i make a project using arduino uno R3,this project have to operate arduino as long as 2 week.
i wanna know, could i operate arduino 24 hours until 2 week?
Sorry, not very clear your question. Do you wish to know for how long you can let your Arduino running without powering it off? If that's the question you basically can let it running "forever" if you project is withing the MCU limits (voltage/current/temperature).
I have a system controlled by Arduino Nano and is running for last three months 24/7, I havent restarted or powered off the system yet.
I have projects running for several years now. There may be a power loss now and then (not very often, maybe once a year because of construction work in the house and mains must be cut for a while) but the idea is that these projects run "forever": 24/7/365 
The TO's question might be about "powering my project by battery - how long will the battery last" - that is a very different question.
To answer it we need to know more about your setup.
Generally speaking: uno R3 is not the very best device to be powered by battery.
rezki:
i make a project using arduino uno R3,this project have to operate arduino as long as 2 week.
i wanna know, could i operate arduino 24 hours until 2 week?
So, what the previous answers are saying is along the lines of:
Yes, you can power an Arduino for a very long time (recommend Arduino Mini instead of UNO) but the run-time will be based on the microcontroller + external power requirements (LEDs, motors, noisy things...)
the technical term for "all of the power requirements" is known as the power budget and that can be in a per-hour or per-day basis. The power budget number is usually in Watts but it can also be in mA/hour.
The next step would be to match the power budget to the battery capacity so that your selected batteries will provide the appropriate run-time.
Battery capacity can be found on the manufacturer's specific web-site or you can use a generic site such as;
http://www.allaboutbatteries.com/Energy-tables.html
One thing you must be aware is that the charts are not normally specified in a voltage-over-time that is appropriate for a microcomputer; that is, the ratings are more appropriate for a flashlight. You have to temper the mA/hour ratings with the ever reducing battery voltage. With 5 Volt Arduinos, this can be an issue because your goal is to avoid wasting as much power as you can in the on-board voltage regulator.
In my projects, I never use a shunt-regulator but rather I use DC-DC voltage converters: buck or boost. These are usually available for about $1 U.S.D. from China (eBay or AliExpress, etc.) The efficiency is around 92% to 97%.
Should I need 5 Volts, I can use a buck or a boost DC-DC depending on how I select my batteries: primary or rechargable; with rechargeable further splitting between lithium and alkaline. (forget NiCad.)
When you power your Arduino, you want to bypass the external power input (9V) and go directly to the board pins that are marked for 5V input... the same as the USB voltage being supplied. One of those USB mini-meters is very useful in determine what the power requirements of a circuit may be - assuming that everything is being powered by your USB port.
(30 minutes later....)
I've done some battery research on the Internet and I looked at different profiles for battery chemistry and voltage-droop verses battery capacity. These profiles are not in your favor.
Remembering that Power = current in Amps x Voltage ... even a simple Arduino project requiring 250 milliAmps at 5 volts is going to require a rather large battery for a run of 2 weeks.
If possible, you may wish to try solar supplemental power in the day and 100% battery at night to keep the battery requirements reasonable.
In most of my battery powered projects, I use a DC-DC (buck or boost) module instead of a linear regulator. Available for between $1 and $2 U.S.D. these units are typically 90% or better efficiency (94% is not uncommon.)
Ray
mrburnette:
So, what the previous answers are saying is along the lines of:
Yes, you can power an Arduino for a very long time (recommend Arduino Mini instead of UNO) but the run-time will be based on the microcontroller + external power requirements (LEDs, motors, noisy things...)the technical term for "all of the power requirements" is known as the power budget and that can be in a per-hour or per-day basis. The power budget number is usually in Watts but it can also be in mA/hour.
The next step would be to match the power budget to the battery capacity so that your selected batteries will provide the appropriate run-time.
Battery capacity can be found on the manufacturer's specific web-site or you can use a generic site such as;
http://www.allaboutbatteries.com/Energy-tables.htmlOne thing you must be aware is that the charts are not normally specified in a voltage-over-time that is appropriate for a microcomputer; that is, the ratings are more appropriate for a flashlight. You have to temper the mA/hour ratings with the ever reducing battery voltage. With 5 Volt Arduinos, this can be an issue because your goal is to avoid wasting as much power as you can in the on-board voltage regulator.
In my projects, I never use a shunt-regulator but rather I use DC-DC voltage converters: buck or boost. These are usually available for about $1 U.S.D. from China (eBay or AliExpress, etc.) The efficiency is around 92% to 97%.
Should I need 5 Volts, I can use a buck or a boost DC-DC depending on how I select my batteries: primary or rechargable; with rechargeable further splitting between lithium and alkaline. (forget NiCad.)
When you power your Arduino, you want to bypass the external power input (9V) and go directly to the board pins that are marked for 5V input... the same as the USB voltage being supplied. One of those USB mini-meters is very useful in determine what the power requirements of a circuit may be - assuming that everything is being powered by your USB port.
(30 minutes later....)
I've done some battery research on the Internet and I looked at different profiles for battery chemistry and voltage-droop verses battery capacity. These profiles are not in your favor.Remembering that Power = current in Amps x Voltage ... even a simple Arduino project requiring 250 milliAmps at 5 volts is going to require a rather large battery for a run of 2 weeks.
If possible, you may wish to try solar supplemental power in the day and 100% battery at night to keep the battery requirements reasonable.
In most of my battery powered projects, I use a DC-DC (buck or boost) module instead of a linear regulator. Available for between $1 and $2 U.S.D. these units are typically 90% or better efficiency (94% is not uncommon.)
Ray
so, if i use supply not from battery such as i make power supply 12 V so can I operate it as long as possible
sorry i made mistake with make two same topic, because this is my first time make a thread and i still dont know how to use the forum, about my first thread i have already known before i reply it. i mean when i know, then i reply it
rezki:
so, if i use supply not from battery such as i make power supply 12 V so can I operate it as long as possible
exactly!
thanks all for your help:)