18650 Primary Cell ? - Is there such a thing ?

[HarryN]

Hi.
This might sound like a dumb question.

I am familiar with the 18650 Li cells for use in recharge applications (often as battery packs) and the cost benefits of using recharge cells.

Does anyone sell a commercially available, standard product, primary cell (non recharge), 18650 size cell that a consumer can buy directly ? I am partial to North American or European suppliers as they are more tightly safety regulated in this area, but I will consider all.

[Ginseng]

You want a cell this size but primary? Does chemistry matter? If not, it's pretty close to a 4/3-fat A (18 x 67mm). That's pretty uncommon for a primary. Try checking the Powerstream website. They might have something but it'll most likely be made in China.

Wilkey

[Doug S]

I follow the battery industry pretty closely. I have not seen one. Something that is pretty close though is the cell used in the 4.5V Duracel MN1203 flat battery. If you open one of these up, there are 3 alkaline cells that are close to the dimensions of a 18650. I don't have one handy to measure.

[HarryN]

Thanks for the info. I have seen some posts on the forum re: 18650 based lights, but it seems like this might be limiting. The power seems to be excellent, but cell availability and chargers might put off some people, and I kind of like the ability to use primary cells I can buy in a store as a backup. (like 123).

How do you thing people would take to a light that allowed use of 18650 or an adapter to use 123 ?

[PeLu]

The clostest I know is the SAFT G36, which is something like a 17600 cell (in LI-SO2). The cells from a MN1203 battery are are too thick, they are more than 20mm. I just know that a replacement made out of three 18650 cells (NiMH) was much smaller.
But is there actually a need for it? A state of the art flashlight should be able to accept a wide range of input voltage (remember, a LiIon cell will give in between 4.1V and 3.0V for a useful life), so the easiest was is to replace the 18650 cell with two CR123A cells. These are relatively easy available. No adapter needed.

[HarryN]

The 18650 is approx 18.2mm dia, but the 123's are "not larger than 17mm" in the spec. I measured 4 brands, and none were larger than 16.5mm. If I work with a light bored out for 18.2mm + a little for clearance, and then stick in a 16.5 mm 123 (in series) the 123 batteries might rattle . (maybe not, but it is a question.)

It seems like this would not be quite as good, so maybe someone knows of a thin sleeve adapter ?

Thanks HarryN

I am not too worried about the voltage range.

[Doug Owen]

[ QUOTE ]
HarryN said:

It seems like this would not be quite as good, so maybe someone knows of a thin sleeve adapter ?


[/ QUOTE ]

If I'm following correctly, how about a strip cut from a plastic soft drink bottle or milk jug? Roll it up and slide it in. Change the length to fine tune the fit.

Doug Owen

[Doug Owen]

[ QUOTE ]
HarryN said:

It seems like this would not be quite as good, so maybe someone knows of a thin sleeve adapter ?


[/ QUOTE ]

If I'm following correctly, how about a strip cut from a plastic soft drink bottle or milk jug? Roll it up and slide it in. Change the length to fine tune the fit.

Doug Owen

[HarryN]

Hi - Thanks for the idea. I was thinking of something a little more professional - like maybe an off the shelf tube. I will do some hunting on the off the shelf tube specs.

[HarryN]

Hi - Thanks for the idea. I was thinking of something a little more professional - like maybe an off the shelf tube. I will do some hunting on the off the shelf tube specs.