How to best power a small freezer in extended grid down situation.

[brettce]

I currently have a leased 3.2KW system on my home tied into the electrical grid alone. Therefore, if the grid goes down, I'll be sitting with useless solar panels.

In a grid down situation, I could live comfortably for quite some time if I can keep my freezer going to make ice and keep food cold, and have a little extra juice to charge batteries for computers or tools.

I was considering a small solar system to provide this small amount of electricity, but then I wondered if I could have on hand the knowledge and components to hook up to my existing system in an emergency situation. I'm sure this would violate my contract with the leasing company, but if this situation were to occur, I wouldn't care about that.

So, do I buy batteries and components to be able to convert my current system in case of an emergency, or put together a separate self-contained system powering my freezer that is up and running?

 

[FilterGuy]

I currently have a leased 3.2KW system on my home tied into the electrical grid alone. Therefore, if the grid goes down, I'll be sitting with useless solar panels.

In a grid down situation, I could live comfortably for quite some time if I can keep my freezer going to make ice and keep food cold, and have a little extra juice to charge batteries for computers or tools.

I was considering a small solar system to provide this small amount of electricity, but then I wondered if I could have on hand the knowledge and components to hook up to my existing system in an emergency situation. I'm sure this would violate my contract with the leasing company, but if this situation were to occur, I wouldn't care about that.

So, do I buy batteries and components to be able to convert my current system in case of an emergency, or put together a separate self-contained system powering my freezer that is up and running?

It sounds like the existing system does not have batteries, so it is not sufficient for your described situation.

I have seen people talk about putting a switch on the PV lines to switch from the existing grid-tie system to a back-up system with storage and inverters. Back when panels were so expensive that made some sense, but with Panels being so cheep, that only makes sense if you don't have room for panels for both the existing system and new panels.

If your existing system has the correct type of inverters for AC coupling, you could look into a system that disconnects the grid and then uses another inverter to make the existing system think the grid is running. (I think sunnyboy has some components that would help build that out)
The backup system would need to be able to charge the batteries from the AC and drive the AC. You would probably need to have a lock-out or transfer switch the only allowed grid or the back-up system but never both. The nice thing about this approach is that you don't have to make modifications to the leased system but you can still get power from it.

 

[brettce]

Thank you for your advice. You are correct that I do not have batteries. I do have room for more panels, so it sounds like I may be better off to have a self-contained system for the freezer. I may look into one of the plug and play systems offered through Will's website.

 

[12VoltInstalls]

Thank you for your advice. You are correct that I do not have batteries. I do have room for more panels, so it sounds like I may be better off to have a self-contained system for the freezer. I may look into one of the plug and play systems offered through Will's website.

If not using the sunnyboy method…
I would do a separate AIO with just enough solar panels to get your critical loads covered daily and recharge the batteries from overnight use plus 20% headroom.

AIO would a) pass through power while grid is up b) maintain battery full charge with grid-up c) automagically switch over when grid goes down d) provide for generator input if desired e) be autonomous for days on end if needed

Batteries are the expensive part.

The sunnyboy solution might not cost much more or different than an AIO + panels as the sunnyboy could utilize the panels you already have.

Look at the battery investment as a separate cost that you choose to size according to how you decide to balance your critical power needs and budget constraints.

I’d compare the costs of both - your skills may be able to diy it or you may need an electrician to integrate.

 

[wattmatters]

1. Don't touch the existing system. It's a lease arrangement, they will no doubt have contract clauses about that. Plus it's most likely a grid tied inverter not designed to add batteries. Switching off during grid outages is exactly how it should perform.

In a grid down situation, I could live comfortably for quite some time if I can keep my freezer going to make ice and keep food cold, and have a little extra juice to charge batteries for computers or tools.

2. How often and for what duration are these outages? Knowing this will make a big difference to what options you might consider and the costs.

A solar PV/battery system is going to be pretty expensive just to power a few items occasionally. And depending on what's caused the outage there is no guarantee you'll have much sun anyway for a PV array to supply much energy.

A regular generator for the occasional outage would be far cheaper as a source of occasional power. It may not however be a practical solution - very much depends on the sort of home you are living in. Apartments or high density living, no. But if you have plenty of space so it is well ventilated and the operating noise and need to have some fuel on hand isn't going to be an issue, then a generator can supply a lot of energy for not a lot of money.

Another option is a portable power station (like a Bluetti or ECO Flow). There are different sizes/capacities at different price points.
This is the simplest solution of all. If outages are not expected be that long, then you may not even need the solar array. But you can plug a smaller portable solar array into them. But as mentioned, these are not cheap. No battery based system is.

if I can keep my freezer going to make ice and keep food cold

Keeping things which are already cold, cold doesn't require that much energy. Making ice however does require quite a lot of energy. Do you really need to make ice during an outage, or do you just need to make sure the freezer contents remain cold and will not spoil?

 

[Browneye]

The first test I did with my new Delta Mini was to run a 5 cubic foot freezer - over 15 hours it used about half the capacity. Freezer draws 100w while running, appears to run about 25%.
I have a pair of 80W folding solar panels for 160W total, and setout and connected to the delta it charges 130 to 150W.
I figure it would run the freezer indefinitely.

And these little power units are pretty handy for any kind of travel or camping as well. Just another option. I gave $700 for the Delta Mini, but would probly opt for the bigger ones for actual grid-down power backup, it's just 880 watts.