free electricity sounds cool, but you’ll know the jig is up when you find a power meter connected to your cubicle 
Phil
I use mine to jump start the ride on mower
1: bust ’em open and recover the batteries
2: paper weights
Where in the world might you be that you cannot just use a plug-in charger?
I have 4 power banks for 4 of my tabs/ mobile.
train travel of 15-24 hrs. So need it.
Travelling by road to nearest city is 6-8 hrs. , u need it.
Unless you know for sure what is inside the power bank, I would be leary of any bank claiming more than 15,000 mAh. The largest power banks for personal use I have seen will hold four 18650 cells, and with the capacity of those cells topping out at around 3600 mAh each, 15,000 mAh is about the max.
90% of powerbanks use 4 –5 cells inside.
Cells are rated @ 2600 mAh in 90% of the cases !!!
So what is said is mostly true.
This valid for li-on cells , i.e , 18650 .
I have seen only 1 model which claim to use 26650 cells!!!
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So is possible to have 20000 mAh in consumer power banks,
Theoretically less ,and there are some models with 20000 mAh, but they bulkky , because they 8-10 cells of 18650 in them .
A 10000 mAh 18650 power bank weight 200-250 grams.
So a 20000 mAh 18650 power bank weights 400 –500 gms!!!
just not the weight, the size and bulk all increases.
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Exceptions : Li-polymer based power banks.
li-polymer are not cylindricall like 18650/28650 cells.
They are mostly like what u see in tablets / phones.
I think the Apple ipad has 11000 mAh li-polymer battery.
So if u r stacking together 2 li-polymer cells then u get 20000 mAh.
there exists some 20000 mAh power banks.
Ideally i carry multiple 10000 mAh power banks for 4 of my devices!!!
that’s mostly better, if u need u can carry 1 or 2 or 3 or 4 or depending on the requirements !!!
A 10000 mAh power bank will give net output of max 7000 mAh. @ 93% efficiency.
For a 10000 mAh power bank anything @ 6000-6500 mAh is Excellent/ superb!!! , that’s the max u should be expecting!!!