Oh then that's perfect. I have in mind intermittent use, otherwise I would be buying solar.
You our idea of intermittent is not the same as the auto MFG
Their idea is closer to a few hard minutes right after startup on a hot day with the dash A/C turned on, so that is dump some quick amps into battery while holding in the a/C compressor clutch and running the blower full blast inside for cool down, and the condenser fan, and the electric radiator fans
When the alternator starts getting warm and or the battery voltage starts rising output is reduced
Your idea is run long enough to charge house battery, then do it again next day or day after
Theirs hard high charge rate,for Minutes every time started,
Yours hard high charge rate, for hours every now and then,
I think.. You have already been suggested better ways, DC to dc voltage converter or jumper cables
Converters are more in the low 70s in percent of efficiency from my observations, converted at or near full output are about 73% efficient, converter or charger will use 1000watts to charge at 730watts into battery, now the inverter is also a loss, even at 80% efficiency the inverter will need 1250w input for the battery to be charged at 730w
At 12.5v that's 100amps from the alternator and that will mean your TOW vehicle chassis battery is being drawn down and not being charged, to keep the vehicle battery charged you need 13.8v
13.8v 90.6 amps 1250watts to inverter,
Plus what ever the vehicle engine system needs are possibly another 30amps or more,that's 120amps total for how ever long it takes for the house battery charge rate to start decreasing,
How well is the alternator going to stand up to that kind of treatment, the 800w inverter is not going to carry 1000watts for more than a few seconds trying to power the converter at full 45 amp charge
I suggest doing this before the battery gets any lower than 75%, try to keep the charge rate closer to 30 amps, so as to not damage the alternator
The heavy load amps is going to be from alternator to inverter, that stock alternator it's the item to worry about, ambulances, POlice cars, fire trucks,
All use heavy full duty rated alternators, this is Optional equipment on vehicles sold for consumer use
