Battery Life for smart Doorlocks


(Geko) #15

I’m sure the lock is not reporting the battery level correctly. I’ve replaced the batteries two month ago (yes, I use alkaline batteries) and it still reports 99% (as of yesterday). Now, my lock is used a lot - 6 to 10 times a day, sometimes more. I measured battery voltage today and got 1.49 volts on all for batteries, which is around 75% at best.


#16

Does sound like a bad lock sensor then. :scream:

I’m using the Yale, which seems pretty accurate at least down to 30%, which is when I replace them. (I move the batteries over to the TV remotes, so I do get full use out of them, I just leave a higher margin on door locks.)


(Geko) #17

Now, the question is whether I got a defective lock or is it a common issue across the entire brand (Schlage Camelot deadbolt)? I would be interested to know if other Camelot users have similar issue.

I’d be very suspicious of this reading, even considering light use. Can you measure your battery voltage?


(Dave N) #18

One thing to note here from the start of this thread is that commercial locks like the ones we use at work on card readers power the release mechanism in the door frame and not the rotating lock mechanism. If Kwikset (and others) were to come out with a Z-wave lock that acted like the commercial locks we would be laughing - 12 VDC (or 24 VDC on longer runs) following the alarm wiring (typically) and your done!
I have had the same batteries in my kitchen door for 6 months and they are at 60% (Kwikset). This lock in manually operated except for the Good Night which locks it if we forgot. The front door is probably on it’s 4th set of batteries in 10+ months as it unlocks when we get home and relocks in 15 minutes. I manually operate it but my wife never does.


(Eric Anderson) #19

My Yale yrd-240 locks do not display battery level? How do I fix?


#20

I’m having the same issue, does not display battery level . Anyone know what the deal is?


(George) #21

I had (2) 240s that did update the level. My new (5) 120s (updated 240)… well, according to Yale, they are “lazy” updates - wait a few days for it. I did reach out as only one of mine did after two weeks. They told me to remove the batteries, manually lock/unlock, then replace batteries. I now have all 5 reporting, but it took two more weeks. The two we use the most have gone through the cheap shipped batteries in two months.


(Dan Ryan) #22

I know this is an old post, but I want to resurrect it!!

I’ve been having to replace the batteries in my Schlage every two weeks. But, I think I know why. The front door gets super hot, as the sun rises directly on it, and I’m in NC. The heat actually makes it hard to open the door. So, that is what’s killing my batteries.

I’m working on wiring it to a USB type plug and bypass the 4 x AA batteries.


(Michael) #23

You may want to try AA Lithium batteries. @rboy did some research and found they lasted much longer and I agree. My batteries now last 4-6 months. If the motor is struggling to actuate the bolt you may consider chiseling out the hole to make it easier. I did this as well.


#24

Check with the lock manufacturer. As far as I know, they all recommend using alkaline batteries and not using lithium batteries.

The discharge curve for lithium batteries is quite different than the one for alkaline batteries. consequently, if you use lithium batteries, the battery reporting from the lock will almost always be significantly off. In particular, it may tell you there is still about a 50% charge when in fact it is just a day or two from dying.

again, check with the manufacturer of your particular lock to see what their recommendation is. But I’d be surprised if any are recommending the use of lithium batteries at this time.

See, for example, the Schlage site:

https://www.schlage.com/en/home/faq.html?id=128684

Schlage recommends using a premium alkaline battery for all of our electronic locks. Lithium and older battery technologies may cause undesirable operation*.
.
*Undesirable Operation: At the end of life for lithium batteries there is a very steep discharge curve. This means that when the batteries do die there will be little or no warning, which increases the likelihood of a lockout condition where the mechanical backup key would need to be used. Alkaline batteries have a more gradual power discharge, so when they are at 20% life remaining, the lock can provide both Nexia alerts (on Nexia enabled devices) and local feedback (blinking red light) providing ample time (weeks) to change batteries before they are at the end of their life.

Yale and Kwikset have similar warnings.

@rboy


(Michael) #25

I appreciate the additional information, but I will still continue to use Lithium because they have double if not triple the life of alkaline batteries in my personal experience. I still carry a key and can unlock the door in the event they are dead or I can use another door to enter the house. For my personal situation the risk is worth the benefit.


#26

Different things work for different people. :sunglasses: As long as you understand the issues and are not intending to rely on the battery life reporting, that’s your choice. Other people may prefer more accurate battery reporting to avoid lock outs.


(Michael) #27

Well I must admit battery reporting for alkaline is garbage too for Schlage locks. Mine died when it reported 60%. So it’s a guessing game regardless. :sunglasses:


#28

I haven’t had that problem with my locks, but I know some people do.

Because I can’t change the batteries myself, I wouldn’t keep a device that didn’t have accurate battery reporting. So I’m fairly sensitive to that feature.


(www.rboyapps.com - Make your home your butler!) #29

@JDRoberts , you’re right, Lithium batteries do have a different discharge curve from Alkaline batteries which creates it’s own challenges (and advantages)

@danryan28 see this post for a look on how different battery chemistry work.

While lithium batteries have 2x-4x the the battery life of Alkaline batteries (depending on type of use) they have a much flatter voltage curve. Most locks, including Schlage, Yale, Kwikset etc use this “voltage” to determine the remaining battery life. They are tuned to use Alkaline batteries. Having said that Schlage Connect locks are very “poorly” tuned to even Alkaline batteries. Without getting into the technical details of how these locks calibrate batteries and the “right” way to calibrate batteries (we had worked with Blink on this on extensively), keep in mind that Schlage connect locks tend to “overestimate” battery life, ie. at about 50-60% battery (alkaline) they will suddenly die (the voltage falls below minimum voltage required to power the lock).

See the first post of this topic for a list of recommended battery thresholds:

Yale on the other hand does a very good job with it’s battery calibration of it’s deadbolt locks and you can use it down to even 20% or so (30% to be safe).

Having said that, do if you now decide to use Lithium batteries (1.5v - keep in mind and not the 3.7v versions) as @ritchierich is using, you’ll have great battery life but you will need to “experiment” to find out at what % your lock goes dead. For example with Schlage connect lock expect the battery to “die” at about 80-90% battery reporting with Lithium batteries. It may seem high but that’s due to the voltage curve I spoke about earlier, so while it may last longer it you need to reclibrate your own expectation on when to change the batteries.

Maybe @ritchierich can share the thresholds he is seeing with using Lithium batteries and when they die on the lock he is using.

The other thing to note is that the deadbolt mechanism should be “buttery” smooth. If there is any resistance or scraping it will dramatically increase the load on your motor and consequently drastically impact your battery life. You may need to realign your door/frame/cutouts to ensure it’s a smooth unhindered operation for best battery life.


(Michael) #30

I installed lithium batteries in a lock we use the most and they have lasted almost a year. ST still says they are 100% so who knows when they will fail on me. Believe I was only getting 4 months from alkalines.


(Dan Ryan) #31

I’ve tried Lithium batteries, they lasted about 3 weeks. I really think it’s a heat issue. I’m thinking about mounting a separate “battery” pack on the door. That would make it not connected directly to the metal doorknob…

Dan Ryan


(Michael) #32

Just another update, noticed Lock was struggling a little last night to actuate the lock. Looked at battery % in ST and it said 97%. I replaced this morning with new Lithium batteries. They lasted just over 1 year. Since the battery reporting doesn’t work with these the audible difference is needed. @RBoy is there a way to update the battery algorithm in the DH for Lithium? I realize the window is much shorter but there is a drop in %.


(www.rboyapps.com - Make your home your butler!) #33

The % figure comes from the lock directly (the algorithm is determined by the lock firmware).

I would recommend settings a custom low battery notification rule for your lock using Lithium batteries (e.g. at 97% or 98%) using this app:


(Henry Chinery) #34

I converted 5 Kwikset electronic locks to Z-wave by purchasing the Home connect cards V 3.8 from eBay. Before the conversion I got months of battery life from each lock. When I first installed them and added the Smarthings hub they seemed to last a couple of months. Then battery life seemed to start dropping dramatically to about 1-2 weeks at best. There does seem to be a lot of polling which I tried to disable but is still showing as happening in the app.