I want to use an Mega 2560 Pro mini in my car. I will like to power it directly from the cars battery. That means that when the engine is off it will get 12.6v and when the engine is running it will get 14.2v. Also, because I want to use a power saving mode I will like to not use a step-down convert…

[image] georgepa: but I was not able to find any information on what happens if I supply more then 12v. The 5V voltage regulator is heating up. If you only power the board without anything connected to it, it's probably fine. What else is powered from Mega in your setup?

I intend to add a relay that when the Mega wakes up it will power all the other sensors.

It's not just the higher voltages you need to worry about but noise and voltage spikes, especially the voltage spikes which can damage an Arduino.

[image] georgepa: relay that when the Mega wakes up it will power all the other sensors It would be better to post a drawing/scheme of your setup.

For now I have just the concept. For the power side I'm thinking somthing like this. [00]

Just put a DC-DC converter between the car's (nominal) 12V net and the Mega and all of its sensors. Power the Mega with 5V from the DC-Dc converter by applying it to the Mega's 5V pin. I don't see the need for a relay for the sensors. If you must use one, why not just use a PMOS high side switch in…

Years ago I used a simple LM7805 to power a small DC voltmeter in my automotive application. Yes, some wasted power. Today there are buck converters designed for automotive applications and they work just fine getting from as much as 40 volts or more down to 5 volts or whatever you want. I would not…

Example of a well documented DC/DC converter (click) , that draws less than 100uA idle and 2uA in shut-down. Leo..

Mega 2560 Pro mini overvoltage

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kmin October 20, 2024, 6:59pm 7

There are buck converters with enable pin, so no need for relay. Are these sensors connected to arduino?

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Mega 2560 Pro mini overvoltage

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