A battery isolator switch can disconnect the battery safely to eliminate any power draw from the battery when your caravan or camper trailer is not in use.

Have you ever had your caravan or camper trailer in storage for a month. You come back to it to find that your battery is flat? Flattening your caravan or camper trailer battery is not a good thing. Flattening your caravan or camper trailer battery can dramatically decrease the lifespan of your battery. It can even kill it then and there.

• Why Does My Caravan Battery Go Flat
• Why Not Just Keep Your Batteries On Charge
• Install A Caravan Battery Isolator Switch
• So How Has It Worked

12v Battery Isolator Switch Installed Beside Fridge On Jayco All Terrain

Why Does My Caravan Battery Go Flat Even When I Have Turned Everything Off?

So you’ve turned everything off. But have you really? Many caravan or camper trailer 12v battery systems will have some kind of parasitic draw on the battery. Even when you think everything is turned off. On our Jayco All Terrain we had multiple positive cables coming off our lithium batteries being fed in to a Projecta PM335J battery management system. As well as a shunt used to measure current input and output. The Projecta PM335J BMS has an on/off switch built in however even with this in the off position the unit would draw about 2.0ah daily from our batteries. Now that’s not much but over the course of a few months it adds up 120ah.

Things that may have a residual parasitic draw on your battery when you think you have turned everything might include but aren’t limited to,

• Battery management systems (BMS)
• Nodes for mobile app connection
• Wifi connection nodes
• Bluetooth connection nodes
• Display screens for battery management systems
• Anything wired outside of the BMS for example a diesel heater display screen wired directly to a battery
• Solar charge controllers
• DCDC charge controllers

Jayco All Terrain Projecta 335J

Why Not Just Keep Your Batteries On Charge When Not In Use?

Many will argue that simply leaving your batteries connected to a charger with a ‘float’ mode will keep the batteries fully maintained and ready for use. To an extent, this is true – but there is also the possibility of gradual degradation of the batteries if kept in this state constantly.

AGM Batteries
Lead acid batteries contain lead plates surrounded by a liquid or electrolyte solution of diluted sulphuric acid, and as the battery charges and discharges a chemical reaction occurs between the sulphuric acid in the electrolyte and the lead plates. The batteries are designed to be charged and recharged on a regular basis, so having them in a float charge mode at a constant voltage (normally between 12.2-13.4V) can cause the battery to become ‘dehydrated.’ When a battery enters this dehydrated state, it means the level of electrolyte recedes below the level of the top of the lead plates. This would cause irreparable damage to the plates, therefore damaging the battery extensively.

LiFePO4 (Lithuim) Battery Storage SOC (State Of Charge)
When not using your LiFePO4 (lithium) batteries it is generally recommended by most manufacturers to store them at around 40%-50% state of charge (SOC). Keep in mind that lithium-ion batteries should never be stored fully charged or completely discharged. On the one hand, LiFePO4 batteries will gradually self-discharge, and they will lose large amounts of their usable life if they’re fully charged all the time. On the other hand, storing lithium-ion batteries fully discharged will be harmful to the battery cell.

Install A Caravan Battery Isolator Switch – Then Off Really Does Mean Off

The solution to stopping your caravan or camper trailer getting a flat battery after storage for a long period due to parasitic draw on the battery is simple. Install a battery isolator switch – sometimes called a battery master switch.

Caravan Battery Isolator Switch Viewed From Behind

The switch is installed between the battery and any possible load. Turn the switch off. The power is stopped. Ours is installed on the positive side however it achieves the same result when installed on the negative side. Of course the new cabling needs to be fused correctly to make things safe.

I have used 6B&S cabling fused with midi fuses at 50amp. More than safe for the current our system is running at.

Jayco All Terrain Caravan Battery Isolator Wiring Through Heavy Duty Bus Bar

To help keep it all nice and tidy I have run all of the cabling in to and out of a heavy duty bus bar. Much neater and tidier than hooking it all up to the out lug on the 12v battery master switch. There are also a few spare lugs on the bus bar so I can hook up any extra cables in future as and if required.

Caravan Battery Isolator Switch Wiring Diagram

So How Has It Worked So Far?

It works 100% as it should. We have LiFePO4 (lithium) batteries. When we get home from a trip we let them run down to around 50% SOC then I simply turn the battery isolator switch to off. I have checked it multiple times, turn it off at 50% then turn it back on a month or two later and the system comes back to life and the LiFePO4 (lithium) batteries are still at 50%. No reduction in SOC whatsoever.

Projecta Display Panel SOC 47 Percent

List Of Australian Caravan Brands That Can Use A Caravan Battery Isolator Switch

Adventura Caravans battery isolator switch, Alpha Fibreglass, Aussie Wide Caravans, Avan Campers, Ballina Campervans, Billabong Custom Caravans, Caravan Manufacturer, Caria Caravan Trailer, Challenge Camper Trailers Caravans, Classic RTM Caravans, Concept Caravans, Coromal Caravans, Creative Caravans, Davsher Caravans, Desert Edge Trailers, Designer Vans Caravans, Discoverer Campers, Dreamhaven Caravans, Dreamland Trailers, Driftaway Caravans, Dryden Trailers Caravans, Eagle Caravans, Elross Caravans, Evernew Caravans, Exodus Campers, Ezytrail Campers, Galaxy Caravans, Goldstream Recreational Vehicles, Golf Caravans, Heaslip Campers, Horizon Motorhomes, I & D Industries, Imperial Caravans, Jayco Caravans, Jurgens Caravans, Kea Campers Australia Caravans, Kingdom Caravans, La Vista Caravans, Lifestyle Leisure RV, Limit Seeker Camper Trailers Caravans, Lotus Caravans, Majestic Caravans, May West Caravans, Millard RV Caravans, Montana Caravans, Nova Caravans, Olympic Caravans, Opalite Caravans, Paradise Caravans, Paradise Motor Homes, Paramount Caravans, Regal Caravans, Regent Caravans, Retreat Caravans, Rivenlee Caravans, Roma Caravans, Royal Flair Caravans, Spaceland Industries Caravans, Suncamper Caravans, Sunland Caravans, Sunliner Recreational Vehicles, Supreme Caravans, Swagman Aust Caravans, Tavlor Motorhomes, Toy Haulers Manufacturer, Track Trailer, Trailblazers RV Caravans, Trailer Manufacturer, Trailstar Caravans, Trakka Caravans, Trakmaster Caravans, Travelhome, Traveller Caravans, Truelux 5th Wheel, Vanguard Caravans, Western Caravans, Windsor Caravans, Winnebago Industries, Wirraway Motorhomes

List Of Australian Camper Trailer Brands That Can Use A Camper Trailer Battery Isolator Switch

Alpine Campers, Altitude Campers, Aussie Camper Trailers, Austrack Campers, Australian Off Road Campers, Austyle Campers, Bayside Camper Trailers, Black Series Campers & Caravans, Blue Tongue Campers, Blue Water Campers, BRS Offroad, Bushranger Campers, Bushwakka, Cameron Campers, Camper Trailers WA, Caretta, Condamine Campers, Conqueror Australia, Conqueror Australia, Cub Campers, Drifta Camping & 4WD, Eagle Camper Trailers, Elite Campers, Emu Campers, Ezytrail Camper Trailers, Far & Wide Campers, Goldstream RV, Hitch Campers, Jawa Camper Trailers, Jayco Camper Trailers, Kerfton, Kimberley Kampers, Kings Camping Trailers, Lifestyle Campers, Lumberjack Campers, Marlin Campers, Mars Campers, Maverick Campers, MDC Caravans, Modcon Campers, Mountain Trail Campers, North Coast Campers, Offline Campers, OPUS Camper Australia, Origin Campers, OutbackHQ, Patriot Campers, Pioneer Campers, Platinum Campers, PMX Campers & Caravans, Quest RV, Rhinomax Campers, Signature Camper Trailers, Skamper Kampers, Southern Cross Camper Trailers & Off Road Caravans, Star Vision Camper Trailers & Caravans, Stockman Pod Trailers, Stony Creek Campers, Sunset Campers, Swag Camper Trailers, Terra Trek, TrackStar Campers, Track Trailer, Trackabout Off Road Campers, Trailer Camper Australia, Travelander, Ultimate Campers, Vista RV, Wild Boar Camper Trailers

Don’t know what tyre pressure your caravan should have? Get essential information and advice with this ultimate guide to caravan tyre pressure.

From ensuring the safety of your caravan on the road to optimising performance, it’s important to have the right tyre pressure for your caravan. In this guide, you’ll get all the information you need about choosing and setting the correct tyre pressure for your caravan.

Lowering Caravan Tyre Pressure Before Travelling The Ivanhoe Menindee Road

What is the Correct Tyre Pressure for a Caravan?

The correct tyre pressure for a caravan will depend on the size of your tyres as well as the load you are hauling. Generally, a good tyre pressure should be slightly higher than the minimum recommended. Check with your tyre manufacturer’s guidelines and adjust accordingly depending on the load and terrain that you are driving through. Ensure that the minimum and maximum limits provided on the sidewall of your tyres are observed; otherwise damage to your tyres may occur.

Use The 4PSI Rule

The 4PSI guideline applies to bitumen road use only. As a general rule the following can be used for road use only.

• For passenger tyres, inflate your cold tyres to the recommended tyre pressure on your vehicle’s tyre placard.
• Then, to determine if you have the correct pressure for a given load, you must note the cold pressure reading.
• Drive for at least 20-30 minutes at normal posted speeds to ensure your tyres have reached operating temperature and then check again. Internal tyre pressure rise is dependent on the cavity of volume of the tyre and the tyres heat build-up.

Ideally, your tyre pressure should be about 4 PSI above the cold pressure. If they are not, adjust the pressure accordingly.

If the pressure is more than 4 PSI above the cold pressure, you should add more air. That is because there is too much friction, which builds up more heat than desirable. Conversely, if they are less than 4 PSI above the cold pressure, the cold pressure is too high and you should release air.

6PSI Rule For Light Truck And 4×4 Tyres

For light truck and 4×4 tyres use 6 PSI as a guide. However rough and corrugated roads cause more flexing and your tyres may rise more than the 4 or 6 PSI guide in which case applying this rule is not recommended.

How Do I Check My Tyre Pressure?

To check your caravan tyre pressure, you’ll need a quality tyre pressure gauge. This should not be confused with the least expensive type of gauge which generally only provide accurate readings up to around 30 PSI. The tyre pressure gauge can be inserted into the valve stem and it will provide an accurate reading after a few seconds. You should always check each tyre individually and adjust the pressures accordingly if needed. Remember to also check your spare tyre separately if you have one fitted.

What are the Benefits of Regularly Checking My Tyre Pressure?

Checking your caravan tyre pressure on a regular basis is beneficial in many ways. Properly inflated tyres enable better vehicle handling, improved fuel efficiency, and safer driving as more of the tyre’s tread comes into contact with the road surface. By keeping your tyres at the correct pressure, you help reduce your chances of damage to both the tyre itself and any other parts of your caravan caused by uneven load distribution due to airflow over an incorrectly inflated tyre.

What Should I do if My Tyres are Under-inflated or Over-inflated?

If you find that your tyres are either under-inflated or over-inflated, you should decrease or increase the air pressure accordingly. This can be done using a tyre pressure gauge and an appropriate pump. If your caravan has vastly different tyre pressures, it is always advisable to start by increasing the pressure on both of these tyres until they reach their optimal inflation level.

Tyre Deflator

What Other Precautions Should I Take When Topping up My Caravan Tyres?

It’s always important to take proper precautions when adjusting the air pressure of your caravan tyres. Before starting, ensure that there are no sharp objects in the area as these can puncture the tyre and allow for a rapid loss of air pressure. When inflating tyres, check that you have a secure connection between the pump and the valve stem and avoid overtightening the valves as this can cause damage to them. Always double-check each tyre after inflation and remember to check that all four tyres have similar pressures!

Tyre Pressure Guide For Different Terrains

Sand 18-26 PSI

A lot depends on the depth and coarseness of the sand. Lower pressure increases the size of your tyre’s footprint increasing its ability to stay on top of the sand instead of digging in. Otherwise known as its flotation characteristics. You also need to have enough momentum to stay on top. Higher pressures will be required when carrying heavy loads. Reduce speed appropriate to the depth and type of sand.

Remember that sand can change and be very different in patches. Sand also builds up heat in your tyres because you are running lower pressures for flotation and because of added friction. Keep a close watch on temperature and if they start to get too high pull over and take a break.

High Speed Smooth Gravel Roads 28-32 PSI

If your tyre pressure is too low on this surface you run the risk of sway and bounce. Higher pressures are generally required when carrying heavy loads. When driving corrugated roads reduce your speed as heat can build up quickly.

Slow Speed Rough Gravel Roads 24-28 PSI

Actual required tyre pressure varies dependant upon on how slow, how rough and with what load. Remember that the higher the speed the more heat generated in the tyre according to your load and the type of road surface being travelled. High temperature in the belts of the tyre is not something you can always feel by hand. Higher pressures are generally required when carrying heavy loads.

Slow Speed Rocky Gravel Roads 20-26 PSI

Ever noticed how easily a balloon pops at higher pressures when it hits something? And when the balloon has low pressure it’s harder to damage or pop? The same thing applies to tyres on rocks in most slow speed situations. Sidewall damage needs to be reduced by careful wheel placement.

Assuming that the going is very slow and possibly in low range and not generating a lot of heat in the tyre. You are looking to improve flexibility over obstacles without damaging the tyre. Very low pressures getting down around 18 psi and below can create a risk of pushing the tyre off the bead of the rim. 20 psi is generally an acceptable minimum low-pressure limit for most sizes. Higher pressures are generally required when carrying heavy loads.

Flexibility at low speed is what you want to achieve. Lowering tyre pressures will increase the size of your tyre’s footprint spreading lengthwise along the tyre.

Caravan weights explained. Use the examples below to help you with weighing your vehicles to maximise your safety on the road. It is important to know the various weight criteria of your towing vehicle and caravan in order to stay legal. Your caravan will have its tare mass, maximum aggregate trailer mass (ATM) and maximum gross trailer mass (GTM) on the compliance plate. It is important to weigh your caravan to ensure that you do not exceed these maximum capacities.

Caravan weights Explained – Weighing Your Caravan

Caravan weights explained. Use the examples below to help you with weighing your vehicles to maximise your safety on the road. You can find the location of public weighbridges on the Department of Industry website.

There are also many companies that offer mobile weighing services. When weighing your caravan and tow vehicle it is important to know the level of accuracy of the weighbridge or mobile scales to make ensure your vehicles stay below the maximum carrying capacities. If you aren’t sure read the rest of this article caravan weights explained to find out more.

Tare Mass

Tare Mass is the weight of the caravan with no load. It includes all standard equipment and any options fitted. Think of it as the weight of the caravan when received brand new from the dealer. Tare mass is measured with all fluid reservoirs, if fitted and required for transport, filled to nominal capacity for service, however, non-transport fluid reservoirs such as water tanks and wastewater tanks fitted to caravans are measured empty. After-market optional add-ons (TV, mattresses, extra gas bottles, awnings etc) are not included in the tare mass and are considered as a load, so must be included in your ATM measurement. The tare mass weight of your caravan can be found on the cplate or in the manufacturer’s handbook.

Tare Mass (Caravan)

Tow Ball Mass (tow ball download)

Tow ball mass (tow ball download) is the maximum mass allowed to be put on the tow ball of the towing vehicle. You can find the tow ball mass capacity in your coupling manufacturer’s handbook. To measure the tow ball mass you can use a ball weight scale. You must not exceed the tow ball mass capacity.

Tow Ball Mass

Aggregate Trailer Mass (ATM)

Aggregate Trailer Mass (ATM) is the total mass of the trailer when carrying the maximum load recommended by the manufacturer. The ATM is generally measured with the caravan unhitched from your towing vehicle and resting on its jockey wheel. The maximum ATM of your caravan can be found on the vehicle plate or in the manufacturer’s handbook and must not be exceeded. To measure your ATM, weigh your loaded caravan resting on its jockey wheel, including full water tank, gas tanks and everything you would pack to go travelling. Ensure that your measured mass does not exceed your specified ATM capacity.

ATM Aggregate Trailer Mass

Gross Trailer Mass (GTM)

Gross Trailer Mass (GTM) is the maximum mass recommeded by the manufacturer of your fully loaded caravan when it is hitched to your tow vehicle. The GTM of the caravan is transmitted to the ground by only the caravan tyres and excludes the mass distributed to the towing vehicle through the coupling. The GTM of your caravan can be found on the vehicle plate or in the manufacturer’s handbook and must not be exceeded. To measure your GTM, weigh your loaded caravan when it is attached to your towing vehicle, and make sure your measured mass does not exceed your specified GTM capacity.

GTM Gross Trailer Mass

Gross Vehicle Mass (GVM)

Gross Vehicle Mass (GVM) is the maximum total mass of a fully loaded motor vehicle as specified by the vehicle manufacturer. For some passenger vehicles, it might be known as the Maximum Loaded Vehicle Mass (MLVM). To measure your loaded vehicle mass, weigh your fully packed towing vehicle, including passengers, with the caravan hitched and ensure it is less than your vehicle’s maximum GVM or MLVM.

GVM Gross Vehicle Mass

Gross Combination Mass (GCM)

Gross Combination Mass (GCM) is the maximum mass set by your tow vehicle’s manufacturer and refers to the maximum combined mass of your loaded tow vehicle and your loaded caravan hitched together. Not all vehicles are provided with a GCM, but if it is, your vehicle manufacturer’s guide will provide you with the GCM of your tow vehicle. To measure the GCM, weigh your fully loaded towing vehicle hitched to your fully loaded caravan. Legally, you must not exceed the specified GCM capacity of your vehicle if a GCM is specified.

GCM Gross Combined Mass