Saving power on low-current application

[refind]

I'm using an Arduino with some load cells to collect weight data over long periods of time (days etc.) and I'm using a 12V lead-acid motorcycle battery to power the entire thing. My electronics only need 7V to operate, so I am essentially wasting 5/12 (~40%) of the power.

The entire setup only draws about 20mA, so I cannot use a DC to DC converter because they have a no-load current of 10mA which is too much.

Is there anything else I can do to save that power and extend battery life?

 

[MrSparkle]

I'm guessing you don't need continuous data because of the long time period. Why not put the circuit to sleep with a low power timer?

 

[refind]

We already are putting the sensors to sleep, but the Arduino microcontroller cannot be rebooted fast enough. The system must be ready to collect data for the entire time. The microcontroller is drawing most of the power.

 

[MrSparkle]

What do you mean it can't be rebooted fast enough? How often are you collecting data? And I'm pretty sure most arduino's have a built in sleep mode that draws less than a milli-amp.

 

[Baluncore]

Try this link for micropower buck regulators.
http://www.linear.com/parametric/Mi...5!vout_7!iout_0.1!vout2_!iout2_!vout3_!iout3_

 

[meBigGuy]

Those regulators look good.

How much of the current is the Arduino processor? See 29-13 in http://www.atmel.com/Images/Atmel-8...PA-168A-168PA-328-328P_datasheet_Complete.pdf

See the section on Minimizing Power Consumption also.

 

[Garyabc]

I'm guessing you don't need continuous data because of the long time period. Why not put the circuit to sleep with a low power timer?

This could be a good idea. You duty cycle the system. So, only a potion of time it is awake.