'Non-rechargeable batteries only' - what happens if you use rechargeables?

We just got the Firebug some toys for Christmas that we knew needed batteries, but the instructions say they only take non-rechargeables. We have been only using rechargeables for some time now, so it looks like I’m going to have to go out and get a pile of regular AA batteries, for the first time in years.

But what’s up with this? What happens if I try to power them with my Eneloop batteries? Will they just not have enough juice to run the toys properly? Or is there some other dire consequence of putting rechargeables in a toy or appliance that specifies non-rechargeables only? And if so, how does the toy know what sort of battery I’m putting in there? Electricity is electricity, isn’t it?

And I’d add, at this late date, why is anyone making gizmos that only run on non-rechargeables anyway? Are some applications just not workable with rechargeables? What’s the story on this?

As always, thanks in advance for chipping away at my ignorance.

I have an old camera that requires non-rechargeable batteries. If you put rechargeable batteries in it, the camera thinks that the batteries are dead due to the lower voltage and shuts down.

Depending on the device, you might get a low battery warning due to the lower voltage, or the device may shut down if it’s really picky.

Something like a remote control or a walkie-talkie type thing might have a reduced range due to the lower voltage levels (and resulting lower transmitting power).

I have a lot of robotic toys that specify alkalines for the remote control then use rechargeables for the motor drives. The alkalines aren’t being drained much so they last a long time. The rechargeables get drained pretty quickly and have to be recharged.

Non recharge AAs are listed as 1.5V

Several of my rechargeable AAs are listed as 1.2V or 1.3V

Works fine in my photo strobes, but I can see how voltage variations might affect other electronics.

Although, don’t 1.5V AAs diminish their power output as they run down?

I’ve seen that warning on items expected to get wet – shower radios, outside weather stations, and so on. I assumed the reasoning was they didn’t want the liability for consumers putting potentially wet rechargeables back into the charger.

Are any of the toys water-related? Super-soakers, boats, etc.?

Back in the 1980s, I had a handheld game (one of these). It died when I tried to run it on nicad rechargeables - they have a low internal resistance and in some cases, can allow an improperly designed load to draw very large currents.

Years ago, I saw handheld radios which required 8 AAs if you use alkaline or 10 AAs if you use NiCad. That’s because the average alkaline AA is 1.5 Volts but a NiCad is 1.2 Volts.

If you’re using NiMH, those are also probably 1.2 Volts. But there are rechargeable alkalines which give you more like 1.4 Volts. https://en.wikipedia.org/wiki/Rechargeable_alkaline_battery

Regular old alkaline AA batteries start out at a nominal 1.5v, and then as they’re depleted, the voltage drops in proportion to just how depleted the battery is. If you graph the voltage vs. depletion, it’s a straight line.

NiMH rechargeable AA batteries also start out at 1.5v, IIRC, but the curve isn’t straight- it’s kind of a sideways “S”, with the initial voltage drop being very steep, and then during the vast majority of the battery’s charge, it holds around 1.2v, and then right at the end, it drops like a stone again.

So anything that looks as the voltage to determine the battery depletion is going to show the alkaline as steadily depleting, while the NiMH battery will drop to say… 2/3 capacity (according to the device), and then stay there until it’s out of charge, at which point it’ll go from 2/3 capacity to not working. That’s how my Xbox controllers work- they show full capacity for like 20 minutes, and then 2/3 capacity for a long time, and then just die without warning.

Yes, as has been said. Also, the total capacity of an alkaline cell is diminished the more current you try to draw from it. E.g. an alkaline AA might have a capacity of 2800 mAh if you’re only drawing 5 mA from it, but try to draw 0.5 A and it might have only 600 mAh to deliver.

Yes! I had forgotten that about loads. Certain brands of nicads would get REALLY hot when my old Vivitar 283s were on full manual discharge. And barely last for a 36 exposure roll of film. That’s when I got my dry cell batt pack (510V) for extended on location shoots. Non recharge, BTW. Switched to Quantum brand batt set ups eventually.

I’ve never had anything go wrong using rechargeables in things that say they won’t work, and I’m not sure I could come up with any way they could cause problems. At worst, they just won’t work well.

Cue some expert coming in and telling me I’m wrong, of course.

So what can happen is that the thing says the batteries are low even though there’s still plenty of charge left. That’s usually not a problem.

NiCad and NiMH batteries can deliver a lot of current when you short them, enough to be somewhat dangerous. (I once shorted a rechargeable AA battery and the wire got hot enough to give me a nice burn.) Regular 1.5 V batteries don’t. But with reasonable supervision and/or without risk factors such as shoddy construction or liquids present, this also shouldn’t be an issue. I mean, it’s not like anything is going to explode.

I switched to Eneloop rechargeable batteries a long time ago, as my strobes go through batteries really fast. This is the first time I hear about some electronics not working well with rechargeable batteries. I use them for everything.

I will have to pay more attention when I get new stuff.

And for your strobes, rechargeables are preferred, anyway (at least with relatively modern flashes). They last longer on a single charge than a AA and have faster recycle times. And it’s not a minor difference. See here for a comparison of various types of batteries on Nikon Speedlights. They even outperform lithiums in terms of recycle time, but not number of total flashes (although they do much better than alkalines on this metric.) I find the same results on digital cameras. I won’t use alkaline AAs on them if I could avoid it–rechargeables last significantly longer and, well, they’re rechargeable.

As for the OP, I would assume, as others, it has something to do with the minimum voltage required for the device to work properly. Rechargeable NiMHs are usually 1.2V, and some devices cut out at voltages higher than that.

One other thing to consider: regular NiMHs usually have a fairly high self discharge rate. So you have to recharge them after a month or so even if you didn’t really use the device. There are newer ones such as Eneloops that don’t suffer from this although they usually have a somewhat lower capacity. These are also, unlike “normal” rechargeable batteries, typically sold charged and ready to use.

That’s supposed to read “alkaline” rather than “AA.”

I hadn’t read about this but did notice that they performed all-around better with my (modern) strobes. Thanks for the information.

So what happens if I use rechargeable batteries in a device when it’s not recommended?

They won’t fit… You can only use one battery. A battery is a collection of cells,
and if you put 4 AA’s , you have four cells… one battery. Is that a nitpick ? Read the blurb…
The 6,9,12 volters are of course batteries on their own… 4,6 , 6 cells… (12 volt batteries use lead acid, a different chemistry, and so get 2 volts from each cell)

The only solid physical ,electrical result may be that you wreck your rechargeables by running them down to 0 volts. The rechargeable may also leak when this happens.

The vendor/manufacturer doesn’t want you to feel it was their fault your new $30 battery set is wrecked on first use, or that your alkaline rechargeables leaked and destroyed your device.

BTW the discussion of longevity (eg for use in cameras) is not much use until you compare rated mAh and $ per mAh…
Because a cheap rechargeable may have a lesser mAh rating…

Another reason to use primaries (non-rechargeable) over rechargeables is that primary cells tend to have a lower self discharge rate. For things with really low current draw like television remote controls and smoke detectors, alkaline is the way to go. If you were to use rechargeables, the battery would fail due to age rather than device use.

There are rechargeable batteries with chemistries that have higher voltage. Nickle-zinc cells are 1.5 volt like alkaline, though with lower overall capacity.

the only thing I can think of is the device might not work if it insists on the voltage being a certain level. as has been said above, alkalines are nominally 1.5 volts per cell, nickel-based rechargeables are nominal 1.2 volts per cell. I don’t think I’ve run into anything that had trouble with rechargeables, though.

yes, it’s a nitpick but technically correct. “Battery” is the colloquial term for all of them, even ones with single cells.

In my experience the danger with running nickel-based (NiCd or NiMH) rechargeables down too low is cell reversal; one cell will go flat before the rest, and with its (-) electrode touching another cell’s (+) electrode (and vice versa) the flat cell will be forced to try to reverse its polarity, killing it. I don’t think they would leak since they use a spiral electrode/separator/electrode construction. The cells notorious for leaking were the “Extra Heavy Duty” carbon-zinc dry cells, and that was as part of the cell’s chemical reaction it consumed the metal case of the cell.

for my radio control stuff, I’ve switched entirely over to the low self-discharge (“pre-charged”) NiMH cells; they’ve seemed to work as advertised. Dramatically lower self-discharge for a minor reduction in capacity.

Nice!

I’m going to have to order a few sets of Eneloops for my strobes. I normally take one of those 20 packs of Duracells to photo shoots, and never really trust them for anything once I have used them in the strobes. Glad to hear the new rechargeables are the right thing for speedlites.