Does real time clock use battery if arduino has power?

Adafruit Ethernet, Motor, Proto, Wave, Datalogger, GPS Shields - etc!

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
captncraig
 
Posts: 3
Joined: Thu Jun 03, 2010 11:30 pm

Does real time clock use battery if arduino has power?

Post by captncraig »

The usage documentation on the Datalogging shield makes it clear that a battey is required for the RTC to function properly. It does not clearly state whether there is any drain on the battery if the module has power from the arduino.

My project is intended to be a permanent installation, and should be powered almost all of the time (excepting a rare power outage). Will the battery drain at all and ever need to be replaced, or is it essentially infinite if the arduino is powered?

captncraig
 
Posts: 3
Joined: Thu Jun 03, 2010 11:30 pm

Re: Does real time clock use battery if arduino has power?

Post by captncraig »

Nevermind, the datasheet for the chip says
The DS1307 has a
built-in power-sense circuit that detects power failures
and automatically switches to the backup supply
I am assuming this means there is no drain on the battery if the chip is powered.

User avatar
adafruit_support_bill
 
Posts: 88087
Joined: Sat Feb 07, 2009 10:11 am

Re: Does real time clock use battery if arduino has power?

Post by adafruit_support_bill »

The battery should last about 8 years. The RTC will only draw power from the battery if there is no power in the circuit. But all batteries self-discharge to some extent, so it won't last 'forever'.

Locked
Please be positive and constructive with your questions and comments.

Return to “Arduino Shields from Adafruit”