Hi everyone,

With my friend we built a solar powered glider (4m wingspan). Yesterday we made a 7 hours flight with 7800mah battery pack, the total load was 17500mah with solar cells.

It was great BUT, during the day the controler was fighting with thermals to regulate the altitude, what a waste of energy !

I tried to set the maximum sink to zero in TECS params but it didn't work. I'm sure there is a solution to let the plane taking altitude with thermals. The max climb max is set to 0,5m/s and it works great to limit the power and it is enought to lock the alti.

Maybe someone know how to let the plane free to climb but managing an altitude floor.

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Andreas Gazis said:

My skywalker and bixler consume about 4 amps @ 3S so, let's say roughly 50W to hold altitude.

How much does your motor draw?

The cells should produce enough to keep it up when the sun is high. What about battery voltage? Was it generally close to full when the sun was high? Did you start noticing the voltage starting to drop at a particular time in the day or was it being slowly being drained throughout?

Hi Andreas,

For the altitude hold it supposed to consume 56W. In fact it consume only 37W !

The weather was bad and we lauched at the morning so the battery voltage started to decrease until 14V. When the sun was high the voltage was 15,8V. Some cells are broken and it was cloudy. With small battery the key is when to lauch, not to early, not to late. The solar controller is a GENASUN GV10 li-ion.

Philipp Oettershagen

Exactly, this is also what we set (and extended) in the "passively thermal compliant" version of TECS (and also the active thermal tracking variant of it) that we use on our Pixhawk- and solar-powered glider. It is really not that tough to adapt TECS in that way, although you need to potentially take care of integrator wind up (due to the altitude error that is not being corrected). See http://diydrones.com/profiles/blogs/ackling-the-european-refugee-cr... and the papers at http://www.atlantiksolar.ethz.ch/wp-content/downloads/publications/... .

@Jean-Jacques: Great great work btw., love to see more of this!

Hi Philipp, thank you for advice, we are following atlantiksolar project, great team. Your groundstation software looks nice but it's another subject.

Post a link to youtube! Great work guys! I'd check out ArduSoar firmwareon gitHub. I used it for an automated soaring project and it went well. 

Thank you, I will try this fork on another plane to test it. It is exately what we need. I hope it's not a too old version of arduplane.

Gavin Greenwood said:

Post a link to youtube! Great work guys! I'd check out ArduSoar firmwareon gitHub. I used it for an automated soaring project and it went well.

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