Powering 3.3v arduino direct from 3.7v battery

Hi all.
I want to power an mp3 module direct from a lithium 3.7v battery. I would like to read the audio output using analogRead on a 3.3v Arduino(plugged into the same battery)
The 3.7v potential peak is out of range for the Arduino if it is plugged in via the RAW pin (through the voltage regulator) meaning I would have to use voltage dividers to reduce the levels.
My question is; is it safe to connect the Arduino via the vcc pin (bypassing voltage regulator) so that I can read the module without a voltage divider?
This would mean that as the battery voltage decreased, it would do so for both the arduino and the module and so the readings would remain accurate whereas that would not be the case if i used voltage dividers.
Thanks.

gonadgranny:
My question is; is it safe to connect the Arduino via the vcc pin (bypassing voltage regulator) so that I can read the module without a voltage divider?

If your Arduino was a Pro Mini, then yes.

But you should isolate the 3v3 regulator on the board (the Pro Mini has a jumper position to do this for example).

Other 3.3v arduinos may have 3v3-only parts.

Yours,
TonyWilk

But you should isolate the 3v3 regulator on the board

What do you mean by isolate the regulator? Thanks.

It indeed depends on the other components on the board.

The processor itself can handle 5V just fine, but you really have to check on the other parts, including the regulator which may not like >3.3V on its output pin.

gonadgranny:
What do you mean by isolate the regulator? Thanks.

If you feed 3.7V into the Vcc pin, that will be connected to the output of the on-board 3.3V regulator.

That could be bad.

The output of the on-board regulator should be disconnected from Vcc. or just unsolder it.

Yours,
TonyWilk

gonadgranny:
Hi all.
I want to power an mp3 module direct from a lithium 3.7v battery.

You realise that the '3.7v battery' will be as high as 4.2v when fully chargerd ?