Really noob dumb question about hybrid inverter wiring

Tarquinbob said:

When wiring a hybrid inverter, they all have AC input and AC Load Output. My understanding is that the AC load output would be connected to critical loads and the inverter acts as a UPS for those loads. Does that mean that the AC input is actually bi directional and when when there's excess solar it feeds back to the rest of the house and acts as a grid tied inverter?

Click to expand...

Tarquinbob said:

I'm coming from plug and play systems where the inverter simply plugs in to an AC outlet and backfeeds the grid, but not sure if a hybrid is capable of doing something similar and if I don't need it to operate critical loads in grid down scenarios I can just connect the AC in and a battery?? I would like to have a setup where the priority is for solar to charge the battery and if there's excess solar it feeds to the grid and when there's no solar I want the batteries to output a constant 600-800W even if it means giving some back to the grid for free. I never want to use grid to charge bateries.

Click to expand...

Tarquinbob said:

Because of the design of my house (fuseboard coming into my living room), the fact that I have 3 phase and the way power is distributed around my house, I've been racking my brain for weeks on a cheap way to add batteries to my basic system. If hybrid inverters work how I hope they work then it's a really easy decision for me to buy one, but every single review video I've seen always show's people connecting up the AC Output Load.

Click to expand...

Tarquinbob said:

I only use between 10-15kWh/ day on average and my current system is exporting between 2-5kWh/day for free and I'd really prefer to put that into a battery to use at night as most of my loads are in the evening when everyone gets back from work and school.

Click to expand...

Tarquinbob said:

I have a question that's been bothering me for a while and I haven't seen it answered in any of the hundreds of videos that I've watched, forum posts that I've read or instruction manuals from manufacturers.

When wiring a hybrid inverter, they all have AC input and AC Load Output. My understanding is that the AC load output would be connected to critical loads and the inverter acts as a UPS for those loads. Does that mean that the AC input is actually bi directional and when when there's excess solar it feeds back to the rest of the house and acts as a grid tied inverter?

I'm coming from plug and play systems where the inverter simply plugs in to an AC outlet and backfeeds the grid, but not sure if a hybrid is capable of doing something similar and if I don't need it to operate critical loads in grid down scenarios I can just connect the AC in and a battery?? I would like to have a setup where the priority is for solar to charge the battery and if there's excess solar it feeds to the grid and when there's no solar I want the batteries to output a constant 600-800W even if it means giving some back to the grid for free. I never want to use grid to charge bateries.

Because of the design of my house (fuseboard coming into my living room), the fact that I have 3 phase and the way power is distributed around my house, I've been racking my brain for weeks on a cheap way to add batteries to my basic system. If hybrid inverters work how I hope they work then it's a really easy decision for me to buy one, but every single review video I've seen always show's people connecting up the AC Output Load.

I only use between 10-15kWh/ day on average and my current system is exporting between 2-5kWh/day for free and I'd really prefer to put that into a battery to use at night as most of my loads are in the evening when everyone gets back from work and school.

Click to expand...

BentleyJ said:

Inverters can be divided up into 2 main categories:
Grid-Interactive can sync with the grid and operate in parallel. This means excess solar can be injected back into the grid or can be set up for zero export so only the load is supported, depending on your local utility rules and available net metering agreements. These are the more expensive, sophisticated, full featured inverters and are ideal for self consumption applications where Time-of-Use billing is in place.

Off-Grid Inverters: Do not sync with the grid and do not have sell back functions. While most do have an AC input, this is used for powering loads and charging batteries in Pass-Through mode only. There is no power blending between the utility and the inverter. These are less expensive and can be used for self consumption and TOU billing or simply power the load while Solar and Battery is available then they switch back to Pass-Through. There is a brief interruption in power flow (few mS) due the mechanical relay transition which may not be suitable for some critical loads.

The terminology gets a bit confusing: All-in-One vs. Hybrid vs. Inverter/charger Etc.

In most cases there is an approval process for installation of a Grid-Interactive, Sell-Back system. Check with your local utility provider. As mentioned above, CT's can be placed on the mains and the inverter can be programmed for near 0 export. Near 0 because in some cases there can be some leakage back into the grid.

How do you hope it works? A simple diagram would be helpful so we could address your specific case and proposed installation method.

So you already have a grid-tie system and an interconnect agreement? Then you will need a Hybrid inverter that supports AC coupling.

Click to expand...

jpwhit said:

Yes, that is the way most hybrid inverters with an AC In and Out connection work if the inverter supports grid export. But there are also hybrid inverters that only have 1 AC connection as well. They are for installations where there is no desire to have a separate backup critical load panel and/or the intention is to backup the whole house, or for when backup isn't desired. Tesla Powerwall, most SMA inverters, and GoodWe offers models for either setup. For that type of inverter setup, if backup is required, you have to have an automatic grid disconnect contactor installed to break the connection with the grid for the backup mode to turn on.

Click to expand...

Tarquinbob said:

How do you tell in advance what type you're looking at? I haven't seen any that don't have an in and an out. Certainly the ones on the French market don't appear to make it obvious if they can be grid tied.

Click to expand...