I’m looking to use some Z-wave dimmers so that I can dim lights but to also automate the brightness of lights depending of the time of day/night. As I’ve never had a Z-wave dimmer (only on/off switches) I was wondering if with a Z-wave dimmer I’m able to update/set the brightness level of the dimmer without turning the light/dimmer on?
Might depend on the dimmer. I can tell you that the GE/Jasco dimmers I have don’t have a way to change their brightness level without turning them on (or, at least, from everything I’ve read there isn’t a way.)
why do you want to adjust the brightness with the device off? I only ask because to me the turning on portion isn’t really a turn on function if the light is already on. It more or less just adjusts the brightness. BTW I have the same dimmers as @pnbruckner. I’m very happy with them.
My guess would be that @q00dee wants to change the brightness the dimmer will go to if manually turned on (at the dimmer itself.) I think this is a perfectly reasonable use case, and something the hardware designers seemed to have overlooked. I’ve seen others ask similar questions about dimmable color lights - i.e., change the settings in the light at various times throughout the day to change the color and level they will come on to if manually turned on. (Obviously this isn’t necessary when turning on from HA, because these parameters can be supplied in that case.) In theory, I think, it would be possible to implement a device where config parameters could control these settings so that they could be changed while the light was off. But, I don’t claim to know a whole lot about z-wave, so I’m mostly just guessing. 
ah that makes sense. I never thought of that, but then again, I don’t have colored lights.
Correct, I wanted to push brightness levels to the dimmers throughout a 24 hour period, during the day might be 80-100%, anything after midnight till sunrise might be 10-20%. Might also depend on light levels in some rooms.
Something like bathroom/toilet don’t really want/need a motion sensor so I would probably turn it and off at the switch.
Other areas where there might be say motion sensors wouldn’t be that much of an issues as I can trigger hass/scenes.
I have a ISY 994 with Insteon dimmer and this is a feature I love about it and really wish it was available with Z-Wave dimmers. You basically have a “On Level” and “Ramp rate” settings that can be set by automations to achieve exactly what you describe.
I don’t know of any ZWave dimmers that do this but if they exist I would be first in line to buy one.
The GE/Jasco z-wave dimmers I have do have config parameters for ramp rate, so that can be changed while the light is off (or on.) And when you turn on the dimmer you can set the level, either via automation (i.e., via z-wave) or manually using the button on the device. You just can’t set the level with the light off. I guess the idea is for the device to remember the last used level when you just turn it off and back on (without setting the brightness.) So, basically, you have to turn it on to set the brightness for later “turn ons”. But I really don’t know that much about z-wave. And GE/Jasco’s documentation is a bit lacking, so who knows!