At what percentage to change batteries in Schlage lever lock?


(Wayne) #1

I’ve had this lock for a year now. Batteries are down to 50%. What should I expect for the remaining life expectancy? Should I replace now? Wait until it drops to 30%? 25%?


#2

For lock, I personally change mine once a year or at 50 percent, whichever comes first, just because it’s too annoying if the battery dies.

We use a battery tester and if the battery has at least 25 percent left, we put it into a case where we draw out batteries for nonessential uses. So we don’t waste the batteries, but we keep ones in mission – critical devices fresh.

It’s just a philosophical thing, like how much gas do you keep in the tank? Some people refill when they get to half, some let it get down to the reserve. :sunglasses:


(Jimmy) #3

Mine starts sounding noticeably weaker around 50% and then starts giving false unknown status around 20-30%.


(Wayne) #4

Sounds like I should replace the batteries. Thanks.


(Chris Hanley) #5

So I’m not the only one with a stack of partially drained batteries :grin:


(Jared) #6

Why not just use rechargeables? That’s what I use in everything. Once you have enough then there is no need to buy new batteries all the time.


#7

Most lock manufacturers advise against using rechargeables in locks. The problem is that rechargeables have a very different usage pattern. They would look like they are almost full charge for a very long time and then drop off very quickly. For this reason all of the usual “low battery” warnings, including those built into the lock themselves, won’t report correctly when when rechargeables are used. And because it tends to be so inconvenient when a lock isn’t working, non-rechargeables are preferred.

https://www.schlage.com/en/home/faq.html?what-type-of-batteries-should-i-use

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’re at the end of their life.


(Glen King) #8

Might be interesting to do this with a mix: all rechargeable, except one which is alkaline.


#9

Never mix Rechargeables and non-rechargeables in the same device at the same time.

https://sciencing.com/not-two-types-aa-batteries-8523093.html

Different types of AA batteries are made for different purposes; mixing them reduces performance and may damage your device. Mixing two different types of AA batteries may also cause batteries to leak or rupture. Using different brands or mixing new and old batteries in one device may have the same results. Each type of battery and each brand uses different technology, capacity and voltage. Mixing will often cause batteries to become overheated. Extremely hot batteries may explode, causing damage to your equipment and endangering the user.


(Jared) #10

I don’t need weeks of notifications to change the lock batteries. The first time it notifies me I just pop a new set in.


#11

Understood, but with rechargeables you may not even get a couple of hours of warning. You could easily leave your home in the morning and have the batteries die before you got home again at night. Rechargeables just have a really sharp drop off curve. But it’s your choice, different people have different preferences in this regard.


(www.rboyapps.com - Make your home your butler!) #12

Generally electronic locks (magnetic levers) should be changed at 50% where as deadbolt (motor) locks should be changed around 75%. This is because of the load the lock/unlock actions put on the battery cause a sudden voltage drop and if the battery capability is diminished, those sudden voltage drops can translate into the voltage falling below the minimum operating voltage of the lock and render is dead suddenly.

So while it may continue to function below these thresholds it can be very unpredictable and have unintended consequences. E.g. if the temperature suddenly drops outside, this can cause the battery voltage to further drop and shutdown the lock.

See this first post image for thresholds we’ve seen for different types of devices when we recommend changing batteries.

See this post for an examples of voltage curves and how suddenly voltages can drop. Remember when the current draw “load” increase, these voltages can drop much faster than the curve shows. Hence for deadbolt locks which have a big draw even at 70% battery with rapidly falling temperature it can send the lock into shutdown mode very quickly.


(Michael) #13

@RBoy recommended lithium batteries a long while ago. I tried them and agree they are worth the price. They have lasted longer and they are stronger to lock and unlock the bolt.


(Realy Living Dream) #14

Replace it when the lock tells you to, don’t rely on ST battery level or you may find yourself locked out.