Electronics and a change in voltage

[dmriser]

Hello,

I am designing a solar powered rc plane as a project. I have an electric motor assembly intended to be used with an 11.1 volt battery. My solar array outputs around a steady 7.5 volts. When configured with a battery the motor drew around 9-10amps of current under full load. Making the output around 111 watts of power. What strength of current would I need the solar array to output to achieve this power? And would this even work? I have calculated around 20amps (approximate). This is far above the output of my solar array in terms of current.

Also, how could I measure the maximum current my battery can supply if I want to include one. I assume that because of the thickness of the wires and other parameters my battery cannot give an infinitely strong current and deplete it's power almost immediately.. But how would
I measure it's peak current outflow? I hope I have asked these questions in a clear manner and some one may be able to give me some information. This is not homework, just for fun and knowledge. Thank you.

 

[Redbelly98]

A 7.5 volt source would have to be capable of producing 15A of current, without a drop in the voltage, to provide 110 W of power.

However, your motor will draw considerably less than that current at 7.5 V, given that it draws 9-10A at 11V.

 

[dmriser]

That helps thank you.

 

[russ_watters]

...note that it will also output less power (thrust) at the lower voltage.

 

[sophiecentaur]

You need to measure how many Amps your solar panel can give you at its normal output voltage. You haven't yet given enough detail of the setup for anyone to give a reliable opinion about how feasible it is,

 

[dmriser]

The solar array can give ~7.5 volts with 2 amps of current. However, I'm not in need of the full power of the engine for flight.

 

[sophiecentaur]

Afaik, solar powered flight is a bit marginal. i.e it has to be engineered right for it to work as there's barely enough energy from available panels. This implies, to me, that you really need your panel and motor to be matched as well as possible.
There are many 12V panels available and also many 12V motors and it may be that you will need to pair them up if you want reasonable results. I think the available power per square meter is much the same for any output voltage.
It appears that you have a panel and motor (?) so why not try it out? If you don't have a panel yet then select a 12V panel of the right dimensions. (New models seem to be arriving almost every week.) There isn't much point in carrying a massive battery on board as that will significantly add to the payload but a 'small one' could give you emergency backup for a minute or two - to land, for instance.