(We need longer topic descriptions.)
Ahem.
Photosynthesis would be a method of spending some energy, to get some energy back for converting things.
You could have to specifically choose what you're going to convert, or maybe not.
(By converting things, I mean converting body, waste, or anything else that can be turned into energy.)
Before I go on, I assume that converting something into energy would cost a number of energy equal to the amount you're converting. (10 body into energy would cost 10 energy.) (As another assumption, unless you're converting waste (which will generate plenty of permanent waste for you), you should gain this much in waste as well.)
But with this method, you can, provided you receive enough sunlight, expend even less energy.
To use photosynthesis, you'd basically set a variable called .photo.
This would be deleted after use. I'm not sure how this would work programming-wise, but it might require the use of a variable in which conversion costs would be added to this, and then later on in the cycle, it would be taken from .photo and then from energy.
Of course, you don't simply gain the energy you put in .photo.
Actually, the program'll read the value stored in .photo, and take this much energy from you.
Only afterwards would it limit it to (Body/50) or something like that.
After THAT, it would then be multiplied by how much light you're receiving (or something.)
Of course, rather then strength, once multiple types of energy storage are in, it would use a size-type number. (That way bigger bots can photosynthesis better, while smaller bots can fight better.)
If I'm wrong about photosynthesis, please tell me. But as far as I know, this is the basis of how it works. (And we shouldn't make DarwinBots TOO complicated. :P )