Pi USV+ Experience - anyone?


I tried to use the Pi USV+ (german for UPS) for safe shutdown / power up during a power failure and used the documentation to connect and install the interface (i2c) and the monitoring tool.

However, after this OH was very slow and specifically the zwave network did not work (the nodes were all green in habmin, but no response from the nodes and no control possible).
The whole system seemed to be very slow (even logging into the Raspi by ssh or opening the openhab.log.

Just a quick question:
Did anybody have some experience like this as well?
I did not find anything about USV except those related to the APC USV Binding.
I guess there should be people using a USP here!?
Thanks in advance.

A short update:
It seems to be related to the sd-card:

My regular original raspberry card (8GB) works fine.
The image of it after I have put it onto another ad-card (Sandisk class 10 with 32 GB) shows the problems mentioned above.

Could this be about the size or is it related to Sandisk?
Any ideas?