Solar powered plane

I want to create a solar powered uav, which charges the battery and runs the motor while the uav is in flight to increase its flight time, is there any way to achieve this without using any sophisticated MPPT systems as the budget has been invested on solar cells, which are 5BB 4.5 wattage, single cell producing about 0.57 volts, current I have no idea, these are 18% efficient polycrystalline cells, the system is intended to increase the flight time of the uav, I am not getting a idea how to do it without an MPPT, could relay be used? or pwm, what should be the battery lithium ion or lipo, I have numerous doubt I am totally new to this. any suggestions guides ? ( i know asking for too much of help but not getting a good source how to achieve it )

A MPPT solar charge controller is not absolutely required a simpler PWM charger can also do the job. But to get the maximum efficiency out of your solar cells you need a MPPT charger. The PWM charger will clipp your solar voltage to the battery voltage, so it is only efficient if the solar voltage is only a bit higher than the battery voltage.

Is there any way that the Pwm would be able to charge the batteries and run the motor at same time, as i am looking to increase the flight time for the aircraft, any way or guide to do do it, i am completely clueless here what to do what not and how to start

How many of those do you plan on putting on the Plane?

rctestflight done some good videos on solar planes

Any kind of (solar) charger will charge the battery and the battery fill feed the plane system and motors. So if the solar panel together with the charger produce more energy as the plane uses the battery will be charged. If the solar panel together with the charger produce less energy as the plane uses the battery has to deliver the differnce and will be discharged.
Mainly for such a system you have to built the charger / powermanagment system by your own based on the parameters of your solar panel and your plane system. To use something directly out of stock will be hard to find.
So first you must designe your plane itself, the drive system, the solar panel etc than you can look for the charger.
So calculate how much Watt you need to fly the plane without altitude changes.
Calculate the size of your solar panel and the possible power output in Watt.
What motor / battery / voltage you want to use?

Great advice, you have given me a great advice, i have little doubts but, like i have the max volts of my single i.e is 0.57volts and it’s rated 4.5 wattage i mean it’s claimed, these are polycrystalline cells not flexible, 5 bus bar hoe could i incorporate these cells, most of the guides are using sunpower c 60 cells and genasun mppt, i know for 12 volt motors i would require something like 14 to 18 volts from my array that I’ll create, any guidance on how to connect the cells,( i mean series parallel connections ). Is it possible to use brushless geared motors to fly it i know it’s whole other level doubt, but just curious, cause i am new to this whole solar soaring thing

I have no idea to be frank, i need as less as possible because the size of cells is little bit on bigger side it’s about 15x15 cm so the chord is increasing the wing span is increasing if i go with only series connection, atleast 25 to 30 are required then and my wingspan would significantly increase i want it to be under 8 ft around that range 8 is also too high but max i guess, these all constraints are due budget only. Quite frankly in my country hobby products are little bit on expensive side, by this if i go have to adjust the Aspect ratio also so getting too much confused.

As I said before we need more information from yourside abaout your plane and project.
In pprincip you can use either brushed or brushles motors. This has nothing to de with the DC source only with the kind of ESC.
The cells need to be connected in series as you need much higer voltage on the solarpanel as battery voltage. 5 bus bars ar no problem, these can directly connect from one cell to the next or
If iI look to the genasun mppt. This is specified for LiFePo cells but not for Lipos or LiIon. So for this we have to look a little deeper in.
Please provide datasheets or links of the components (cells, charger, motor) you want to use.
And I said before we need an estimation of the power you need to fly your plane.

yes got that, first ill do that only, i am avioding to use the genasun mppt, any alternate method that is there for the battery to be charged while flying and also powering the motor, i am not getting that part, how to achive it. the constraint i am taking are weight to be less than 2.5 kg overall

charging battery and powering motor at the same time is simple as the charger and the Motor / ESC are connected in parallel to the battery. So if the power from the Charger / Solar panel is grater than the power used by the ESC / Motor the battery will be charged. In the other case if power from the Charger / Solar panel is less than the power used by the ESC / Motor the battery will be discharged.

Any suggestions on charge controller for solar panels and the battery, what type of charge controller could be used ? I don’t want to use mppt, could a system with relay board be made. Is there any other solutions? For it

As I told you before you can either use a MPPT charger or a PWM charger.
The PWM charger is basically a switch, a semiconductor relay, a solid state relay, which is connected the solarpanel to the battery as long as the battery voltage is less than the absorbtion voltage. If the battery voltage rises to the absorbtion voltage the charger opens the contact and closed it again with a small hysteresis. This kind of regulator is not optimal under all solar conditions but it will work if you are using your plane moreless under the same sunny conditions.
But a real mechanical relay is not recommended.

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Check out my old post:


Thinking to use

This mppt module

And this motor 5010-360KV Brushless Motor 5010-360KV High Torque Metal Outdoor Big Load Multiaxis Thick Line Hollow Cover Double Bearing Brushless Motor – REES52

These are the cells i have i guess as the supplier didn’t mention about the data sheet though the power range is 4.5watt

Please only use these motors if you have the means to not only balance the props, but the motors as well. They are cheap for a reason and come horribly unbalanced from the factory and cause terrible vibrations if left untreated. And yes, I speak from experience :face_with_peeking_eye:

Although it may be not as bad in a plane as it is in a multirotor…


I have a little doubt if all this is working to gether as you don’t show your overall power requirements and elctrical design.
The shown motor is taking 20+ A while the converter can deliver max 5 A
So far I see the converter is working with constant current mode. If this is the only mode it will kil the battery. Constant current is good if the battery is not nearly full charged. If the battery is fully charged constant voltage must be used together with balancing of cells.
As the converter is a buck converter the voltage of the solar generator must be higher than battery voltage. This is possible by serial connection of the cells. The current of the generator can be up to 8.7 A. Is the converter working with this?
So just with this small informations without any exact datasheets I am not able to evaluate this all.

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Agree with Jan. “generic” is the key phrase in your link. These are probably the same motors sold by the likes of RC Timer and others and they are very poor quality.

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I am thinking of making it a rechargeable system, this module would be connected to thhe solar panel input and then will be connected to a 3s lithium ion cells, and the motor would be connected in parrallel, and i am hoping that this system would recharge the batteries while the glider/ aircraft is in its crusie phase as the cruise power requirements for an aircraft are lesser, i am new to this part so i might be very wrong, the panels i am getting the voltage readings but i don’t get how to measure its current. any suggestions on this ideation, and as motors, there are very less motors avalible in my region, i thought this one is good as it is of a lower kv value, as the weight of whole uav i am trying to keep it under 2.5 kg, so motor selection for that is a little bit difficult