Any CE devices that can recharge AA/AAA batteries within themselves?
December 15, 2014 2:42 PM

I'm wondering if there exist any (portable) consumer electronics devices - so like music player, mouse, flashlight, audio recorder - that take any chemistry rechargeable AA or AAA batteries, and can recharge them right in the device.

Maybe the device can be separately powered with a wall wart or via USB, maybe it's got a spot to plug in whichever sort of charger solely for topping off the batteries. Imagine a cell phone with a removable battery - except instead of a special size and shape pack, it just takes 4 AAAs, or whatever, and they can be charged by plugging in the phone - rather than removing the batteries and putting them in a special charger.

If this doesn't exist, I would assume it's because it's a bad idea or just impractical for some reason - tell me why!
posted by attercoppe to Technology (20 answers total)
Some Walkman tape players has rechargeable batteries like the WM-GX788 but I think those used gumstick nimh batteries sometimes in conjunction with AA or AAA batteries. Not what you're looking for I guess.

Most modern cordless phones use battery packs that are basically AAA batteries taped together into a single unit.

As to why that's the case as opposed to loose AAAs I can only guess.
posted by GuyZero at 2:50 PM on December 15, 2014


I think this radio satisfies your conditions.
posted by girl flaneur at 2:50 PM on December 15, 2014


I think this is pretty common in wireless mice. My Logitech G700s recharges its AA battery when I plug it into the USB cable.
posted by a2a87 at 2:58 PM on December 15, 2014


There were certain models of flip cameras that would do this. The "rechargeable battery" was just a couple cheap NiMH batteries shrinkwrapped together, they didn't even cover the contacts or anything cute like that.
posted by emptythought at 3:20 PM on December 15, 2014


I had a Panasonic portable CD player that had special rechargeable AA batteries that had to be recharged in the player itself. I lost the batteries somehow and went to the local electronics store to get replacements. I spent $20 (well 2,000 yen but roughly the same thing) and then found out the batteries wouldn't recharge in the player. This was in Panasonic's hometown of Osaka, and deciding that if I couldn't find the batteries there I wouldn't be able to find them anywhere I went out and spent an obscene amount of money to get an iPod (this was in 2003).
posted by any portmanteau in a storm at 3:22 PM on December 15, 2014


I've got a pair of wireless headphones (Sennheiser RS 160) that take rechargeables and charge by plugging in. I'm pretty sure they came with a pair of eneloops, but I might have dreamed that part.
posted by you could feel the sky at 3:32 PM on December 15, 2014


I think some Garmin GPS units do this.
posted by ssg at 3:40 PM on December 15, 2014


If this doesn't exist, I would assume it's because it's a bad idea or just impractical for some reason - tell me why!

From the point of view of someone designing a device, the big benefit of using removable batteries is that getting the energy into them is somebody else's problem. You don't need to pay for the circuitry for charging them, you don't need to test with various types of batteries, you don't have to answer support calls when someone's battery didn't charge, or when they tried to charge it backwards, or whatever. And there's plenty of high quality external battery chargers available.

If you do decide you're going to tackle battery charging, it's then very appealing to use built-in lithium-ion batteries. Because making a cheap, durable, easy-to-open, reliable battery compartment is difficult. And because lithium-ion batteries are more energy dense than anything sold as AA. And you can make them a shape that's convenient for your device. And you still don't have to deal with idiots putting their batteries in backwards, or using 4 batteries of different amounts of charge and different chemistry.

To put it another way: The iPhone 6 has a 1810 mAh 4.7V battery, and the whole phone is 6.9mm thick and weighs 129g. 4 Eneloop AA's is 2000 mAh 4.8V, and the batteries alone weigh 108g, and are 14mm diameter.
posted by aubilenon at 4:52 PM on December 15, 2014


I have a Sangean clock radio like the one girl flaneur links to and it does indeed satisfy your conditions.
posted by gudrun at 5:10 PM on December 15, 2014


This Label Maker does it.
posted by Confess, Fletch at 7:24 PM on December 15, 2014


They are typically going to be high-drain devices where you can live with a larger case size and ability to run without being plugged in, but on the other hand ability TO plug in (to save battery expense where AC is available), are both critical. So - mostly older-school recorders and video cameras. I owned a Mini-Disc recorder (don't judge - it was the early 2000s and solid-state recorders were hella expensive) that worked like this. You had to go into a menu setting and tell it whether you had rechargable batteries in the hopper. If you said you did, it would apply power to the batteries to recharge them when you had it plugged in; if you said you had non-rechargable, it wouldn't (because standard batteries will blow if you power them).

Somewhat similar deal - I've owned a couple of video cameras that had external battery packs (the pack snapped onto the device, not in it) where you could buy an adapter type pack that was filled with AA or AAA batteries.

aubilenon's points are well taken - on the other hand you have the benefit of charging a power-hungry device whenever it's plugged in, without having to carry a separate charger, and ALSO the benefit of being able to buy more batteries at any drugstore, etc. (but the charging circuit better be set for the kind of batteries you have -- another point against doing this for devices that very non-tech-savvy people use)

Unfortunately the cost (aside from aubilenon's points) is the risk of damage if a user gets the switch set wrong.

I used to think there was something kind of idiotic about the supplemental charge packs for cell phones (I guess because I thought they were expensive and who doesn't have some kind of charger for their phone at all times?), but as I've wound up taking more bus trips with my high school age children, and the prices have come down for these gadgets, I'm beginning to see the light.
posted by randomkeystrike at 7:30 PM on December 15, 2014


I have a $2 powered screwdriver that does this.
posted by flabdablet at 8:39 PM on December 15, 2014


impractical for some reason - tell me why!

It used to be much more common before mobile phones started shrinking. Battery holders for batteries that very rarely need changing are essentially dead space and weight, so any design competing on smallness and lightness will benefit from eliminating them.
posted by flabdablet at 8:42 PM on December 15, 2014


randomkeystrike mentioned the problem I think is most pertinent: what happens if the user puts the wrong kind of battery in?

NiMH, NiCd, and Li-Ion batteries all require different kinds of charging circuits. That gets complicated, expensive, and confusing to the consumer. And what if the consumer puts in non-rechargeable batteries, and absentmindedly plugs in the AC power? Bare AA and AAA cells don't come with protection or identification circuits, so the camera can't make the right choice for the user.

I've seen plenty of other devices that use a custom battery pack, or even a standard hobbyist battery pack form factor, that can charge in the device itself or in a separate charger, but those are always limited to one battery chemistry (and often one type of charging circuit integrated into the pack).

I have a battery charger that can charge either NiMH or NiCd batteries, but you have to set the switch yourself, and that switch applies to all 4 paired banks.
posted by WasabiFlux at 8:43 PM on December 15, 2014


Many years ago I had a Radio Shack police scanner that did this with AAs.
posted by primethyme at 9:04 PM on December 15, 2014


My cordless phone uses standard off-the-shelf AAA NiMH batteries, and changes them when docked.
posted by mbrubeck at 9:06 PM on December 15, 2014


Circa 1998 I had an off-brand Discman that did this with AAs.
posted by fiercecupcake at 6:10 AM on December 16, 2014


Motorola Talkback 2-way radios typically work this way. They sell their own shrink-wrapped battery packs but you can also run them on individual AAs, which could be rechargeable.
posted by contraption at 9:45 AM on December 16, 2014


My cordless phone uses standard off-the-shelf AAA NiMH batteries, and changes them when docked.

I just looked in the back of my own cordless handset (also Panasonic though not that model) and found that it does too.
posted by flabdablet at 10:00 AM on December 16, 2014


My Ixon IQ (scroll to second item) bicycle light does this. It charges NiMH batteries, and with an add-on gadget, it can charge them not only from a wall plug but also from a hub dynamo on a bicycle.
posted by brianogilvie at 11:04 AM on December 16, 2014


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