This thread makes one grateful for living in near Tropical conditions.

I love my Cateye lights as they work flawlessly for me.

I've seen reduced capacity for NiMH in cold weather too. It's pretty standard for anything that relies on chemical reactions for operation.

Just to get some idea of what was normal, I dug up some tech info on Panasonic lithium ion 18650 cells...
https://industrial.panasonic.com/cdb...A4000CE240.pdf

The graph at the lower left shows how the battery capacity is affected by temperature. A change from 25C to -10C should only reduce the capacity by 10% or so. Of course, this applies to new batteries. I suppose an older battery would be somewhat worse.

Given; Warm batteries work better than Cold ones. if you can put your battery pack inside your coat,

And, have a Headlight on a cord , for mounting, remote from the battery,... that will probably work better in the winter.





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Same here - love the Volt 800!

I'm a big fan of lithium ion batteries but was not aware that they may be useless at -10 degrees celsius (14F) and seriously compromised when it approaches freezing as shown in this chart https://www.google.com/search?q=Lith...A3V4Wd6zo2M%3A or figure #11 in this article Willkommen bei BaSyTec. It's not the fault of the light. We all love having bright lights that have a long run time between discharges and LED/Li-ion battery combination provides that for the time of year that most people ride.

You might do better by buying an inexpensive 1000 lumen XML-T6 LED flashlight that uses both 18650 Li-ion batteries or three AAA alkaline disposable batteries. In really cold weather it will still give you an excellent output with alkaline batteries and when it is warmer switch to rechargeable batteries.
Like this - two (real output 1000 lumen) flashlights for $8 USA 2PCS Zoomable CREE XML T6 LED 5000LM 3-Mode 18650battery Flashlight Lamp | eBay the battery case for using 3 AAA batteries $1.48 for five of them 5X Plastic Flashlight Cylindrical Holder Case Battery 18650 Black Box For 3 AAA | eBay
and a really good mounting clip for $1 360 Degree Cycling Bicycle Bike Mount Holder for LED Flashlight Torch Clip Clamp | eBay from China

Looking at that chart NiMH looks to handle the cold very well, which fits with my experience. I have a AA headlight that I leave in the cold garage and it works fine. I haven't had the best luck with NiMH in tail lights though. Even when the weather is warm the runtime is much shorter than alkaline.

Well, it's official: this resurrected winter thread signals it's C-O-O-O-L-D out again. |wink|