Moving to lithium - inverter/charger choice

[alctel]

Hi there,

Replacing my old LA battery set with a lithium 400AH set.

I'm going to need to change out the charger (as it is non-programmable) and would like to add an inverter - is it best to go with a dual inverter/charger unit?

The main thing I'd be using the inverter for is boiling water with the kettle and occasionally my hot water heater, so max would be 1500 watt draw (the kettle). I could downsize to a smaller kettle if needed - though my water heater draws 800 watts so a 1000 watt unit is probably the minimum. The only other thing I'd use AC for is charging laptop and power tools.

No genny and no plans to get one, I have a bunch of solar power.

I was looking at the Victron Multi-plus which is a bit pricey at 1000 USD but seems to do everything I'd need it to - are there any other good options?

Along the same vein, I need to do something with my alternator so I don't burn it out. It's only a 20amp one though, and my engines only 20HP. Would it work without an external regulator?