measure CMOS battery

[YonatanS]

Hello

I'm using NUC7 and have some concerns about the internal CMOS battery.

I can't physically access the battery itself (and terefore can't measure the voltage)

===> my Quetions: Is there a way to measure the voltage of the battery by a software? 


I've been trying to use 3rd party SW tools, and looking at the VBAT parameter, but i'm not sure these actualy measure the battery itself, or just the inout to the BIOS which may be the battery of the external power. 
(I've tested in on a device that had NO battery - and got 3.17V which is not reasonable).

[CarlosAM_INTEL]

Hello, @YonatanS:

Thank you for contacting Intel Embedded Community.

The information stated on the following website may help with the situation that you have reported:

https://www.intel.com/content/www/us/en/support/articles/000097279/intel-nuc.html

Best regards,

@CarlosAM_INTEL.

[n_scott_pearson]

Point-by-point,
1. The CMOS battery is attached to the top surface of the board, so the board must be removed from the chassis in order to access it.
2. I am on the road, so I can't access my resources regarding this board. The EC may have a VBAT sensor that can be accessed; I'll have to respond regarding this later. Regardless, I will point out that, in general, using this sensor type requires a current draw, so it does adversely affect the lifetime of the battery. As well, many of the software apps out there do not fully or properly comprehend the sensors offered by the EC.

...S

[YonatanS]

Thank you n_scott_pearson

The reason I don't have access to the battery, is that the specific board is installed within a device and reaching to it may mean dis-assembly of the device.
I do, however, have stand-alone board on which i'm doing the tests of measuing the battery voltage. (i can measure it physically, anbd then use an app / python command to get a VBAT reading).
I'm trying to find a reliabile method to measure the battery from remote, and currently was not able to do so (as mentioned, the tools i've used provided wrong voltage reading).

[n_scott_pearson · Accepted solution]

You never identified exactly which NUC7 you had, so it took me a while to collect the information for all of the NUC7 (and, because of design overlap, NUC8) products. As it turns out, all of the NUC7/NUC8 products utilized the same Embedded Controller (EC) product and this EC does not expose a VBAT sensor. Any software that is exposing a VBAT sensor is doing so incorrectly.

Bottom line, your only way to test the CMOS battery in any of the NUC7/NUC8 products is through physical access; there is no way to do so in software.

Sorry,

...S

[YonatanS]

Thank you very much n_scott_peason

Sorry for not recognzing you need to know the exact NUC7 model (it is NUC7i5BNH)
As a amtter of fact, I Also have a similar case with NUC5  -NUC5i5MYBE which i'de like to know the VBAT
One tool that i've been using DID show some VBAT measurement for the NUC5 (although still a suspected value) but did not even had the option for the NUC7, that mighr explain that. 

Where can i find the EC details myself so i can go over them?  

[n_scott_pearson]

The 3rd - 6th gen NUCs utilized older SIO devices that *did* have VBAT sensors, so you should be able to trust VBAT readings (presuming the app you are using properly supports this device) from these NUCs.

The SIO/EC devices are proprietary to the vendors producing them and thus Intel cannot share their datasheets with you. For the SIOs used in the 3rd - 6th gen NUCs, you ~may~ be able to find their datasheets on the vendors' web sites. Once you get to the 7th gen and the EC devices, well, I was retired by then and thus do not know what specific devices were used where (other than by looking at the boards in question myself). All I can tell you is that the requirements for the set of sensors exposed by these ECs do not include a VBAT sensor.

...S

[YonatanS]

Thank you very much

[n_scott_pearson]

You are welcome. Sorry that the results are not what you wanted.

...S