With sustainability in mind, and trying to do something new, I am looking forward to charge my car battery using Solar Power, without making much changes to my car's electrical system.
Basically I want the alternator and solar power to charge the battery to a certain level, lets say 13V. The rest 1-1.5V, I want to charge using solar power only, taking the battery upto 14-14.5V. Meaning if solar power isn't available (night driving/cloudy day etc), at least the alternator charges the battery to a certain extent to keep the car working as expected(starting etc).
For the solar power, I will make use of a solar charge controller, charging the battery to a configurable voltage between 12.5-14.5V.
My question is, how do I limit the alternator to ¬13-13.5ish V ? Is adding a diode from the alternator to the battery a good and sane option ? Lets say this diode seems to do the job, as my car alternator outputs a maximum of 70A.
Is there a better way to achieve the above mentioned ?