Multiple voltages on a LIPO

Hello All,

I am working on a project using as much prebuilt modules as I can to avoid my short coming of hardware knowledge. Currently I am looking to power a couple different units up with different voltage needs from one battery and still be able to charge the battery without having to disconnect it.

There are a few goals to try to achieve:

  1. Be able to run this device on Battery or thru USB
  2. If it is running on USB it will be charging the battery
  3. Not put 5v into the Adafruit 7seg Backpacks since I believe they take 3v
  4. Run a Mega with 5v in the VIN to avoid another Voltage converter
    a) It says 7-12v but 5v should be enough for logic stuff and an IR RX and TX... right?
  5. Not have to disconnect anything to go from battery to usb power.

I would run everything off the Mega but I think I will be coming close to maxing the Amperage draw.

I'm looking for any advice or additional hardware to make this happen fluidly.

Thank you in advance,

"Run a Mega with 5v in the VIN".

Can't do that.
V-in is the input of the onboard 5volt regulator.
5volt on V-in will be <=4volt on the 5volt rail of the board.

V-in needs >6.6volt.
5volt can be connected directly to the 5volt pin, if you understand the dangers of backfeeding 5volt into a connected PC/laptop.

Thanks, I was thinking about doing the 5v on the rail but I didnt want to bother disconnecting it if i connect via usb.

I’m curious because I have done similar projects with 5v in the VIN and it work perfectly with a 16x32 led matrix and and IR RX and data to the sound module and 2x led arcade buttons.

One of my other goals it to not have to disconnect anything.

Yes, a Mega will most likely run on >=3.7volt, but some things like the A/D will give problems.