So for a project I am looking at making a solar charge controller for a 3S Li-Ion battery system used in an RC Plane.
The issue I am running into now is that I am unsure how to go about designing the charge controller for specific performances.
So currently our battery pack is going to be 5000 mAh. However based on our calculations the maximum current from our solar array is atleast 6 Amps. The problem is that we want to be able to control the maximum current coming from the solar panel to the battery while it is in use.
What I mean is that while we are flying we might be drawing 5 amps from the battery for the motors but charging 10 amps from the solar array which leaves us at a safe 5amp charge. However, if we go below this in motor draw, say 4 amps, that means we are now charging at 6 amps which is over the recommended charge rate for the li-ion batteries. Does anyone know of a way we could somehow adjust the current going to the system to prevent the battery from overcurrent? The mppt charge controllers we have looked at like the LT8491 do not have a method of controlling the maximum current except for the resistance values you pick when you create the PCB.
I wasn't sure if there was a way to just shunt of the current safely without wasting a lot since we are trying to get the RC plane flying as long as possible.