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I am not sure if this is the best place to ask, but I am trying to make a solar panel system which will charge batteries with excess energy and will be connected to the mains (i am going to try the lights circuit initially).

I also want a backup from the grid if the batteries run out and I am not producing electricity (like at night).

I am starting with a 300W panel http://www.naturalsparx.co.uk/product/2500638030/LG-Mono-X-Neon-G3-300W-Mono-PV-Module-Black.

I would need to connect this panel to a 3 phase MPPT charge controller, then batteries, then a True Sine Wave inverter to 230V mains to the circuit breaker.

Is there an inverter that will allow me to charge batteries when needed and power the mains when needed and take power from the grid when needed?

Is this a solar hybrid inverter?

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You are describing a Solar Hybrid SOMETHING that may or may not exist in todays vast Marketplace? Step back and revisit a Block Diagram of a Complete Solar Panel Whole House System. You describe several Blocks or Components of the complete system and seem to want all of them in one Device which may be possible today but not practical for the DIY person that dwells within you. It is my impression your main question is of a "Charge Controller" who's function is to charge your Battery using your Solar Panels as the Charging Power Source. Todays Charge Controllers decide for you when the Mains need to take over, when the Battery is fully charged by the Solar Panels, and also when to divert the Solar Panels output to a Dump Load if and when your Batteries are completely charged. The Inverter is the expensive item who's sole purpose in life is to Convert the DC Battery Voltage to a usable AC Voltage ( not necessary for LIGHTING Circuits ONLY ) and Current your household appliances will agree with exactly like your Mains Power from your local Utility Company 230 VAC at 50 Hz I suspect. In an effort to thoroughly answer your question in the form of a recommendation.... Do not look for a single Component that "does it all", if it fails you will loose everything. Rather purchase a quality Charge Controller, a quality Inverter of size and capability to handle your entire anticipated Load, which will indeed be expensive! Most of all, read up / study the topic and fully understand what each individual Block or Component of the Basic,Entire System is responsible for and mostly how they interact to form a Complete System before making any investment. Read, understand, and then make an informed decision / plan to purchase equipment.

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What you describe is almost perfectly identical to the "Sunny Boy" (brand name, one of many) inverters, which are built for "net metering" (wherein you draw from municipal power, running the meter "forwards", when you need it, and "push" power to the grid, running the meter "backwards" when you have a surplus of photovoltaic power). They're rapidly gaining popularity in my area. Actually, they're rapidly gaining popularity all over the US (I have contacts everywhere).

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  • \$\begingroup\$ He talks about a battery based system which needs a relatively low input voltage inverter (often 24-48V range - maybe up tpo say 96v in=some cases). The SMA "Sunny Boy" family are superb inverters but need several hundred volts Vin minimum Vion to run in their [referred MPPT mode and Vmin abs max is also higher than batteries will usually supply. There are inverters targeted at battery based systems. \$\endgroup\$ – Russell McMahon Dec 10 '15 at 8:24
  • \$\begingroup\$ The Sunny Boy 240-US has a max input of 45VDC. \$\endgroup\$ – TDHofstetter Jan 4 '16 at 14:53
  • \$\begingroup\$ - Yes. You are correct re the SB 240 US (as you know). The following mostly for others - you will know this: That is a special exception and comes from the company using the same name across product ranges which are significantly different. The Sunny Boy 240 is a "microinverter" made to work wityh a single PV panel and produce a maximum of 230 VA AC output. As it works per panel in its basic form it both needs only handle Vout from one panel AND MUST work with Vout from one panel - hence the 45 VDC max Vin. .... \$\endgroup\$ – Russell McMahon Jan 5 '16 at 4:50
  • \$\begingroup\$ .... If used on a one per panel basis the Sunny Boy microinverters would provide a viable solution to the OP's panel to AC mains requirement. SMA note "Any number of additional micro inverters can be connected thanks to the flexible design of the Sunny Multigate...". However, I'm not sure how suitable they are for battery based systems which need PV-> battery and usually Mains-> battery charging. If they handle thopse as well they would meet the OP's need. Good list of SMA inverters here \$\endgroup\$ – Russell McMahon Jan 5 '16 at 4:51

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