Find a better quality unit then, I ended up in the same boat with an SPH6000 (6 kW Inverter), only 3 kW on battery. That's what started me off on designing and building an AC coupled battery, now I have 9 kW plus of inverter power and my meter registers very little on peak consumption.
The all-in-one is Givenergy's AC coupled offering. Basically a Powerwall but much cheaper. That provides a better backup option than the hybrid inverter.
However, you'd then need a separate solar inverter. The hybrid units do solar and battery in one and thus are cheaper, plus fewer losses from converting DC-AC-DC-AC so many times. Pros and Cons really.
The 16A limit only applies when using the off-grid backup facility. The 5kw inverter we have can output 21.7A when on the grid. The 3.6kw does have a 16A limit generally though.
Personally I found that the roughly 4kw output (5kw when the sun is shining) saved us using the grid. Just try to time the big-draw items (immersion heater, kettle, oven, dishwasher, washing machine) where possible so that they aren't on at the same time.
16A backup means you'd have to give a bit more thought to usage, but the Givenergy EV charger is pretty good as you can limit the amps and it does solar divert so should work well even on backup mode. We've not had a power cut since the backup was installed 6 weeks ago and ideally we never will! Nice to know that we can run the lights/fridge freezer and continue to get solar energy if the grid does go down.
During the Summer we are on IO where the entire grid is your battery so no need to worry about solar divert, or even if you go over the inverter's limit.
In the winter you are happy to draw from the grid overnight when it is cheap anyway, so time some big-draw items like the dishwasher and hot water immersion (via eddy for instance) for then and you're golden.
The inverfter is too small, switch on the kettle and the toaster or washing machine and cooker you will be importing from the grid. Installers go for 3.6 kW because it makes their paperwork easier. Go for at least 6 kW inverted, theres minimal increase in price and it will fit your system so much better. You have around 7 kW of solar panels on your roof and an inverter that can only handle half of that. EDDI and Zappi work really well together.
Hmm looking at the datasheet perhaps the 3.6kW can take in more solar, it just can't
output at the same rate. But it is DC coupled with the battery.
Am I right in thinking that means it could take in more than 3.6kW
as long as there is spare battery capacity available?
https://givenergy.co.uk/wp-content/uploads/UK-Datasheet-Hybrid-Gen-3-3.6.pdf