Ideal 5V USB battery for Arduino

Projects General Guidance
1

Hi there,

in the jungle of available USB batteries everyone focusses on capacity but what I would need to know is

  1. The battery must charge (fast) WHILE supplying 5V on the USB out without interruption
  2. The battery needs to supply power of around 70mA without shutting down automatically (cause it assumes a too less power consumption)
  3. It should power back on automatically (no trigger switch)

Any ideas? Experiences?

Thanks!!

2

it sounds like you want to have a power supply.

battery
charger
voltage regulator

if you get a cell phone battery pack, the battery inside is 3.7vols.
you can connect a booster to pump that up to 5v, tied directly to the battery.

as for speed of charging, I get paid on Fridays and by Wednesday, I am low, the money goes really fast.
so, by fast, if you mean about 4 days, you should be fine with any charger.

3

beejayf:
Any ideas? Experiences?

External USB batteries will generally cut off USB power output supply after a couple of seconds, when the connected USB device is drawing too little current.
The intended use for such devices is to act as a mobile USB charger for smartphones.

A current sonsumption of 80mA should be enough to keep thexternal USB battery running until its battery is empty.

A typical "UNO board" has a current draw of about 55 mA only, so you's perhaps add some power consuming components like two or three brightly glowing 20mA LEDs to your circuit, if you are planning to run an UNO from a USB powerbank attery for some time in mobile mode.