I am a rank amateur in electronics, so please assist.
I have a solar system (PV) charging 2 x 12v / 100Ah Lead Acid batteries for emergency lighting in my house (Max charge 13.8v). I also have an electric gate which has a 12v 7Ah battery with a built-in charger connected to municipal power.
I wish to disconnect the municipal power and charge the gate battery through the PV system. However, I find that if connected directly, and we have a couple of days overcast, the PV lighting system draws the current out of my gate motor battery as it depletes.
I would like the gate motor battery to not return any charge even if the home batteries are discharged to 10.4v.
Can I prevent this from happening by adding a diode?
What diode should I use? where is the best place to add the diode?