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Off Grid Solar Panel System Switch

PostPosted: Sun Aug 19, 2018 6:12 am
by ewherrera
Hello, My name is Ernest Herrera,
I am a retired Field Service Engineer. I moved to live with one of my sisters three years ago and realized quickly that the electric utility bills had gotten very high because our usage had caused the power monthly consumption had pushed us into a higher pay tier. I decided to try installing power panels to see how much it would cost and how much it would lower our bill. I knew very little at that time about solar panel system, but quickly learned. I bought enough power panels and the required associated equipment to power up most of mu equipment. I was amazed at how efficient and reliable it was. After testing the system for a year I built a manual switch to change from solar power to prime power when ever my battery bank voltage got to low to drive the inverters. I was not happy with the manual switch since it depended on me checking the battery voltage periodically to determine when to switch to the other power source. I then designed an automatic switch which users a micro controller with transceiver to measure the battery bank voltage and transmit it periodically to the receiver microcontroller which is also based on a micro controller. When the battery voltage received is below 12 volts it switches to prime power and above 12 volts to the solar power. It is a wireless system and is very reliable. I have now been using it for about a year and only an occasional bad reading received by the switch but the default is prime power so it has never failed at this time.

Re: Off Grid Solar Panel System Switch

PostPosted: Sun Aug 19, 2018 11:35 am
by Gordon-Loomberah
Welcome to the Energy Matters Forums Ernest :)

It's great that you have designed a reliable transfer switch, but you may not be aware that there are a number of commercially available inverters on the market that will automatically switch between battery and mains power, or even automatically start a generator. Victron is one manufacturer of such units.
12V is a very low voltage battery to run a house on an inverter, 24 or 48V is much more common, 12V being mainly used for portable camping systems these days.

Re: Off Grid Solar Panel System Switch

PostPosted: Mon Aug 20, 2018 12:45 am
by ewherrera
Thanks for the quick replay Gordon-Loomberah ,

I am using a 12V solar system mainly because when I started working with the solar panels I was a novice and decided that was a system that was least expensive and could learn a lot at minimum cost. The transfer switch I designed does not depend on the voltage type of solar system that a person is using since I use a voltage measuring sensor and a micro controller to transmit wireless the voltage to the transfer switch. The switch will switch on what voltage I have programmed for that particular micro controller. Thanks again for the information you have provided me.
Ernest Herrera