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Can I replace cr2032 powered devices with AAA or li ion?

NVZN

Dec 17, 2016
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So I have a tuya smart key finder that using Bluetooth technologies, and they claim it can last up 6 month 1 battery, but when I use it, only lasted 1.5 months and it self shutdown.

I'm fed up changing 2032 cells, now I got a thinking.. Can I instead keep using 2032,i wired this device to a single lithium battery (18650 or 14500).

But I'm afraid damaging the circuit, I heard 2032 is 3.2V max, meanwhile li ion has max voltage 4.2V.

Probably second alternatives is putting 3 AAA rechargeable energizer battery it would result 3.6V... What u guys think? I don't mind it getting a bit bigger-atleast it lasting a lot longer.

Here is the device pics :
IMG-20220302-152009.jpg


IMG-20220302-152055.jpg


IMG-20220302-152026.jpg
 

Martaine2005

May 12, 2015
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Changing the voltage or battery shouldn’t cause any issues providing the new voltage is stepped down to 3.2V.


Martin
 

Martaine2005

May 12, 2015
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I'd tend to try using quality CR2032 cells first.
Good point. OP might get up to 6 months then.
I buy CR3032’s on a card of 12 for £1. Testing purposes only!.
But buy quality ones for my car key fobs that last a couple of years.

Martin
 

NVZN

Dec 17, 2016
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I'd tend to try using quality CR2032 cells first.
This panasonic is the most high quality ones sold in my country.. Got other brands like maxell but fake maxell is everywhere in stores like a plague.

Maybe tell me some brand of 2032 that u think is high quality, and I'll try to look up. The brand I familiar is only panasonic tho. Is panasonic not good?

Btw the original tuya smart key finder is KTS brand, and same it died 2 months after initial use.
 

NVZN

Dec 17, 2016
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Changing the voltage or battery shouldn’t cause any issues providing the new voltage is stepped down to 3.2V.


Martin
That's the problem, I dunno how to step down that small fraction from 4.2v to 3.2v...most step downs here draws current even at idle (60mA) and it's quite larger than the tuya key fob itself
 

NVZN

Dec 17, 2016
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Good point. OP might get up to 6 months then.
I buy CR3032’s on a card of 12 for £1. Testing purposes only!.
But buy quality ones for my car key fobs that last a couple of years.

Martin
What brand is that?
 

Alec_t

Jul 7, 2015
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Two alkaline AA or AAA cells will give you ~3V. Non-rechargeable, but should give far longer life than a CR2032.
 

crutschow

May 7, 2021
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How about a CR123A 3V lithium?
It has a 1500mAh capacity vs. the CR2032 225mAh rating, so should last at least 6 times as long.

Alternately the largest coin cell is the CR2477 with a 1000mAh capacity, for about 4 times the life of the CR2032
 
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NVZN

Dec 17, 2016
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How about a CR123A 3V lithium?
It has a 1500mAh capacity vs. the CR2032 225mAh rating, so should last at least 6 times as long.

Alternately the largest coin cell is the CR2477 with a 1000mAh capacity, for about 4 times the life of the CR2032
i dont know how to charge those cr123A ones, all i have here is 3.7V charger (tp4056 and nitecore d4)

or u have recommendation which bms and charger to charge this thing?
 

NVZN

Dec 17, 2016
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Two alkaline AA or AAA cells will give you ~3V. Non-rechargeable, but should give far longer life than a CR2032.
yeah i was thinking about this, its okay its disposable battery atleast lasted far more longer though. Will try it.
 

Martaine2005

May 12, 2015
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may i know why use 2 diodes ?
To drop the voltage by 1V or 1.2V. Each diode has a voltage drop between 0.3V to 0.7V (approx) depending on the diode type. It’s just a crude way rather than dividers or regulators for such a small amount.

Martin
 
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