Hi,
I've been looking for any charts or information on what would be the maximum coldest temperature that would be the safest to fly electric aircraft. Meaning maximum battery time. Does temperature really effect time ?
Thanks.

It seems to me that the temperature would only affect the battery at the very beginning of the flight until it warms up. Then it would depend on how you fly or where the battery is located on the plane. Aggressive flying would warm the battery up quicker than docile flying. Also, if the battery is located outside the fuselage, as on a Slow Stick, this might prevent it from warming up altogether.

Just my $0.02.

I do a lot of flying in temps between 20 and 40 degees F using Nicads and Lipos. If you charge and warm the batteries up prior to putting them in the plane you will notice no loss of time or power. If you don't keep them warm prior to use you will notice more loss of power than loss of flight time, but you will lose both. After charging, I keep the batteries I am going to fly in my pockets close to my body so they will stay warm, or I leave them over the defrost vent in my truck. Sometimes I stay in the truck and stick my antenna out the window! I suspect judging from were you live that you might be wanting to fly in temps much colder than 20 degrees F. You might have to check with some clubs "local" to you or find out by trial and error what you can get away with!

Hi Cool Pool
Batteries of all kinds are affected by the cold. But take it from someone who does fly in the cold (so far this year as low as +5 degrees F). The amount the cold degades your batteries is prportionate with how fast your hands get cold. I do keep battery packs warm in a car or pocket until just before flight. Good luck and try to stay warm.
OEMFlyer

For my profile fuses., I make an envelope from that foam plastic, about 1/8 in. thick, that electronics is wrapped in. Scotch taped together with a velcroed closure and velcroed to the side of the fuse. As said above, my fingers freeze up before the batts do. Maybe I should make an envelope for my fingers too.

You mentioned that your question was mostly focused on batteries. I haven't found batteries to be the issue. As noted above, they can be managed. This issue I find in low temps is that various plastic parts can become brittle and easily break. As a rule the thinner the plastic, the more fragile it gets. Just an fyi in case that wasn't considered....

I think below about -20F some batteries might have problems working.

I have flown at 0F with no problems. I keep may spare packs in my pockets to keep them warm. I never leave them out in the cold overnight. They are chemical engines and the chemical reactions that produce electricity slow down when they are very cold. So keep them in the house. Keep them warm before you fly them to get the best life and power out of them.

I also run the next size bigger prop in the winter in order to make the motor and batt. work a bit harder to generate a bit more heat.