Which Arduino for automotive application

Projects General Guidance
1

I'm completely new to the Arduino world so please make allowances!
Whilst I have done some research and reading on the subject I've come to a point where I need some advice from someone with experience of battery powered Arduino applications.

My intended project is to build a timer relay which will switch power from an automotive 12V leisure battery to various ancillaries like LED lighting and USB charging sockets. At it's simplest implementation I intend that a single button press will power up the arduino which will latch the power on for a preset time (say 4 hours) after which the latch will drop out and power consumption will drop to zero. A future enhancement could be to allow adjustment of the delay and to display time remaining.

This should be simple enough, I'm sure I'll manage it after a relatively steep learning curve!

My question relates to deciding which Arduino board to select for this project.

The main requirement is for low power consumption without getting overly complex.

My research so far makes me think a Lillypad would be ideal. Is this the best choice for low power, ease of learning and interfacing to? Are there any other options?
Thanks

2

I'd got with a promini for lower power draw while on - fewer parts drawing current.
Check Pololu.com for a power switch like you describe.

3

At the bottom of all the Atmel data sheets it says:-

Atmel products are not suitable for, and shall not be used in, automotive applications. Atmel’s products are not intended, authorized, or warranted for use as components in applications intended to support or sustain life.

4

Thanks Grumpy_Mike, obviously I need to clarify a few points then...
I used automotive in the subject heading to describe the environment succinctly. Sorry if this misled.

I am aware that for liability Atmel do not authorize their products for automotive use. Clearly it is not a suitable platform for an ecu or abs control system but that is far from my intention.

As described my application is to power a leisure circuit for LED lighting and USB phone charging. It will not be used whilst the vehicle is running. If it helps your understanding of the application think of it as a power/lighting control circuit for a caravan rather than a car.

I'll take a look at the promini usefully suggested by CrossRoads. Thanks