Making the jump to batteries (only)

[Gomev]

I'm looking to add batteries to the home. No solar, that's decided.

We are low users, average less than 5kWh per day excluding car charging. The purpose of the batteries is for my own satisfaction, it will not pay back (even/especially with solar), so that is not the dilemma.

The purpose will be to move all use to overnight cheap rates. So should I go with my preferred set up of
A).
Battery
3 × Alpha ESS SMILE-G3-BAT-4.8S · 4.8kWh
610 × 435 × 212 mm · 4.56kWh usable · LFP · Datasheet · Warranty
Battery size (14.4 kWh 13.68 kWh usable)
Inverter
1 × Alpha ESS SMILE-G3-S5 · 5000W
Single phase · 97.3% max. efficiency · Datasheet · Warranty

Installed cost £6010 including £500 to add a second CU for the EVSE which is currently on the main CU.

or
B)
Fox ESS EVO10 Battery 10.24kWh of Battery Storage
1 x EVO 10-5-H (Fox ESS) 3.68kW Inverter.

Installed cost £4600 (no additional CU)

I think the common sense answer is staring me in the face, but I need help convincing myself or otherwise.
We rarely if ever use more than 3.6kW power and whichever I'm not really going to make anything out of export, or am I, to contribute towards the cost.

This is the basic info.

 

[MickeySw]

The purpose will be to move all use to overnight cheap rates. So should I go with my preferred set up of
A).

Absolutely, bigger inverter, larger battery is the way to go (I also use a 5KW inverter with an ex Zoe battery), never looked back..

3 days backup without much limitations, plus the MGs V2L capacity to recharge the batteries if (localised) outages last longer…

 

[Everest]

We rarely if ever use more than 3.6kW power

Really? What is your peak power usage? It only takes two appliances out of any of the following to exceed 3.6kW. Kettle, Washing Machine, Oven, Non-gas hob, Microwave, Immersion heater, Granny charger.

 

[Bam Bam]

I think energy trading potential is probably the key determinant.

Does the Alpha system fare any better on this front?

If not I would go for the Fox as it is much cheaper.

While you might very occasionally exceed 3.6kw when having two or three items on at once it will probably be rare in the grant scheme of things. Plus the battery will still cover over 50% of your usage even when you are drawing 6kw.

It is probably only going to happen when you are cooking as you might have hob, oven and microwave on at the same time. Possibly kettle depending on the meal. Washing matchine and car charging can be done at other times of the day.

Ovens switch off and on periodically once they get up to temperature so it isn't continuous once pre-heated.

It might mean you limit your behaviour, though, and try not to have the oven running at the same time as the other items @Everest lists. Would that be a pain for you?