Welcome back to Adventure Kings’ Guide to choosing a portable 240v generator for your caravan! Let’s take an in-depth look at the true cost of a 2kva generator or a 3kva generator, what it’ll cost you to run per hour and how to get the most use possible out of yours.

RUNNING COSTS PER HOUR

To work out running costs per hour of our 2000w inverter generator we brimmed the fuel tank up to the very top and set up a test to simulate roughly 30A of load on the generator. That represents a typical vanner’s setup that would require powering for a couple of hours of an afternoon, running things like the three-way fridge (flat out to get it as cold as possible while the generator is on), lights and fans.

Of course that 30A, while it sounds like a lot, barely puts a dint in what the 2000w generator can supply. In fact, with the economy mode set to on, the generator was barely above idle for our test. Using a precise fuel measuring jug we re-filled the 2kva generator to the brim after an hour, and found that it used near enough to bang-on 500ml of unleaded. Fuel prices obviously fluctuate, but let’s call unleaded $1.50 a litre as a nice even figure. That gives us a running cost of about 75c an hour.

GENERATOR SERVICE COSTS

To look at total cost of ownership we need to look at the cost of servicing the generator. A typical maintenance schedule for a 2000w inverter generator is as follows;

Clean air filter element every three months or 50 hours

Check and adjust spark plug, change engine oil and clean fuel tank and filter every six months or 100 hours

Replace spark plug & valve clearance check every year or 200 hours

Clean combustion chamber every 300 hours

That’s pretty low-key maintenance. It boils down to cleaning your portable generator air filter every three months, and having a service done every six months. Service costs of course vary depending on the labour rates a workshop charges, but around $80-$100 is a fair guide. You’d definitely have change out of $200 for your yearly camping generator servicing costs, put it that way.

ADDING DEEP-CYCLE BATTERIES TO YOUR POWER SYSTEM

Of course if you haven’t got one or two deep cycle batteries in your electrical system then you can only run your electrical accessories when you’re running your portable camping generator, but the problem is then that you’re just waiting power because you’ll be running the 2000w generator at a mostly fixed speed, but only using a tiny fraction of the power it produces!

The much better way is to add a couple of AGM deep cycle batteries to your system to power your electrical accessories while your portable camping generator is switched off, and recharge them with a 240v battery charger while you’re running your inverter generator for camping of an afternoon.

BATTERY CHARGERS

To replenish your batteries, you’ve got a couple of options. The one that works hand-in-hand with a generator is a 240v battery charger. These are available in a number of different sizes, but generally speaking – as with all electrical camping gear, especially camping generators – the bigger, the better.

Let’s go back to our power requirement figure we talked about in part one of this series for a moment. We’re looking to replenish lets say 70A of battery capacity in a 24hour period. Using a charger with a 5A charge rate connected to your portable camping generator means we’d need to run  the 2kva generator for 14 hours to charge the battery back up – that’s 6am in the morning til 8pm in the evening – and that’s just not realistic! However a much better idea is to grab a 25A charger and connect it to the same 2000w inverter generator – it’ll recharge those same 70A back into the battery in a little under three hours – that’s a lot better sounding!

To test this, we over the course of two concurrent nights drained our 200A battery bank by approximately 50A, with it reading 12.28V once everything was switched off and the battery left to stablise. The first morning, we connected a 5a battery charger to our 2kva inverter generator and let it run for two hours before switching it off. We measured fuel usage at approximately 960ml across those two hours, and when everything was switched off again the battery voltage read 12.38V. Okay, not bad but not the full 12.8-13.0V we’d be looking for to indicate a full battery.

The next day a 25A charger was connected for that same two hour period. Our batteries read 12.26V, showing we’d drained them to a nearly identical level. On completion of the two hour test, we’d used 1020ml of fuel but the voltage was sitting at a completely full 13.1V after stabilsation.

WHAT THIS SHOWS: While we used a tiny bit more fuel across that two hour period considering the generator was a little more loaded up, we’d topped up our batteries to completely full again with the 25A charger. The 5A charger however only added 10A of capacity back into the batteries – about half-full. There’s definitely a lot of merit in investing in a bigger 240V charger so you can run your portable camping generator for less time.

A 240v battery charger is an essential upgrade for any caravanner taking a portable 240v generator with them to go free-camping – and the bigger the battery charger, the better value you get – because you don’t have to run your generator for as long to achieve the same battery recharging results!