Choosing between an AGM and lithium leisure battery affects more than how long the lights stay on.

The battery influences:

• How much usable energy the campervan can store
• How quickly it can recharge
• How well it supports an inverter
• The weight carried by the vehicle
• How the system performs off-grid
• Whether existing chargers can be retained
• The total cost of the electrical installation

For regular off-grid use, lithium iron phosphate—usually called LiFePO4 or LFP—is normally the stronger option. It offers more usable capacity for its size, lower weight, better voltage stability and a much longer potential cycle life.

However, AGM has not become pointless.

A correctly sized AGM battery can still be a sensible choice for an occasional-use campervan that spends most nights on hook-up, has modest electrical loads and does not justify the cost of replacing otherwise functional charging equipment.

At WeConvert, we assess and install leisure-battery systems from our Blackburn workshop, considering the complete charging and electrical installation rather than comparing batteries by their amp-hour number alone.

AGM vs Lithium: Quick Comparison

These are general differences. The specification of the actual battery matters more than the chemistry name printed on the case.

What Is an AGM Leisure Battery?

AGM means Absorbent Glass Mat.

It is a sealed valve-regulated lead-acid battery in which the electrolyte is held within glass-fibre separators rather than moving freely as liquid inside the battery.

AGM batteries are commonly found in:

• Campervans
• Motorhomes
• Caravans
• Boats
• Backup power systems
• Vehicles with existing lead-acid charging equipment

Their advantages include:

• Relatively low purchase cost
• Wide availability
• Established charging technology
• No routine topping up with water
• Good high-current performance
• Compatibility with many existing motorhome systems

AGM batteries still need appropriate charging, protection, mounting and ventilation in accordance with the manufacturer’s instructions. “Sealed” does not mean that the battery can be fitted anywhere without considering heat, fault conditions or pressure relief.

Repeated deep discharge has a significant negative effect on lead-acid battery life, and high-current loads can reduce the amount of capacity that is practically available. Victron’s AGM data, for example, shows effective capacity decreasing as discharge current rises.

What Is a Lithium Leisure Battery?

Most lithium leisure batteries used in campervans are lithium iron phosphate, abbreviated as:

• LiFePO4
• LFP
• Lithium leisure battery

The battery normally contains four lithium cells connected internally to create a nominal 12.8V battery.

A lithium battery also requires a battery-management system, commonly called a BMS.

Depending on the product, the BMS may monitor and protect against:

• Cell overvoltage
• Cell undervoltage
• Excessive charge current
• Excessive discharge current
• Short circuit
• High temperature
• Low-temperature charging
• Cell imbalance

Some batteries contain the complete BMS inside the case. Others require an external BMS as part of the wider electrical system.

Do not assume that every lithium leisure battery has the same protection. The continuous-current rating, surge limit, temperature protection and permitted connection arrangements vary substantially between products.

Which Battery Is Better for a Campervan?

For frequent touring and meaningful off-grid use, lithium is usually better.

It becomes particularly attractive where the campervan has:

• Compressor fridge
• Diesel heater
• Regular laptop use
• Large inverter
• Induction cooking
• Limited payload
• Several days between hook-ups
• High solar capacity
• Strong DC-to-DC charging

AGM may still be the more proportionate choice where the vehicle:

• Is used occasionally
• Stays mainly on campsites
• Has low electrical consumption
• Already has a healthy compatible system
• Does not operate a large inverter
• Is likely to be sold soon
• Has a limited upgrade budget

The correct answer depends on how the vehicle is used—not on which battery technology is newer.

1. Initial Cost

An AGM battery normally costs considerably less to purchase than a lithium battery of a similar advertised amp-hour capacity.

However, comparing only the battery prices can be misleading.

A lithium upgrade may also require changes to:

• Alternator charging
• Mains charger
• Solar controller
• Battery monitor
• Fuses
• Isolators
• Busbars
• Cables
• Battery mounting
• Low-temperature protection

This means a £500 lithium battery could result in a considerably larger installed cost if the existing system was designed entirely around AGM.

AGM can therefore remain attractive where a straightforward replacement is needed and the existing chargers are still suitable.

For detailed installation price examples, read How Much Does a Campervan or Motorhome Lithium Battery Upgrade Cost?.

2. Usable Battery Capacity

Two batteries can both be labelled 100Ah while providing very different amounts of practical energy.

Usable capacity from AGM

An AGM battery can physically be discharged beyond 50%, but repeatedly discharging it deeply generally shortens its service life.

For planning purposes, many systems therefore treat approximately half of an AGM battery’s stated capacity as the normal usable amount.

A 100Ah AGM battery may consequently be planned around roughly:

50Ah of normal usable capacity

That is not an absolute cut-off. It is a design approach intended to avoid continual deep cycling.

Lifeline recommends designing AGM banks around an average depth of discharge of 50% or less to improve cycle life.

Usable capacity from lithium

Many lithium systems are designed around a greater percentage of the stated capacity, subject to the battery manufacturer’s limits and the reserve the owner wants to retain.

A 100Ah lithium battery might therefore be planned around:

Approximately 80Ah of usable capacity

Some products permit deeper discharge, but regularly driving the battery into BMS shutdown is poor system management.

The low-voltage BMS cut-off should be treated as final protection rather than the normal point at which the owner stops using power.

Practical comparison

A single 100Ah lithium battery can therefore provide substantially more practical stored energy than a single 100Ah AGM battery.

This is why amp-hours should not be compared without considering:

• Permitted depth of discharge
• Voltage
• Battery condition
• Discharge current
• Temperature
• Required reserve

3. Battery Weight

Weight is one of lithium’s clearest advantages.

A conventional AGM leisure battery can weigh approximately 25–35kg, depending on its capacity and construction. Larger battery banks can add a considerable amount to a campervan’s payload.

A lithium battery providing similar usable energy may weigh much less.

As a manufacturer-specific example, Victron compared a 60Ah lithium battery weighing 9.5kg with a 90Ah AGM battery weighing 27kg. Using 80% depth of discharge for lithium and 50% for AGM, the two offered a broadly similar amount of usable energy in that comparison.

The exact saving varies between products, but lithium can be particularly valuable in:

• Smaller conversions
• Motorhomes close to their payload limit
• Vehicles with two or more existing AGM batteries
• Installations beneath seats
• Pop-top campervans
• Vehicles carrying water, bikes or other heavy equipment

Battery weight should still be included in the vehicle’s payload calculation.

4. Physical Space

Lithium can also provide more usable energy within a smaller installation space.

This may allow an owner to:

• Increase capacity without enlarging the battery compartment
• Replace two AGM batteries with one lithium battery
• Free storage space
• Install the battery beneath a seat
• Create room for an inverter or distribution equipment

Physical dimensions still need checking carefully.

A lithium battery advertised as a “drop-in replacement” may have:

• Different terminal positions
• Greater height
• Different case width
• Different mounting requirements
• Less clearance around terminals
• Integrated heating or communication equipment

The battery should be selected from actual measurements, not from its amp-hour rating.

5. Cycle Life

Cycle life describes how many charge and discharge cycles a battery may complete before its capacity falls to a defined level.

There is no single lifespan figure for all AGM or all lithium batteries.

Cycle life depends on:

• Depth of discharge
• Temperature
• Charge settings
• Time spent discharged
• Current demand
• Battery quality
• Installation
• Storage
• How end of life is defined

However, lithium generally provides substantially more cycles in demanding leisure use.

As one manufacturer example, Victron specifies approximately:

• 2,500 cycles at 80% depth of discharge
• 3,000 cycles at 70%
• 5,000 cycles at 50%

for its Lithium Battery Smart range before remaining capacity falls below 80% of nominal.

By comparison, Victron’s published AGM comparison used approximately 600 cycles at 50% depth of discharge, while Lifeline publishes approximately 550 cycles at 50% for one of its AGM performance examples. These numbers should not be transferred blindly to every battery, but they illustrate the difference between representative products.

For an occasional-use campervan, calendar age may end the battery’s useful life before its full cycle rating is reached.

For a full-time or frequently used campervan, cycle life becomes much more important.

6. Lifetime Cost

AGM is cheaper initially, but lithium may cost less per usable cycle for someone who uses the battery heavily.

Consider two owners.

Occasional campsite user

The vehicle is used for:

• Six weekends each year
• One summer holiday
• Mostly hook-up camping
• Lighting and a water pump
• Little inverter use

The owner may never cycle an AGM battery heavily enough to recover the additional cost of lithium.

Frequent off-grid user

The vehicle is used for:

• Regular multi-day trips
• Compressor fridge
• Diesel heater
• Laptop work
• Inverter appliances
• Limited mains hook-up

This owner may make much better use of lithium’s higher cycle life, usable capacity and faster charging.

Lithium does not automatically save money. It offers better value where its advantages are genuinely used.

7. Charging Speed

Lithium batteries can often accept a higher charging current than equivalent AGM batteries, particularly through the middle of the charging cycle.

This can be valuable where charging time is limited.

Examples include:

• Short journeys
• Limited generator time
• Brief mains connections
• Strong solar periods
• Daily touring

AGM charging normally slows as the battery approaches full charge because the charger must complete an absorption stage.

Lithium can often continue accepting a relatively strong current until it approaches its upper charging limit, although actual current remains restricted by:

• Battery specification
• BMS
• Charger rating
• Alternator
• Cables
• Fuses
• Temperature

A large lithium battery will not charge quickly from a small charger merely because the battery can accept more current.

8. Partial State of Charge

AGM batteries benefit from being returned to full charge regularly.

Leaving a lead-acid battery partially charged for prolonged periods can contribute to sulphation and permanent capacity loss.

This commonly becomes a problem where:

• Solar is too small
• Journeys are short
• The vehicle is stored while partly discharged
• The mains charger is rarely connected
• Daily use exceeds daily charging

Lithium is more tolerant of operating at a partial state of charge and does not need to reach 100% after every cycle. Victron specifically identifies partial-charge tolerance as a major LiFePO4 advantage over lead-acid batteries.

This makes lithium well suited to campervans where the battery receives energy intermittently from driving and solar.

9. Solar Charging

Both AGM and lithium can be charged from solar panels when the controller is correctly configured.

However, lithium can make better use of short periods of strong sunlight because it can often accept a higher current and has greater round-trip efficiency.

Victron publishes approximately 92% round-trip efficiency for its lithium range and around 80% as an average lead-acid comparison. The precise efficiency varies by product and operating conditions.

An AGM system can still work very well with solar, especially where:

• Daily consumption is modest
• The battery reaches full charge regularly
• The system is used mainly during summer
• The panel capacity is properly matched
• The controller uses the correct AGM profile

Lithium does not compensate for insufficient solar.

A 300Ah lithium bank paired with a 100W panel may provide several days of stored energy, but it may also take a long time to recover after heavy use.

Read How Much Solar Does a Campervan or Motorhome Need? before choosing battery capacity in isolation.

10. Alternator Charging

Both battery types may be charged while driving, but the method matters.

An older campervan may use:

• Split-charge relay
• Voltage-sensitive relay
• Manufacturer charging unit
• DC-to-DC charger

Lithium can accept a strong current, which is useful but also means the charging system needs controlling.

The installation must consider:

• Alternator capability
• Vehicle smart-alternator behaviour
• Charger output
• Battery maximum charge current
• BMS limit
• Cable size
• Fuse rating
• Journey length

Simply replacing AGM with lithium while retaining an unsuitable split-charge arrangement can create poor charging performance or excessive current through old wiring.

The presence of a modern DC-to-DC charger does not automatically confirm compatibility either. Its charging profile and output still need checking against the chosen battery.

11. Mains Charger Compatibility

An existing AGM charger may or may not be suitable for lithium.

Compatibility depends on the actual charging profile rather than whether the charger produces approximately 14V.

Questions include:

• Does it have a lithium setting?
• What absorption voltage does it use?
• How long does absorption continue?
• Does it apply equalisation?
• Does it use temperature compensation?
• What float voltage does it maintain?
• Can the charger be controlled by the BMS?
• Does it respect low-temperature charging restrictions?

A charger designed for AGM may apply behaviours that are unnecessary or unsuitable for lithium.

Likewise, selecting a generic lithium mode does not prove that it matches every lithium battery.

The battery manufacturer’s charging specification should be compared with the charger manual before installation.

12. Solar Controller Compatibility

The solar panels themselves can often remain when changing from AGM to lithium.

The solar charge controller may need:

• Reconfiguration
• Firmware update
• External temperature sensing
• Low-temperature charge control
• Complete replacement

Check whether it allows:

• Correct absorption voltage
• Correct float voltage
• Equalisation to be disabled
• Temperature compensation to be disabled where required
• Charge-current limitation
• BMS control

Lead-acid charging voltage is commonly adjusted with battery temperature, whereas lithium systems may use temperature information to stop charging when the cells are too cold.

13. Inverter Performance

Lithium is generally better suited to large inverter loads.

Examples include:

• Microwave
• Coffee machine
• Hairdryer
• Induction hob
• Air fryer
• Power tools

Lithium typically maintains a more stable voltage under high current.

AGM voltage drops more noticeably as load increases, and its effective capacity can fall when discharged quickly. Victron’s AGM data shows that a battery’s effective capacity reduces as the discharge rate rises, with the effect particularly relevant to constant-power loads such as inverters.

AGM can still operate an inverter, but a larger battery bank may be needed to:

• Control voltage drop
• Provide sufficient current
• Avoid excessive depth of discharge
• Achieve reasonable runtime

Lithium must also be checked carefully.

A 100Ah lithium battery may store enough energy for an appliance but still have a BMS current limit too low for a 2,000W inverter.

Battery capacity and discharge-current capability are separate specifications.

Read What Size Inverter Does a Campervan or Motorhome Need? for detailed inverter calculations.

14. Battery Voltage Under Load

AGM voltage gradually changes as the battery discharges and can drop significantly when a high-current appliance starts.

Possible effects include:

• Diesel heater low-voltage fault
• Inverter shutting down
• Fridge cutting out
• Lights dimming
• Control panel reporting a low battery

The voltage may recover once the appliance stops, even though the battery has not been recharged.

Lithium has a flatter voltage curve and normally holds its voltage more steadily through much of the discharge.

This helps demanding equipment operate reliably, but it also makes voltage a poor way of estimating how much energy remains.

A lithium battery can appear healthy from its voltage and then approach BMS shutdown relatively quickly.

15. Battery Monitoring

Monitoring AGM

Battery voltage can provide some indication of AGM state of charge, but only when interpreted properly.

Readings can be affected by:

• Current load
• Recent charging
• Temperature
• Battery age
• Cable voltage drop

A resting-voltage reading is more informative than a reading taken while the inverter or water pump is operating, but it still does not directly measure remaining capacity.

Monitoring lithium

Because lithium voltage remains relatively flat through much of the discharge, a simple voltage display is even less useful.

A shunt-based monitor can measure:

• Current entering the battery
• Current leaving the battery
• Amp-hours consumed
• Estimated state of charge
• Historical energy use

All chargers and loads must pass through the correct side of the shunt. Otherwise, its state-of-charge calculation will drift.

A monitor improves visibility, but it does not replace BMS protection or correct system design.

16. Cold-Weather Use

Cold-weather performance is an important consideration for UK campervans.

AGM in cold weather

An AGM battery can normally be charged below freezing, subject to its manufacturer’s specifications and correct charging-voltage compensation.

Cold temperatures reduce available capacity, and the charging voltage may need adjustment. Victron’s AGM guidance requires temperature compensation during prolonged operation outside its normal temperature range.

Lithium in cold weather

Many LiFePO4 batteries must not be charged when their cell temperature is near or below freezing.

The precise cut-off varies.

For example, Victron’s Lithium Battery Smart permits charging between 5°C and 50°C. Other manufacturers may use 0°C or a different threshold.

Possible solutions include:

• Internal low-temperature cut-off
• Heated lithium battery
• External temperature sensor
• Charger controlled by the BMS
• Battery installed within the heated living area
• Insulated battery compartment

Do not assume that a battery advertised as having a BMS automatically includes low-temperature charge protection.

This matters in Blackburn and across Lancashire, particularly where the battery is beneath the vehicle or inside an unheated external locker.

17. Diesel-Heater Use

Both AGM and lithium can power a diesel heater.

The heater uses electricity for:

• Glow plug
• Combustion fan
• Fuel pump
• Circulation fan
• Control electronics
• Shutdown cycle

The highest current is usually required during startup.

Lithium’s stable voltage can reduce low-voltage faults where the system and wiring are otherwise suitable.

However, replacing AGM with lithium will not correct:

• Undersized heater cable
• Poor connection
• Excessive voltage drop
• Loose fuse holder
• Battery not being charged
• Heater fault

A properly sized AGM system can also operate a diesel heater reliably.

18. Storage

Storing an AGM battery

An AGM battery should not be left deeply discharged or partially charged for prolonged periods.

Before storage:

• Fully charge the battery
• Remove unnecessary loads
• Check the charging arrangement
• Inspect terminals
• Monitor voltage periodically

Alarm systems, trackers and control panels can continue drawing power after the main habitation switch has been turned off.

Storing a lithium battery

Lithium batteries are more tolerant of partial-charge storage, but they must still be protected from:

• Excessive discharge
• Uncontrolled parasitic loads
• Unsuitable temperature
• Moisture
• Charger faults

Do not assume that the BMS makes a battery immune to storage damage.

A very small permanent load can continue discharging the battery after other equipment has shut down, depending on how the system is wired.

19. Maintenance

Neither AGM nor lithium should require routine topping up with water.

However, both systems still require inspection.

Checks may include:

• Terminal tightness
• Cable condition
• Fuse holders
• Isolators
• Heat discolouration
• Battery mounting
• Charger settings
• Battery-monitor accuracy
• Signs of swelling or damage

Lithium may provide additional information through an app, such as:

• Cell voltage
• Battery temperature
• Current
• Alarm history
• State of charge

The amount of available data depends on the battery and BMS.

Bluetooth does not automatically make one battery safer or better than another. The quality of the cells, BMS, installation and technical support remains more important.

20. Safety

Both battery types can supply enough current to overheat cables or cause a fire if installed incorrectly.

A safe system requires:

• Suitable fuse close to the battery
• Correct cable size
• Secure terminations
• Rated isolator
• Protected battery terminals
• Secure mounting
• Protection from water and impact
• Suitable charging equipment
• Compliance with manufacturer instructions

Lithium batteries should have appropriate BMS protection, but the BMS is not a substitute for external fusing.

The fuse protects the cable and electrical installation against fault current. The BMS protects the battery within its programmed operating limits.

Do not fit a larger fuse simply because the lithium battery can deliver more current than the previous AGM battery.

21. Can You Replace Two AGM Batteries With One Lithium Battery?

Often, but the comparison must be made using usable energy, not only stated capacity.

For example:

• Two 100Ah AGM batteries provide 200Ah stated capacity.
• Designing around 50% discharge gives roughly 100Ah of normal usable capacity.
• One 150Ah lithium battery designed around 80% discharge provides roughly 120Ah.

In this simplified example, one 150Ah lithium battery could provide slightly more practical energy than two 100Ah AGM batteries.

The lithium battery may also be much lighter.

However, confirm:

• Maximum discharge current
• Inverter requirement
• Charging compatibility
• Physical dimensions
• Cable and fuse suitability
• Battery-monitor setup
• Required reserve

The example is not a universal replacement formula.

22. Does 100Ah of Lithium Replace 200Ah of AGM?

Sometimes it can provide a similar amount of practical energy, but the common “one-for-two” rule is too simplistic.

A nominal 100Ah lithium battery used to 80% provides approximately:

80Ah usable

A 200Ah AGM bank used to 50% provides approximately:

100Ah usable

The AGM bank provides more in this example, although it will be heavier and may deliver less practical capacity under a large inverter load.

The correct comparison should use watt-hours:

Watt-hours = battery voltage × amp-hours

Then account for:

• Depth of discharge
• Current demand
• Voltage drop
• Temperature
• Battery condition
• Conversion losses

23. When AGM Is Still the Sensible Choice

AGM may remain the better purchase where:

• Upfront budget is the main constraint
• The vehicle is used infrequently
• Most nights are spent on hook-up
• Electrical loads are modest
• No large inverter is fitted
• The existing charging system is fully compatible
• The vehicle may be sold soon
• Winter charging below freezing is likely
• The existing AGM battery has not actually failed

There is little value in replacing a healthy battery simply because lithium is technically superior.

The upgrade should solve a real limitation.

24. When Lithium Is Worth the Extra Cost

Lithium becomes more compelling where the owner:

• Camps off-grid regularly
• Uses the vehicle throughout the year
• Runs a compressor fridge continuously
• Relies on a diesel heater
• Charges laptops daily
• Uses an inverter
• Wants to reduce payload
• Needs faster charging
• Has limited roof space for solar
• Keeps the vehicle long-term
• Frequently cycles the battery deeply

It is particularly valuable where one lithium battery can replace a large, heavy AGM bank while providing equal or greater usable energy.

25. Should You Upgrade a Healthy AGM System?

Not automatically.

A lithium upgrade may be unnecessary where the current system already supports the owner’s needs.

Before spending money, ask:

• Does the AGM battery last through the night?
• Does it recharge fully?
• Are the appliances working reliably?
• Is payload a problem?
• Is more inverter power needed?
• Are longer off-grid stays planned?
• Is the current battery actually faulty?

A battery that keeps going flat may indicate:

• Solar fault
• Alternator-charging problem
• Failed mains charger
• Hidden electrical drain
• Fridge running continuously
• Inverter left switched on
• Battery-monitor error

Read Why Does My Campervan or Motorhome Leisure Battery Keep Going Flat Overnight? before assuming lithium is the solution.

26. How to Choose the Correct Battery Capacity

Start by listing the equipment used each day.

For each appliance, estimate:

Daily energy in watt-hours = appliance wattage × operating hours

Include:

• Fridge
• Diesel heater
• Lighting
• Water pump
• Laptop
• Television
• Router
• Phone charging
• Inverter standby use
• Control systems

Then consider:

• Number of days between charging
• Solar capacity
• Driving frequency
• Access to hook-up
• Winter use
• Required emergency reserve
• Battery depth of discharge

Do not size the battery from the available cupboard space alone.

A larger battery extends runtime but also requires enough charging capacity to replenish it.

Example 1: Occasional Summer Campervan

Usage:

• LED lights
• Water pump
• Phone charging
• Occasional fridge use
• Regular campsite hook-up

A suitable option might remain:

• 100Ah AGM battery
• Existing compatible mains charger
• Modest solar
• No large inverter

Lithium would reduce weight and increase usable capacity, but the owner might gain little practical benefit from the extra investment.

Example 2: Regular Touring Campervan

Usage:

• Compressor fridge
• Diesel heater
• Lighting
• Phones
• Television
• Several nights off-grid
• Regular driving

A suitable option may be:

• 100–200Ah lithium battery
• DC-to-DC charger
• MPPT solar controller
• Battery monitor
• Compatible mains charger

Lithium’s additional usable capacity and stronger charge acceptance become more valuable in this type of use.

Example 3: Remote Working Campervan

Usage:

• Compressor fridge
• Laptop and monitor
• Wi-Fi router
• Diesel heater
• Inverter
• Several days parked
• Limited hook-up

A suitable system may include:

• 200–300Ah lithium battery
• Strong DC-to-DC charging
• 300–500W solar
• Shunt-based monitor
• Pure sine wave inverter
• Lithium-compatible mains charger

A similarly useful AGM bank could be significantly heavier and larger.

Example 4: Factory Motorhome Used Mainly on Hook-Up

Usage:

• Campsite touring
• Regular mains connection
• Existing integrated charging system
• Modest off-grid demand
• No large inverter

Replacing a functional AGM battery with another good AGM may be the most economical option.

A lithium conversion might require alterations to an integrated charger or control system without giving the owner a meaningful return.

AGM and Lithium Battery Installation in Blackburn

WeConvert provides campervan and motorhome leisure-battery assessment, installation and electrical upgrades from our Blackburn workshop.

We can help with:

• AGM leisure-battery replacement
• LiFePO4 battery upgrades
• Battery-capacity planning
• DC-to-DC chargers
• Mains chargers
• Solar charge controllers
• Battery monitors and shunts
• Inverters
• Cable upgrades
• Fuses and isolators
• Busbars and distribution
• Low-temperature lithium protection
• Existing self-build installations
• Factory motorhome electrical systems
• Battery-drain diagnosis

Our Blackburn workshop serves customers travelling from:

• Blackburn
• Darwen
• Accrington
• Burnley
• Rossendale
• Bolton
• Chorley
• Preston
• Wider Lancashire

Learn more about our campervan electrical and solar services in Blackburn.

Related guides include:

• How Much Does a Campervan Lithium Battery Upgrade Cost?
• How Much Solar Does a Campervan or Motorhome Need?
• What Size Inverter Does a Campervan or Motorhome Need?
• Why Does My Leisure Battery Keep Going Flat Overnight?
• Why Is My Campervan Leisure Battery Not Charging?
• Campervan or Motorhome 12V Electrics Not Working?
• Campervan and Motorhome Repairs and Fault Finding

Frequently Asked Questions

Is lithium better than AGM for a campervan?

Lithium is generally better for regular off-grid use, large electrical loads and owners who want more usable energy with less weight.

AGM can remain the better-value choice for occasional campsite use and modest electrical consumption.

How long does an AGM leisure battery last?

It depends on battery quality, depth of discharge, charging and temperature.

Repeated deep discharge and prolonged undercharging can shorten its life substantially. Manufacturer cycle figures should be checked for the exact product.

How long does a lithium leisure battery last?

A quality LiFePO4 battery can provide several thousand cycles when operated within its specifications.

The real lifespan depends on depth of discharge, temperature, charge settings, BMS operation and battery quality.

Can I replace an AGM battery with lithium?

Possibly, but the existing mains charger, solar controller and alternator-charging system must be checked first.

Cables, fuses, monitoring and low-temperature protection may also need changes.

Do I need a new charger when changing from AGM to lithium?

Not always.

An existing charger can remain if its charging profile is suitable for the selected lithium battery. Older or integrated chargers may need replacement or reconfiguration.

Is a 100Ah lithium battery better than a 100Ah AGM battery?

It normally provides more usable capacity, lower weight and better voltage stability.

The actual comparison depends on each battery’s current limits, permitted depth of discharge and specifications.

Can AGM batteries run an inverter?

Yes.

However, large inverter loads can cause voltage drop and reduce the amount of usable capacity. A larger AGM bank may be required.

Can a lithium battery run a 2,000W inverter?

Possibly, but its BMS must support the required current.

A 2,000W appliance can draw well over 150A from a 12V battery, so the battery, cables and fuse must all be correctly rated.

Which battery is better in winter?

AGM can normally accept charge below freezing when charged correctly.

Many lithium batteries must not be charged below approximately 0–5°C unless they have suitable heating or low-temperature protection. The exact battery specifications take priority.

Does lithium charge faster than AGM?

It often can because lithium may accept a higher current and does not require the same extended upper absorption stage.

Actual charging speed still depends on the charger, alternator, cables and battery limits.

Is lithium worth it for a weekend campervan?

It depends on the electrical use.

For a lightly used van that stays on campsites, AGM may be sufficient. For fridge use, heater use and regular off-grid weekends, lithium may provide a meaningful improvement.

Will fitting lithium stop my battery going flat?

Only where insufficient battery capacity is the real problem.

Lithium will not fix failed charging, hidden drains, incorrect wiring or an appliance using excessive power.

Can WeConvert test my existing AGM battery before replacing it?

Yes.

We can assess battery condition, charging behaviour and voltage under load before deciding whether replacement or a wider electrical repair is needed.

Book a Leisure-Battery Assessment in Blackburn

To discuss an AGM replacement or lithium upgrade, send us:

• Vehicle make, model and year
• Campervan or motorhome type
• Existing battery make and capacity
• Battery age
• Photographs of the battery compartment
• Mains charger make and model
• Solar-controller details
• DC-to-DC charger or split-charge system
• Solar-panel capacity
• Inverter size
• Appliances you want to operate
• Typical time spent off-grid
• Whether the vehicle is used in winter
• Your postcode

We can then advise whether AGM remains appropriate or whether a lithium upgrade would provide a worthwhile improvement.

Contact WeConvert to request a campervan or motorhome battery assessment in Blackburn.