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tldr: How do I adjust the power being dumped by my grid tie inverter? Is it possible to use a constant-current power supply to do so?

I am planning create a PV system that will help reduce my electric bill. However, here in my place, net metering is not really a thing which means that there's no use injecting power back into the grid. I was planning however to monitor my power consumption to closely match it and let the grid tie inverter output the power that I am using. For example, if my house is using 300w, I will adjust my 1000w grid tie inverter to output 280~300w of power. However, if I see that the house is using 1500w (for example, a water heater running), I will just let the grid tie inverter output 1000w and get the extra 500w from the grid.

I was originally thinking of connecting the batteries directly to the grid-tie inverter and use some kind of DIY solution to increase-reduce the voltage but based on my research, I don't think the inverter would like it, as they are usually designed to be connected directly to a constant-current power supply i.e. solar panels. Is this true? Will I be forced to use a constant current power supply (that has to deliver up to 1000w of power)? Or am I missing something here?

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    \$\begingroup\$ to insert power into your household wiring, you need a close match of both the voltage and the phase, then slightly LEAD the phase. Does your electric company like that? \$\endgroup\$ – analogsystemsrf Aug 23 '19 at 2:39
  • \$\begingroup\$ Grid tie inverters are capable of doing that already (match the voltage and phase). That's the reason why I want the grid tie inverter to output power based on the demand that my house is using, so that I will not inject extra power back into the grid. Also, I'm not sure what you meant by slightly lead the phase, as good quality grid tie inverters are able to match the phase up to +-1 degrees \$\endgroup\$ – thisjt Aug 23 '19 at 2:52
  • \$\begingroup\$ There are grid tie inverters which you can set to zero export for the very purpose. I would recommend buying one of those. \$\endgroup\$ – winny Aug 24 '19 at 10:38

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