USB POWER BANK // PORTABLE POWER SUPPLY

That's a lot of text.. think it's been mentioned multiple times, pick a 1A capable supply and plug it in and just try it..

Yep just like the shoe advert ... Just do it !!

ok, i came to a conclusion that im going for a passthrough/charge through capable powerbank.

Zendure brand seems promising. but cant get it at the moment

This UPS/passthrough/charge-through powerbank that comes close and can be found in shops here is Xiomi.

the brand also has a look out for a not genuine powerbank and doesnt have all its glory,which i think the real thing is a good brand but what comes to mind is, is it ok?

from reading this blog

http://www.the-area51.com/2014/09/xiaomi-mi-power-bank-10400-review.html

a turn on haha

but this part of the blog;

" Pass-Through Charge is Supported

Another good thing about this Power Bank is that it supports pass-through charging, this means that you can simultaneously charge your phone and Power Bank. The Power Bank will pass the charge to the device and once the device is 100% charged, it will charge itself.

This type of capability is seen in top brand Power banks which are quite expensive as compared to the Mi Power Bank.  "

what comes to mind is, from its spec, http://www.mi.com/en/pb10400/#params

" Power sourceDC 5V

• Input voltageDC 5.1V
• Input current2.0A(TYP)
• Output current2.1A(TYP)
• Rated capacity3.6V/10400mAh(TYP)
• Charging time5.5 hrs with 5V/2A plug and standard cable
• 12 hrs with 5V/1A plug and standard cable "

its output 2.1A but 12 hrs with 5V/1A plug and standard cable, i dont get that part is it saying the output is realty just 2.1A and depending on the hardware thats need charging if it can filter amps

shabaz, is this safe for my raspberry pi2mB?if the pi2mB can filter how many amps it needs just like nokia's python script for amp input and the iphone required adapter power source.

If it can, 1 more thing comes to mind when this type of tech capabilities power bank is " 100% chanrge" do you think it draws 2.1A or less and safe for the pi2mB. or 2.1A is too much for the pi2mB

or its all jibberish and just go for a powerbank that has 1A printed on the usb port??haha

MOST powersupplies provide a voltage and the device you connect can use whatever it wants in current. (amps). Up to a certain maximum of course.

That 2.1A is such a maxium. So as long as you provide the 5V to the 'pi it will use whatever current it needs (as long as the 'pi doesn't need more than 2.1A, but the 'pi is specify to require at most 700mA (=0.7A). )

omg after doing some  reading about pass throughs powerbanks I forgot the pi's adapter output is 2.0A, most of powerbanks adapter that I saw on shops, needs 2.0A power source adapters similar as the pi, but output 2.1A and most branded and similar dimensions as the pi and some passthroughs its output maxed at 3.6A or so..

correct me if I wrong please...again heh. since watching from youtube about power source if the pi doesn't meet its required current it will display a colour rgb box which means the current acquired is not efficient. Power source within 2.1A of 5V is safe for my pi2mB, even if the pi2mb adapter max output is 2.0A and the pi2mb manual which said 700mA. Which you made clearly Roger Wolff, its 0.7A.

for a smart buy, if the powerbank outputs 1A or 2A printed on its dual usb port, both port is safe for my pi2mb because the power bank's spec is "output: maximum of 2.1A" even if it doesn't mention 2.1A for both ports or 2.1A on each port. correct?

OH btw I get it now, by reading back my post earlier haha about xiomi powerbank, it is actually 2.1A, but when pass through/ charge through is perform, its maximum 2.1A becomes less, which I think that it is safe for my pi2mB. if and IF 2.1A power source for the pi2mB is safe. Waiting on replies lol, hope this doesn't bore u guys haha I myself is waiting patiently hihi

Somehow, the last few years, it has become "acceptable" to advertise with technical specs that the devices advertised cannot achieve. This started about 20 years ago with printers and scanners that claimed 600, 1200 and then 2400 DPI.

So, when the raspberry pi foundation recommends you get a 2A adapter, they mean: one that can actually deliver at least 700mA. This is just avoiding the trouble of having to explain that even though you might have an adapter that claims 1A, and the pi doesn't need more than 0.7A, because of the "inflation" of the specifications, the adapter might not be able to deliver on it's specs. It becomes really confusing for many consumers if said 1A adapter works to charge a phone. The phone can (and will!) just adapt its charging rate, if the adapter can't deliver what it claims to be able to do.

Below officially 4.65V the red light on the pi2 will go out and the screen (if attached) will show a rainbow-square. The 'pi will continue to work reliably down to below 3.3V, but this cannot be said about the peripherals on USB and HDMI. (HDMI has a "5V powerline" just like USB, and it can power things like for example HDMI to VGA converters. My first such converter is a bit picky about the voltage).

Again, charging phones is "easy" because the phone runs off its battery. The pi (the first one, for which I can find the schematics) can tolerate a voltage sag for about a third of a milisecond. So if the adapter would need "a break" for millisecond, the pi crashes. When charging a phone such a millisecond voltage drop would not be noticable.

you say: ".... not efficient". That is not the correct way to say it. "not enough" Ah.. Maybe you meant "not sufficient".

Some powerbanks claim to have a 1A and a 2A port. Internally they are mostly wired together. However, through some tricks the adapter can signal to an attached phone that it can do 1A or even more: 2A. This "signalling" is necessary because standard USB only supports 0.5A. So if they say they have a 1A port and a 2A port, they have one signalling wired up like that, but the power, which is what matters to a pi, is the same. The 'pi is not equipped to monitor that "signalling".