The numbers don't seem to add up unless you're charging it every night.
Yep that's fair, so a bit of refinement as I wasn't clear previously.
Current battery inverter is capable of 3.6kWh charge/discharge. The charging at 75% is 75% load of max - so about 2.7kWh is pushed into the batteries per hour. (I can extract at full 3.6kWh though - these are 16A feeds into the house.)
The US5000 recommends max depth of discharge of 95% - I do 90%. (and 95% for the EPS - UPS type - socket - though not in use yet). These are 4800Wh, so * 90% gives you ~4320 x 3 in this stack = ~12,960Wh storage.
Adding another 3.6kwh inverter is planned (hopefully this year, funds dependent - it's the same unit but you add parallel comms between them so they work in tandem) - which will give me the ability to do 7.2kWh in/out of the batteries. With another stack of the same batteries. So doubling the amount of storage, and doubling the input/output performance.
Car charging - I WFH full time, and only sort of potter around in the week. Usually most driving is at the weekend.
Usually if I'm away for the weekend I'll be home late Sunday night, so whatever remains of 23:30-> 05:30 gets dumped into the car on the Ohme Pro. Interestingly because the grid voltage at the house is so high (~248v+ ) I achieve a bit over the "standard" 7kwh speed, the VW app registers 8kwh regularly. (32a house feed * ~248v is 7,936). House is 100A feed but I've got the Ohme to back off at 90A, just so the charger/car has time to react and dial back/pause without me overloading anything. (I get nowhere near this, ever - realistically)
Battery is usually topped up from ~20% to 80% by midway through Monday "eco 6", worst case scenario. I will bump the car to 100% if I know I'll be doing a journey that'll need a stop-off charge, to make sure I take "as much with me" as possible.
Solar:
Winter - extends the battery by whatever it can generate (keeping them separate I like, but it means there will always be a touch going in/out of the grid during load spikes etc)
Summer - is able to charge the batteries back up to 100% usually by midday, then I have some excess to burn off (fans/AC etc weather normally!) so this is usually easily done, any excess I'm not burning off (e.g. I've gone out - and switched off those things) - gets sent back into the grid (I try and do as little of this as possible)
Additional - Gas (Combi Boiler):
Summer - I realised pretty quickly it's not worth bothering using the hot tap in my house when washing hands etc. as it gets to lukewarm by the time I'm done, so boiler only runs for showers in the Summer, else it's standing charge only.
Winter - I've got TRVs on all the radiators in the house, and Home Assistant monitors those temps, anything "very low" - think frost protect - it turns on a relay which is on the thermostat wiring to the boiler (Shelly 1PM, though a Shelly 1 would have done, I just had this to hand). So I have no temperature "controls" automatically set, it's all done (usually manually) by me unless it hit's a preset minimum temp.
Also run the heating anytime the shower is in use - Pushing the boiler slightly harder to do both sets of water heating is more significantly more efficient than running both cycles separately, on my pretty old (but perfectly adequate) Vaillant boiler... Replacing this for a new gas boiler isn't economical vs the efficiency saved. Had some pinholed radiators which I've replaced myself to cut cost, and flushed and added inhibitor to the rads. Boiler is now significantly quieter and hopefully lasts a few more years until I can look at swapping the lot out for heatpump & bigger rads.
My house is absolutely awful in terms of insulation in my opinion. Late 90s house with cavity walls (none-insulated, but horror stories...) and windows that are probably due replacement (uPVC but beading is exterior so shows the age, and they're using foam between the glass and the upvc frame - I've "temporarily" fixed the living room window by sealing the frame around the air vent with expanding foam. My neighbour' drive is close to that window and his tank of a diesel used to fill the living room with fumes. I'm thinking I'll have a crack at replacing these myself. Though over the conservatory/garage roof is the only ones that will give me an issue I think)
Hope that helps / is clearer. If anything isn't clear or you have more questions then please let me know.
Apologies from taking this thread veeeeeeeeeery off-piste

it might be worth splitting some of the messages from the thread but I'm not sure how easy that'd be.