hello friends,

i am thinking of project in which i want to merge two power source in a single lead acid battery one is the grid supply and other is the power from solar panel please any one can provide me the circuit diagram for this. actually i dont want to waste the solar power i am going to use 250 watt solar panel and a 12v 120ah battery for charging it, i want to run 2 fans and 2 tube light for 8 hrs in the absence of grid .

actually the problem in india there is a massive power cut we use to get a power cut in every 2 hrs for 3 to 4 hrs so the battery need at least 8hrs to charge i want to use both in the presence of grid i want both of them charge the battery and in the absence of grid solar panel should do its work . actually the planning is not to waste the solar power while grid is available.

eg: it is like if a battery need 230v of supply to charge and if i am getting 120v from the solar so i want rest of 110v only from the grid, by which i can save the electricity bill based on this consideration can any body help me and what r the other equipment i should have while constructing this project​

 

That doesn't sound so hard. If you need a light I assume someone is there, and that someone could turn a switch at sunrise and sunset. That would change from solar to grid charging.

What is the size of your load? Batteries do not last very long if you drain too much out of them. You should stick to 50% or even 25% of capacity, or 60AH max 30AH typical from your battery. Is that enough for the 2 fans and 2 lights for 8 hours?

Did you pick a PV panel (solar cell) yet? Got a link to the specs?