Lipo Batteries and Cold Weather

[SecretBuilder]

Hi everyone,
This is one of my first winters/time of cold weather in the RC hobby (during my first all I had was the HobbyZone Champ) and I am wondering what the short and long term effects of using Lipo batteries in cold are. Any help would be appreciated.

[retiredVTT]

..found some info here...
https://www.google.com/search?sxsrf=ALe ... ent=psy-ab

[MGC]

Hi Aiden,
The link Bill sent is exactly what happens to lipos in the cold. You can find ways to work within these restraints though. For example, small 280mah 3s batteries you would use in a umx plane, i find that after a couple min in cold weather they pretty much die. I've crashed a few times last winter due to this. However, a larger 2200mah pack may hold up to (or close to) its typical flight time as there is a lot more heat generated in the larger battery, countering the cold. Some tips to flying safe in the cold are, one, shave a minute or two off your flight timer to see how that particular battery behaves in the cold. Second, before flying, keep them warm. Maybe wrapped and kept in the car for example. Next you would ask the question, is the battery exposed to the cold air when in flight? Like on the front of some of the flight test planes, cold air slaps that battery face first. Other planes the battery is tucked deep in the fuselage keeping it warmer. If its one if those brutal cold days where you wouldn't want to take your gloves off, its probably safer to keep the planes at home and wait for a warmer day. Flying off of snow with floats or skis is super fun, and luckily in NS we have lots of warm winter days!
Thats just my experience, I'm sure others would have more info and recommendations.
Cheers!
Mark

[bdg]

Sounds like lots of good advice.

Ultimately, the internal resistance of the batteries is higher in the cooler temperatures, meaning that losses in the battery are high and voltage to the motor is reduced. And the ESC could even see a LVC prematurely. Once the batteries run for a short time, they can warm up.

I have a battery heater bag (https://hobbyking.com/en_us/turnigy-pro ... tore=en_us) which helps too. Ultimately, keep them warm for the best performance. In the car, your pocket (be careful with them there!) or in some other warmer enclosure.

The DJI drones will not even take off if the batteries are below (I think) 15°C. So that is how they address cooler temperatures.

Brian

[SecretBuilder]

So, all in all I don't think I will be flying very often (or at all) this winter because a lot of my planes are Flite Test planes and a lot of them have the battery exposed. Also, almost all of my batteries are small (850 mah 3s) and they would not fare very well in the cold, especially combined with the exposed battery problem on most of my planes. Also as a follow-up question, are there any long term effects of using Lipo batteries in the cold? (like reduced life span or worse performance even in warm weather)

[bdg]

Aiden,

I wouldn't let an "exposed" battery hold you back for winter-like conditions! A small amount of foam - with all of the ventilation around it - is not that different than being fully exposed. Best performance would be from a higher-C battery as the internal resistance is lower. But warm them up just a little beforehand and you should be ok (a warm car is fine!). It will take some time for them to cool down too.

Will these conditions reduce the number of cycles? Now that is a question that I can't answer with certainty. But, I would tend to say "no" as you aren't heating them to high amounts and therefore abusing them. They will like you to take it "easy" for the first start of the flight just to let them warm up.

This is from a DJI quadcopter publication:

Warm = happy But there are certainly reasonable levels to very much allow you to have fun in these cooler winter months!

Brian

[the-mailman]

Hi Aiden, I fly all winter with a variety of battery sizes. I haven't had any problems flying 1000 - 1300 3s batteries on my Flitetest style cub. It has the battery exposed and I get pretty much the same time as in the summer. You won't know until you try.

[SecretBuilder]

I think that I will try flying a few of my planes with different battery sizes to test it out. My FT Mini Guinea has the battery (850mah 3s) buried away inside the nose away from any air flow so hopefully that one will work.(in the fall when I take the battery out It is a bit warm, even only discharging at a third of the C rating) I am also working on a bigger plane with a bigger motor (1000kv) and a bigger battery (3000mah 3s) so with the bigger battery I think that this one could work even though the battery has a bit of air flow going over it. Also, how often do most of you go flying in the winter compared to the summer? Once a week? Once every few weeks? Thanks for all the information on the batteries.

[bdg]

I agree with Bruce - just get out and fly! Be aware that there could be a few differences but nothing that should hold you back!

Speaking of cold weather.... what the heck? Brrr.... Time to get out the float planes!

Brian

[JohnOSullivan]

A couple of weeks ago I was out on a Sunday when the temperature was 0 deg C. I had my models in the car since Saturday and were subjected to sub zero temps overnight. I don't recall what the overnight temperature was but likely -6 degC or so.

I was flying my Mayfly 2m sailplane. Battery was a Hi voltage Bolt (4.35v per cell) 500mah 3S, 65 to 130 C(lots of capacity). I started the motor and within 1 second, before I launched, the motor died. No problem, perhaps I had not given it a full charge.
I changed the battery for an 800mah 3s, Normal voltage battery.
It worked OK for about 2 seconds after launch when the motor died. this took it to about 70 ft. Rudder or elevator functions were fine so after it glided down to about 15 ft, I started the motor again. This time the motor ran for about 5 seconds before it cut. This took the model to about 200 ft. After I glided down to about 20 ft when I started the motor again. This time the motor ran faultlessly for 12 seconds (my normal climb time) before I cut the throttle.

It looks like the initial attempts with the very cold batteries brought the batteries to the low voltage cutoff. The second launch may have heated the battery to a more usable temperature, while the third climb raised the temperature sufficiently that the low voltage cutoff was not reached.

On checking the batteries at home a few days later, both batteries were still up to full voltage and performed flawlessly.

Answer is to make sure your batteries are at room temperature (keep them in a warm pocket) before using them.

In spite of many winter seasons flying, this is the first time I have run into low temperature motor cutoff.