Power- arduino -help - =(

Hello, I’m doing a sort of lantern,
I’m using 8 leds 5mm connected arduino digital pins.
but for every pin, I connected 2 leds, I mean use, only 4 digital pins.

I want to use this battery Portable Power Bank Mobile Charger 5000mah [/ b]

As the duration of the battery?
if I use an Arduino Uno or Arduino Pro Mini 328 - 5V/16MHz, or an arduino nano,
change the input voltage from arduino?,
I have seen some of these operate at 5v, 7v others, so this battery will not work for some Arduinos.
Am I wrong?
The Arduino Pro Mini 328 - 5V/16MHz, is the only one that works 5v (Vcc) and also has a regulated entry of (5v-12v)
which I use and recommend baeria use?
the advantage of this battery, battery charger traee built.
Thanks for your attention!

The picture says 5000mA, but don't say the voltage. If is USB, it must be 5V. If so, you can attach a cable USB (A->B) and power the Arduino directly from the battery pack. But read very well the datasheet of the battery pack and confirm that the battery voltage is 5V.

5v battery is

Then I believe that you can power your Arduino with a USB cable directly from the battery pack.

As the duration of the battery?

That would depend on the power consumption of your LEDs. I believe a Uno requires 40mA by itself and you add the LED requirement onto that but, if you get to 250, I believe you then exceed the overall power to the board and need to consider driving the LEDs separately, rather than direct from Arduino, which is may a better bet in the first place.

In the meantime you might do some further research into that battery. It seems very small to deliver 25 watts and you might find it is not only suss, it's also inappropriate. It's bound to be expensive, and it might be designed to provide a lot of power fast (indeed it surely is), which could mean it might not be so good at delivering less power for longer. Most particularly, your minimum voltage requirement is that device's maximum delivery. So tread very carefully.......

No battery is going to deliver 25 watts. Where does this number come from ? That is 5 amps of current at 5V. Do the OP's leds require 5 amps to run ? How is he going to switch that, with the arduino ?

The mAh rating of the battery, is a measure of the product of the current and the duration for which it can be supplied.

So, a 5000 mAh battery can supposedly supply 50 mA for 100 hours. Or 100 mA for 50 hours. Or 25 mA for 200 hours.

If you were to supply 20 mA to each of 8 leds ( 160 mA ), and about 40 mA consumed by the arduino itself, that is 200 mA which is around the limit which the arduino can handle. Using that as an indicative figure, it suggests that that battery should be able to run your arduino and leds for 5000/200 = 25 hours, if the claimed capacity of the battery is correct.

michinyon: No battery is going to deliver 25 watts. Where does this number come from ? That is 5 amps of current at 5V. Do the OP's leds require 5 amps to run ? How is he going to switch that, with the arduino ?

The mAh rating of the battery, is a measure of the product of the current and the duration for which it can be supplied.

So, a 5000 mAh battery can supposedly supply 50 mA for 100 hours. Or 100 mA for 50 hours. Or 25 mA for 200 hours.

If you were to supply 20 mA to each of 8 leds ( 160 mA ), and about 40 mA consumed by the arduino itself, that is 200 mA which is around the limit which the arduino can handle. Using that as an indicative figure, it suggests that that battery should be able to run your arduino and leds for 5000/200 = 25 hours, if the claimed capacity of the battery is correct.

25 hours ??? sure ? :astonished:

The trick is that they don't state the voltage at which it delivers that mAh rating... That package size seems to be the right size for a single 18650 cell. If it is a nice high quality battery then you might get around 3400 mAh out of it. Because the output is 5V it will contain a small DC to DC converter, which won't be 100% effective either, let's say it's 90% and it has to bump the voltage from 3.7 to 5, thus requiring about 1.5 times (5 / 3.7 / 0.9) more current on the 3.7V side than what is drawn at the 5V side.

So, given that we estimate the arduino+LED's to require 200 mA, this gives us 300 mA draw from the battery, giving you just over 11 hours of constant operation. With a lower quality battery this time will be reduced even further.

Also, since this is a lithium based battery, you don't want to run it completely flat, otherwise the battery gets damaged, but hopefully this package contains a cut-off protection circuit as well.

I know someone will probably correct me on minor technicalities, but that's what's great about this forum. Constant strive for perfection.

25 hours ??? sure ?

Probably not.

A trawl through eBay suggests it is suss. One on eBay is specified at 18.5Wh and delivers 5v , 1A but it is about three times as big as the one you propose, and all the others you see are much the same. The size may be determined by the size of an iPhone, or practical solar panel size, but it does seem more reasonable and, when all else is equal, the grunt of a battery is essentially determined by its volume. Further, the eight hours charging time for that one suggests that it is for real. As I said

your minimum voltage requirement is that device's maximum delivery.

By their nature the battery would hold its voltage well then drop off suddenly but I imagine that when it drops a piffling 0.5v to 4.5v it can hold that voltage and will still do its job OK. But its job is to charge a 3.7v phone battery. Your problem is that 4.5v, even when applied direct to the 5v pin, is not likely to impress an Arduino into reliable action.