Z-Wave devices not reporting battery

Is there a trick to get Z-Wave devices to properly report battery levels? All of my devices are stuck at 100% or 99%. I know they used to report, because I have a rule that warns me when they get too low, but at some point they stopped reporting properly. Is there a Z-wave equivalent of a re-pair/repair? This may have started when I had to exclude and include everything to get rid of a ghost.

My Z-wave devices:
(3) First Alert Zcombo (Z-Wave Plus)
(1) Kwikset 910 lock
(1) Ecolink Tilt Sensor

Not sure what I have in the Ecolink, but the others all use Energizer Lithium AA batteries. Could they be running a slightly higher voltage, making it look like they're still 100%?

The lithium batteries tend to keep their voltage up and then drop off very quickly.

2 Likes

Battery reporting is a crapshoot. Also if you use lithium ion batteries they won't show a drop in reporting until they're almost dead. But like I said, don't trust battery reporting ever...

2 Likes

Remove battery . Reinstall and if not dead should then check in.

2 Likes

This :point_up:, the percent is based on voltage and Li-ion batteries hold their voltage very well right up to the end.

And also, go to the device page, click events at the top. Browse it or search for battery. Most drivers will force the battery events as "change" events so it should show in the events every time it reports in. If you see 1-2 100% events every day, it is reporting in properly.

2 Likes

It's probably the lithium batteries, then. I finally got rid of my leaky Duracells (not impressed lately!), which was probably the last time the smoke detectors reported battery level properly.

The smoke detectors report about once a week, but I did this...

...and it reported back with 100, so I'm going to assume it's right. ¯\_(ツ)_/¯

2 Likes

Fair warning, not all devices will report the battery or do a "wake up" when you replace the batteries. They may wait until the next wake up interval which is typically 12 hours. To force a wake up there is usually some sort of a button to press or hold (depends on device). Usually a wake up will trigger a battery report (but also not always).

The level can never be reliably correct.

Look at the typical Li-ion discharge curve below. You can see from 70% to 30% there is virtually no change. Lets look at different cases:

  1. Battery is "exactly" per the chart below. On could say maybe at 3.5 Volts the device should tell you to change the battery. However we don't know is the device will die at 3.5 volts or maybe hang in until 3.25v.

  2. Lets say two batteries are different by 0.15 volts. Then at 3.5 volts one battery could be about to die or could stay running much longer.

Also note, battery devices rely on the circuit using the minimum of current, so the voltage measurement is far from you very cheap multimeter.

image

1 Like

The level reporting from most devices even with alkaline batteries lies more than my ex-wife and are about as reliable.

Yeah, just for giggles, I pulled them from the smoke detector and put them on my multimeter. They both registered 1.71v. I didn't date the batteries when I put them in, but they've been in a while, so I'm sure I'm somewhere along that horizontal line.

Looks like my battery level rules are pretty useless for lithium batteries now, but after a few leaky Duracell alkaline batteries recently I'd rather have the lithiums.

Set this up an activity checker as well, then if they go dead without reporting low battery you find out. I have all my battery devices setup for 14 hours, since they should report in every 12 hours at least. Most drivers set the wake up interval to 12 hours.

1 Like

I've discarded all my Duracell and Kirkland Alkalines after they damaged a number of devices. Now using Energizer MAX. So far no leakers but too soon to tell.

1 Like

I did the same after having a couple of devices damaged.

I place an annual buy of CRx Panasonic lithium batteries from Mouser, and have started throwing Panasonic alkalines onto that order. I haven't done any detailed analysis of longevity on the Panasonics, but they don't feel to be substantially less lengthy in life than the Energizer MAX and they're way cheaper to boot. (As of this writing, Energizer MAX AA is ~$0.72 from Amazon, and Panasonic AA is $0.50 for 1+ and $0.36 for 10+ with further quantity breaks from Mouser.)