Inverters are sometimes proposed to allow 240v appliances to run when a 230v Electric Hook Up (EHU) is not available. An inverter uses the 12v Catering battery voltage and boosts it to 230v. Unless they are used to supply power for very low wattage appliances, like a iPad/phone charger they will degrade the 12v catering battery in months.
A 3,000watt Inverter can draw up to 290amps (including conversion losses) from a 12v battery, as much as a small car draws to start the engine. It doesn't take much to realise that this is going to place an enormous strain on an old fashioned Leisure battery that was designed to provide a just few amps over a long period of time, for example for the LED lights in the van. Even if you choose your battery technology carefully, it can be destroyed in months.

If you have an Inverter, or any device that draws a lot of current in a short space of time, your Catering battery should be more like a Starter battery in construction as this will be designed to provide a lot of amps. The Bosch S5 will handle this abuse better than most, but do not expect any battery to last, a big invertor is a load few batteries can cope with for long. Even a car Starter Motor only draws its 250amps load for 3 seconds until the engine starts.
Consider also the load this places on the Charger/Alternator, they have to put back all that power that was taken out, it is a load they were not designed to take.
There is a lot of advice about Inverters, but none covers the abuse aimed at the battery and the very short Battery/Alternator life that results.
They are often at the heart of many of the problems we see as a H van Dynamo/Alternater just isn't man enough to cope with the load an Inverter places on it.
Some of the earlier 12v Dynamo's have just 15amps charge rate. The first Alternators around 25amps, barely enough to illuminate the Headlights, let alone put back the charge in the Catering battery taken by the Invertor.
So, for example, if you draw only 50Ah from your Catering battery for Lights, Invertor, etc, a typical H van Dynamo with 5 amps 'spare' capacity (after the Ignition, Side lights, etc had drawn their share) would need to be driven for about 10 hours to charge the batteries back up. That is a long drive home after work!!! A typical drive home, even with a later type Alternator would not get the battery up to even 10% charged.
A 3,000watt Invertor will flatten a 100Ah battery in less than 15 minutes. To charge it up would take a 10 hour drive.

Some battery manufacturers recommend that to maintain battery life a battery bank should be '5 times' the Inverter output. I.e. a 3,000 watt Inverter needs a 1,500Ah battery bank

Inverters : Citroen H Van