Use two 2025 batteries instead of one 2032 battery

Question

Intro:

2032 and 2025 are literally the dimensions of the battery. A 2032 is 20mm in diameter, 3.2mm thick, and a 2025 is slightly thinner, at 2.5mm thick. They usually both have the same voltage (3V), and assuming they fit in the case, they are interchangeable.

For my scale, I accidentally bought a pack of thin 2025 batteries instead of the thicker 2032 ones.

I couldn't get the scale to work as it was too thin. So I used 2 batteries stacked. Scale works.

Is there another way to get it to work with just one wrong thin battery? Feeding it 6V can't be good for it.

^{IOW: What could I use to pad the thinner battery?}

Answer 1

A penny is 1.52mm and a dime is 1.35mm, according to the specs from the US mint.

The OP is incorrect about the thickness of the CR2032 and CR2025, but correct that the name indicates the thickness... 3.2mm for CR2032 and 2.5mm for CR2025. The difference is therefore 0.7mm.

While many folds of aluminum foil will no doubt work, my preference would be to use a dime for best conductivity and to keep the battery secure from moving under the spring.

Since he has been using two CR2025 batteries (bad plan on several levels - stressing out the spring and the voltage regulation circuit as the two biggest problems), we can be sure that one CR2025 plus a dime will fit in the space. But now that the spring is stretched out (guessing... Likely but maybe not), a penny might be better in his case.

As far as a "life hack" goes, a simple dime would be ideal (you have one available 99% of the time, and no "work" is required for the hack), and a penny will often suffice although it will stress/overextend the spring slightly more.

As far as options for optimum outcome, buying the right battery is always the best way to go.

Answer 2

The reason two cells worked in your scale is that the scale is internally regulated to compensate for voltage drop as the battery runs down. If the scale worked with two of the 2025 cells, there's no reason to expect it'll suddenly stop working or sustain damage -- if that were going to happen, it would have happened either immediately on inserting the cells, or as soon as the device powered up.

That said, a spacer (for the dimensions you give, a US or Canadian five cent coin might work) on the flat end of the cell is preferred over a second cell. If you're trying to substitute a thinner cell in a device that hasn't previously been tested, this will ensure you get the correct voltage and avoid the risk of damaging the device.

Worth noting that using 6V instead of 3V with cells this size poses no hazard other than possible damage to the device. There isn't enough current available from this type of cell to start a fire (short of a device specifically designed to do so) or produce a shock you can even feel (except on your tongue, or again with a device specifically designed to step up the voltage). With much larger cells (say, the size of those that make up a car battery or radio control model power pack), there's a slight possibility of fire or burns, but even then, 6V won't give a shock you can feel on dry skin (likely not on damp skin, either).

Answer 3

In this sort of situation, I normally use aluminium foil. It can be folded the required number of times to achieve the 0.7mm that you need. A good tip is to cut a strip of foil, maybe 20cm long and 1cm wide, then fold it until it's a 1cm*1cm square. If it's too thick, unfold, cut some off and re-fold. Having a continuous strip ensures that there is always a path from one face to the other, regardless of the inevitable gaps between layers.

I think the greatest danger you face from using 2 * 2025 is that 2.5mm times 2 is FIVE millimetres - which is quite a bit more than 3.2mm. At the moment, you are relying upon a little spring to compensate for the extra 1.8mm. In my experience, these springs aren't that good and you may have already caused it to lose the ability to properly connect with a 2032 battery in the future. You might be able to bend it back again, but it will be difficult. You might have to continue using 2 * 2025s.

Answer 4

First you are lucky if your scale still works. Doubling the voltage (as you described) by putting them in series can kill it.

This is not advisable as it's dangerous to use electrical equipment with anything else than what their user manual mentions. However for a short term use, (depending on holder shape and terminals) you can fold some aluminum foil tightly until you get proper thickness with the battery on positive side. Be careful not to short the connections of the holder as there's risk of fire.

Anyhow, since you mentioned a pack, it's best to ask for a replacement.

Answer 5

Forgetting all the other issues, two 2025s are much thicker than one 2032. They would never fit. Better to buy the right batteries.

Answer 6

These batteries are so inexpensive, I suggest you just purchase the correct one. Then you have no worries about damage or continuity of contact or anything else. I know what it is like to have little money but you can buy the right battery for $1 or even less if you shop around.

Answer 7

My 2032 was too weak, and I only had a new 2025.
A penny is 0.06 inch thick and will work.
A dime is 1.5mm and will also work if you have a bigger gap.