Hot Climate, Brushless Motors, & LiPo Batteries
03-22-2004, 01:38 PM
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Hot Climate, Brushless Motors, & LiPo Batteries
Has anyone flown electric 3D aiplanes in very hot climates (120 F)? Any issues with brushless motors and/or LiPo batteries?
In the summer, I have flown an electric Zagi with an Astroflight 020 brushless motor running on NiCad batteries in Arizona in 115+ F & discovered problems with engine & battery heat. I am thinking about purchasing one of the flat foam airplanes from TBM in Florida which utilizes a Himaxx 2105-3600 brushless motor & LiPo batteries.
Does anyone know if this will also be a problem in the heat.
Thank you,
Bob
In the summer, I have flown an electric Zagi with an Astroflight 020 brushless motor running on NiCad batteries in Arizona in 115+ F & discovered problems with engine & battery heat. I am thinking about purchasing one of the flat foam airplanes from TBM in Florida which utilizes a Himaxx 2105-3600 brushless motor & LiPo batteries.
Does anyone know if this will also be a problem in the heat.
Thank you,
Bob
03-23-2004, 07:50 AM
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RE: Hot Climate, Brushless Motors, & LiPo Batteries
I'm not sure what would make you think it would be any different than the Astro and NiCds, but it won't.
By the sounds of it, you have to compensate for the extreme temperatures by not working the motor very hard. You don't want the motor heating up on its own, since the ambient air temperature will do that just fine on its own.
Same thing goes for the batteries. LiPolys catch fire when they experience "thermal runaway." That is, they get to a certain temperature where a self-sustaining chemical reaction starts, and it's all over but the fire extinguising. If it's 120F outside, you don't have much wiggle room between ambient and thermal runaway. I'm not sure of the exact temperature, but I believe it's around 160F. Worked hard, a battery can easily increase in temperature by 40 degrees.
You don't want to come anywhere near the maximum current for either the motor or the batteries. With lightweight 3D planes, it's generally not an issue because you're hardly ever pouring the coals to it. Most maneuvering is done with very little throttle, as there is an excess of power and thrust.
By the sounds of it, you have to compensate for the extreme temperatures by not working the motor very hard. You don't want the motor heating up on its own, since the ambient air temperature will do that just fine on its own.
Same thing goes for the batteries. LiPolys catch fire when they experience "thermal runaway." That is, they get to a certain temperature where a self-sustaining chemical reaction starts, and it's all over but the fire extinguising. If it's 120F outside, you don't have much wiggle room between ambient and thermal runaway. I'm not sure of the exact temperature, but I believe it's around 160F. Worked hard, a battery can easily increase in temperature by 40 degrees.
You don't want to come anywhere near the maximum current for either the motor or the batteries. With lightweight 3D planes, it's generally not an issue because you're hardly ever pouring the coals to it. Most maneuvering is done with very little throttle, as there is an excess of power and thrust.
03-23-2004, 10:59 AM
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RE: Hot Climate, Brushless Motors, & LiPo Batteries
The main differences are:
In the Zagi, both the battery & motor are under a canopy, although with cooling vents. In the flat foam plane, both the motor & battery is exposed. Additionally, the Zagi was being continually run at moderate to high power settings. I am hoping the very light foam plane is drastically overpowered & able to be hovered at low to medium power settings.
I have no experience with LiPo batteries. That was the reason for my post. It sounds like they get hot just like NiCads under high amperage draw. Are they similar to NiCads in that they should not be charged until they are cooled? After discharging the NiCads, I was placing them in a waterproof container inside an ice chest to cool, prior to charging.
Any suggestions as to where to find the "self sustaining" critical temperature?
In the Zagi, both the battery & motor are under a canopy, although with cooling vents. In the flat foam plane, both the motor & battery is exposed. Additionally, the Zagi was being continually run at moderate to high power settings. I am hoping the very light foam plane is drastically overpowered & able to be hovered at low to medium power settings.
I have no experience with LiPo batteries. That was the reason for my post. It sounds like they get hot just like NiCads under high amperage draw. Are they similar to NiCads in that they should not be charged until they are cooled? After discharging the NiCads, I was placing them in a waterproof container inside an ice chest to cool, prior to charging.
Any suggestions as to where to find the "self sustaining" critical temperature?
