[nateairman]

Long and short I recently picked up a used Maule and have been flying it in 50c 4s 2200 batteries. A weird thing is happening:

Fresh battery 2°C ambient temp. Flaps set at 30° take off roll to vertical and full power. Sudden power loss and drop the nose glide in for a controlled landing. This has happened a twice now. I have attributed it to hi amperage draw and the esc cutting power to save itself. When checking the battery it is not hot nor is the esc. Flight testing continued with a moderate takeoff a circuit then full power vertical shenanigans again with out power loss.

I am not sure how to diagnose this? Amp meter? Watt Meter?

FYI I am not using the BNF reciever. I am using a futaba system. I could set up telemetry.....

I do have surface control just loose thrust....

[ballast]

My first go to tester would be a wattmeter. It will display your current draw at different throttle command and will display the amp draw you are at when this engine starts dropping RPM. The ESC could be your problem.

[Pauld]

I had this problem with a similar set up. Turned out it was internal resistance built up in the batteries. They charged fine and tested fine cell voltage view but when you put them under higher current draw loads their voltage would tank. The batteries still work but are only good for low current draw....

PaulD

[stegl]

Could be high battery internal resistance causing an issue as I had that happen once. Not a lot of information to go on. Let’s try for more , like motor size , ESC make and model , prop size and if you can get the current draw with a wattmeter that might help , does it do this with just this battery or have you retried it with another battery ?
Thanks

[cessna180]

I only fly electric and have made a point of trying to educate myself in all aspects of the power system, battery, esc, motor ,prop. Chasing an electrical problem could be a challenge.
I try not to run the system at max. I use a watt meter religiously and I regularly check the resistance when charging. Also I do not leave fully charged batteries for more than a day, then into storage mode they go. I have found that as the resistance increases the battery performance is degraded and flight times are less. Just try another battery. All the best.
Michael

[nateairman]

Originally Posted by stegl

Could be high battery internal resistance causing an issue as I had that happen once. Not a lot of information to go on. Let’s try for more , like motor size , ESC make and model , prop size and if you can get the current draw with a wattmeter that might help , does it do this with just this battery or have you retried it with another battery ?
Thanks

It is a stock BNF Maule. The battery is a new 4s2200 50c full charged with in the hour. I will fly again tomorrow and try to duplicate. I have a few 3s2200 50c as well but they have 10 more cycles than the 4s. I will also start a log book with more detail.

I just don't want it to become a preventable accident.

[rucoy]

Hi Nate,
2 degrees is "cold" to a lipo, new or old, if you haven't already done this try warming up the battery just before inserting it into the plane. I have an electric battery warming bag that I use during the colder fall and winter flying and it has made a big difference. The Maule doesn't like to fly with 3s very well
Hope that information is helpful.

[nateairman]

Originally Posted by rucoy

Hi Nate,
2 degrees is "cold" to a lipo, new or old, if you haven't already done this try warming up the battery just before inserting it into the plane. I have an electric battery warming bag that I use during the colder fall and winter flying and it has made a big difference. The Maule doesn't like to fly with 3s very well [IMG class=inlineimg]https://www.rccanada.ca/rccforum/images_rcc/smilies/dontknow.gif[/IMG]
Hope that information is helpful.

A good point. I believe that day the airplane was prepped and we flew rockets first, so the battery was probably cold. Usually they are kept inside my jacket until flying.

[Mytmerc83]

I would test with a watt meter, for some reason I think the esc is shutting down in overheat mode, I had an esc do the same thing. Motor stopping with surface control is a sign of esc in over heat protection. 2⁰ is "cold" but I've flown in -20 winter after winter and have only noticed a shorting of flight times by at most 1 minute with a cold battery.

[rucoy]

From the info stated by the original post "When checking the battery it is not hot nor is the esc. Flight testing continued with a moderate takeoff a circuit then full power vertical shenanigans again with out power loss"
I think the esc has gone into LVC (low voltage cutoff) with the cold lipo and the initial punch on take off. With a cold battery, the IR is usually high and causes a drastic voltage sag to engage LVC, that is why there is no motor power but still has control to flying surfaces. This can also happen as mentioned in the last post when esc goes into thermal protection but given the the information posted it's unlikely that. I've experienced this exact issue when I first started flying in winter without "preheating" my batteries. Good luck and hope you sort this issue out, enjoy the flying