For z-wave.
Have a look at the “Ring Extender’
I think it will run for about 24hrs on battery (although I have not tested this)
It also functions as a really good indicator of mains power.
I use one to automatically shut down my hubs if there is a power loss (hubs are on a ups)
I think ihiyardi's has made some Environment Sensor models (Zigbee) with battery backup, but I'm not sure if it's included on this latest run (or if it ever was...maybe it always was and still is an optional "extension"?). Regardless, since it's USB power, there are lots of DIY options here that would be pretty easy to do as they would be for several others with USB power (USB power bank with Xbee as above, Ikea Trådfri USB repeater, or this module, for example). The Dome Extender (DMMS1) is also able to be powered by USB and would work with these options--which are not as pretty as ones with a battery built-in, of coure, but I suppose it depends on how much that matters.
Thanks @bertabcd1234. I just want to confirm the module that I have been making has built in battery backup circuit. One still need to purchase LIPO/Lion battery. I have plenty of availability these days.
This is enough 99.9% of time for me since I also have generator.
I also try below for my testing. With Lion battery, you can get about a day use.
You can find cheaper one. You need to get 18650 battery holder and Plug:PH 2.0 Connector. To save some money, make sure you find the unprotected battery. The sensor has LIPO/LI-On battery protection already. I think it should work with double protection. I just never test it. I just think why have similar battery protection in parallel. I do not like this solution since It is bigger. If you put it inside a case, this is a reasonable solution.
Just a note on the connector. Battery connector is not standardized. Please make sure that the polarity is correct before you plugged it in.
@snell do you use the Centralite Nightlight 3420? I'm interested in knowing if the range and quality of the repeater is good. Looking for a reasonablly simple battery backup for the mesh.
I never bought it for the repeating and the battery backup was nice when I thought it could report that it was on battery (mains had gone out)... but since they lied about most of the features it is very disappointing. Centralite might have updated their website and made the features on the page a bit more vague about it (so THAT does not technically lie) but they did not update the spec (and they are very aware of the problems with it, I had multiple emails with them) so they still have blatant falsehoods about it and no intention to correct them obviously (via firmware or even just updating the spec).
It is still in use though. One of my daughters loves that she has a pink nightlight (have to set the color manually). At least the light can be turned on/off via ZigBee so I made rules so it goes on at sunset, off at sunrise, and off if her bedroom light is on.