Caravan Leisure Battery | The Basics of Leisure Batteries

Before you head off to recharge your batteries touring, take a minute to check your 12v leisure battery. Whether you're new to caravanning or you've travelled far and wide with your trusty tourer, it can't hurt to pick up a few tips before you start budgeting for a motorhome or caravan leisure battery.

The 12v Leisure Battery
In a nutshell, a 12V leisure battery can:

• power electrical devices like appliances, motor movers, alarms, water heaters, etc. within the caravan or motorhome;
• facilitate power delivery to electrical devices when the caravan or motorhome is hooked up to the mains, smoothing out variations in the supply;
• store extra energy collected by solar panels.

Most tourers can make do with a single battery, but those who spend most of their time off-grid have a second battery as backup between hook-ups. When they're not in use, these batteries need minimal maintenance to keep a good state of charge, but they also reduce space and payload considerably.

Motorhome and Caravan Leisure Battery Categories
A 12V leisure battery is different from a car battery in that the lead plates within it are much thicker and far fewer. This helps it cope with frequent charge and discharge cycles. It's also much heavier, because lead is a dense metal with high mass, and so it's better suited to caravanning. Here are some of the main types of caravan and motorhome leisure battery based on their properties:

TECHNOLOGY
There are two types of caravan leisure battery in terms of how they're built: lithium-ion (LiFePO4) and lead acid. Most people opt for the latter because they're cheaper, even though lithium batteries are safer, more compact, easier to mount, more reliable, and there's virtually no maintenance involved. Lead acid batteries can also be classified as:

• flooded batteries are the most common and they're made of lead plates doused in sulphuric acid;
• gel or VRLA batteries are resistant to vibrations and they have pressure regulating valves - but they're also easy to damage by overcharging because they have added silica gel that thickens the electrolyte;
• AGM batteries are vibration resistant, maintenance-free and spill-proof batteries with flat or spiral glass mats that absorb the electrolyte and store more energy than any other lead acid batteries;
• lead crystal batteries have a silicon dioxide electrolyte that transforms into crystals after several cycles and they're supposed to last twice as much as other lead acid batteries.

CAPACITY
Motorhome batteries are classified by the National Caravan Council in three categories. To check that your battery is right for the kind of usage you had in mind, look for the NCC label. All batteries are labelled as one of the following:

• Cat. A – batteries with high storage capacity for self-sufficient, off-grid caravanners;
• Cat. B – batteries for tourers that rely mainly on electrical hook-up, but need some extra juice for their devices;
• Cat. C – batteries for basic equipment used sparingly.

PURPOSE
Batteries are job-specific and finding the right battery isn't just a matter of NCC rating. It pays to think about how you'll be using it and to check that the battery is marketed for your specific purpose. There are three types of battery to choose from:

• Cranking batteries or starter batteries have a massive output, perfect for kickstarting a motor.
• Deep-cycle batteries have low but lasting output, and their performance isn't affected by heavy discharge (up to 80%);


• Dual-purpose batteries are hybrids suitable for both short bursts of power with devices like a motor mover and long-term use with small appliances.

SIZE
Caravan batteries come in various shapes and sizes, usually proportional to their ampere hour, amp hour, or Ah rating. The Ah unit is a measure of the amount of energy charge that allows 1A to flow for 1 hour. The higher the Ah rating, the longer a battery will last and the fewer the times it will need recharging.

PRICE
You'll find the price tends to be determined by the battery's technology, size, and capacity.A lithium-ion battery can be a whopping 20 times more expensive than a lead acid battery, with a price tag above £2,000.

LONGEVITY
How long the battery will last will depend on its technology, capacity, usage, and maintenance. The number of recharge/discharge cycles is a good indication, but you should expect a battery to last anywhere between 2 to 5 years.

Caravan Leisure Battery Maintenance
To extend the lifespan of your battery, maximise its performance, and avoid running out of power when you need it most, you should make sure to:

• opt for a slow charge rather than a high-speed boost, whenever possible;
• recharge a flood battery when it's at 50% of capacity (so the lead sulphate doesn't crystalize on the plates), or as stated in the manufacturer's instructions;
• do not overcharge because this uses up the electrolyte (in a sealed battery, there's no way to top it back up);
• check for the tell-tale signs of overcharging: it's hot or it smells of sulphur (like rotten eggs);
• buy a voltage-controlled charger, which switches off automatically, to prevent overcharging the battery;
• if your battery isn't sealed, check annually that the electrolyte levels in each cell cover the lead plates, and when necessary, top up with de-ionised water available in supermarkets;
• clean the terminals on your battery and apply petroleum jelly on the connectors;
• charge the battery over the winter and when it's in storage, or remove it from the caravan and store it in a ventilated room, after checking your alarm, tracker, and other devices that rely on it;
• keep the battery at ambient temperature to preserve charge – the Ah rating is based on a 25°C temperature, and for every 1°C below that you lose 1% in performance;

Checking Your Battery Charge
To check the level of charge in your battery, check the control panel. For a more accurate reading, turn off all your electrical appliances, and switch off all your sockets. Use a basic handheld voltmeter to view voltage.

• a full charge will yield a reading of 12.7V;
• a reading of 12.4V is consistent with a 75% charge;
• a result of 12.2V means it's half-charged.

If you find yourself recharging more and more often even when you don't use extra appliances, that's a sign your battery needs replacing. When your caravan or motorhome leisure battery is exhausted, make sure you replace it with a like-for-like battery.

Leisure Battery Safety
Before you replace your 12V leisure battery, consider the issue of safety. Sealed within this battery is sulphuric acid, which is very corrosive. Don't forget to wear gloves and safety goggles when you top up the electrolyte. Use clean, good-quality, and rust-free clamps when you connect the battery. Always unplug the negative cable first and reconnect it last. Also, never smoke in its vicinity, because the gases released from a battery are flammable and explosive.