How Long Does a RCR123A Rechargeable Battery Hold It's Charge in Storage? (I Think They Are Half Length 18650's)

• 

  FLICKIT on 06/07/2022 - 18:59

  +2

  Li-ion cells when in good condition hold their charge for years, but, if you're planning to store them for long periods it's much better to store them at around 50% charge, they say they degrade a lot less at half charge rather than at a full charge…

  Edit: maybe swap out the non-rechargeables for the rechargeable ones, then hold onto the non-rechargeables to swap in when you need to recharge the others…

  Edit2: also, RCR123A's are 16340 16mm diameter, 2mm smaller diameter than a 18650, which is why their capacity is less than half of a 18650…

  • 

    harshbdmmaster718 on 06/07/2022 - 20:02

    Hi FLICKIT,

    Some great information there that I did not know. I was under the impression only Li-Po batteries were unhappy at 100% for extended periods, but now I know it applies to Li-ion as well especially for long term storage.

    I have taken your advice and just swapped out the included Lithium CR123A for a rechargeable RCR123A. I ran into a small problem though, I thought getting protected cells would be the safe smart option when purchasing, but turns out they are 1 to 1.5mm longer than the CR123A battery it replaced!

    No issue though I have gotten different sized coin batteries to fit before when I purchased the wrong thickness, just squashed the contact part a bit and it fits. This time with a RCR123A though the plastic pieces that hold the contacts are a tiny bit warped when I look at it from the side but the motion sensor is working I just tested it. I can close the rear case which had some curved bits that hold the battery firmly in place so it won't be popping out inside which is good news.

    Ok so the 16340's (RCR123A) is noticeable thinner than the 18650 that makes sense I was just judging the similarities via product photographs. I guess the protected circuitry of the cells I have also might affect capacity negatively..

    And for any other users wondering, I have the 3V version of the RCR123A so the voltage matches the original battery in the Motion sensor. Most RCR123A are 3.7V so it took me a bit to track down the 3V version.

• 

  Eatslikeacat on 06/07/2022 - 23:16

  -1

  Goodness, what sort of motion sensor requires such a beefy battery? I use the Xiaomi Motion Sensors. They take CR2450 coin batteries. The battery lasted me about 1.5 years until I had to replace them. The Xiaomi app informed me when the batteries were low. I use them to detect motion in the living room to automatically trigger the smart switch to turn on the lamps. It's a very convenient and pretty effect. After 2 minutes of no motion detected they turn off the lamps. I also use them to control the air conditioner. If no motion is detected for 40 minutes it triggers the IR blaster to turn off the air conditioner. They have about a 1 minute pause after each motion detection.

  See https://homekitnews.com/2019/05/23/mi-motion-sensor-review/

  • 

    lgacb08 on 07/07/2022 - 12:40

    Xiaomi motion sensor is the least reliable of the bunch. Samsung one uses cr2 batteries and will chew through it in a month or so if you put it in the kitchen or hallway.

  • 

    harshbdmmaster718 on 07/07/2022 - 20:33

    I understand from your comment that you are happy with your Xiaomi sensors and button batteries.
    But I have already made it quite clear I already have the Motion sensor product and the rechargeable batteries for them, therefore the question I posted is specifically requesting the information about the batteries.
    Are you suggesting I get rid of everything and switch to Xiaomi based on your single experience?

    Also as far as I know all coin batteries are disposable and not rechargeable. Not sure how come the size of the battery seems to be the biggest issue when rechargeable batteries can achieve 300~500 cycles before I need to consider replacing them, compared to coin batteries which are single use then need to be tossed.