Anyone using rechargeable CR2 batteries?

I'm thinking about switching to rechargeable CR2 batteries which power my contact and motion sensors. I was wondering if anyone has had experience with them and which brand seems to be best?

I haven't switched yet, I'm watching the reviews on these:

Have you actually had to change them that often? I have some Iris contact and motion sensors that are almost 2 years old and still on their original batteries. These are almost 3 times the cost as regular CR2's. So, to break even, if you figure a 3 year battery life, you'd have to have the device for almost a decade before you started saving money. I suspect I will have moved on to the next best thing by then.

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Nice find! I looked a while back and couldn't find much--I think I maybe found batteries but wasn't sure about a charger.

My CR2 cells advertise 750 mAh, and these advertise 400. I'm wondering if it would be worth it if I have to charge/change the batteries nearly twice as often. But considering how long the regular ones last in most of my devices, maybe I wouldn't even notice. I also see they say 3.7 V. I have no idea what their discharge curve is like, but my new CR2s that are nominally 3 V usually measure around 3.2 and plateau before dropping off a bit below 3 V at the end of their life. I'm sure this would not work well with battery reporting (not surprising as most rechargeables--and even primary lithiums--
don't), but hopefully the slight voltage excess is within the amount tolerated by the device.

I have purchased a few of these (https://tinyurl.com/y39g6874) to work in my IRIS contact and motion sensors. None of my sensors have the original batteries in them but the contact sensors are V1 and the motion sensors V2 and they are all at least 3 years old. I don't trust what the sensors are saying is % remaining as I have had them fail showing over 80%. Also I always check them with a battery testing device when I replace them and despite showing a high percentage they measure as marginal on the battery tester.

My thought was to use rechargeable batteries, see how long the one with the shortest life lasts, and then set up a schedule and replace them all on that schedule. I still have quite a few batteries left so it will be awhile before I actually need batteries but wanted to see if anyone is using rechargeable batteries.

Okay...that's great but my point is you would have to have the sensor for another decade to make the rechargeables cheaper than the non-rechargeables. Since the rechargeable is 3 times as expensive, you won't break even until 3x the battery life of the regular, which is 3 years. So, I don't think you're going to save any money, is my point.

Ryan's right about the cost. That's why I'm mostly just watching.

I used rechargeable batteries for a while in my Iris V2 motions. They ended up being more hassle than worth. I didn’t have extras, so i had to charge them overnight and remember to replace them. I would get about 6 months on them IIRC. The weirdest part was the battery reporting. It would show 99%, then just drop to 1% instantly at some point. They never reported battery level correctly, not that the battery level reporting is SUPER reliable for regular batteries.

I've done extensive testing with rechargable CR2's(aka 15270). Most brands are junk, although I've not used EBL. The best I've used so-far are the soshine brand. They make 2 types, a black one 400mAh 3.0V and a blue/white one 300mAh 3.2V.

In iris v2 motion sensors I get 9 months in low traffic areas & 6 months in high traffic w/ the blue/white version. The black ones only last about 70% of above numbers, possibly due to differing chemistries.

Last place with a good price(same a disposables) was fasttech.com(5.58 for 4 batteries) I already own 4 advanced chargers(you need a special 3.2volt charger for these) from a longstanding flashlight addiction.

These have already paid for themselves and kept down waste. and @buzz is accurate, can't trust battery reporting, so time your recharge dates and you'll be fine. I have 2 sets I rotate out.
And I agree battery reporting is not reliable, even with disposables,but I think that's just lithium
batteries in general.

I have over 80 devices that use CR2 batteries and I agree with Ryan the cost of using a rechargeable battery just doesn’t make sense. I only pay $1 for the batteries I use and depending on the sensor they usually last 1 - 2 years.

Here’s a link to the batteries I use if you’re interested:

https://www.batteryjunction.com/w2en-lcr2.html

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I have. Some sensors don't behave well with the rechargeable. Aeotech for example gets repeated active/inactive when no motion is detected. I don't know what devices y'all are using them in or how you have them configured, but my alkaline don't last 2-3 years, or I wouldn't be considering the rechargeable. I get mere months out of most of my sensors.

I think CR2 batteries are generally Lithium Ion these days not Alkaline.

Ya, you're right. A mis-statement.

Most of the sensors I have use CR123a batteries and I do easily get 3 years, however those batteries hold twice the charge. It seems somewhat unusual to get such a short life on your sensors.

Is it worth ordering the 40 pack? Will batteries lose their charge if stored for years?

They have a 10 year shelf life so I buy them in bulk to take advantage of the free shipping option.

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So you are saying I should pull the trigger on the 40 pack :smiley:

That's up to you. They offer free shipping on orders over $50 so I usually buy 50 at a time.

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