I2C and grove RTC

Hi! I'm having a little trouble with a brand new grove RTC v1.2 module.
I'm finishing a project with 2 sevos, 1 grove compass and 1 grove RTC.
I do not yet have de battery for the RTC but according to seedstudio page you only need it to not have to set the time each time you reset/unplug the board.

So I used the library example to set the time and then read it but it did not set and only outputs 165/165/2165 165:165:85 without incementing (well the walues are impossible anyways so...)

After a bit of troubleshooting i discovered these values are always sent even if the module is unpluged.
So I ran an I2C scanning script and it sees the compass module (I2C too) but not the RTC (if the compass is in, 1 device detected else 0, even if the RTC is plugged where the compass was previously si it can't be the I2C port not working.

I use the grove module so it can't be bad wiring since I juste have to plug it in an I2C port on the Base Shield...

I tried powering the board through USB, the with an external power supply, same result.
Do you have any idea why this does't work and will it work when i get the battery? (as it is optional I am worried adding it won't solve the problem).

I used the library suggested by Grove - DS1307 RTC (Real Time Clock) for Arduino - Seeed Wiki and their example code, as well as the git library here: GitHub - adafruit/RTClib: A fork of Jeelab's fantastic RTC library and this example code: Loading...

Hope sombody knows how to fix this!
thanks

The link that you posted states at least twice:

In order to gain a robust performance, you must put a 3-Volt CR1225 lithium cell in the battery-holder. If you use the primary power only, the module may not work normally, because the crystal may not oscillate.

I would certainly try it with the battery before wasting any more time.

So I ran an I2C scanning script and it sees the compass module (I2C too) but not the RTC

If you cannot see the rtc module on the bus, that is a problem which must be fixed. Confirm continuity of power and ground as well as SDA and SCL to the rtc module. The batttery should not be required to find the device on the i2c bus.

I use the grove module so it can't be bad wiring since I juste have to plug it in an I2C port on the Base Shield...

Can you post a photo of your connections.

If you don't use the base shield, but just connect power/ground/SDA/SCL can you see the module with the scanner?

Just looked at the DS1307 spec sheet, this could also be relevant:

If a backup supply is not required, VBAT must be grounded.