A few weeks ago I bought several cheap RTC1307 modules to use with my Arduino Uno. They do not include the CR2032 3V back up battery.
I have heard a few comments about not energizing the chip module with a 3V CR2032 battery in place due to safety concerns regarding a charging circuit in the module that will try to charge the CR2032 from the 5VDC connection to the Arduino. Is this true?
Then, how can I set the RTC module Date-Time variable with the Arduino and the back-up battery in place to avoid loosing the programmed set-up? Is this possible?
I will appreciate some advice from any of you guys, in regard to this concern.
appliedpr:
I have heard a few comments about not energizing the chip module with a 3V CR2032 battery in place due to safety concerns regarding a charging circuit in the module that will try to charge the CR2032 from the 5VDC connection to the Arduino. Is this true?
I depends on the actual module you have, whether you need a CR2032 battery or a LIR2032 rechargable Lithium storage battery.
Which module do you have?
Is the module labeled "Tiny RTC"?
In case of a "Tiny RTC" you have purchased wrong.
Tiny RTC is a synonym for "pure crap".
This Tiny RTC needs a rechargable LIR2032 storage battery for backup.
Sometimes it works.
Sometimes it doesn't work.
But always: It depends on the actual module whether it needs a CR2032 (non-rechargable) or a LIR2032 (rechargable lithium battery for backup.
Thank you for answer. You are right! This is a "Tiny RTC".
I understand then, that I must never try to use this little crap with a standard not rechargeable CR2036.
Thank you again for this valuable information. Regards!