If you’re planning a caravan or motorhome holiday this year, it’s worth knowing about leisure batteries and the benefits of bringing one on your trip.
But what type of leisure battery should you get and how do you charge it? We answer lots of commonly asked questions on caravan leisure batteries below.
In this article
What is a leisure battery?
A leisure battery is a deep-cycling battery which is designed to provide a low current for long periods – these are sometimes also referred to as secondary or auxiliary batteries. Leisure batteries can discharge a greater amount of their capacity without being damaged, and can be recharged if needed.
They can be used for different purposes, but are popular for powering certain appliances in caravans and motorhomes when they’re stationary and not hooked up to mains electricity.
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Do I need a leisure battery for my caravan?
A leisure battery allows you to power some appliances in your caravan or motorhome when stationary and you don’t have access to an electrical main.
A single 12v battery can power appliances such as:
- LED lights
- 12v television
- USB charging
- Laptops
For other appliances, such a kettle or oven, it’s best to connect to electrical mains or get a generator.
Generally new build caravans don’t come with a leisure battery so you might need to buy one separately, along with a battery charger.
Motorhomes do tend to come with one, as they generally feature a split-charging system. This means the vehicle's starter battery and leisure battery can be charged by the alternator when the engine is running.
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What are the different types of leisure batteries and how do they work?
There are several different types of leisure battery available. Which one suits you best will depend on a range of factors including budget and how you're using it.
Most leisure batteries are lead acid, but there are variations in terms of how they’re constructed.
Different types of lead acid batteries
1. Open lead acid leisure batteries
These the cheapest of the selection but also the most maintenance heavy. Open lead acid leisure batteries work via lead plates which sit in a solution of sulphuric acid, known as electrolyte. There are removable caps so you can top the battery up with electrolytes or distilled water to maintain performance.
Open lead acid batteries are not as common as they used to be. This is because there are more convenient lead acid batteries available now which don’t require you to top up the liquid acid.
2. Sealed lead acid leisure batteries
These are very similar to open lead acid batteries but they're sealed so you don’t have to top up the battery with electrolytes or distilled water, making them maintenance-free.
Sealed lead acid leisure batteries are a popular option for caravans and motorhomes as they’re cheaper than many of the other types available.
3. Absorbed glass matt (AGM) leisure batteries
A key benefit of AGM batteries is that there is no chance of acid spillage, due to the electrolyte being trapped in a non-liquid state within a fibreglass matt.
But they’re a bit pricier than open or sealed lead acid batteries and generally have a shorter service life.
4. Gel leisure batteries
The electrolyte is stored as a gel in this type of battery, making it leak and maintenance free.
But they are more expensive, and don’t cope well with high discharge and recharge rates.
5. Lead crystal leisure batteries
In this type of battery, the electric is stored as crystals so they’re also leak-proof, but they aren’t commonly used.
One of the main draws of a lead crystal battery is that it generally offers a much longer lifespan then a typical lead acid battery – but they're a lot more expensive.
Lithium batteries
An alternative to lead acid batteries are lithium batteries. A key selling point for these is they provide much higher energy density for a much lower weight, making them a lighter object to cart along on your road trip.
The main drawback is the price, being much more expensive than lead acid batteries. Lead acid batteries are therefore still generally far more popular compared to lithium batteries.
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What size leisure battery do I need?
What size of battery you need depends on what you might want to use it for.
Think about the different appliances you’d like to use while your caravan or motorhome is stationary and not connected to mains electricity, for example LED lights and phone chargers.
The number of appliances you’d like to use should help give you an idea of the size you need.
And remember, if you don’t have a full inverter system, you should only use the battery for powering 12v appliances as this is what it’s designed for.
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Can you charge a caravan leisure battery from the mains?
Generally, caravans and motorhomes will offer 2 main methods of charging a leisure battery. One option is via the onboard mains charger (which can be used when the caravan is hooked up to mains electricity). The mains charger is normally able to charge the battery fully.
If you have a motorhome, the other option is to charge it using the engine-driven alternator when on the road. But if you have a flat leisure battery, charging it this way may damage the alternator. It’s therefore better to charge a flat battery using the mains.
A battery maintainer can also help keep the battery in a good state of charge when you’re not using it.
Can you use a solar panel to charge a caravan leisure battery?
You may wish to invest in a single solar panel system to keep your leisure battery topped up during the day. They are usually sold as a small kit or as a stand-alone unit.
Depending on the solar panel you opt for, it might come with multiple outlets ranging from 12 to 24 volts. Some have over-voltage protection built in while others come with a separate charge controller to prevent too much voltage going to the battery.
Small systems can cost as little as £70, but costs increase considerably for more powerful solar systems. These systems can be portable folding “brief case” style panels or can be more permanent installations, typically mounted to the roof of the caravan or motorhome to get the best of the sunshine.
If you’d like more off-grid power capabilities than a single leisure battery can offer (for example, the ability to power appliances like kettles and hairdryers), you might want to consult a specialist about an advanced solar system.
A specialist can advise on and provide the equipment required, including panels, a solar controller, leisure batteries, an inverter, wiring and mounting.
This type of system typically costs several thousands pounds and needs to be installed by an experienced electrician, but may be worthwhile if you’d like to power certain appliances without access to mains electricity.
How much is a caravan battery?
The price of caravan batteries will depend on the type and model you opt for, ranging from around £150 for a standard lead acid battery to around £500+ for a lithium battery (some can cost upwards of £1,000).
How long does a leisure battery last?
How long a fully charged battery lasts depend on the type you buy and how well you look after it. Different types of battery have different lifespans but it’s also important to maintain and look after the product based on the manufacturer’s instructions.
There might be a warranty period for the battery (some come with a warranty of up to 5 years) but you should always check the terms and conditions of this before buying.
How to maintain your caravan or motorhome leisure battery
Here are some of the key ways you can look after your leisure battery:
1. Be mindful of discharging too much
Most leisure batteries are only supposed to be discharged by a certain amount - over-discharging can sometimes lead to permanent damage.
Follow the instructions for your battery to avoid over-discharging it.
2. Use a solar battery maintainer
A solar battery trickle charger helps to maintain a healthy battery by feeding a tiny amount of current in to keep it in a good state of charge.
3. Don’t forget about your leisure battery over winter
It’s likely you’ll mainly be using a caravan leisure battery during the summer months, and it can be easy to forget about it during the winter.
But if you don’t keep the battery at a reasonable charge during the colder season, you may find it doesn’t work properly when you try to use it the following summer.
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How long to charge a leisure battery from the mains?
The time it takes to fully charge a leisure battery from the mains can vary, depending on the type of battery you've got, its current charge level, and the output level available from the mains.
On average, a completely charged 100Ah leisure battery will take around 10-12 hours to fully charge (assuming the source of your charger has the standard 10A output.
Does a caravan battery charge while on hook-up?
Yes, hooking your caravan up to a mains supply at a campsite will charge the leisure battery. Be aware that new-build caravans won't always come with a leisure battery, so you may have to buy one separately.
However, most caravans do come with a leisure battery that is designed to charge while hooked up to a power supply, part of the design involves adjusting the charging current to make sure it doesn't overcharge or take damage.
How long does a leisure battery last off-grid?
How long a leisure battery lasts off-grid will depend entirely upon how much you use it, and whether the appliances in your caravan or motorhome are particularly power-hungry. If we take a fully charged 100Ah leisure battery as an example again, you could expect it to last between 2-4 days if you only use the battery a moderate amount.
However, if you're using appliances like large TVs, heaters and air-conditioners, you can expect your power levels to run out significantly faster.
Why does my caravan battery keep going flat?
Often the cause of battery drain is due to a faulty battery. If your battery is quite old, this may be causing problems. Cold temperatures can also affect it.
If you don’t think it’s the battery itself, a broken charger could also be causing issues or there might be a “leak” or drain caused by a faulty appliance or fuse.
Can you overcharge a caravan battery?
It’s quite difficult to overcharge a battery. If you’re using an intelligent battery charger, shouldn’t be able to overcharge it.
But if you’re charging the wrong type of battery from the alternator in a motor caravan, you may have overcharging issues. It's recommended that you use a charger with an automatic shut-off feature or a timer to prevent unnecessary overcharging.
Do I really need a leisure battery in my caravan?
If you're only going to use your caravan at a campsite with a mains hook-up and other amenities available, then you may be able to get by without a leisure battery. However, it can be really convenient to have one as it allows you to spend time off-grid.
If you are off-grid, and let's say the weather starts to take a nasty turn, you'll be able to keep yourself warm with a leisure battery as it can power the heating system in your vehicle. At the end of the day, the decision is up to you.
What drains a caravan battery?
Appliances that drain lots of power from leisure batteries include heaters, TVs and air-conditioners, but other factors can cause your power to be sapped at a fast rate. For example, leaving your lights on for long periods or having generally poor insulation for your caravan.
It's also possible to use your leisure battery too much, even if your appliances aren't overly ostentatious. If you use it frequently for lots of small things without recharging it, this can increase the rate at which power is drained.
How long will a caravan battery run a TV?
A standard fully charged 100Ah battery will probably get you a full day of use out a 12v TV. You can increase the amount of usage time you'll get by choosing a smaller, LED TV.
Should you leave a caravan plugged in all the time?
No, you shouldn't leave your caravan plugged in all the time, as this can cause the battery to overcharge, impacting its overall lifespan. If you're going to be away from your caravan for some time, or you already know it's fully charged, then it's a good idea to disconnect it for a while.
Additionally, leaving your leisure battery hooked up to the mains can increase the risk of electrical fires, and at the very least could cost lots of money due to the high amount of electricity you're using.
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Can you run a 12v TV off a leisure battery?
Yes, you can run a 12v TV off a standard 100Ah leisure battery for around 24 hours, assuming you aren't using lots of other power-hungry appliances at the same time.
How long will a 120Ah battery run a fridge?
On average, powering a fridge with a 120Ah battery will get you between 24-36 hours of use. You can maximise that potential time by avoiding opening the fridge door for too long. You might also want to invest in a fridge thermometer to make sure your food isn't getting spoiled.