I am trying to create battery powered sensor from Arduino mini. I am allready aware and I am using sleep and clock regulations, but my concern at the moment is voltage regulator of the board. I am using HM-10 as transmitter and it works well.
I know, that the board is using linear voltage regulator (7805?) which is not efficient and consumes power even if the board is not consuming power. I do not like this.
I would like to know if there is a possibility of bypassing this regulator and powering board directly from battery?
I would like to prevent soldering...
You can't power it directly from a battery, because batteries do not output a constant voltage.
You can use a switching regulator like the LM2936 and power your Arduino through the 5V pin. That would bypass the onboard regulator and supply your Arduino with a nice steady and efficient 5 volts. Switching regulators use very little power on standby, and are extremely efficient.
Just make sure to check the output voltage of your regulator before you connect it to the 5V pin on the Arduino - anything more than 6V on that pin will likely smoke something, since you are bypassing the onboard regulator and all of the protection circuitry that goes with it.
There are plenty of switching regulators to choose from - the LM2936 is just one I happen to have used before - google "switching voltage regulators" and find one with specs that meet your needs.