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Thinking of modifying your caravan? What you must know

If you’ve owned a caravan for a while, you might start thinking of ways you can improve it.

But does modifying or adding accessories to your van make more sense than simply trading it in for a new model that has everything you want?

Our partners at caravancampingsales have created this comprehensive guide covering the key considerations you must be aware of if you’re weighing up the pros and cons of modifying your caravan.

Buy a new van like this one or modify your existing purchase? We consider the key points.

Caravan weight

When fitting additional accessories, the extra weight eats into your van’s allowable payload.

So, for example, if your van has a 400kg payload and already has two 90l water tanks and two 9kg gas bottles fitted, that’s around half the payload covered – with both filled – before you start.

You need to work out weights before even considering adding accessories or your van could end up exceeding its Aggregate Tate Mass (ATM), and thus be overloaded and illegal to tow.

Correct weight: It's everything in towing land.

After getting your van weighed – with empty tanks and gas bottles and no payload – at a public weighbridge or other method, you’ll have a better idea of how many accessories you can add.

If the combination of luggage and new accessories fitted ends up with a caravan that exceeds allowed masses (ATM and/or GTM), then the only option is to get an engineer involved so that the van can be re-plated with a higher ATM and GTM.

This may involve alterations to chassis, suspension, wheels, brakes, safety chains and wheels/tyres. And none of this will be cheap.

Alterations can be pricey.

Risk of caravan swaying

Another factor in any heavy accessory fitment is how it will affect towing dynamics; put the component in the wrong place and your van will become dangerous to tow.

Accessory placement can also introduce other weight problems. While you might not breach any caravan mass limits, fitting a heavy accessory towards the front of the van may result in excessive towball download — so your caravan might be legal to tow, but not by your tow vehicle.

It's imperative that your caravan and tow vehicle are compatible.

Installing a caravan air-conditioner

A reverse-cycle air-conditioner is a boon for camping in both the colder and hotter months, but it requires 240v power, and therefore a licenced electrician to wire it up plus access to mains power or a gennie to run it once installed.

It also adds substantial weight to the van: around 50kg for a rooftop air-con unit and fitting hardware. And if fitted in the wrong spot, it will adversely affect towing stability.

With some ingenuity, you can fit a household-type split system, but more likely than not it will compromise dynamics. The better option is to install a dedicated caravan cabinet or underbed-mounted aircon unit (as fitted to may pop-tops), although neither option is cheap.

Air-conditioners are great. But if your van doesn't have one, beware the installation costs. 

Where to put jerry cans

If you feel you need to add water capacity, there are a few options.

The choices boil down to jerry cans in dedicated holders or additional or larger replacement water tanks.

Measure your van to see if you even have space to install jerry can brackets or water tanks. Even if you have space available, it might not be the right space for towing balance.

Jerries shouldn’t be fitted to the rear bar of a van, as it adds weight in the worst possible place for chassis balance. And even then, the rear bumper might not be strong enough to support the weight of the brackets/enclosures, the jerry can, and its contents.

Modifying your caravan is a balancing act.

Remember that one litre of water weighs one kilogram, so you’re potentially adding around 100kg (with two full jerry cans) swinging out in the breeze at the back of your van – swinging being the operative word.

Jerry holders should go on the A-frame, assuming that they don’t bump up the towball download too high. You also need to ensure there’s enough space, and that the A-frame is strong enough to support the additional weight (this is really only a concern for lightweight vans with C-channel A-frame beams) and the jerries won’t impede access to things like tool boxes or gas bottles.

While bolt-on jerry holders are available, a more secure – but costly – option is to weld the holders on.

Everything is accountable when it comes to a van's weight.

Adding an extra water tank

Like jerry holders, when adding an extra under-slung water tank, you need to ensure there’s enough space to fit the tank.

The tank should also be fitted as close as possible to the axles for balance reasons, and the cost of the tanks themselves, the welded brackets, and extra plumbing can add up.

Another option is to fit larger, replacement water tanks – 90l tanks instead of 60l units, for example. This can save money, as the original tank might already be in the best position for good towing balance and you can re-use or adapt existing brackets. However, you still have to check there’s enough ‘real estate’ under the van to fit them.

Whatever you do, the general rule is to not fit the new water tank too far from the axles, so as not to upset the van’s balance or increase or decrease downball weight too much.

It's all about using available real estate.

Additional caravan storage

Fitting a toolbox to a caravan is a great way to get additional external storage. But think twice before hanging a big steel box off the back, as many people do.

Like jerry cans and water tanks, fitting extra weight at the back isn’t recommended.

If you must create more external storage, then the best place to put a toolbox, if there’s space, is either on the A-frame or the undersides of the van, forward of the axles.

The lighter the box, the better. So, aluminium is the way to go rather than heavier steel.

Adding storage is helpful but must be done correctly.

Adding a shower to a caravan

The inclusion of an internal shower/toilet is a game-changer for caravanners who are tired of traipsing to the amenities block at night.

However, fitting a shower/toilet to a non-ensuite van involves a lot of work, carpentry and plumbing skills, and adds weight that is often difficult to calculate until after the work is done.

Choosing an ensuite site at your chosen BIG4 park is another alternative!

Having a shower/toilet in your van can be a game-changer.

More clearance

Improving ground clearance for a leaf-spring van is possible, but there are a bunch of problems if you do it the wrong way.

While some consider an over-slung axle the way to go (over-slung means fitting the axle under the leaf springs instead of the standard underslung configuration of the axle over the leaf springs), this can be dangerous.

If the axle U-bolts were to fail or securing nuts loosen, there’s nothing to stop the axles from coming away entirely.

With a straight axle, not much can be done to increase suspension clearance. But if your van is fitted with a drop axle, it can be flipped (while remaining underslung) and provide the additional clearance you need.

Safety is the number one priority from top to bottom.

Off-road tyres for caravans

Fitting off-road tyres to a van is a relatively easy way to improve stake resistance and grip for dirt road touring.

But in most situations, a strong light truck commercial tyre as fitted to many caravans is more than enough for stake resistance and grip over most terrain.

Light truck mud terrain tyres are heavy, and their rolling resistance will also increase your tow vehicle’s fuel consumption.

Going off road? There are choices when it comes to tyres.

Power struggle

Updating a standard 12-volt caravan electrical system to a more capable, modern 12v lithium system may seem like a no-brainer – especially for off-grid camping – but it’s not as simple as it seems.

Firstly, a good, off-grid capable kit is expensive – around $10,000 or more for the solar panels, lithium battery, battery management system, and wiring.

You’ll also need enough roof space for the solar panels, cupboard space, or wall space for the battery management system and associated components – such as battery monitoring gauges – and storage space for the battery.

In addition, you’ll require the skills or money to pay someone suitably qualified to fit it. If the system can accept charge from a 240-volt source, it may need to be wired up by a licensed electrician.

You could just buy a new caravan!

Then there’s the extra weight – a large 300Ah off-grid set-up could add around 100kg to your van’s payload despite the weight savings of converting to lithium.

To be clear, a 12v lithium system can transform your camping experience. But ample research is required to make sure the system is big enough to do what you want it to, you have the space and payload to incorporate it into your van, and can justify the cost.

Clearly, there is plenty to keep in mind, but we hope these tips come in handy when considering whether you should modify your caravan.

For more handy info from caravancampingsales, click here.

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