You're making a mistake in your thinking ........ off grid is the way to go.
Why do you want to provide power to the grid?
1. The grid doesn't want your power.
2. The grid won't pay much for your excess power.
3. Grid tie costs a lot more money in installation, inverter and permissions.
4. When TEOTWAWKI happens, and the grid ends forever, you'll still have no power.
Best to use a cheap off grid inverter with no battery.
1. Most will use solar, then top up any needs from the grid.
2. You can add a battery later.
3. You'll still have power after TSHTF.
Grid tie using batteries is the way to go if grid power is connected to the house.
1.2. It doesn’t matter if the grid wants your power. There’s limiters on many grid tie inverters that stop power from going into the grid.
3. Using grid tie inverters with limiters does not cost more, in fact a lot less. The inverter and batteries can be sized to only cover the maximum constant loads. Offgrid the inverter and battery needs to be a lot bigger to handle all of the loads.
4. I small offgrid inverter wired to a small critical loads panel is all that needed for the essentials.
Advantages of Grid tie inverter Connected to battery over off-grid inverter for places where grid is available and for people who are experimenting on Lithium batteries to save money at night.
1. No overload.
In case the load exceeds the Grid tie inverters capacity, the Gti will just keep on running at full load. The power shortage will be supplied by the Grid, hence no power failure. Unlike the off grid inverter, The off grid inverter will shutdown in case of overload, hence you have power interruption in your house. Based on my experiences, this is problematic if it happened at night and when I am far away from home. Overload is one of the major cause of off grid inverter failure.
2. High surge current of big inductive loads like aircon and pump is supplied by the grid Because Gti with limiter is slower to react to changes in load current.. While off grid inverter will solely absorb the brunt of surge power, which is also one common cause of inverter failure.
You can use electric drill, grinders and any power tools without stressing your Gti and battery. I had several experiences where welding job was done in the house and the GTI and battery are not stressed out or battery voltage will not drop to a very low level. Off grid inverter , in case of high load starting current, the battery voltage may drop down to a very low level, causing it to shift to grid power prematurely.
3. Most GTI have a low no load loss of about 3-5w. Off grid inverter has about 15-60w no load loss depending on the size of inverter.
4. Off grid inverter max efficiency is about 85%. Grid tie inverters usually have a much higher max efficiency 95%+. When using batteries, this cost a lot of money.
5. To prolong life of inverter, it is a practice not to operate the inverter at max power for a long period of time. This is very hard to do when using off grid inverter, because you don’t have control of how people in your house will use electricity. For GTI, you can easily adjust the max power you want for your GTI
6. When using Off grid inverters for motors and compressor, you have to size it based on surge power . Common to see 3x surge power for off grid inverter. Surge power normally runs for a few milliseconds. So you will be force to buy a large capacity inverter to serve your surge power. While GTI is sized based on your regular load.
Meaning you have to buy off grid inverter atleast twice the power of GTI.
7. In case of inverter breakdown when using off grid inverter, you lost power in your house.
While using a gti no power interruption in your house.
8. Prolonging life of battery-
a. In my personal experiences, high battery temperature is one of
major reason why batteries fail prematurely. Never operate batteries at more than 40degC. Less is better. And you can easily control battery temperature by controlling the discharge current or power. For GTI, this is easy to do because you can easily adjust the current or power discharge by your battery.. Its very hard to control this when using off grid inverter.
During summer months, where ambient temperature can go very high even at night, you can easily adjust battery temperature by reducing further the current or power discharge by your battery.
b. Manufacturer has recommended discharge current rate of batteries to meet the required lifespan specified in their datasheet. For example, If the manufacturer recommended max 10A, then you can easily do this when using GTI consistently. While its very hard to do consistently using off grid inverter.
Bottomline is, use only off grid inverter for emergency or power failure. Power supplies will eventually fail. Make them ready for emergencies. Not for everyday use when grid is available. Use GTI with or without limiters instead which has far more advantages.
No I didn’t come up with all that but I agree with all of it