Best all in one for TOU arbitrage.

[Fuzzx]

I live in Quebec where I have cheap reliable power, about 5 cents US per kWh.

But recently they've launched a new rate specifically for people with dual energy (gas plus heat pump heating) that's very interesting.

The regular rate drops to about 3 Cents US per kWh, but when temperatures are below -15C it jumps to 20 cents and a special Thermostat forces gas heat. The goal is to limit electricity use during cold snaps.

Non-heating electrical consumption gets very expensive in those moments, but the idea is that the savings the rest of the year make up for it.

But this got me thinking, I was already planning on getting a 30a transfer panel installed and a something like a EG4 3000EHV-48 with a 100ah battery for emergency use.

Do any of these units have the capacity to help me do rate arbitrage?

What I would want is a battery system that is plugged into the transfer switch and normally just passes 120v from the grid to selected circuits transparently.

But in cold weather events I would be able to switch to battery until such time that the battery drained and it would go back to grid power.

I am aware that I have a power imbalance as I have 15a or 20a of line power feeding multiple circuits. But my plan is that in non emergency use I'd limit the setup to a handful of circuits that would stay under the limit.

I've read through the eg4s manual a bit and I think it has a line mode that can do this? Is there an amp limit I need to be aware of?

And are there other units that do it better that I should consider? Also how do portable units like the delta pro or the 3000w Jackery perform in this use?

 

[Rusty959]

There are plenty of units that should be able to do this, but I think the main question would be where you want to go with your system as a whole.
One question - how often is it below -15C where you are? Daily in the winter? once a week? once a month? The amount of time you spend there and how often it happens would effect my suggestions.
Do you lose power enough to want automatic backup or will you always be ok throwing a switch, which may cause any running devices to shut off and be bad for fridges/freezers?
Do you have solar or are planning to add it?
Do you think you'd ever want the ability to run off grid for more than ~5kWh worth of battery? (100ah 48V)

The all in ones like the sol ark or the new EG4 18kpv (which I have) can likely do everything you're wanting. I'm not familiar with Canada to know what other units may be ok code-wise.

I have my 18kpv set up so that when there's not enough solar power to cover my loads it uses battery power before pulling from the grid. It's not perfect regulation so still pulls a tiny bit off or puts some on, generally in very quick spikes when a new load turns on or off. But if night is when you would tend to be below -15C, this is the same time a system like I have set up would be automatically running on battery power. For me, 15kWh is perfect to get me through the night in most cases.

So sun up: PV charging batteries and powering house. Sun down: house powered by batteries. If you don't have PV, the 18kpv and the sol-ark can also be set to charge from the grid at some set time every day, which might work in general or might require hopping on the app and making some changes depending on the weather.

 

[Fuzzx]

My expectations is that these events will occur weekly during the winter months. Also I hope to be selective with what circuits I backup so they momentary shutdowns won't have any bad effects.

While I don't plan on any solar(due to climate and also the very cheap power I get), One other interesting reason why I plan on getting a system is that I currently own a ioniq 5 Ev which has V2L.

Im fact I have already used it for power outages already. But the issue there is While this does give me 50kwh of power, it's limited to 1800w.

So the primary reason to purchase a system is to act as a "buffer" to absorb spikes in my use during emergencies and not trip the cars inverter.

Plus it means I can drive away without shutting the hours down. Heck I can even leave to find a DC fast charger and bring a substantial amount of power back to the home.

So the rate arbitrage capability is all extra. The primary purpose is emergency use.