Many revisions ago this used to work fine, but now all my zwave sensors only report 100% when I know this is nonsense.
I have two ZM1601EU-5 Battery Operated Sirens, they both report 100%. I have two PIR Motion Sensors. They both report 100%. I have four Sensative sensors and they all report 100%.
Any ideas on how to correct this?
Everyone else’s battery sensors work perfectly? Nice to know.
Some yes, some no - it’s up to the device to report accurately.
For example, my Fibaro multisensor lies. It goes from 100% charge to dead in a heartbeat. My Fibaro door/window sensors are reporting a steadily declining battery level that looks believable. Others are reporting 100% all the time 
Some devices report battery levels in 10% increments, so they’ll keep reporting 100% until it hits 90%. Sometimes it’s because they’re coded with a particular battery chemistry in mind, and a particular decay curve - with a different battery chemistry they don’t get that curve.
I wonder if something more is going on here. About six months ago, I remember my sirens properly reporting battery voltage as 80%. There have been many updates to HA and even zwave, so perhaps there’s an issue that’s not related to the sensors?
You can check OZW_Log.txt to see what the device reports, but it’s unlikely that changes in either HA or OZW are the cause (not impossible though). I’ve a bunch of devices reporting a battery level other than 100%.
I am having the same problem also. Suppose there is still no fix for it?
I had contacted Aeotec about their Door Sensor 6s exhibiting the behavior of reporting 100% and then 0% with nothing in between. They explained that 100% means battery is good and 0% means low. It’s specifically designed to do that, probably because the sensors are rechargeable and rechargeables have very small decay curves. I plan on changing my sensor to read Good/Low rather than 100%/0% at some point.
I don’t think this is a Home-Assistant Z-Wave issue, rather with the devices themselves. I have 2 door sensors and 1 PIR motion sensor still connected to my Wink hub since I’ve been too lazy to move them over to Home Assistant. They’ve been running for around 3 years now and they still show 100% battery within the Wink app.