Change over circuit from solar to mains and vice versa

[Karimulla Baig]

Dear,
please any one help me in designing the change over circuit from solar to mains and ,mains to solar.
the problem what im facing is even though there is no power from the panel it will display voltage across the panel so im facing difficulty to change from solar to mains and vice versa.


Regards,
Karimulla Baig

 

[alec_t]

The solar panel provides a DC voltage whereas the mains is AC. How do you plan to interface them with a load?

 

[unclejed613]

you need to use the panel to charge batteries, then the batteries drive an inverter., then you need an AC transfer switch to change over from the AC line to the inverter. transfer switches are available that have ratings from 50 amp service, all the way up to 600 amp service and beyond..... inverters and batteries are another piece of the puzzle.... how much power do you need and what are you intending to run off of solar power, and for how long? when you answer all 3 parts of that question, you can then figure out what you need for batteries and an inverter. the transfer switch only needs to be rated for the service that is available for your house (most often 100A in the USA, probably 50A in countries with 240V service).

 

[4pyros]

the problem what im facing is even though there is no power from the panel it will display voltage across the panel

Are you talking about the open-circuit voltage? You can reduce that with a dummy load.

 

[Karimulla Baig]

Dear,
My idea is to design a change over circuit to charge the battery from both mains and solar for battery charger.
when ever there is no power from solar the battery should get charge from mains for this i need a change over circuit.

kindly help me in the designing the circuit

 

[blueroomelectronics]

Opps.

 

[alec_t]

Tell us the specifications of your battery and solar panel.

 

[Karimulla Baig]

Dear ,

Solar panel output volatge is 6VDC.
ac(230VAC/6VDC).
Battery 6V 4.5Ah.
I need a change over from solar to mains and vice versa i have made the battery charger for both AC mains and solar .
wher i will be getting out put of 6VDC from both solar and ac mains.
now i need a change over circuit for this because whenever there is no power from the panel its should change over to mains.
the problem is we will be having always 6VDC voltage across the panel so, im facing problem in the change over.

Regards,
Karimullla Baig

 

[alec_t]

the problem is we will be having always 6VDC voltage across the panel

Only if the sun shines brightly enough and only if the panel has a built-in voltage regulator.....which I doubt.
A real problem is you will need more than 6V to charge a 6V battery .

 

[ChrisP58]

Instead of looking at the panel voltage, look at the charge current from the panel.

Switch off the AC charge whenever there is enough solar energy to charge.

 

[ChrisP58]

Sorry, wrong thread.

 

[MikeMl]

To charge a 6V lead-acid battery requires almost 7V. The correct specifications for a suitable panel required to charge a 6V 4.5Ah battery would be that the deliver 7V at a current of ~1/2A, which means that the panel should produce an open-circuit voltage of 12 to 15V. Is that the sort of panel you have?

 

[Qaisar Azeemi]

if you know microcontroller programming. then it will be very easy for you to design and program a changeover switch.. or just use a simple relay of 220 volts. keep its coil connected to 220v mains supply and connect normally open contact of the relay to your load. while solar contacts must be connected to the normally closed terminals of the relay (you can easily find such relays in local made simple UPSes). now you can imagine what happen when mains fails the relay will automatically switch your load to solar.

 

[unclejed613]

you don't even need a microcontroller for that, just run the relay from a line powered supply. the relay is energized while the line has power, and provides charging current through the NO contacts. when the power fails, the relay de-energizes and the NC contacts connect the panels. or even simpler, diode OR the supply and the panels to the battery.... no moving parts at all

 

[lowla]

if you know microcontroller programming. then it will be very easy for you to design and program a changeover switch.. or just use a simple relay of 220 volts. keep its coil connected to 220v mains supply and connect normally open contact of the relay to your load. while solar contacts must be connected to the normally closed terminals of the relay (you can easily find such relays in local made simple UPSes). now you can imagine what happen when mains fails the relay will automatically switch your load to solar.

can you tell me more about the changeover switch UPS relay using a microcontroller?

 

[alec_t]

Well, he might be able to if he's still around. Do you realise this thread is >4 years old?