Can't find CR2032 3V rechargeables, safe to use 3.6V LIR2032?

Discussion in 'General Electronics Discussion' started by computer-joe, Jun 13, 2018.

  1. computer-joe

    computer-joe

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    I have several electronics in my home that require 3V CR2032 batteries, I don't want to keep buying them so I'm looking on eBay for rechargeable batteries. The problem is all I can find is LIR 2032 3.6V

    Is it safe to use 3.6 instead?
     
    computer-joe, Jun 13, 2018
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  2. computer-joe

    kellys_eye

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    The CR2032 is usually only used in applications that draw very little current and, as such, run for 'years' without interruption. Under which circumstance I can't see why you need to make an extra effort for what would (normally) be an isolated occasion.

    Equally, the application of the CR2032 won't include charging facilities which will necessitate purchasing a separate charger for the Lithium version.

    Whether or not the difference between 3V and 3.6V is significant will depend on the application - some circuits that require 3V will have a supply tolerance of 10% so 3.3V is the limit..... you'll have to specify what the use is before we can confirm with any accuracy.
     
    kellys_eye, Jun 13, 2018
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  3. computer-joe

    Alec_t

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    Here's the basis for a primitive volt-dropper.
    The first plot shows variation of the output voltage for a fixed 100uA load current as the cell voltage drops from 3.8V to 3.2V.
    The second plot shows variation of the output voltage for a fixed 3.7V cell voltage as load current is ramped from 0 to 200uA.
    The yellow and blue traces are for temperatures of -20C and +50C respectively.
    PrimitiveVoltDropper.PNG
     
    Alec_t, Jun 13, 2018
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  4. computer-joe

    dave9

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    Don't see the point, you can get a 50 pack of CR2032 on eBay and elsewhere for under $10. They have a long shelf life and this low self discharge means they'll run a typical device using them for several years. Rechargeables, you'll probably end up having to recharge them every year or two and the initial purchase price will probably never be recovered in savings from recharging, especially having to buy a charger too as kellys_eye mentioned.
     
    dave9, Jun 14, 2018
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