Flying at 39˚C - Issues and issues?

[vyoufinder]

Took a Spark and Inspire 1 Pro out yesterday in 39˚C weather and just as we left the air conditioning stopped working. So it got pretty hot in the truck, definitely above 40˚C as DJI recommends for the top temperature for flying in.

The Spark stammered around on the ground and bounced up once or twice but could not really take off. It acted like it was not getting enough voltage, then a few bursts.

I sent the Inspire 1 Pro up real quick with a battery temperature of 44˚C at takeoff, then went up close to 100 meters, and basically back down since I notice the battery temperature at 55˚C. I've had issues before flying in 100˚F weather (about 40˚C) but always been able to fly. Always with a bit of fear when doing so.

What is the best way to keep batteries cool? How cold can I get them in the fridge before I start walking out so as to maintain as much coolness by flight time? What do others do in hot climates?

 

[Goavgas]

I always bring the temperature of the battery down to 23 C before charging.
I also keep them in the discharged at 20% in the refrigerator at 20C when not in use. In the Field I just have a small cooler with Cool packs in the bottom with a towel on top to insulate from the batteries. They stay about 25 C in there. This way they stay cool before flight in the TEXAS HEAT.

 

[vyoufinder]

I always bring the temperature of the battery down to 23 C before charging.
I also keep them in the discharged at 20% in the refrigerator at 20C when not in use. In the Field I just have a small cooler with Cool packs in the bottom with a towel on top to insulate from the batteries. They stay about 25 C in there. This way they stay cool before flight in the TEXAS HEAT.

What is the reason for storing the batteries at 20 percent in the fridge instead of 50% and at room temperature, more like DJI recommends? Do you let them warm up before charging, then stick them back in? I'm thinking I'll start cooling them off about an hour before I leave, then by the time I get out to where I am going, they should be about 70F I am expecting.

 

[Goavgas]

You are Right!!!!

Wow.. After all these Months, They survived my torture. Guess I''ll store them at 50%..
I just have a small wine cooler it keeps my wine and batteries at 70 degrees.
Seems like a good place to store them.
My thought process is HEAT Kills but as it goes with LIPO's so does Cold.. 16 C and below, they don't like. But I have never had any issues with my Lipos

 

[vyoufinder]

You are Right!!!!

Wow.. After all these Months, They survived my torture. Guess I''ll store them at 50%..
I just have a small wine cooler it keeps my wine and batteries at 70 degrees.
Seems like a good place to store them.
My thought process is HEAT Kills but as it goes with LIPO's so does Cold.. 16 C and below, they don't like. But I have never had any issues with my Lipos

I've been cooling mine in the fridge for about 45 minutes before flying, or when out camping, I put them in the cooler a couple hours before flight. Has worked great and I'm landing without the batteries being hot like they used to get. No more erratic flying, dropping altitude either.