Low Battery % for rechargeables

I just moved to Hubitat, and was having some issues with one of my deadbolts not working correctly. I was not getting the notifications, controlling it was flaky, etc. The others worked fine. The battery indicator said 50%, but I swapped them anyway, and everything cleared up. The level now shows 70%.

I am using rechargeable batteries (eneloops), and I have had issues in the past with rechargeables and battery monitors. Am I better off going back to regular alkalines (I hate the waste!) instead of using rechargeables? Or is there a better way of figuring out if I need to swap the batteries, even though the monitor seems to indicate there was plenty of juice at 50%?

Of course, there is also the possibility I am missing something incredibly obvious, but give me a break, I only installed the hub yesterday! :smiley:

Honestly, for something as important as door locks, I'd stick with regular batteries until someone comes out with a better rechargeable. I've tried Eneloops in the past and the battery life was craptastic compared to regular AA batteries.

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I won't use rechargeable in that service for the same reasons.

Plus there are plenty of battery recycling drop offs where I live (best buy, etc) so the waste isn't as big a deal to me.

The life of the eneloops has been fine, I just cannot tell when they need replacing since someone is lying to me! :stuck_out_tongue: Fortunately, I have big dogs backing up the locks.

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I know I can take used batteries to recycling, but they are still very wasteful compared to rechargeables.

Everyone's situation is different... If mine die unexpectedly my kids can't get in the house (easily). So predictable battery life is very important to me.

Yeah, my kids are grown, and the adults all know to use one of the other two entrances if the front door deadbolt gets cranky. :smiley:

You can also use lithium batteries as well. I use rechargeable batteries at my main entrance and Lithium for my other doors.
I swap the rechargeable batteries every 3 months with a calendar notification. Yes, it's a pain but I do this in conjunction with my smoke detectors test.

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Are there any rechargeable lithium AA batteries that you know of? Last search I did (I think it was last year?) didn't yield any results. :frowning:

Sorry I didn't make it clear. Regular alkaline rechargeable and Lithium non-rechargeable.

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You can expect the battery levels in devices to always be fairly inaccurate vs what capacity is really left in the battery. Devices only read the battery voltage without a load on them, and that will always give you inaccurate readings. HE driver have little to do with it. I just installed a new Yale HomeKit lock yesterday with fully charged set NiMH batteries, that measure 100% with my ZTS MBT-1 that properly measures batteries with a pulse load by type. The Yale lock app is reading the NiMH batteries as 73% charged.

Device manufacturers also do a calculation based on the higher 1.5 volts from Alkaline batteries, versus the typical 1.2 volts from NiMH batteries. Whether you can, or should use rechargeable batteries in a lock depends on the device, and your preferences and needs. Most locks have one or more indicators that your batteries are low, so you have ample time to change them. They type of warnings that estimate time remaining will be inaccurate with rechargeable batteries, but other indicators like the speed and sound of the lock will be relatively easy to recognize once you're used to how it "should" sound and how quickly it operates normally.

I have been using these IKEA rechargeable batteries in my YRD256 for several months with no issue, so I'm now using them from the start in my YRD246 too. I was also using them in an August lock for about two years, before the accelerometer cable broke inside the lock a few days ago. That was fine too. I had to go by sound with that, because they would always warn me that the batteries were going to die in a week, but they would keep going for another month or two after that warning.

I have learned to ignore battery levels for reported by devices in general. If they are reporting low, I take them out an confirm what the real level it with my tester.

I'm sorry, I don't understand this. How can a battery powered device take a measurement without having a load on said battery? Do you mean not a "known load"?

They read voltage from the batteries when the device is inactive. The OP was asking about door locks, so that's primarily what I'm addressing. Yes there is technically a very tiny load on the battery at all times, but not the same as when the device is actively operating, and it is insufficient for an accurate measurement of remaining capacity.

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Well, the microprocessor must be running in order to take the measurement, right? It's not taking the reading by magic. It's taking the reading by reading the voltage, right? Wouldn't that be more accurate if it wasn't under any load at all?

No because that is an assumption made of the battery discharge curve. This is a long video, but it's a good explanation.


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We're not talking about the best way to test a battery. We're talking about how your contact sensor is doing it. Stop trying to change the subject. Your contact sensor is taking a reading of the voltage, correct?

Besides, how can a device do anything without using it's battery?!? This makes it sound like measuring the battery is magic.

The problem is the load isn't known.....not that there is no load.

Read my original post and find where I’m talking about a contact sensor. I’m not trying to find anything out on this subject. I didn’t ask the question, I gave a reply based on the knowledge that I have accumulated through research. Google is available to everyone outside of China for free.

You don't address any of the points that I raised with your post.

One key point that I personally have found.

I used Eneloop pro's originally for my door locks.
However, I live in a cold climate which is not very forgiving for batteries.
In a cold climate, it's Ultimate Lithium all the way.
During the spring/summer months are the only times that I can use the rechargeables.

I’m in Toronto and I haven’t found there’s a difference since the batteries are on the inside. The lock you have is exposing the batteries to the cold?