Everspring motion sensor HSP02 (US version) - Battery level = 50%

I am currently looking for a “zwaveplus” motion sensor (US version) but as per this list of certified sensors from Zwave alliance , there are only multisensors and no device with only a function “detection of presence” :

http://www.z-wave.com/find_products/sensors

Finally I bought 2 Everspring motion sensor HSP-02 .
They have been integrated easily in my VeraEdge but I noticed a very strange issue :

==>> Battery level is shown in Vera UI at 50 % from the beginning !

Were they the batteries that came with the sensor…? Try putting a fresh set in and see what happens…!

Yes there are the original batteries which weredelivered in the same box than the sensors .

I will continue to use them and will see when they will have to be changed .
Anybody notice this kind of behavior ?