Power supply for arduino nano

[idreamof3d]

What would be the best power supply to power 2 arduino nano boards with one battery?

I wired two 6v 4500mah rechargeable batteries in series with a voltage regulator stepped down to 7.4v to power the 2 nano boards & 7 mg90 servo motors. I added a on/off switch between the nanos to be able to turn them off however the voltage regulator stays on which isn’t good, I don’t want to add a second on/off switch for the regulator, I want to use one on/off switch for everything. This setup works great & powers the 7 servos efficiently however the battery loses power in roughly 30-45min which causes a voltage drop then causes the servos to act funny when triggered.

My question is, what would be the best way to set this up? Swap the 2 batteries wired in series for 1 7.2-9v battery without a regulator?

** I am not very experienced with this stuff, please keep this in mind & keep responses respectful. Thank you very much for your assistance **

[rsmls]

@idreamof3d

I want to use one on/off switch for everything.

So switch the input from the batteries to the regulator. This way, all power draw is cut if the switch is off.

Can you post a schematic diagram of your present project and a good photograph of how everything is connected? This may trigger some more suggestions.

[TomGeorge]

Hi, @idreamof3d

Can you please post a copy of your circuit, a picture of a hand drawn circuit in jpg, png?
Hand drawn and photographed is perfectly acceptable.
Please include ALL hardware, power supplies, component names and pin labels.

Thanks.. Tom...

[jim-p]

Max voltage for an MG90 is 6V. 7.4 is way to high, you will probably damage them in the long run.
What is connected to the nanos, other than the servos?

[PaulRB]

You could use just 1 6V battery, or wire 2x 6V battery in parallel for longer battery life if needed.

Nano isn't guaranteed to run with only 6V connected to Vin, but you may find that it works ok.

If not, use an external 5V LDO (Low Drop-Out) regulator.