NiMH Rechargeable AA Batteries are too Thick!

[paulhdietz]

For my school animatronics kits, we use a 4xAA battery pack. To reduce waste, I want to switch over to using NiMH batteries instead of alkaline. However, all of the higher capacity NiMH cells I have tried are too thick to fit properly in the holder I'm using. The spec for AA cell diameter is 13.5mm to 14.5mm. Since alkaline batteries are typically 14mm or thinner in diameter, the holders were designed to fit 14mm cells, max. But most of the easily obtained NiMH cells I find in the US are about 14.3 - 14.5mm.

So two questions: does anyone know of a manufacturer that makes 4xAA battery boxes designed for the wider diameter cells?

Is there a commonly available (in North America) brand of NiMH AA battery which is 14mm in diameter or less?

I tried putting out a request for quotation on Alibaba, but no one is able to supply a box that works with 14.5mm batteries.

Thanks!

[paulhdietz]

For an example, here is the size data from EBL. You can see that the size of a "standard" AA battery is VERY variable!

https://www.eblofficial.com/blogs/blog/ebl-battery-size-chart

[BILLPOD]

       This is news to me, as I have switched from alkaline to NiMH batteries several years ago, because of the leaking electrolyte situation.   I have a LOT of battery operated devices, and I have never had a situation where the NiMH did not fit the
battery box.  But I do believe in Paulhdietz's predicament.   Doing a quick look on Google, there are many, many battery boxes for sale, but all the description says is "for AA batteries".    I'm sure there must be some that would work, but my Google-Fu is not working well today.   Paul, be sure and let us know if you find any that will work.

[floobydust]

What kind of AA battery holder is so tight that say 14.3mm won't fit in it? They usually have spring clamp sides that flex quite a bit. Most are made in china and have a fair bit of slop.
Eneloop and Ladda AA I measure at 14.30mm, all alkalines are 13.90-14.00mm

[wraper]

So two questions: does anyone know of a manufacturer that makes 4xAA battery boxes designed for the wider diameter cells?

The proper question would be: does anyone know of a manufacturer that makes 4xAA battery boxes designed according to AA battery standard? Up to 14.5mm diameter is within AA battery dimension spec, but who cares?

[wraper]

What kind of AA battery holder is so tight that say 14.3mm won't fit in it? They usually have spring clamp sides that flex quite a bit. Most are made in china and have a fair bit of slop.
Eneloop and Ladda AA I measure at 14.30mm, all alkalines are 13.90-14.00mm

High capacity eneloop/LADDA are thicker than regular ones.

[floobydust]

I'd also measured a 2,500mAh Eneloop Pro and it's 14.30mm... but where the label wrap overlaps it's a fat point at 14.50mm

[The Doktor]

I've had the same problem myself. I've got an old mini Maglite from the 80s, the old incandescent type that really eats batteries, and I wanted to put NiMH in it. Both the Eneloop and some Chinese ones I tried will not fit in. AA alkaline no problem at all. Careful measuring shows that I need to bore it out by .020" (.5mm) To make it work. But I've also got a new mini Maglite, the good LED kind, so I've not been in a hurry to chuck it in the lathe.

I also have an old AT&T model 9100 900 MHz portable phone. Yes, I still have a landline. This thing is from the mid-90s and I have had apart several times to clean the keyboard, but it is the only portable phone I've ever used which works every bit as good as a wired one. Oh yes, on to the point. The original battery pack for this phone was five AA NiCad's shrink-wrapped together with a short wire and connector that plugged into the phone. I had made a few replacement packs in the past using Sanyo NiCad, I would glue the five cells together and secure the old shrinkwrap over them with a piece of tape. That would fit in fine and beheld secure by the foam that quit the original pack from rattling. Now I use the NIMH cells, and it don't work so good. I had to take out the original foam and not use the shrinkwrap anymore, as well as making sure the wires fit down between the cells instead of under them. Even at that it requires some force to get the battery cover back on.

So basically, yes the new NIMH cells are bigger than old batteries. They may be within the official standard, but their size definitely differs from "tradition".

[David Hess]

I've had the same problem myself. I've got an old mini Maglite from the 80s, the old incandescent type that really eats batteries, and I wanted to put NiMH in it. Both the Eneloop and some Chinese ones I tried will not fit in. AA alkaline no problem at all. Careful measuring shows that I need to bore it out by .020" (.5mm) To make it work. But I've also got a new mini Maglite, the good LED kind, so I've not been in a hurry to chuck it in the lathe.

I have gone through several 2xAA cell Maglights back to the 1990s and they all worked fine with Eneloop cells.

[wraper]

I'd also measured a 2,500mAh Eneloop Pro and it's 14.30mm... but where the label wrap overlaps it's a fat point at 14.50mm

I measured (thinnest-thickest orientation):
3rd gen Sanyo Eneloop 14.08 - 14.33 mm
4th gen Panasonic Eneloop 14.08 - 14.25mm
White High capacity LADDA (rebadged eneloop pro) 14.25 - 14.30mm
Grey LADDA (rebadged eneloop) 14.13 - 14.26mm
2100mAh LSD VARTA 14.13-14.41 mm
Amazon Basics (rebadged GP ReCyco) 14.16 - 14.50mm

[aeg]

You could try AAA batteries in AA adapter shells.