[asterisk (Geoff)]

Hello Matt

Cheaper generators will supply 240v (often ranging between 230 to 250) but the cycle will fluctuate around 50Hz. Usually the more expensive the generator, the more stable the power cycle and the quieter it gets. However, as long as you keep fuel up to it, a generator will provide more power than you will need.

A quieter alternative is a deep cycle battery. The 600 amp battery you mention is usually only about 17 amp - it can deliver 600 for a very brief period, but then loses power quickly after that.

240v inverters are notoriously inefficient - that is, a lot of power is consumed by the inverter to deliver 240v from 12v. A more efficient alternative is a Notebook power supply delivering 15 through 24v at a max of 5 amps. (Jaycar have these)

I am using 2 x 30 amp deep cycle batteries connected through 2 switches/fuses to 4 cigarette lighter sockets housed in a cheap Bunnings tool box.

Deep cycle batteries are designed to run for longer periods without suffering the internal damage that car-type batteries can suffer - car batteries are designed to provide a quick burst of power for starting and are then re-charged by the alternator. Using a car-type battery for long periods without immediate recharging will quickly damage the battery and reduce it's effectiveness.

A laptop will use about 3 amps; dew zappers about 2 amps: total 5 amps. Divide the battery capacity (30 amps) by 5 amps and you can expect to run both for about 5 hours - I know 30/5=6, but total discharge is not recommended - lower the voltage to the lappy so that it is not attempting to recharge it's own battery and you can use a 30amp for longer. Alternatively, calculate your total power use in amps, multiply by the number of hours you expect to use your setup and look for a deep-cycle battery with that amp size.

Good luck