Hi, I was a little distracted and accidentally plug my external battery (11.1V) GND on Arduino Mega 2560 VIN and 11.1V on arduino GND. The arduino still work (at least by USB power), I can compile code, 5V and GND work properly (I measured with a multimeter), digital/analog write and even serial works.
But the problem is that the VIN isn't reducing the input voltage properly, when I tried to reconnect the battery the microcontroller heated to much, I measure the 5V and GND and multimeter says that there's about 9V. Can I fix the VIN power supply? There's another way to feed arduino with my 11.1V battery?
I'm using it to a line follower robot, so I need to use portable power sources. The battery also supply a H-Bridge, it can give to me an 5V.
Thanks.
Sounds like you popped the 5V regulator. The easiest fix is to buy another Mega. It is possible to replace the regulator, but in my opinion it is not worth it unless you are good with a soldering iron and SMT parts.
In the future, use the power plug to connect the battery. The power plug has a diode in series with the regulator to protect the regulator from reversed power connection.
There's another way to feed arduino with my 11.1V battery?
I guess that you could get a 5V regulator for the battery like a 12V to 5V buck converter and connect that to the 5V input. But I would worry that the reversed voltage degraded or damaged something else that may fail later.
Well in 04/18 I will need the Arduino to a robotic competition, I live in an inner city on Brazil, I only can get a new arduino and eletronics components by Internet. I haven't enough time, delivery takes at least one month, so I need to work with what I have.
I think that I could use the H-Bridge (It's give to me a GND and 5V) to feed the Arduino, but I don't know how. Through USB? Or can I directly connect it to Arduino GND and 5V?