Help me find the right AA battery!

[Joe Hone]

It is scorpion season here in the desert and they seem more numerous than usual this year, probably due to the proliferation of small bugs from all of the rain we got over the winter. I'm using a surprisingly good generic, 3xAA, 51 led UV light I picked up online – the right frequency, decent spot and throw. I'm able to see them as far as 20 feet when the batteries are fresh. And that is the problem; it runs on high for about an hour, then drops about 50%, to where I have to bend low to the ground to see anything.

Rechargeable batteries, including Duraloops and Energizers, won't fit it. I did some research and discovered that rechargeable AA batteries run larger than standard AA size, and I found some websites actually advising that rechargeables won't fit their products– who'd have thought that?

Anyway, I'm running Fujifilm green AA alkalines from Big Lots. I could get the big backages of Kirkland or Duracells from Costco, but the Fuji's are landfill disposable and I feel better about using them. I'm going through 3 cells week and the costs are adding up.

Anyone know of a rechargeable that is standard size? That is my first thought. I'll look for a machine shop to touch the inside walls of the cylinder if I can't find a rechargeable that will fit.

 

[VidPro]

strange , but wont fit in the cylinder itself??

~.09mm wider max, energyser 2500 bigger than enloops.

how about the ol Brake cylinder Hone , and a drill? if it is cheap steel it will go easy, if it is aluminum it will "fill the stone" quickly and make it a pain, but it might avoid machine shop costs. the dudes in Machining would know more about that stuff.

 

[Mr Happy]

It's a bit odd that you can't find a rechargeable battery to fit. There are some rechargeables that are over sized, notably GP cells, or Kodak pre-charged, but I have never found Eneloops to be notably different in size from a standard Duracell AA battery.

Do you find your Fujis to be smooth fit or a tight fit?

 

[Mr Happy]

For instance I just did a quick measure and I found the diameter of some Duracells and some Eneloops to be approximately the same at 14.2 mm. This is less than the specified maximum diameter of an AA cell at 14.5 mm.

 

[VidPro]

oh AA, oops, let me fix that.
i was doing AAA.
cant see how they could have a problem with AA rechargables vrses Duracell unless the rechargables were beloted from gas.

 

[Joe Hone]

The Fuji's are a smooth fit.

The Duraloops and Energizers are the same - can't force them in and when I try the outer case gets scratched to where the paint comes off.

The battery carrier is plastic for 3 cells. I know this sounds goofy, but I can't force them into the cylinder without destroying the carrier.

I've held Duraloops and Duracell alkalines end to end and the Duraloops are larger, but it wouldn't seem that they're so much larger to make the difference it does.

If I can't find the right AA I'll try a router on a drill bit. For the cost of the light there is no way it isn't cheap aluminum that won't shave easily.

 

[Joe Hone]

I just did a quick look for a source on rechargeable sizing and came up with this:

"Care should be taken when designing parts using NiMH AA batteries as the diameter trends toward the upper spec limit of 14.5 mm, presumably to maximize charge capacity."

They definitely don't fit my light. I wonder if the same is true for NiCad rechargeables?

 

[Mr Happy]

If you haven't tried it already, try rotating the cells in the carrier a bit. Sometimes the bulge of the seam down the side makes a difference to whether they fit or not.

 

[ampdude]

I have a 4AA Responder that I can't get any rechargeables to fit. Kind of makes me wish I had some old lower capacity cells to try in it.