Best power saving Arduino temperature recorder

I currently use a home made micro board (non Arduino) programmed using Bascom which is a basic compiler from MCS Electronics to record the temperature every hour to a eeprom 24LC256 chip and I download this to a computer about every 2 weeks. I also incorporate a 2 x 16 LCD display showing the current temperature refreshed every 5 sec. This gives me a system which has fairly low current consumption which is important as it runs with a battery back up to guard against power fail.

However, I would like to use an Arduino Uno and data logger shield incorporating a RTC. I have already got this working fine but the current consumption is too high and the battery standby runs down rapidly.

Ideally, it would be good to have the Arduino sleep for say 4 out of 5 sec to save battery and use the one second period to do the temperature conversion and update the LCD. Of course the LCD display would need to be available at all times as well as the RTC.

I can think of many ways that this may be achieved but wonder if there is a "best" way??

http://www.mushclient.com/power has much info on saving power with a 328 based board.

http://www.mushclient.com/breadboard Making a stand alone 328 based board.

Arduinoitis which apparently is incurable.

One of a number of silicon based afflictions which I also have.

Battery powered temp and humidity logger.

Thanks groundfungus and jremington for the helpful replies. I must say that Nick Gammon's explanations are very well documented and so clearly explained.

Nick's Battery powered temp and humidity logger shows just what can be done to get an extremely low powered system going and still do useful things. However, I don't require such a low powered system and will probably modify the Uno and its s/w to get a compromise result.

I haven't spent much time in analyzing his approach so maybe some questions below might be very obvious.

Why not use an LCD display? How long does the 3V battery last for the DS3107 last in that circuit? His sample spreadsheet doesn't show the date.

The idea of using a switch to display essential information such as date, time and temperature etc rather than a continuous display is a good idea.

Gaggymoon: Nick's Battery powered temp and humidity logger shows just what can be done to get an extremely low powered system going and still do useful things. However, I don't require such a low powered system and will probably modify the Uno and its s/w to get a compromise result.

Do you happen to design for car manufacturer's by any chance :P?

Having the standalone chip, even an attiny84 could be a nice solution for this, will mean a cheaper/replaceable, smaller and neater package imho. Your power source will be cheap (a half credit card sized solar panel, couple of diodes and a super cap) and essentially never ending.

How long does the 3V battery last for the DS3107 last in that circuit?

Five years, give or take a couple.

groundfungus: Arduinoitis which apparently is incurable. One of a number of silicon based afflictions which I also have.

I also suffer from that affliction coupled with a passion for photography (and associated supporting equipment). Makes it tough negotiating with the budget director (aka wife) sometimes !!

gpsmikey: I also suffer from that affliction coupled with a passion for photography (and associated supporting equipment). Makes it tough negotiating with the budget director (aka wife) sometimes !!

Tell me about it. My bodies and lenses (although it is technically one of my incomes...about 50%) has hit £13000 worth of cover on insurance...oops.

Johnny010: Tell me about it. My bodies and lenses (although it is technically one of my incomes...about 50%) has hit £13000 worth of cover on insurance...oops.

Not quite there, but my primary camera is a Nikon D810 with a 80-400mm Nikon zoom lens on it. I keep it fairly tightly grasped in my grubbly little paws when we are out and about :)

"Five years, give or take a couple." Maybe use a rechargeable 3 V source to power the DS3107 and trickle charge it so it could never become an issue for long term set and forget operational use??

Rechargeable batteries eventually die, do not hold their charge as well. Maybe a couple of years?

Charging a battery requires more components.

Note my solar panel and super cap option. You can use a small 5V Low Drop Out regulator and say a 4F 5.5V super cap.

Johnny010: "Do you happen to design for car manufacturer's by any chance?"

No, my background is in radio frequency design and I mostly but not exclusively use Arduino and other devices such as ESP8266 for hobby purposes.

I have been running many projects off rechargeable batteries in many instances for in excess of 7 years without any failures however some rechargeable types as you say may fail earlier. Thanks for the supercap idea it could be a possible solution.

I am not trying to produce a unit suitable for production but as a one (or 2) off recorder so will go down the path of modifying a standard Uno using both s/w and h/w techniques. There are still a lot of unanswered questions which I will plow through.