SmartThings Community

Anyone using rechargeable CR2 batteries with Iris motion sensor?


#1

If yes which one’s and how is the performance? Any recommendation on which batteries are best value for money, rechargeable or non rechargeable?


(Bryan) #2

Edit . . . confused battery types. Disregard, lol.


#3

I have used these CR2 batteries for almost 2 years now:
https://www.bhphotovideo.com/c/product/856364-REG/Watson_cr2_3v_CR_2_Rechargeable_Battery_3V.html

NO ill effects, and they are exactly 3V, the same as a regular CR2 battery. As for durability, they last a long time, long time being dependent on the exact motion sensor it is in. I have 2 motion sensors that do not get a lot of traffic, and they are almost a year in there & still going strong (and yes, I do test the motion periodically). Heavy traffic areas I get anywhere from 3-5 months out of them. Here is an odd observation: even when using regular CR2 batteries, some motion devices are just “heavier” on juice usage than others, and they are all of the Iris brand. The rechargeable CR2 usage reflects a similar usage pattern.

DO NOT confuse CR123a batteries with CR2. They look almost identical, but the CR123a is slightly taller than the CR2 and they are indeed 3.4-3.7V.

Also be aware of any CR2 rechargeable battery that claims 600mA or higher capacity. You get what you pay for! And technically it is not possible for the battery to hold that much current, at least not in a rechargeable format at 3V. To get 600+mA you need to bump the voltage up! See where I am going with this?

I have recently also purchased these CR2 rechargeables, but I have yet to use them: https://www.amazon.com/gp/product/B010FMRWG2/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

Edit 18/08/16 - The Watson CR2 batteries are actually 3.2V, but they still do the job very well!

J


(Eric) #4

I’m really interested in this thread. I have a ton of Iris motion and contact sensors that use CR2. I’m going to try this.

Looking at this also. Comes with 6 batteries.


(Eric) #5

I use mostly rechargeables.

I suggest locate the charger in a fireproof area - I’ve had batteries melt in chargers, not the charger you show, but you might as well avoid the problem.

I usually monitor the chargers with a wireless temp sitting on them, and a couple of times it has indeed triggered a shutdown when the temp got unexpectedly high. Many chargers claim to be temperature-protected, including mine, but after 1-2 meltdowns I added this external shutdown.


#6

Well since I’m outside of USA I’ll can’t buy with shipping restrictions on lithium batteries so will be looking to sell my sensors. I have two brand new Irish Motion Sensors if anyone is keen. Payment by PayPal and I can ship them by Airmail. Would be easier and cheaper to remove the packaging before shipping. If no one keen here will list them in Deals section and eBay.


(MarkTr) #7

@whoismoses Did you wind up picking up that charger set? Looks like a good value, as long as it isn’t junk…


#8

Most manufacturers recommend not using rechargeable batteries in home automation devices because the “battery life remaining” reports will end up being wildly inaccurate as the depletion curves are very different than the regular batteries for which those reports are designed.

Even worse, the most typical inaccuracy is that the battery report will say there is still about 35% of battery life remaining and then the battery will die the same day. :rage:

For home automation, predictability is usually important, which is why the manufacturers suggest that you not use them.

If you don’t have a problem with your devices going off-line because of unpredictable battery life, then you can certainly consider them.


#9

Not worth the trouble. Most rechargeable batteries operate below the standard voltage, if they are the standard voltage then they typically are physically larger than the standard size. Like JD said reporting battery percentage will be off so you won’t know when they are truly dead/low.


(Eric) #10

My results have been mixed. When I first got it the batteries were only lasting a few days. After a couple cycles on the same batteries I’m on 2 weeks without needing to change. I assume even if they end up working ok they won’t be as good as regular.


#11

I know this is an old thread… but wondering how the battery life reporting is like. As others have noted, I’m concerned about accuracy.

How long do you go between charges?

Thanks!


#12

Simply put: Battery State Accuracy reporting and Rechargeable Batteries do not go hand-in-hand. I really cannot say anything more than that.

My sensors all report a slightly different battery state depending on the battery in use. I have a cheat-sheet when a certain battery reports a certain level it is time for a recharge. Having said this, I am more and more leaning in the direction of recharging all batteries on a set-time basis, ie. 4 months for the Iris motions, 2 months for the door locks. Just makes my life easier. Now if I can only remember when I last charged them! :joy:

The slight charge state inconvenience out-weighs buying batteries all the time by a very big margin, IMO. Based on my experiences, it is best never to trust the battery charge state reported by the device / app!

J


(Eric) #13

True the reported-%-battery is not as useful as hoped.

any particular device’s ability to operate with rechargeable, varies a bunch by manufacturer. e.g. The Zooz 4in1, ZSE40 is a great device on paper, but operates for months while reporting 1% battery.

The workarounds I use are 1. rename the device instance to include a shorthand “recommended-recharge-percent” based on that device experience, and 2. periodically 1/week or so, check “SimpleDeviceViewer” for no-activity-devices and lowest-battery-devices.


#14

Agreed, I get almost 4 months out of the Zooz when it says 1% battery, hence by rigid charge regime every X months for different devices, and then I do it for all devices of the same type, whether they need it or not.

J


(Jared) #15

I went ahead and purchased these to test. They are all about 200mah, not the 400mah they are marked as. So these are fake batteries. I put them in my Iris sensors and will see how long 200mah lasts me.


(Eric) #16

I bought the same ones from Amazon. My guess is 2 weeks.


(Ron Talley) #17

My Iris sensor batteries last forever.


#18

What’s forever?


(Ron Talley) #19

Ok, not forever but way longer than I expected. Some more than 2 years. I mostly use Iris sensors and I have a lot of them. However, I rarely have to change batteries. This one was installed 10/2016 and I never once changed the battery.

If you do find yourself having to change batteries in Iris sensors often, then something is not right. Also from my experience, recharable batteries have proven to be a maintenance nightmare for me as they tend to drain way quicker than a good performing disposable battery.


(Eric) #20

First let me explain that I have ~350 devices, probably 45% zigbee, 45% zwave, 10% wifi. I’ve been having a lot of issues with certain devices (not all of a type/brand) draining super fast. I it started after I added about 12 additional zwave wall switches. That said, the devices I’m having issues with are zigbee. My hub location has never changed.

Super Fast = 5-6 weeks

Most of my Lowes Iris contact sensors and motion sensors will last 13-15 months.

Most of my early (2+ years old) ST motion and contact sensors will last 12-13 months.

Most newer ST devices will only last 6-9 months. (my experience, just saying).

My ecolink zwave contact sensors and motion sensors seem to last “forever”. Have 3 year old ecolink sensors that have never had a battery change and work perfect. That said, because they are large and ugly (my opinion) I generally put them on doors / windows that never open or use them was water sensors which generally never detect water.

My LeakSmart water sensors (zigbee) used to burn through batteries every 3 months. After the latest firmware update of those devices they last for ~8-9 months.

The devices that are draining super fast I decided to try these rechargable batteries because the money for the other batteries is too much and I suspected there was a cause I didn’t have time to figure out just yet. I’m going on 4-5 months with these rechargeable batteries in about 12 devices. For me they only last 2 weeks.

I tried replacing one of my “super fast” drain devices with the same type of device, and that device has yet to need a battery replacement going on 3 months, so yes something might be wrong with those devices or the path to the hub is bad. I tried rebuilding my zigbee network (powering off for 30 minutes) several times. No luck. To be sure, during some recent electrical work at my house I left the hub offline for 5 hours! No luck.