Oregon 450

This isn't really the place to raise this, but I'd suggest you try Sanyo Eneloops ... they last 3 to 4 days in my Etrex 20

I doubt you are using lithium rechargeables, I presume they are actually NiMH rechargeables.
All batteries are affected by cold temperatures, NiMH batteries can be bad for this. Some of the 'low self-discharge' types (eg Eneloop) are apparently a bit better.
Non-rechargeable lithium batteries (eg Duracell Ultra) would probably last longer in cold temperatures, but they are rather expensive.

Also, try and keep the GPS warm, ie keep it inside your jacket.

I'm not sure whether you would get much useful power from a solar panel, unless it is rather large, and you are somewhere very sunny.
Maybe more useful to use a separate Lithium-ion battery pack (eg Powermonkey). Then you can keep this warm in you pocket, with a cable connecting it to the GPS.

I keep non-rechargeable Lithium's in my 450. They're lighter than standard AA's and are better in cold weather. However they're not cheap.

http://www.energizer.com/batteries/performance-lithium/advanced-lithium/Pages/aa.aspx

You can keep your GPS warmer by keeping it in a pouch with a chemical handwarmer. Some last as long as 8 hours. That should help keeping the charge of the batteries up for a longer time

I am the happy owner of Oregon 450 which i mostly use during wintertime. The battery capasity is reduces in cold environment therefor it is not possible to have the GPS operative during a whole day. I use 2 Lithium rechargable batteries mAh 2100.

Is there a way to improve the "on-time" for the GPS or is there any solarcharger which one could use during longer trips away from civilasation.
Looking forward for any tips and info.






Regards Kris