25 Motorhome Mistakes That Could Cost You Money and How to Avoid Them

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A rooflight left open. An awning caught by a gust of wind. A water system that wasn’t quite empty when the temperature dropped. Some of the most expensive motorhome problems start with something surprisingly small.

And they don’t only happen to beginners. Once you know your motorhome and have a routine, it’s easy to skip a check or assume something is working the way you think it should. Add a new appliance, change your batteries or pack for a longer trip, and there can be more to consider than you first realise.

After years of travelling full-time in motorhomes and now an overland truck, we know how much there is to learn about the vehicle you’re living in. Understanding its limits and how its systems work can save you money, inconvenience and a holiday spent trying to find someone who can fix it.

These are 25 motorhome mistakes worth avoiding, with practical advice to help you get things right.

Motorhome Mistakes Key Facts

Guide: The Gap Decaders’ guide explains 25 costly motorhome mistakes and how to avoid them, covering vehicle weights, driving, electricity, gas, water systems and maintenance.
Technical checks: Overall weight and axle limits, battery and charger compatibility, frost protection and servicing requirements all need separate checks.
Best for: New and experienced motorhome owners who want to understand their vehicle, prevent damage and avoid unexpected problems while touring.
First-hand experience: Phil and Izzy of The Gap Decaders have travelled full-time in two motorhomes and an overland truck since leaving the UK in 2018. Phil built their overland truck, bringing hands-on knowledge of vehicle systems, installation and maintenance.

1. Assuming Your Motorhome Has Plenty of Payload

A motorhome can have six seatbelts, a huge garage and cupboards everywhere without having the payload to use them all at once.

Payload is the weight available for everything you add to the motorhome beyond its specified starting weight. That includes people, belongings and equipment, but exactly what’s already included in the manufacturer’s figures needs checking. Don’t assume the advertised allowance accounts for your particular passengers, full water tank or optional extras.

An awning, extra leisure battery, solar panels and bike rack all use some of that allowance before you’ve packed any clothes or food. Add bikes, outdoor furniture, tools and the things you keep “just in case”, and the remaining capacity can disappear quickly. Water is another significant load: every litre weighs approximately one kilogram.

The best way to find out where you stand is to visit a weighbridge with the motorhome loaded as you normally travel, including the people who’ll be on board. Compare the result with its maximum permitted laden weight, and weigh each axle too.

If you’re overweight, moving things between cupboards won’t reduce the total. You’ll need to remove weight or investigate whether a suitable uprating is possible, taking account of the vehicle’s technical limits and your driving licence entitlement.

Make weighing part of your routine after significant changes, too. A weighbridge ticket from before you fitted a scooter carrier won’t tell you what your motorhome weighs now.

2. Checking the Total Weight but Ignoring Axle Limits

Being under your motorhome’s maximum permitted weight doesn’t automatically mean you’re within all its weight limits. Each axle has its own limit, and it’s possible to overload the rear axle while the vehicle as a whole still has capacity to spare.

This is particularly relevant to motorhomes with large rear garages, long rear overhangs or bike and scooter carriers. Much of what you load ends up towards the back, where the water tanks, fixed bed and storage may already place a substantial load.

Check the applicable vehicle plate for the front and rear axle limits, then get separate axle readings at a weighbridge with the motorhome loaded for travel. Don’t assume that adding the two axle limits gives you a higher permitted overall weight: you must stay within both the individual axle limits and the vehicle’s total limit.

If one axle is overloaded, you may be able to redistribute some belongings. But if you can’t bring every limit into line, you’ll need to remove weight or seek specialist advice about the available options.

3. Filling the Garage with All Your Heaviest Kit

A big rear garage is useful, but its size can give you a misleading impression of how much it can carry.

Tools, electric bikes, spare parts and outdoor furniture soon add up. And when that weight sits behind the rear axle, it acts as a lever: it adds more than its own weight to the rear axle while taking some load off the front. The farther back you place it, the greater that effect.

That’s why fitting a scooter carrier involves more than subtracting the weight of the scooter and carrier from your remaining payload. Their position matters too, as do the carrier, chassis extension and mounting limits.

Keep heavy items low and as close to the space between the axles as your layout allows. Use the far rear of the garage for lighter belongings, secure everything properly and check the garage’s stated load limit.

If you’re adding a rear carrier, ask the installer to assess the loaded axle weights and the mounting arrangement before committing to it. Having enough overall payload is only part of the calculation.

4. Using Tyre Pressures That Don’t Suit Your Loaded Motorhome

The pressure moulded into a tyre’s sidewall isn’t automatically the pressure you should use. Nor is a figure shared by someone with a similar-looking motorhome necessarily right for yours.

The correct pressures depend on the tyres fitted, the loads they carry and the vehicle manufacturer’s requirements. Two motorhomes built on the same chassis can carry very different loads once their layouts, accessories and belongings are taken into account.

Start with the motorhome manufacturer’s pressure guidance. If you need clarification, provide the tyre manufacturer with your loaded axle weights and the full tyre specification, including its size, load index and whether it carries a C or CP marking. Don’t reduce pressures based solely on a generic online chart.

Check pressures when the tyres are cold, using a gauge capable of reading your motorhome’s required pressures. Don’t release air from warm tyres simply because the reading has increased during a journey.

While you’re checking, look for cracks, bulges, cuts and uneven wear. Motorhome tyres can deteriorate through age and periods of standing even when there’s plenty of tread left.

5. Following a Sat Nav Without Checking the Route

A sat nav doesn’t have to be wrong to send you somewhere unsuitable. The road may reach your destination perfectly well, just with a narrow village, tight bend or low bridge along the way.

A motorhome sat nav or navigation app with vehicle profiles can help, provided you enter accurate dimensions and weights. Measure your actual travelling height, including rooftop equipment, and account for accessories such as a rear bike carrier when recording your length.

Even then, vehicle settings don’t guarantee a suitable route. Mapping can be incomplete, restrictions can change and the final approach to a campsite or aire may need particular care.

Check the destination’s own access instructions before setting off, especially if the owner recommends arriving from a particular direction. Preview any doubtful stretches and keep your dimensions somewhere visible in the cab.

If the road ahead looks unsuitable, find somewhere safe to stop and reassess. It’s much easier to change your route before entering a narrow lane than to reverse out once you’re committed.

6. Forgetting About Rear Swing

When you turn a motorhome, the bodywork behind the rear wheels swings in the opposite direction to the turn. Steer right and the back initially moves left; steer left and it moves right.

The longer your rear overhang, the more space you need to allow. A bike rack or rear carrier can extend that movement further.

It’s easy to get caught out when leaving a fuel pump, pulling away from a wall or manoeuvring between campsite pitches. You concentrate on getting the front clear, turn the steering wheel and catch something with the back.

Before pulling away, check the space beside the rear of the motorhome as well as the road ahead. Where space allows, move forwards far enough to clear nearby obstacles before making the turn.

Practise somewhere open so you understand how your particular motorhome moves. If someone is guiding you through a tight space, agree clear signals and keep them visible in your mirrors. Stop if you lose sight of them.

7. Driving Off Without a Proper Departure Check

It only takes a distraction to break your usual routine. Someone stops for a chat while you’re packing away, you go back inside for something, and suddenly you’re ready to leave with the electric cable still connected.

A short departure checklist is useful however long you’ve been motorhoming. Work through it in the same order each time, followed by a final walk around the vehicle.

Outside, check that the hook-up cable is disconnected and stowed, ramps and chocks are collected, the awning is fully retracted, and external lockers are closed and locked. Check the step, any raised aerial or satellite dish, and the security of bikes or other equipment carried outside.

Inside, close and latch rooflights and habitation windows as required for travel. Secure cupboards, drawers and the fridge door, stow loose belongings and check that any swivel seats are locked in their travelling positions.

Include gas and appliance settings according to your installation’s instructions and any ferry or tunnel requirements for the journey.

Give the final check to one person, even if you share the packing. “I thought you’d done it” is an expensive way to discover that neither of you did.

8. Leaving the Awning Out When You Leave for the Day

An awning can make a sheltered pitch feel like an extra room, but it also gives the wind a large surface to catch. A sudden gust can damage the fabric, bend the arms or pull the mounting points away from the motorhome.

The weather when you leave isn’t necessarily the weather you’ll return to. That’s particularly true on exposed coastal pitches and in mountain valleys, where conditions can change quickly.

Wind it in before heading out for the day, and before bed if you won’t be able to respond to a change in conditions. Use the supports and securing equipment specified by the manufacturer whenever it’s extended, but don’t assume a tie-down kit makes it suitable for strong winds.

Follow the instructions for setting its pitch so rain can drain away. Water pooling in the fabric adds considerable weight and can damage the awning even without much wind.

If you have to retract it wet, open it again to dry when conditions allow.

9. Overloading the Campsite Electric Supply

Plugging into a campsite bollard doesn’t mean you can use electricity as freely as you would at home. The supply has an amperage limit, and everything running at the same time contributes to it.

At a nominal 230V, a 6A supply provides approximately 1,380W, 10A provides 2,300W and 16A provides 3,680W. A domestic kettle can use most or all of that allowance on its own.

The less obvious loads are often what catch you out. Your water heater, electric heating, fridge and battery charger may already be drawing power before you switch on the kettle or hairdryer.

Check the available amperage when you arrive and select an appropriate electric setting on your heating and hot-water controls. Where your system allows, reduce the charger’s demand or set the incoming current limit too.

Check appliance wattages and stagger the larger loads. Selecting a lower electric power setting on the heating, or briefly switching off the heating and water heater before boiling the kettle, can save a trip to reception to have the bollard reset.

10. Assuming Every Socket Works Off-Grid

You unplug from the campsite bollard, stop somewhere lovely and plug in your laptop charger. Nothing happens, even though the lights work and the control panel says the leisure battery is full.

Most motorhomes have two electrical systems. The leisure battery supplies 12V equipment such as lights, the water pump and suitable charging sockets. The mains sockets generally need an electric hook-up or an inverter that converts battery power into 230V electricity.

Having solar panels doesn’t automatically make those mains sockets work. Solar charges the battery; you still need an inverter to power mains appliances from it.

Check which sockets, if any, your inverter supplies. Some installations power only a dedicated socket, and the inverter needs to be switched on before you use it.

For phones, laptops and other compatible devices, a suitable 12V or USB charger can be a more efficient option. Check its output and your device’s requirements rather than assuming any USB socket will do the job.

11. Underestimating How Much Power an Inverter Uses

An inverter makes it possible to run mains appliances from your leisure battery, but the energy still has to come from somewhere.

A 2,000W appliance running through an inverter can draw roughly 180–200A from a 12V battery system, depending on battery voltage and inverter efficiency. That’s a substantial demand, even if you only use it briefly.

There are two separate questions to answer: can your system supply the power, and how long can it sustain it? A battery might store enough energy for an appliance but be unable to deliver the required current. The inverter, battery management system, cables and protective devices all need to suit the load.

Check both the appliance’s running demand and any starting surge against your installation’s limits. Don’t assume that fitting a larger inverter makes the rest of the system capable of supporting it.

Plan around how much energy you’ll use between charges, too. Boiling a kettle for a few minutes is a very different proposition from running an electric heater for an evening. Switch the inverter off when it isn’t needed, as it can continue drawing power with nothing plugged in.

12. Treating Every Leisure Battery the Same

Advice that suits one battery type can be wrong for another. Flooded lead-acid, AGM, gel and lithium batteries have different charging requirements, usable capacities and operating limits.

Even the familiar advice to judge charge from a voltage reading has limitations. A lead-acid battery’s voltage is affected by charging and loads, while lithium’s relatively flat voltage curve makes it difficult to estimate the remaining charge that way.

Check the requirements for your particular battery and make sure the charging equipment uses the appropriate settings. Don’t assume a control-panel percentage is accurate simply because it appears on a screen.

A correctly installed and configured shunt-based battery monitor can give a much clearer picture of what you’re using and what remains. It still needs the right settings and periodic synchronisation according to its instructions.

Follow the battery manufacturer’s discharge and temperature limits. For lithium iron phosphate (LiFePO₄) leisure batteries, check the minimum charging temperature and whether the battery has low-temperature charging protection or an integrated heating system.

13. Assuming Hook-Up Also Charges the Starter Battery

Your motorhome starts perfectly when you park it for winter. You leave it connected to hook-up, confident that the batteries are being maintained, then return to find the engine won’t turn over.

Some motorhomes charge both the leisure and starter batteries on hook-up. Others charge only the leisure battery, or provide limited starter-battery charging under particular conditions. Solar arrangements vary in the same way.

Meanwhile, alarms, trackers and the vehicle’s electronics can continue drawing from the starter battery while it’s parked.

Check your handbook or ask the motorhome manufacturer how your particular system works. Confirm which batteries receive a charge from hook-up and solar, and whether any control-panel settings affect this.

If the starter battery needs additional maintenance charging, use a suitable arrangement approved for the vehicle and battery. Don’t assume that running the engine briefly every few weeks will replace the energy used during storage.

14. Expecting Summer Solar Performance in Winter

A solar setup that comfortably meets your needs in July can struggle to keep up in December.

Shorter days and a lower sun reduce the available energy. Flat roof-mounted panels are particularly affected by the low winter sun, while shadows from trees, nearby buildings or rooftop equipment can further reduce output.

At the same time, you may use more electricity. Longer evenings mean more lighting, and even gas or diesel heating usually needs electrical power for controls, fans or pumps.

Plan around the energy your panels actually harvest over a day, rather than their advertised wattage. Compare that with your daily consumption using your battery monitor or solar controller’s records, where available.

Keep panels clean, choose an unshaded pitch when practical and have another charging option for prolonged dull weather. Extra battery capacity gives you a larger reserve, but it won’t solve an ongoing shortfall unless you can recharge it.

15. Changing to Lithium Without Checking the Charging System

A lithium battery can offer more usable capacity and faster charging, but replacing a lead-acid battery isn’t always a straightforward swap.

The mains charger, solar controller and alternator charging system all need to be compatible with the new battery. Selecting a lithium setting on one device doesn’t change the others, and a battery advertised as a “drop-in replacement” doesn’t guarantee compatibility with your motorhome.

Alternator charging needs particular attention. Lithium batteries can accept high charging currents, so an existing split-charge arrangement may need modifying. A correctly specified battery-to-battery charger can control that demand and provide an appropriate charging profile.

Before buying, have the whole installation assessed, including cable sizes, fuses, battery mounting and temperature protection. Check any requirements from the motorhome manufacturer, too.

A properly planned conversion should give you reliable extra capacity. Simply fitting the battery and hoping the existing equipment will cope can leave you with charging problems or components operating beyond their limits.

16. Leaving the Fridge on the Wrong Power Source

A fridge that worked perfectly on the campsite can start warming up after you leave if it hasn’t switched to a suitable power source.

How this works depends on the fridge. A three-way absorption fridge may use gas, mains electricity or a 12V supply while driving. A compressor fridge works differently and will usually run from the leisure electrical system, so it needs to be included in your battery calculations.

If your fridge has automatic energy selection, check the display after changing circumstances. Automatic selection can’t overcome a closed gas valve, an ignition fault or a missing electrical supply.

With a manually selected fridge, make changing the setting part of your arrival and departure routine. Don’t assume an absorption fridge’s 12V mode will operate while parked: many installations only enable it when the engine is running.

Follow the fridge and vehicle instructions for use during travel, and switch it off where required at fuel stations, on ferries and in tunnels. Check that it has restarted successfully afterwards.

17. Blocking the Fridge’s Ventilation

An absorption fridge needs airflow through its external vents to release heat. Cover those vents with luggage, park with them pressed close to an obstruction or leave unsuitable covers fitted, and cooling performance can suffer.

It’s easy to overlook the effect of an open habitation door, an awning enclosure or items stored beside the motorhome. In hot weather, anything that restricts ventilation can make an already demanding job harder.

Keep the vents clear and check them periodically for leaves, debris or insect nests. Follow the manufacturer’s cleaning instructions, particularly around the burner and flue.

Winter covers are designed for particular conditions and fridge models. Fit and remove them according to the fridge manufacturer’s temperature guidance rather than leaving them on throughout the touring season.

If you have a compressor fridge, check its ventilation requirements too. It may not have the same external grilles, but it still needs a way to lose heat.

18. Turning on the Water Heater Before Filling It

Filling the fresh-water tank doesn’t necessarily mean the water heater is full. After draining the system, the heater and pipework need refilling and the trapped air needs somewhere to escape.

For a typical pressurised system, close the drain valves, fill the fresh-water tank and turn on the pump. Open a hot tap and allow the air to clear until water flows steadily, following the procedure in your handbook. Repeat at other outlets as required and check for leaks.

Only then switch on water heating if your appliance requires a full tank. Some heating systems can provide space heating with the water vessel empty, but that doesn’t mean every operating mode is suitable.

Check the instructions for your particular model rather than assuming all motorhome boilers work alike. This is especially useful when collecting a new motorhome or using a hire vehicle with unfamiliar controls.

19. Refilling the Water System with a Drain Valve Open

You’re filling the fresh-water tank, but water is pouring out underneath the motorhome. Before assuming there’s a split pipe or failed tank, check the drain valves.

A valve may have been left open after winter draining, or an automatic frost-protection valve may have released during cold weather. Depending on the plumbing and whether the pump is running, water can escape as you try to refill the system.

Locate the fresh-tank drain, boiler drain and any additional drain points before you need them. Knowing which valve does what makes troubleshooting much easier.

If an automatic frost valve has opened, follow its reset instructions. Some won’t stay closed until the valve itself has warmed sufficiently, so repeatedly pressing the button won’t necessarily solve the problem.

Don’t wedge or tie the valve shut. Restore the conditions needed for it to close normally, then refill the system and check that the flow underneath has stopped.

20. Assuming the Boiler’s Frost Valve Protects the Whole Water System

An automatic frost-protection valve can help protect the boiler by releasing its water when the temperature around the valve drops. It doesn’t empty every tank, pipe, tap, filter or shower fitting in the motorhome.

Water left elsewhere can still freeze and cause damage. A small amount trapped in a shower head or filter housing may be enough to leave you with a leak when the system is used again.

Follow your motorhome’s full draining procedure whenever it will be left in freezing conditions without reliable frost protection. That may include draining both water tanks and the heater, opening taps in the specified position, and emptying shower hoses, filters and external shower connections.

Check the toilet’s instructions too, particularly if it has a separate flush-water reservoir.

Layouts differ, so use the vehicle and appliance handbooks to identify every drain point. Don’t assume that an empty fresh-water tank or an open boiler valve means the whole system is empty.

21. Leaving the Water Pump Running When the Tank Is Empty

A pump that keeps running is telling you something. The fresh-water tank may be empty, a drain valve may be open, or there could be air entering the system or water escaping through a leak.

What’s normal depends on the installation. A pressure-operated pump should generally stop once the taps are closed and the system reaches pressure. A system with microswitch taps works differently, but the pump still shouldn’t run continuously with everything switched off.

Turn the pump off and investigate rather than leaving it running while you get on with something else. Some pumps tolerate dry running; others can be damaged by it. Either way, you’re using electricity without achieving anything.

Check the tank level, taps, drain valves and visible pipe connections. If a pressure-operated pump repeatedly starts for a moment when nobody is using water, look for a dripping outlet, a leak or another pressure-loss problem.

Switch the pump off when leaving the motorhome unattended. If a connection fails while you’re out, that can prevent the contents of your fresh-water tank being pumped into a cupboard or under the floor.

22. Putting Unsuitable Products Down the Drains

A motorhome’s waste system can include flexible hoses, plastic fittings, seals and relatively narrow pipework. A product intended for household drains may not be suitable for those materials.

Harsh drain unblockers can damage components, while mixing cleaning products can create further problems. Check compatibility with your motorhome’s plumbing and waste tank before using them.

If a sink is draining slowly, start with the accessible strainer and trap, where fitted. Check for food debris, grease build-up or a kinked waste hose rather than immediately reaching for a chemical treatment.

Persistent smells deserve investigation too. An empty trap, dirty overflow or waste-system venting problem won’t necessarily be fixed by adding more cleaner to the tank.

Use products suitable for the installation and follow their instructions. Keep food scraps and cooking fat out of the sink, and clean accessible components regularly to prevent build-up.

23. Assuming Any Gas Bottle Bought Abroad Will Connect

Gas bottles aren’t interchangeable across Europe. Connections, bottle sizes and exchange arrangements vary, so finding somewhere that sells gas doesn’t mean you can buy a cylinder and connect it to your motorhome.

With an exchange-bottle system, you may need a compatible local cylinder and the correct high-pressure hose or connection arrangement. The cylinder also needs to fit securely in the gas locker. Don’t improvise connections or assume an adapter makes every combination suitable.

Before a longer trip, identify your regulator, hose connections and available locker space. Check what you can obtain at your destination and ask a competent LPG specialist which equipment is appropriate for your installation.

Refillable systems need planning too. Check which filling adapters you’ll need and the rules of the stations you intend to use. A filling adapter for a refillable system serves a different purpose from a connection for an exchange bottle.

Sort out your options before the bottle runs empty. Finding compatible equipment is much easier when it isn’t also holding up dinner or leaving you without heating.

24. Sealing Over a Leak Without Finding Where Water Gets In

A damp patch inside the motorhome doesn’t necessarily sit directly beneath the failed seal. Water can travel along framing, behind wall coverings or through insulation before becoming visible.

Adding sealant around the nearest window might leave the actual entry point untouched. It can also make a later repair more difficult, particularly if the product is incompatible with the existing sealant or bodywork.

Look for the cause rather than simply covering the symptom. Rooflights, windows, body joints and accessory mounting points are all possible sources, but condensation and internal plumbing leaks need considering too.

If you find damp, limit further water exposure where practical and arrange a proper investigation. Moisture readings can help establish the extent of the problem, although they need interpreting alongside the motorhome’s construction.

Use the sealant and repair method specified for the materials involved. Some joints need dismantling, cleaning and resealing properly; another bead over the top won’t necessarily provide a lasting repair.

25. Confusing a Habitation Check with Vehicle Servicing

A habitation check and a base-vehicle service cover different parts of your motorhome. Having one completed doesn’t mean the other has been taken care of.

The base vehicle needs servicing according to its manufacturer’s schedule, including time-based requirements that apply even when your annual mileage is low. Depending on the vehicle, those can include oil changes, brake-fluid replacement and timing-belt changes.

A habitation check assesses the living-area systems and condition within the provider’s stated scope. It doesn’t replace engine servicing, and it may not include every maintenance task required by individual appliances.

Water-ingress inspections can have their own schedule and conditions, particularly where a manufacturer’s warranty is involved. Check the deadlines, required provider and documentation rather than assuming any annual inspection will qualify.

Keep a record of what was checked, what was serviced and what remains due. If a report identifies a fault, arrange the repair: the inspection itself hasn’t fixed it.

Get to Know Your Motorhome

You don’t need to become a mechanic or an electrician to look after your motorhome, but knowing what it weighs, how its systems work and what needs checking will make life on the road easier. If you haven’t already, put together a departure checklist and keep a note of your servicing dates. Those two small jobs could save you a much bigger one.

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