Battery storage with grid feed solar

25 February, 2017

Can I have my solar with batteries and grid connect too?
When it comes to home electricity, majority of consumers don’t understand it and would rather not as its dangerous and sounds complicated and it can be both of these. We then add a renewable energy system to the mix and we have even more confusion and less consumer’s that are really interested in understanding how it works. Most consumers expect to pay someone else to install or advise the correct system that will work for the customer. The problem we have here is that most consumers don’t understand so they cannot communicate what the best solution for your situation will be and most renewable energy sales consultants just want to get another sale. They will sell you the system that they make the most out off or a system they think you can afford. Now saying this I know there are honest humans out there that do care for their customers and want the best system for the customer. At the end of the day if you the customer have an understanding and can communicate what you want you will end up with a better outcome.
So can you have a battery bank and still be connected to the grid system? The short answer is yes and technically not at the same time. Let me explain.
Installing batteries to your solar system if you haven’t planned for it will most likely require rewiring of your solar panels. The reason for this is if you have had a system installed that feeds the dinosaur your panels are normally wired in series which gives your system high DC Volts to put into the grid system, batteries require lower voltages so your panels are normally wired in parallel so that it increases the amps per hour not the volts. This is the reason it is important to plan your system and educate yourself. Majority of sales reps and installers have only had experience with grid connect systems and they will tell you the way they have been trained and if they do not have a technical background or an understanding of electrical engineering systems they will tell you this can’t be done because my boss says it cant.
Ok so you have now had your panel’s rewired and now we are going to install some batteries? No wrong answer, next thing to get the best performance out of your solar panels is to install and MPPT or a solar charge controller; in short they protect your batteries and give you better performance. Once these are installed they will feed power into your batteries. Yay you can now install batteries. Don’t get too excited as you can’t use that stored power just yet.
The next part of your system is your inverter and if you already have a grid feed system then it is likely that your inverter will not work with batteries. So now you off to the shop to buy another inverter that work’s with your batteries and allows you to connect to the grid. Most likely the guy at the shop is going to tell you this cannot be done!
What you want is an inverter charger for a DC system which you will most likely only find from solar guys that have been in the industry for a very long time and build off grid systems. This will allow you to now use your battery storage in your home!
There are a few different ways of having the final parts of your system wired back to the grid and most of the time a simple switch that sensors a low voltage in your batteries and will switch your home back to grid power while your batteries get charged back up from the grid or your renewable energy supplies and in this example we will use solar.
If your system is sized correctly to your load and your requirements the only time your system will switch back to grid power is when you have had a few days in a row of low renewable energy production or maybe you have had a house full of unexpected guests (more daily consumtion).
Having batteries installed can allow you to do lots of tricky things with your energy consumption, for example if you wanted to you could size you batteries to be large enough to run your lights at night and one power point that you watch your TV from and maybe your computer, for most households you can get away with a simple set up like that and the more users and consumption you want at night the more battery storage you will require and maybe a more complex set up.
The point is planning your systems if you have not got a system yet plan for battery storage now as a part of your system design, If you already have a dinosaur feeding system it might require some more research and a complicated re jig of your system.
I hope this hasn’t scared too many people away or made it more complicated about batteries? It’s pretty simple at the end of the day you have renewable energy system that puts power into the batteries of a day or night depending on your renewable source and the excess that doesn’t go into the batteries you use that day. If your batteries are low the system will switch your power consumption back over to the grid until your batteries are charged and ready to go again, simple!
Solar Battery storage is something that is and will be apart a most houses in the future when it comes to energy usage in the home.
Remember the best thing you can do is reduce your consumption and your load. The greenest energy is the one that you don’t have to make!

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