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Topic: Powering arduino pro mini 3.3v (Read 601 times) previous topic - next topic


Im wanting to make a low power porject powered from a 3.6v lithium iron battery. When the battery is fully charged it is around 4.1v can i power an arduino pro mini 3.3v directly from this without using the on board voltage regulator as it uses more power


Yes, up to 5.5V.

You need a 8MHz version, to allow 3.4V (or even 3.0V). The ATmega328P chip can go up to 5.5V. The frequency stays 8MHz of course, and in the Arduino IDE the 8MHz 3.3V version should be selected.


When you connect the battery to VCC instead of RAW, make sure that your board allows for bypassing the voltage regulator this way. Some people suggest to remove/disconnect the regulator for such operation. Some vendors specify this as valid operation mode, depends on the concrete board.

Also take care of the voltage levels when programming the board! I'd remove the battery and power the board from the programmer, so that the signal levels don't exceed Vcc. Even if you use 5V for programming, choose the 8MHz 3.3V board option, as Peter_N already mentioned. Otherwise the compiler will try to program the board to run at 16 MHz later, out of the specs and with wrong baudrates and other system clock depending features.

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