Arduino Battery Life?

If I were to run an Arduino (let's say the Arduino Pro Mini) and an alphanumeric LCD screen (lets say a 16 x 2). Ruughly how long would it last running it off battery power? (e.g 9v battery?)

You need to know the total current requirement to figure that out.
My Arduino draws about 25 mA while running just about any code that doesn't light any LED's.

An Energizer 9V alkaline battery is rated at 600 mAh or "mili-amp hours" with a 25 miliamp load - so 600 / 25 gets you about 24 hours. One problem though is that they rate their battery at 600 mAh down to 4.8 volts. The Arduino regulator will stop putting 5 volts out once the battery drops below 7 volts so you should probably cut that 24 hour calculation in half.

when needing to run from batteries, I run my Arduino from a 6 AA cell battery holder which has a typical 9V battery clip type connector on the end, I fill it with 6 NiMH batteries. Arduino circuits are a little power hungry for a little 9V alkaline.

KG2

I did a little test the other day. I wrote a program that illuminated a single LED in an 8x8 matrix (randomly jumping from one led to another every 10ms), and it ran about 6 hours on a brand new 9V alkaline battery. This seems to roughly corroborate KG2's observations.

LadyAda's MintyBoost project has a good discussion of battery power: Minty Boost! - USB charger for your gadgets

Mikal

Thanks for the info.

Hi,

I´ve done a test with Diecimila + LCD Displaytech 162 B (2x16). The consumption is 32 mA.
I´ve used a PP3 Sony Stamina PLUS 6AMB-B1A (Alcaline)

In my application, I capture an analog signal from a sensor and show it, with a refresh time of 350 ms.

My results are:
Start.- 9,23 voltios
1h.- 8'41 v
2h.- 8'07 v
3h.- 7'82 v
4h.- 7'61 v
5h.- 7'46 v
6h.- 7'32 v
7h.- 7'22 v
8h.- 7'11 v
9h.- 7'03 v

(Continuos Working. I think in a non continuos application, this time increase)

Searching curves of this type of batteries, they look like http://docs-europe.electrocomponents.com/webdocs/01b2/0900766b801b2da8.pdf (Duracell).
The service hours depends of the power of your application.

Kind Regards,

Igor R.

I guess you use a LCD without backlight?
As my power consumption was about 140mA for arduino+LCD(with backlight always on)+1wire temperature sensor.

I've got a similar question, so I hope it is ok if I post it here.

What is the arduinos power consumption when I put it to sleep using
set_sleep_mode(SLEEP_MODE_PWR_DOWN);

I'm also curious because I am building a circuit that runs arduino on an atmega168, using a 16mhz oscillator.

I'm also wondering if pinMode makes a difference too. I know I want all OUT pins set to LOW for minimal power output, but would it be even better to set them as inputs before I sleep?