NiMH Rechargeable AA Batteries are too Thick! - Page 1
Forum section: electronics / projects

author: paulhdietz
author_rank: Contributor
timestamp: November 24, 2024, 05:11:45 am
content: 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!

author: paulhdietz
author_rank: Contributor
timestamp: November 24, 2024, 05:22:33 am
content: 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

author: BILLPOD
author_rank: Frequent Contributor
timestamp: November 24, 2024, 07:59:57 pm
content: 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 thebattery 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.

author: floobydust
author_rank: Super Contributor
timestamp: November 24, 2024, 08:25:36 pm
content: 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

author: wraper
author_rank: Unknown
timestamp: November 24, 2024, 08:36:25 pm
content: Quote from: paulhdietz on November 24, 2024, 05:11:45 amThe 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?

author: wraper
author_rank: Unknown
timestamp: November 24, 2024, 08:38:47 pm
content: Quote from: floobydust on November 24, 2024, 08:25:36 pmHigh capacity eneloop/LADDA are thicker than regular ones.

author: floobydust
author_rank: Super Contributor
timestamp: November 24, 2024, 08:51:08 pm
content: 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

author: The Doktor
author_rank: Regular Contributor
timestamp: November 24, 2024, 09:09:03 pm
content: 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".

author: David Hess
author_rank: Super Contributor
timestamp: November 24, 2024, 11:41:09 pm
content: Quote from: The Doktor on November 24, 2024, 09:09:03 pmI have gone through several 2xAA cell Maglights back to the 1990s and they all worked fine with Eneloop cells.

author: wraper
author_rank: Unknown
timestamp: November 25, 2024, 12:09:41 am
content: Quote from: floobydust on November 24, 2024, 08:51:08 pmI measured (thinnest-thickest orientation):3rd gen Sanyo Eneloop 14.08 - 14.33 mm4th gen Panasonic Eneloop 14.08 - 14.25mmWhite High capacity LADDA (rebadged eneloop pro) 14.25 - 14.30mmGrey LADDA (rebadged eneloop) 14.13 - 14.26mm2100mAh LSD VARTA 14.13-14.41 mmAmazon Basics (rebadged GP ReCyco) 14.16 - 14.50mm

author: aeg
author_rank: Regular Contributor
timestamp: November 25, 2024, 01:03:19 am
content: You could try AAA batteries in AA adapter shells.