existing solar going on to the grid

Re: existing solar going on to the grid

Generally, there are two requirements... First is to have an inverter that is rated for "Grid Tie" (or Utility Interactive) connection, and second a utility that allows the interconnect.

As always, the devil is in the details...

If you have an off-grid system right now, there is a 99% chance that you would have to replace your current inverter to do this (and do some new wiring too).

Second, you have to ask the question--do you want to keep the Off-Grid capabilities of your current system (i.e., batteries and charge controller) or do you want to convert to pure grid tie.

Efficiency and cost wise, getting a new pure grid tie inverter, re-wiring the solar panels for the new inverter, and dumping the old batteries and charge controller would be the best solution. However, unless you are lucky, you will probably need to add solar PV panels (or remove one or two) because the voltage/current requirements (high voltage, low current), typically, don't match those of an off-grid charge controller (low voltage, high current).

In the end, the cost of the typical grid tie system is about 50% for the panels, 10%-20% inverter, and the rest for installation.

-Bill