NiZn (nickel zinc) AA/AAA battery charger?

[92saturnsl2]

Curious if anyone knows of a decent Ni-Zn battery charger for AA/AAA size batteries. Batteries are plentiful, but all I'm finding for chargers are cheap Fleabay / Amazon Chinese stuff.

I bought my daughter a digital camera for Christmas-- it's a great camera but many of the reviews stated that it ate through batteries like crazy. I thought nothing of it because I have a horde of high capacity Ni-Mh batteries. Turns out it doesn't eat batteries, instead the camera's battery logic is flawed-- it cuts the camera off around 1.25V (likely designed for alkaline), which on a Ni-Mh battery still has around 80% capacity. That renders Ni-Mh / Ni-Cd an absolute no-go. I've tested it with alkaline and rechargeable, both cut off at 1.25V, even alkaline has some juice left at that voltage. Poor engineering.

That got me thinking of a Ni-Zn rechargeable battery, which performs in many ways similarly to Ni-Mh, but has a much higher 1.6V nominal voltage. But it requires a battery charger that cuts out at 1.9V, so a normal Ni-Mh/Ni-Cd charger will not suffice. Anyone know of a decent charger that exists for the Ni-Zn battery type?

 

[eljefino]

Surprised they still make these-- I got a set of cells and charger at "Big Lots" 10 years back with the understanding that something about the tech flopped.

I, like lots of us, would have liked a little more power in my power.

 

[Quattro Pete]

Look into Li-Ion 1.5V cells. They maintain constant 1.5V output from beginning to end. They're basically 3.7V Li-Ion cells with circuitry to down convert to 1.5V. Great for applications that require it.

I've got a bunch of these, although they were a lot cheaper at the time I bought them:

Amazon.com

Test of TenaVolts AA 2775mW (Black-blue)

 

[92saturnsl2]

Look into Li-Ion 1.5V cells. They maintain constant 1.5V output from beginning to end. They're basically 3.7V Li-Ion cells with circuitry to down convert to 1.5V. Great for applications that require it.

I've got a bunch of these, although they were a lot cheaper at the time I bought them:

Amazon.com

Test of TenaVolts AA 2775mW (Black-blue)

Have you had good luck with them? I'm aware these cells exist, but I figured the extra circuitry to kick the voltage down would compromise capacity (taking up some of the room in the cell). But 2775mWh isn't too shabby, assuming it's not just marketing.

 

[Quattro Pete]

Have you had good luck with them? I'm aware these cells exist, but I figured the extra circuitry to kick the voltage down would compromise capacity (taking up some of the room in the cell). But 2775mWh isn't too shabby, assuming it's not just marketing.

Yes, they work fine.

Look at the link to the test results I posted above. Capacity/energy is legit.

The only thing these cells can't do is deliver very high current (above 2A).

Alas, at their current price they're tough to justify. I paid $12 for 4, including the charger.

 

[Dave9]

I hate to suggest it but you bought the wrong camera.

I recall a camera I had that ran off 2 x AA. Using NiMH, I got 15 pics, maybe 20 if the batteries were hot off the charger. That was a long time ago. I replaced it with a camera using a single Li-Ion, which today was also a long time ago, but it gets over 300 pics per battery charge.

Just suggesting that no matter what battery magic you choose, it's still fighting an uphill battle if trying to get more pics out of an x AA powered camera. (edit: lol how did my writing two times, end up as a thumbs down icon? It was not intentional).

The Li-Ion AA cells with a buck converter circuit inside, may help some but Li-Ion tech isn't leveraged well when a small form factor that is smaller still due to the converter circuit taking up some space in that form factor too.

However regarding the NiZn, any charger that can hold a 1.9V variable current for 2.5-3 hrs should do the job, then you don't want to leave it on the charger longer. Since the tech was more or less abandoned, if you must resist buying a different camera then then Li-Ion buck based cells do make the most sense.

Back to my original thought, I'd prefer something that ran off a Li-Ion 3.7V battery in the first place, if you need more than a modern phone can do.

 

[jhellwig]

Eneloop nmhi batteries hold a higher voltage in operation on par with alkaline. Most LSD nmhi batters do that. I have a meter at work that throws fits with Duracell alkaline batteries being low even brand new but it never has an issue with Eneloops.

Either your cells are old and crummy and have been burnt by a dumb charger or the camera is just weird.

 

[K.Aoi]

I strongly recommend picking up some li-ion rechargeables with built in USB chargers. I got the pownergy ones in AA and AAA and they've been excellent. The only use I found they won't work in is a very high current draw like a high power UV flashlight, seems like the draw is too high and trips the OC protection. But unlike nimh batteries it doesn't drop voltage, it puts out a solid 1.5v until the internal battery voltage drops too low and then they just cut off. For electronics, li-ion is the way to go. Expensive upfront but they pay fort themselves if you use them a lot.

Amazon.com

Eneloop nmhi batteries hold a higher voltage in operation on par with alkaline. Most LSD nmhi batters do that. I have a meter at work that throws fits with Duracell alkaline batteries being low even brand new but it never has an issue with Eneloops.

Either your cells are old and crummy and have been burnt by a dumb charger or the camera is just weird.

Not quite true, all nimh batteries by virtue of the way they function have extreme voltage drops. Heck, most nimh AA/AAA batteries aren't even rated at 1.5v, they are rated at 1.2-1.3v.


Edit: who the heck uses a point and shoot digital camera these days that isn't a DSLR or mirrorless? I guess it's for a younger daughter too young for a cell phone?

 

[92saturnsl2]

I hate to suggest it but you bought the wrong camera.

I recall a camera I had that ran off 2 x AA. Using NiMH, I got 15 pics, maybe 20 if the batteries were hot off the charger. That was a long time ago. I replaced it with a camera using a single Li-Ion, which today was also a long time ago, but it gets over 300 pics per battery charge.

Just suggesting that no matter what battery magic you choose, it's still fighting an uphill battle if trying to get more pics out of an x AA powered camera. (edit: lol how did my writing two times, end up as a thumbs down icon? It was not intentional).

The Li-Ion AA cells with a buck converter circuit inside, may help some but Li-Ion tech isn't leveraged well when a small form factor that is smaller still due to the converter circuit taking up some space in that form factor too.

However regarding the NiZn, any charger that can hold a 1.9V variable current for 2.5-3 hrs should do the job, then you don't want to leave it on the charger longer. Since the tech was more or less abandoned, if you must resist buying a different camera then then Li-Ion buck based cells do make the most sense.

Back to my original thought, I'd prefer something that ran off a Li-Ion 3.7V battery in the first place, if you need more than a modern phone can do.

There's nothing inherently wrong with the AA format, or even using two in a digital camera.

To illustrate the point, two 2700mah high capacity NiMh batteries is roughly 6.48Wh. The li-ion battery in my $800 Lumix mirrorless camera is ~8.64 Wh. About a 25% difference in stored power. I'd venture to guess the mirrorless camera with its much larger screen, processing power, etc. uses a good bit more power than the compact point and shoot.

I suspect the issue at hand here is that Kodak (camera mfg) used 2 cells, likely to make the camera as compact as possible, but the electronics really could use 3 cells, given that it cuts off at around 2.5V (1.25V per cell). That leaves plenty of juice, I'm going to guess 80% of capacity (and Ni-Mh can provide a LOT of current at that charge level) unused in a Ni-Mh cell, so again, it's not a battery or battery format issue.

Fact is, this problem can be remedied by using cells which stay above that 1.25V/cell minimum for most of the discharge cycle. So if you had issues with your 2xAA camera, there's a solution, you just had to find it.

FWIW Ni-Mh doesn't have significant voltage drop, it's just that they don't have the normal 1.5V to begin with. If you look at a discharge curve they start around 1.4V fully charged, quickly fall to 1.2-1.25V and will stay that way until the cell is nearly dead, at which point it drops to around 1.0V.

 

[92saturnsl2]

I guess it's for a younger daughter too young for a cell phone?

Exactly. It'll be a cold day down under before I purchase a 10 year old a cell phone. I actually prefer a standardized battery format like AA or 18650 when available, as opposed to the proprietary stuff that disappears or becomes hard to find in a few years-- or prohibitively expensive to replace.

The Kodak camera in question takes great photos, lots of features to keep younger kids, even teens entertained-- just engineered poorly given that it can't drain batteries all the way, even alkaline, which at 1.25V would only be about 60% discharged.

Sounds like the Li-Ion AA replacements are the way to go here, since the Ni-Zn batteries seem to be going the way of the dinosaur.

 

[jhellwig]

Not quite true, all nimh batteries by virtue of the way they function have extreme voltage drops. Heck, most nimh AA/AAA batteries aren't even rated at 1.5v, they are rated at 1.2-1.3v.


Edit: who the heck uses a point and shoot digital camera these days that isn't a DSLR or mirrorless? I guess it's for a younger daughter too young for a cell phone?

Yes quite true. Look it up. Eneloops are very popular in photography for that exact reason. The voltage rating on cells and batteries is not standardized so some manufactures use resting voltage instead of nominal or in use voltage at a certain current. Same reason various li ion batteries have varying voltage ratings when they use the same chemistry and cell count.

 

[92saturnsl2]

Yes quite true. Look it up. Eneloops are very popular in photography for that exact reason. The voltage rating on cells and batteries is not standardized so some manufactures use resting voltage instead of nominal or in use voltage at a certain current. Same reason various li ion batteries have varying voltage ratings when they use the same chemistry and cell count.

I own both-- Genuine Eneloops and an assorted variety of other brand LSD and non-LSD (higher capacity) Ni-Mh batteries.

I haven't seen a substantial difference in the voltage an Eneloop puts out versus other brands/types of Ni-Mh. But then again I haven't graphed it or done semi-scientific testing like these folks have: [warning: lots of info/reading]

https://eneloop101.com/batteries/eneloop-test-results/#quality-comparison-tests

Looking at the graphs, it doesn't seem that Eneloops put out appreciably more voltage than the others. Perhaps 0.05V, but only under light current loads (< 500ma).

From a quality/longevity perspective and their low discharge capabilities-- you can't beat Eneloops. The voltage output on the other hand, I don't see a distinct advantage there.

 

[K.Aoi]

I own both-- Genuine Eneloops and an assorted variety of other brand LSD and non-LSD (higher capacity) Ni-Mh batteries.

I haven't seen a substantial difference in the voltage an Eneloop puts out versus other brands/types of Ni-Mh. But then again I haven't graphed it or done semi-scientific testing like these folks have: [warning: lots of info/reading]

https://eneloop101.com/batteries/eneloop-test-results/#quality-comparison-tests

Looking at the graphs, it doesn't seem that Eneloops put out appreciably more voltage than the others. Perhaps 0.05V, but only under light current loads (< 500ma).

From a quality/longevity perspective and their low discharge capabilities-- you can't beat Eneloops. The voltage output on the other hand, I don't see a distinct advantage there.

NiMH definitely have a place, but for most modern electronics that you plan on using repeatedly I recommend the Li-ion ones, personally. Especially if you're seeing voltage cutoff issues with the nimh, not much you can do about that.

 

[92saturnsl2]

NiMH definitely have a place, but for most modern electronics that you plan on using repeatedly I recommend the Li-ion ones, personally. Especially if you're seeing voltage cutoff issues with the nimh, not much you can do about that.

TBH this is the first issue I've had with NiMH. Most devices that accept AA (or traditional alkaline sizes) will allow an alkaline to deplete fully (or close) which is around 1.1V.. At that voltage a NiMH battery is also nearly fully exhausted. So they work even though the battery indicator is sometimes a little off (if they use voltage as the input) since NiMH stay around 1.25V nearly the whole time.

But indeed NiMH is absoultely a no-go with this camera. After the camera cuts off, if it put them in my Opus battery analyzer and do a discharge test, they still have 2200 mah remaning, so they haven't hardly been used.

Sounds like the Li-Ion AA equivalents will do nicely for this application. Appreciate everyone's feedback.

 

[Quattro Pete]

Sounds like the Li-Ion AA equivalents will do nicely for this application.

Just keep in mind, you'll get no "low-battery" type warning with these cells. They'll go from full to nothing in an instant due to the completely flat voltage discharge curve. Trying to measure their voltage with a DMM will also not provide any indication of their discharge level.

 

[92saturnsl2]

Just keep in mind, you'll get no "low-battery" type warning with these cells. They'll go from full to nothing in an instant due to the completely flat voltage discharge curve. Trying to measure their voltage with a DMM will also not provide any indication of their discharge level.

Thanks for the heads up. I assumed that, given they use a DC-DC converter of some sort to step down the voltage and hold it at 1.5V. With no load, I bet they read 1.5V at all times, unless they're really, really dead to the point they can't be revived.

Shouldn't be an issue. I'll make sure to get at least a 4-pack so there's spares when the camera quits.

 

[Quattro Pete]

With no load, I bet they read 1.5V at all times,

Even with load, they'll still be at 1.5V.

 

[Dave9]

There's nothing inherently wrong with the AA format, or even using two in a digital camera.

To illustrate the point, two 2700mah high capacity NiMh batteries is roughly 6.48Wh. The li-ion battery in my $800 Lumix mirrorless camera is ~8.64 Wh. About a 25% difference in stored power. I'd venture to guess the mirrorless camera with its much larger screen, processing power, etc. uses a good bit more power than the compact point and shoot.

Why guess when you can just count # of pics taken? It's not just Wh that matters, with only 2 x NiMH you have 2.4V rather than 3.7V so higher current, so more voltage depression during use, while many cameras cannot operate down to the ~1.0V/cell rating needed to attain full rated capacity from a NiMH cell.

Which camera uses more power has quite a lot to do with the age of the tech. Long ago I replaced a 2X AA camera with one that was much nicer, newer, unquestionably more processing power and larger screen, yet achieved roughly 10-20X as many pics from the newer Li-Ion instead of 2X AA (freshly charged). Major camera manufacturers are much more sensitive/competitive about battery life than someone like Kodak who probably only licensed their name to a 3rd party.

I suspect the issue at hand here is that Kodak (camera mfg) used 2 cells, likely to make the camera as compact as possible, but the electronics really could use 3 cells, given that it cuts off at around 2.5V (1.25V per cell). That leaves plenty of juice, I'm going to guess 80% of capacity (and Ni-Mh can provide a LOT of current at that charge level) unused in a Ni-Mh cell, so again, it's not a battery or battery format issue.

They either used two cells because very old design pre-dating Li-Ion generation, or yes to save volume except that NiMH has lower power density than Li-Ion. Some better cameras of the NiMH era used 4X AA instead of 2X. NiMH is just a poor alternative for portable devices, which is why almost everything modern went Li-Ion.

Fact is, this problem can be remedied by using cells which stay above that 1.25V/cell minimum for most of the discharge cycle. So if you had issues with your 2xAA camera, there's a solution, you just had to find it.

FWIW Ni-Mh doesn't have significant voltage drop, it's just that they don't have the normal 1.5V to begin with. If you look at a discharge curve they start around 1.4V fully charged, quickly fall to 1.2-1.25V and will stay that way until the cell is nearly dead, at which point it drops to around 1.0V.

Except for a few things. 1) Most alternative chemistries have lower power density so still not as good as Li-Ion. 2) The AA with a buck converter and smaller Li-Ion stuffed inside, tend to suffer from a lot of voltage depression under the load a camera puts on them, so even if they start with a higher voltage, it still pales in comparison to something built to run off Li-Ion. IIRC, Project Farm and others have done youtube videos showing this voltage depression from the Li-Ion based AA.

NiMH do have significant voltage drop under load. Cameras use current in bursts, not a steady drain like you see on a discharge plot on some datasheet. It's temporary, they'll recover some with rest, but when using only 2X cells that drop puts them under the minimum a typical camera needs, very quickly.

Yes a higher voltage cell can help but nowhere near as much as a more modern design built to use a Li-Ion battery. It's not like we're talking about an $800 camera either, still applies to something a decade old and now worth very little on the camera market... though might have cost a few hundred when it first came out.

 

[Quattro Pete]

The AA with a buck converter and smaller Li-Ion stuffed inside, tend to suffer from a lot of voltage depression under the load a camera puts on them, so even if they start with a higher voltage, it still pales in comparison to something built to run off Li-Ion. IIRC, Project Farm and others have done youtube videos showing this voltage depression from the Li-Ion based AA.

On the Tenavolts I mentioned above, voltage sag is not an issue until you try to pull more than about 2.5A of current from them, but I can't imagine a typical alkaline cell would fare any better. Not sure how power hungry the OP's camera is, so this may or may not be an issue. Some of these cameras do in fact ask for a lot of current, as you noted, like when recharging the flash capacitor, for example.

 

[Dave9]

^ I appreciate the info, but still, the proof in battery vs tech is what a more modern camera can achieve, even if not a current, high expense cam. Anything major brand, runs circles around any 2 x NiMH. This is just fact, dismiss or argue all you like but it is what it is. Only some crappy retro tech camera with excessive power consumption and poor desigh, runs off 2x AA cells. It was idiotic of any cam manufacturer to design for 2 x cells in the first place, even if alkaline or some other >1.2V/cell chemistry.

Do whatever you want, while I laugh at it all, achieving over 300 pics from my decade old camera, if I pull it out instead of using my phone.

#learning disability : this is not directed at anyone in particular, but this whole topic is madness