Campervan Lithium Battery Upgrades

For most campervan owners, upgrading to lithium is about one thing: having useful battery power for much longer.

You may already have lived with a leisure battery that seems to run out surprisingly quickly, performs less well as it gets lower, or needs replacing sooner than you expected. Lithium can transform that experience.

Where your existing electrical system is suitable, changing to lithium can be a relatively straightforward upgrade with an immediate improvement in usable battery capacity, off-grid time, weight and expected battery life.

Where other parts of the electrical system need changing as well, we look at what you already have and what you're trying to achieve before deciding whether lithium is still the best-value solution.

Thinking about upgrading? Tell us what you have now and what you'd like your campervan to do.

What do you actually gain by changing to lithium?

The biggest difference most owners notice is how much longer their useful battery power lasts.

A conventional lead-acid or AGM leisure battery has much less routinely usable capacity than its headline Ah rating suggests. Its performance also falls away as it discharges, and repeatedly taking too much energy from it can considerably shorten its life.

Many campervan owners don't realise how quickly they're reaching that point. In some installations, less than two days of normal use may already be taking the battery lower than is good for its long-term life.

Lithium allows much more of the battery's stated capacity to be used while maintaining strong performance much further through its charge.

It also has a much greater potential cycle life and can provide substantially more usable energy for its physical size and weight.

That doesn't mean changing a 100Ah AGM battery for a 100Ah lithium battery automatically doubles your off-grid time. Real-world duration depends on what you're running, the condition and capacity of the system you're replacing, and how much charge you put back while you're away.

But the practical improvement can be substantial.

How much lithium battery capacity do you need?

There isn't one correct lithium battery size for every campervan.

We start with how much power you use and how long you want it to last before you can recharge. That's more useful than sizing a battery simply from a list of appliances. Someone running little more than a fridge, lights and phone chargers for seven days can need more stored capacity than someone using much higher-powered equipment for a night before driving again.

We look primarily at:

what you want to run;
how long you want to run it;
when and how you can recharge;
the physical space available for the battery; and
your budget.

For many customers, increasing battery capacity is the best-value way to gain more off-grid time before spending money on increasing charging capacity. Space can eventually become the restriction. At that point, putting more energy back through solar, driving or hookup can become more useful than trying to add still more battery capacity.

It's never a one-size-fits-all calculation.

Cold beer on day seven

A customer recently came to us with a particularly straightforward requirement for a music festival:

Cold beer on day seven.

The campervan had a typical electrical demand from its fridge, lighting and device charging, but its solar panel had failed and the customer didn't want to replace it.

We fitted a 314Ah Fogstar Drift Eco lithium battery.

Because stored energy is still finite, we didn't promise that a particular battery could guarantee seven days regardless of use. We also discussed simple ways of reducing fridge consumption, including removing the freezer compartment and reducing consumption where practical.

The outcome was cold beer on day seven.

That's ultimately what battery capacity is for. The specification matters because it has to deliver what the customer actually wants from the campervan.

Can you simply replace an AGM battery with lithium?

Sometimes.

One of the first things we check is whether the existing electrical system can correctly support the lithium battery being considered. A campervan may charge its leisure battery from the alternator while driving, from solar and from mains hookup. Some existing chargers can be configured appropriately for lithium and don't need replacing. Older equipment needs more consideration, but that doesn't automatically mean replacing everything.

Battery technology is developing too. Some newer lithium batteries are designed to work with a wider range of existing motorhome and campervan charging systems, making lithium practical in vehicles where an upgrade might previously have required much more extensive changes.

The important question isn't simply "is this a lithium charger?" It's whether the battery and the charging system around it are suitable for each other. We look at what's already fitted before deciding what genuinely needs changing.

Do you need a DC-DC charger when changing to lithium?

Not every lithium upgrade automatically means fitting a new DC-DC or battery-to-battery charger.

We first look at how the existing battery is charged from the vehicle and whether that arrangement is appropriate for the battery being fitted. Where alternator charging does need upgrading, a suitable DC-DC charger gives us controlled charging from the vehicle. Its output can then be chosen according to the battery capacity, how much energy needs replacing, the amount of driving you normally do and what is suitable for the vehicle.

A larger lithium battery may be capable of accepting a high charge rate, but that doesn't mean you need to exploit all of it. The useful question is how much charge do you actually need to put back during the time you normally spend driving?

Does the solar controller need changing for lithium?

Not necessarily. The solar charge controller needs to be suitable for the battery being fitted and correctly configured for it. Many existing controllers can be configured appropriately, in which case replacing them simply because the battery has changed may achieve very little.

Where the existing controller isn't suitable, is limiting the performance available from the panels, or doesn't fit with the system we're trying to create, changing it may make sense.

Our preference for new installations is to fit Victron equipment because of its quality, configuration, monitoring and ability to integrate with the rest of the charging system. But the starting point with an existing campervan is always what can we sensibly keep?

Do you need more solar when you upgrade to lithium?

Not necessarily. If increased battery capacity already gives you the off-grid duration you need, there may be little value in changing a solar installation that's already making a useful contribution.

Solar becomes more important when you stay in one place for longer, when physical space limits how much battery capacity can be installed, or when daily consumption means a significant amount of energy needs to be replaced while you're away.

This is where looking at the complete system matters.

We consider what is currently limiting performance and where there is unused capacity. Sometimes more solar is the right upgrade. Sometimes the battery was the restriction. Sometimes the existing equipment can deliver more than the rest of the system currently allows it to.

The objective is to improve the useful performance of the whole system, not simply keep adding components.

Battery capacity and charging capacity aren't the same thing

A larger battery gives you more energy to use. A larger charger determines how quickly you can put energy back. They solve different problems.

For many customers upgrading from a conventional leisure battery, increased time off-grid is the priority. Once they have enough battery capacity, there may be no reason to increase charging rates simply because lithium can accept them.

Someone who stays off-grid for a few days and then drives for several hours has a different requirement from someone who parks in the same place for a week.

For the first customer, charging while driving may be the best-value way of replenishing the battery. For the second, solar may make a much greater contribution.

Higher-power or longer-term off-grid users may need substantial battery capacity and several ways of putting energy back.

We size the charging around power use and charging opportunities, rather than fitting the largest chargers the battery will accept.

Can solar, driving and hookup all charge the same battery?

Yes. A campervan can charge its leisure battery from solar, the vehicle alternator and mains hookup, and more than one charging source can be available at the same time.

They don't necessarily have to be the same make or communicate with each other to work correctly. Each charger does, however, need to be suitable for the battery and correctly configured.

Where we're designing or substantially upgrading the charging system, we generally use compatible Victron equipment. This allows the different parts of the charging system to communicate and work together rather than simply operating as separate chargers. It also gives us an integrated way to configure and monitor the system.

That doesn't mean we replace perfectly good equipment just to make everything match.

On an existing installation, we'll first look at what's already there, whether it's suitable and what benefit changing it would actually provide.

The objective isn't to maximise every charging source. It's to have enough stored capacity and enough opportunity to replace the energy you actually use.

Can lithium run an inverter and high-power appliances?

Yes, but the battery needs to be selected for the job.

Customers increasingly want to run equipment such as induction hobs, microwaves, coffee machines and air fryers from their campervan batteries.

For these systems, battery capacity is only part of the specification. The battery management system, or BMS, also has to be capable of supplying the current demanded by the inverter. A battery can therefore have plenty of stored energy but still be the wrong battery for a large inverter.

We match the battery capacity and BMS capability to the inverter and the equipment the customer wants to use.

Again, the starting question isn't "how big an inverter can we fit?"

It's "what do you want to be able to run?"

Lithium still isn't unlimited power

A large lithium battery can make a campervan feel much more like using electricity at home, but the energy still has to come from somewhere.

A fridge, lights, devices and inverter loads continue taking energy from the battery every hour they're used.

Lithium gives you considerably more useful capacity and maintains its performance much further through that capacity, but it doesn't make energy consumption disappear.

Sometimes the answer is more battery.

Sometimes it's more solar or more charging while driving.

Sometimes a small change in how an appliance is used gives you the additional duration you need without adding any equipment at all.

The aim isn't unlimited power.

It's enough power for what you actually want to do.

Why do lithium leisure batteries vary so much in price?

Two lithium batteries can have similar headline capacities and very different prices. There is usually a reason. Capacity is only part of what you're buying.

We also look at:

battery management;
cell management and balancing;
low-temperature protection;
internal heating where appropriate;
monitoring and connectivity;
the current the battery can safely supply;
warranty; and
UK technical and service support.

Good battery management helps the individual cells inside the battery continue working properly together. The batteries we choose provide cell management and allow their condition and balance to be monitored, with some products offering more sophisticated balancing and management technology. You don't need to understand or manage any of this yourself. It's part of our reason for choosing the batteries we do.

We don't automatically specify the most expensive option, but we don't select batteries on headline Ah and price alone either.

The lithium batteries we fit

We normally fit lithium batteries from Fogstar and Roamer.

We choose them because their ranges give us the battery management, monitoring, protection and support we're looking for, together with a choice of capacities and specifications for different installations.

Warranty matters as well.

Our preference is generally for the longer-warranty ranges where the budget allows. Where a lower-cost range provides a worthwhile alternative with a shorter warranty, we'll explain the difference and let the customer decide whether the saving is worthwhile.

Physical size and weight matter too.

Lithium's much greater energy density means substantial usable capacity can be fitted into spaces where achieving the same useful capacity with conventional batteries would be impractical.

That's particularly valuable in smaller campervans where space and payload are always at a premium.

The objective is to choose a battery we're comfortable installing and supporting for the job it's being asked to do.

Are lithium batteries safe in a campervan?

The leisure batteries we fit use LiFePO4 lithium battery technology and include battery management and protection designed for this type of application.

As with any high-capacity battery installation, safety isn't simply about the battery itself. The battery, charging equipment, cabling, circuit protection and any high-current equipment such as an inverter all need to be suitable for each other.

Temperature protection is also part of our battery selection.

Charging lithium batteries at very low temperatures needs to be managed correctly, so we look for low-temperature charge protection and internal battery heating.

For the customer, the important point is that you shouldn't need to become a battery expert every time the temperature falls. The protection and management built into the battery are part of what we're choosing on your behalf.

How do you know how much battery power is left?

This is another area where lithium can make campervan life considerably easier.

Many older installations give the owner little more than LED battery indicators or a voltage reading. Neither makes it particularly easy for someone without electrical knowledge to understand how much useful battery capacity remains.

The lithium batteries we normally fit provide monitoring through their BMS, usually accessible from an app.

Initially, customers often watch this closely. They can see the battery state and see the effect of charging from a journey or from solar. Then they tend to stop looking at it so much.

Once they're confident that the battery comfortably supports the way they use the campervan, they don't need to continually manage the electrical system.

For most owners, that's exactly what we want.

More detailed shunt-based monitoring can make sense as part of a higher-end integrated electrical system, particularly a complete Victron installation. Those customers are often interested in the technology itself and want detailed visibility of charging and consumption.

Most customers simply want enough power and an easy way to check what's left.

How long does a lithium leisure battery last?

Lithium costs more initially than a conventional lead-acid or AGM battery, but purchase price isn't the whole comparison.

Conventional leisure batteries have a relatively limited cycle life, particularly if they're repeatedly discharged more deeply than they should be.

Good LiFePO4 batteries are designed for cycle lives measured in thousands rather than hundreds.

They also allow considerably more of their capacity to be used, which means the customer can gain both more useful energy on each trip and a much longer potential service life.

The exact cycle life depends on the particular battery and how it is used, so we look at manufacturer specifications and warranty rather than applying one headline figure to every battery.

For many customers who regularly use their campervan off-grid, that changes the economics of the higher initial purchase price considerably.

When lithium isn't the best-value upgrade

We don't recommend lithium simply because lithium is newer or better battery technology.

If changing the battery would also require replacing most of an otherwise serviceable charging system, a good-quality conventional replacement battery may meet the customer's requirements for considerably less money.

Sometimes there is room for a second conventional battery and that provides the additional duration required.

Newer battery technology is also creating more options for older motorhomes, caravans and campervans. Some lithium batteries are specifically designed to work with a wider range of existing charging equipment, potentially avoiding changes that would previously have been necessary.

We assess those options where they're appropriate.

The objective is better battery performance for the way you use your vehicle, not lithium for its own sake.

Common problems we find with lithium installations

Lithium systems are generally reliable when the battery and surrounding electrical system have been correctly specified.

The problems we've encountered have usually been elsewhere in the installation.

Incorrect chargers or charging profiles

An existing charger may not be suitable for the battery, or a configurable charger may simply have been left on the wrong battery profile.

That's why we check the charging sources rather than assuming that replacing the battery is the whole job.

Battery and inverter mismatch

A high-power inverter can demand very high current.

The battery may have ample capacity while its BMS isn't designed to supply the required load.

Battery, BMS and inverter therefore need to be considered together.

Missing inverter circuit protection

We've also encountered inverter installations without appropriate circuit protection.

An inverter can place some of the highest current demands on a campervan's 12V system. The battery, cabling and protection therefore need to be considered as a system rather than treating the inverter as an appliance that can simply be connected to any large battery.

What we look at before upgrading a campervan to lithium

For a straightforward battery upgrade, we want to establish whether the existing electrical system can support the lithium battery and whether the change will actually achieve what the customer wants.

We look at the existing battery and available space, the ways it is charged, what equipment the customer runs, how long they want to remain off-grid and their budget.

For higher-power systems, we also consider the inverter and the current the battery will need to supply.

That tells us what can stay and what genuinely needs changing.

Sometimes the answer is simply a better battery.

Sometimes lithium provides a substantial improvement without changing much else.

And sometimes the requirement justifies a larger electrical upgrade involving battery capacity, solar, alternator charging, mains charging and an inverter.

We don't start by deciding how much equipment we can fit.

We start with what you want the campervan to do.

Better battery performance without having to think about batteries

Most campervan owners aren't particularly interested in batteries.

They're interested in keeping the fridge cold, using their lights and devices, spending several days away from hookup and knowing that the power will still be there when they need it.

Lithium can make a very large difference to that experience.

A good upgrade isn't necessarily the largest battery or the most complicated electrical system. It's one that provides enough capacity for the way you use the campervan, works properly with the charging system around it and gives you confidence that you don't need to keep thinking about the battery.

Want to know what lithium would actually give you in your campervan?

Get in touch and tell us what's fitted now, what you normally run and how long you'd like to stay off-grid. We can look at whether a straightforward battery upgrade will achieve it, what can be retained and whether anything else is genuinely worth changing.

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