CMG-Ultra-G and Heat

Calling CPF Experts,

I have an extra CMG Ultra-G loaded with a lithium AA battery, so I placed it in my car for the rare occassions I might need it there. My car interior is black and I live in Florida, to make a long story short(er) I noticed when I got in my car after work today that the body of the CMG was way too hot to touch. I know nothing can damage that HA body, but should I worry about the heat damaging any of these components:

1) The LED itself
2) The voltage step-up circuitry
3) The battery

PS: Holding it with a towel, I turned it on for a second and it seemed to be working fine.

1) The LED itself

nope, don't think so. The UV in the sun is more damaging than the heat so keep it in the glove compartment. Over a very long term, or in much higher temperatures than that it may start to cloud the resin it's made from, but not in any sense that you have to worry about now.

2) the voltage step-up circuitry

Nope, not unless you get it hot enough inside there to melt and reflow the solder. I don't think it gets that hot, even where you are /ubbthreads/images/graemlins/wink.gif

3) The battery

YES, unfortunately, in the heat even the lithium AA's will degrade much faster than usual. I don't have any figures or anything scientific, but this question has been asked before around here and they do die quicker in the heat.

Check it every few weeks until you find out how long it is going to last under those circumstances.

About the only thing I can think of that might be affected by the heat is the o-ring...

i see orings in automatic transmissions that see high temps and hot oil that are still ok after 20 years.
the battery will suffer long before the rest of the unit.
unless of course the cars interior catches fire.

[ QUOTE ]
snakebite said:
Unless of course the cars interior catches fire.

[/ QUOTE ]

Only a flashaholic would think of the light first if the car caught fire. /ubbthreads/images/graemlins/grin.gif

Are all o-rings created equal? Otherwise, you can't put in anything but synthetic motor oil into auto trannys... What's the issue of petroleum based products being bad for o-rings? Is it because of drying? Chem reaction?

@Choua - Ordinary O-Rings are made of simple rubber stuff. Since this is made of mineral oil, it will dissolve if mineral oil is used for lubrication. There are synthetic materials like Viton or Buna-N that can handle mineral oil and I guess these are used in cars. Here's a link for further information: http://www.marcorubber.com/material_chart.htm

Chris

Thanks Chris!

How about keeping the AC running to keep the battery good? /ubbthreads/images/graemlins/grin.gif

I had cloudy weather and a low of about 30 F, High about 55. My Ultra is fine /ubbthreads/images/graemlins/smile.gif
So another alternative would be to move /ubbthreads/images/graemlins/smile.gif Lithiums handle -40 well.
Sorry for the lack of true help but I think James and Choua have identified the 2 weak points.

I would keep the CMG-Ultra-G (or any flashlight for that matter) under the car seat. I find this to be a really nice place to put things that might be affected by heat.

Even on a really hot day, the area underneath the car seat is only just warm, if not still cool (compared to the rest of the car, and ESPECIALLY the glove box, which can become a friggin' oven!).

O-ring on CMG Ultra is made from Viton - this was from the Email response I got from CMG:

From : "Julie Moncrieff" <@cmgequipment.com>
To : V T
Subject : Re: Lubrication Recommendations for CMG Ultras?
Date : Thu, 16 Jan 2003 11:29:27 -0600
Vincent,

The visible O-ring is made from Viton, which is a synthetic material. We
use and recommend a silicone grease to lubricate our lights.

Julie
CMG Equipment
www.cmgequipment.com