DIY Solar Inverter Backup System...(Where's the simplicity)

[JS Ottawa]

I have a concept for a backup system for my house in Ottawa Canada. I think it is a little more complicated than necessary but as a newbie, this is what my brain put together. I would like the system to do the following:

• Have a battery that will support about four circuits in the house (fridge - 4.16kWh, freezer - 0.91kWh and lights) should the main power go out
• Have the fridge circuit normally on the backup (this way I know the system is operating, the battery cycling and no surprises when the power goes out...i.e. the system is not sitting idle for months on end)
• Have minimal or no changes to the main breaker panel (I want to be able to take everything with me if I move)
• Have a generator as a secondary source of charging for the battery should the sky be dark for several days (which can happen in Ottawa in winter or maybe I'm just nervous)

I've put together a diagram of what I think the system might look like conceptually but I would like to know if I have any pieces missing. Should I be looking at some other way of doing it than is simpler? Better? Thanks for any help.

 

[shavermcspud]

What you have planned there is a fancy Lithium UPS which already exist.

 

[Bluedog225]

Why go though the house wiring? Simplicity is running a cord to the appliances.

 

[JS Ottawa]

What you have planned there is a fancy Lithium UPS which already exist.

Thankyou shavermcspud for your reply. If you are referring to the Bluetti and EcoFlow solar generators, I have looked into those. I even had a diagram laid out for the EcoFlow products. However I then discovered that the Canadian government is offering a $1000 grant for the installation of an inverter and battery system and $1000/kW of installed solar panels. The catch with the battery system is that it cannot be a portable system. My understanding is that the pre-built systems would not qualify and so I opted to break the system down to take advantage of the grant. I also thought that if I was going to get an electrician in to do the wiring of a EcoFlow generator then why not buy the components of a solar generator and build my own (adding a little more to the electrician's bill but saving money on the solar generator).

 

[JS Ottawa]

Why go though the house wiring? Simplicity is running a cord to the appliances.

Thankyou Bluedog for replying to my post. Extension cords attached to a generator can be a simple way of going for an outage here and there but the prepper in me wants to have something more robust and fairly permanent. Also as I have mentioned in my response to shavermcspud there are government grants to help cover the costs of a system like the one I have laid out.

 

[MichaelK]

Assuming that you might get between 2.0 and 2.5 sunhours in Ottawa in December, I don't think a 1.2kW solar array is going to provide you with enough power if you need ~5kWh/day? Too much solar is usually easier to deal with than too little solar. You might want to consider at least doubling your array wattage.

Your plan for 5.1kWh of storage I think is also too small. One single cloudy day, and the battery is gone.

 

[dougbert]

the plan looks good but as pointed out, it is not big enough to run a singe circuit to a refrigerator

I did similar back in 2000 and found that the refrigerator we had consumed 2.75 kwh per day. It was quite the learning experience

 

[Quattrohead]

Too many transfer switches, the AIO can do that for you.
Just connect the AIO output to the required loads, give it 120 input and program to use Solar Battery Utility mode.
If you need to pull a permit, good luck.

 

[JS Ottawa]

Assuming that you might get between 2.0 and 2.5 sunhours in Ottawa in December, I don't think a 1.2kW solar array is going to provide you with enough power if you need ~5kWh/day? Too much solar is usually easier to deal with than too little solar. You might want to consider at least doubling your array wattage.

Your plan for 5.1kWh of storage I think is also too small. One single cloudy day, and the battery is gone.

Thanks for your thoughts MichaelK and dougbert. I will admit to doing a newbie (which is what I am) mistake...actually reporting kWh and not kWh/day. If I do the proper calculation I get 0.49 kWh/day for the freezer and 1.4kWh/day for the fridge for a total of 1.89kWh/day (plus some amount for lights). Sorry for the mistake, I know this now changes things a fair bit. As for doubling the array wattage, that's mainly a matter of roof space. My house faces east/west so no roof is really good for an array. I was hoping to use the garage roof which is about 3m by 3.5m for ease of installation which would hold the three 1m x 2m 400W panels. The back roof is fairly open and faces east. If I get a professional installer than that doesn't matter as much but it is another piece to the puzzle.

 

[JS Ottawa]

Too many transfer switches, the AIO can do that for you.
Just connect the AIO output to the required loads, give it 120 input and program to use Solar Battery Utility mode.
If you need to pull a permit, good luck.

Thanks for the reply Quattrohead. I'm going to have to do a little more exploring to understand your answer but I'll it explore it as an option.