The modern world really can’t live without an electrical supply, and everything from your weekly shop to parking apps rely on it to work. Your motorhome is exactly the same and, while a flat habitation battery won’t leave you stranded, it will mean an early bedtime, limited toilet use and a warming fridge. Not the end of the world, then – but not ideal.
So what can you do to avoid the issue? Well, the obvious answer is to make sure that when you’re choosing the best motorhome sites to pitch up at, you only stay on sites that have an electric hook-up. In this scenario, your leisure battery automatically receives charge from the vehicle’s inbuilt battery charging system.
The 240V AC mains supply powers a transformer and is converted to a 12V DC supply, which tops up the leisure battery – usually at 10-20A, depending on the brand of charger. This is easily enough to keep pace with all the usual 12V drains in a leisure vehicle, including LED lighting, motorhome fridges and so on.
Saving energy
These days, the best motorhomes are pretty efficient in terms of their energy consumption, and they all come with LED lighting as standard. If you have an older motorhome that’s still fitted with any incandescent bulbs or mini fluorescent tube lighting, it’s well worth ditching these for an LED unit.
If you look online, you’ll find a large selection of LED lights in all manner of different shapes and sizes, to suit most applications at very reasonable prices. But there are only a handful of vehicles that do not already use LEDs, so this won’t apply to many.
LED lights sip electricity and you can add more lighting to an older vehicle while still decreasing the net energy consumption – which is an easy win.
Generally speaking, it’s all the bulky additions that you’re kitting out your motorhome that tend to be the big consumers of electricity, and any device that needs to be driven by an inverter (providing mains power directly from the leisure battery) is usually a heavy user of current.
Microwaves, fan heaters, air fryers and coffee machines all draw hundreds of amps from the leisure battery when paired with an inverter, so are best used fairly sparingly.
Run a small 800W microwave from an inverter paired to a 100Ah leisure battery and you’ll be lucky to get half an hour of run time out of it. Coffee machines are equally bad, but as the modern pod machines tend to heat the water rapidly and are only on for a couple of minutes at a time, the battery isn’t depleted as much.
Gaining energy
A few years ago, we’d have said that motorhome or campervan solar panels are worth having but not something you can always rely on, especially in the reduced daylight of winter in the UK. Although this is still the case, the efficiency of panels has climbed and the price has shrunk.
However, the latest solar panels can kick out some impressive current in summer and can be valuable motorhome upgrades to consider. One 400W panel that we tested recently was whacking out a pretty decent 24A during those months.
The general rule with solar panels is to go for as large an array as your roof and your payload can support, and pair them up to a matched solar regulator.
The 400W panel we mentioned is paired with a beefy 30A dual regulator, which tops up the leisure battery at up to 29A and trickle-charges the vehicle battery at a steady 1A when needed.
the thin, self-adhesive style of panel
In the UK, I think the minimum size of solar panel needs to be at least 150W, preferably 200W or more, to allow for the inevitable reduction in performance during the cooler months, which will be a particular issue if you’re not winterising a motorhome and prefer touring all year round.
In the colder months, the angle of the sun in the UK reduces solar panel efficiency and the longer shadows can also partially shade the panel, causing it to reduce the output.
You might only get a tenth of the maximum output in winter, so the 24A from a 400W panel might be as little as 2.4A. You can see how an old 40W panel, which might be able to produce a maximum 2A in summer, will be of limited use in winter; 0.2A is barely going to tickle a leisure battery, let alone charge it up.
A large solar array in the summertime also allows you to use all of your high current devices, although it might require a full day of sunshine to recover a full charge again.
The other methods of gaining charge include wind turbines – these can be bolted to vehicles with brackets or fixed on sturdy stands. Although they can be effective, they’re bulky to store, might make humming noises while in use and can give a variable output. Many campsite guests complain about the noise and the strobe effect from the blades, so they’re not popular and are not something we’d advocate.
A roof-mounted solar panel is a fit and forget item that doesn’t intrude on your leisure time and needs minimal maintenance, other than remembering to give it some attention when carrying out the motorhome roof cleaning task.
There are other methods for getting extra power into a vehicle, such as methanol generators and traditional petrol or diesel-powered generators (which can be noisy), but all use fossil fuel in one form or another. Many people are seeking to move away from this to reduce their carbon footprint and are looking for more ways to enjoy eco-friendly campervan tours.
Upgrading lead-acid batteries
One important factor is when you use devices in your leisure vehicle. Most motorhomers will be exploring the area during the daytime, or relaxing outside the vehicle if it’s a sunny day.
All their energy use tends to be in the evening or at night, when the bulk of the heating and cooking takes place. So while solar panels can top up the battery during the minimal daytime current usage, they don’t help at night.
For those who like year-round camping or are after ways of powering a motorhome off-grid, you’re going to have to increase your battery bank. Most ’vans have provision to add a second battery, and this is the cheapest, easiest way to gain a longer battery run time.
However, the downside to lead-acid units is their physical size – two 100Ah batteries will take up a lot of locker space – and their weight. Nobody has ever used the phrase ‘as light as lead’! So you need to check your payload to avoid overloading an axle.
If you do want to go down this route, there are a few things to be aware of. The first is that both batteries need to be of identical capacity, brand and age. In practice, this means you need to fit two new batteries and can’t just add a second 100Ah battery to whichever brand you have in your battery locker.
Two new batteries, in other words!
The reason is safety. Mismatched batteries can have different cell resistances and can behave differently when they are charging or discharging. This can cause one battery to overheat and fail, or produce excessive gas (highly flammable and smells like rotten eggs). They can even catch fire.
So you’ll need two new identical batteries to go down this route. Each battery must have its own separate fuse, close to the positive terminal of the battery. One fuse split between two batteries can also cause a fire risk if one battery fails. Fuses protect wiring against fire and are not optional items.
You can get a couple of good 95Ah batteries for as little as £200 these days, so if you’re looking for the best campervan leisure battery and running to a tight budget, don’t rule out lead-acid.
Upgrading to lithium
Eagle-eyed readers will notice that we have jumped some battery types here and ignored gel and AGM batteries.
These battery types are designed to avoid spills following accidents and are primarily used in applications where this might be an issue – underseat use, for example. But because they’re more expensive than lead-acid and the price of lithium batteries keeps dropping, they don’t make as much sense anymore. Spend the extra money and get the benefit of increased capacity and reduced weight with a lithium unit.
Much is made in some sections of the media of lithium batteries being linked to fires (although some research indicates that in cars, lithium is actually 80 times less likely to catch fire than a fossil fuel vehicle). It’s important to note that many electric cars use lithium ion batteries, while units designed for motorhomes are lithium iron phosphate (LiFePO4), which is generally considered to be safer. Tesla has switched to this technology in newer models.
We would not recommend buying a LiFePO4 battery that will be shipped direct from anywhere outside the EU – online retail sites are awash with these items. In my opinion, they’re a total lucky dip in terms of quality and longevity.
So I’d suggest only buying lithium batteries from a UK supplier – one that advertises in the UK press and has a UK shop – or at a show, such as the upcoming Motorhome and Caravan Show. Ideally, pick a firm that has been in business for several years and has good feedback online.
Happily, there are lots of great UK suppliers offering excellent batteries at reasonable cost, and the capacities are increasing all the time. A couple of suppliers are now offering 628Ah batteries, which will basically allow you to forget all about your battery consumption and simply plug all of your devices into them all day.
However, do bear in mind that the bigger the battery you go for, the more space and payload it will consume and the longer it will take to recharge from flat. In the case of our 400W panel outputting 24A, it would take around 26 hours to fully recharge a 628Ah battery from flat.
In reality you can’t fully discharge a lithium battery – their inbuilt battery management system (BMS) would cut out to prevent it – but in this case, it would still probably take a couple of days of sunlight to fully charge it.
In that situation, you would pair this massive-capacity battery with a larger heavy-duty charger that could output up to 80A to the battery, and possibly link it to an inverter charger.
This also brings us very neatly to another very important point – you will need to ensure that whichever charging system you happen to have fitted in your motorhome, it will be compatible with the battery that you are planning to use.
Most modern LiFePO4 batteries come with built-in electronics, the BMS, which are designed to make them behave like a normal battery when installed in a vehicle.
However, they do require a battery charger that is lithium-compatible, to ensure they receive the correct charging profile. This will also make sure they get fully topped up and last for a long time.
As with all batteries, each lithium battery you install must have its own dedicated fuse. It is not acceptable to share one fuse between two batteries or rely on a battery cut-out switch.
You can always add an additional charging system to cope with a beefy lithium battery and many of the UK battery suppliers can help with this, but it does add to the cost.
Lithium batteries also respond well to rapid recharging on the road from battery-to-battery chargers, and when they are paired with a large solar array, you can have pretty much the ultimate set-up for excellent battery duration and trouble-free off-grid motorhoming.
Battery banks
Another method for operating your high-powered devices without having to worry about installation costs and complicated wiring is to operate them from one of the best portable power stations for a campervan.
If the battery bank goes flat, you might miss out on an espresso or using the best air fryer for a motorhome, but all of your ‘van appliances will still work well.
Firms such as EcoFlow, Jackery and Sherpa can sell you an all-in-one battery bank with a built-in battery that powers a selection of mains sockets and USB outputs.
They are practical to use as they all have a display that tells you how much current is being drained and how long they can power everything for. They can also be linked to a fold-out solar panel if you don’t want to have a panel permanently fixed to your roof.
The downside, though, is that they are expensive compared to a battery upgrade, and the larger ones are bulky and heavy. But if you want mobility and ease of use, they can be handy items and are well worth looking at, as you can easily carry one from your ‘van to your awning, for instance. Just be mindful that your motorhome already has mains outlets and USB points, so you would be doubling up on a lot of kit you already have.
Battery longevity
One aspect of batteries that we haven’t mentioned so far is how to look after what you have. All batteries are rated in terms of their life cycles, and these are the number of times the battery can be discharged from full to empty before it starts to degrade to a point where it can’t hold meaningful charge.
It’s a bit like animal heartbeats – a mouse’s heart beats at up to 750bpm at rest, while an elephant’s can plod along at 8bpm when resting. A mouse won’t live past 18 months, while elephants can last until they’re 70.
So if you hammer your leisure battery with all your high-powered devices, you’ll eat into your available battery lifespan, while if you can use current lightly and regularly top it back up, you will reduce the number of cycles and extend its life.
Batteries really hate going flat and each time you allow this to happen, you lose another life cycle.
In summer with a good solar array, the life cycles and risk of flattening the battery are minimal – assuming that your hobby isn’t welding or holding microwave cookery seminars.
It’s in winter when you really need to think about battery management. Two things happen to batteries in winter – their capacity physically reduces with temperature and the demand on them increases as heaters and lighting are used more frequently.
To make life really hard for them, solar panel efficiency drops off a cliff and can’t always be relied on to fully charge them – for example, in the case of our 628Ah battery, you would struggle to recharge it with a roof entirely covered in solar panels.
There’s a simple (and almost free) solution to this problem – plug your motorhome into the mains in winter, or during any long periods of lay-up. As mentioned above, batteries hate going flat and this will keep them topped up and ready for use. Equally, during the winter months, try to stick to campsites with electric hook-ups, to keep the battery warm and happy.
The verdict on extending the life of a motorhome battery
The market is awash with lead-acid and lithium upgrades, so this is the perfect time to upgrade your electrical system with something beefier.
It has never been easier or cheaper to opt for lithium, too, and that’s the current best option to future-proof your ’van. We expect that gas use will diminish on campsites and pretty soon, everyone will be merrily air-frying food directly from their massive electric campervan batteries!
Don’t miss my tips on how to avoid a flat motorhome battery, either, as I share what you can do to prevent it from happening.
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