LiFePO4 or lead-acid: choosing a leisure battery

Choose for your trips, not the biggest label

For occasional weekends with modest loads and regular hook-up, retaining a healthy existing battery may be sensible. For frequent off-grid stays, usable storage, weight and charging opportunities become more important. A battery that suits one campervan can be an awkward purchase for another.

Write down daily demand in watt-hours, how long you want to stay without dependable charging, the largest load you want to run and the space available. Leave room in the budget for fitting and any charger changes. Buying the battery first can lock the rest of the design into compromises.

Flooded, AGM and gel are all lead-acid

Flooded batteries contain liquid electrolyte. They need the maintenance, secure mounting and ventilation specified for that model. Trojan's guidance includes electrolyte checks and watering for flooded batteries, and charging in well-ventilated areas away from sparks or flames. [1]

AGM holds electrolyte in an absorbent glass mat. Gel immobilises it as a gel. These sealed VRLA designs avoid routine watering, but their valves can still release gas under overcharge or failure. Victron's conventional AGM range favours high-current performance; its gel range offers greater cycling durability. Check the datasheet for the particular battery you are considering. [2]

LiFePO4 is lithium iron phosphate. It combines a different operating voltage and charging requirements with electronic battery management. Compare each battery's current ratings, protection and charging requirements. [3]

Put both batteries on the same energy basis

Amp-hours measure charge, so voltage matters. For a first planning comparison, nominal volts multiplied by Ah gives nominal watt-hours. Multiplying that by a chosen discharge fraction gives an illustrative operating window.

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These are our arithmetic examples using manufacturer nominal specifications. The smaller Ah label provides more planned energy in the selected window. The 50% and 80% windows are chosen for this comparison. Exact battery instructions govern. [2] [3]

This is energy at the battery. An inverter, cables and other equipment consume some of it. Cold, ageing and discharge rate also affect the result. Victron rates its AGM capacity over a 20-hour discharge at 25°C; faster discharge reduces effective capacity. A large inverter load is a different duty from a few lights. [2]

Compare usable energy assumptions

Read the small print beside the cycle count

Victron quotes conventional AGM Deep Cycle design life of 600 cycles at 50% discharge, versus 400 at 80%. Fogstar quotes 3,000 cycles at 80% depth of discharge for the ECO100. These illustrate why discharge depth belongs beside the headline number. [2] [3]

The test conditions differ, so these cycle claims need careful interpretation. The cited Fogstar specification does not state temperature, charge/discharge rate or a retained-capacity endpoint alongside that claim. A fair lifetime-cost comparison would need cycle results measured under the same conditions.

Calendar ageing, charging habits and storage also matter. Read the warranty's capacity terms and exclusions alongside the cycle claim. For occasional trips, purchase cost and keeping the existing installation may matter more than a high cycle count.

Winter charging needs an exact model check

Charging and discharging can have different temperature limits. Fogstar's ECO100 specifies charging from 0°C to 60°C and discharging from -20°C to 60°C. It has low-temperature charge protection but no internal heater. [3]

Some heated models use incoming charger energy to warm their cells before normal charging resumes. Fogstar describes that behaviour for its heated Drift ranges. Check whether the exact model has a heater and how much incoming energy it uses. [4]

Limits differ: Victron's Lithium Smart range allows charging from +5°C to +50°C, with chargers controlled accordingly. Follow the exact manufacturer's limit and control arrangement, including solar, alternator and mains sources. [5]

Capacity and power are different requirements

A battery can hold enough energy for an appliance yet be unable to supply its current or starting surge. Check continuous and time-limited discharge ratings, charging limits and the BMS behaviour. The ECO100, for example, specifies a 100A maximum discharge. Treat this current limit separately from its storage capacity. [3]

The installation also needs correctly rated fuses, cables and compatible chargers. Battery faults can involve very high current, and protection must account for the fuse's DC voltage and breaking capacity as well as its amp rating. Have the complete installation assessed when changing chemistry or adding large loads. [6]

Two UK product references, with the differences visible

Prices checked on 15 October 2026. The links give you two current models to investigate alongside the energy examples above.

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The close displayed prices make usable energy and fitting costs especially worth comparing. Confirm both checkout totals on the same VAT basis. Include installation, protection and charging changes before deciding which route costs less.

Build a shortlist around the whole system

• Match planned usable energy to daily demand and reserve.
• Check physical fit, secure mounting and weight.
• Confirm cold charging protection and every charging source's compatibility.
• Match output and surge demands to battery and BMS ratings.
• Read warranty exclusions and compare the complete delivered and fitted cost.

Storage also needs a realistic replenishment plan. More storage can extend a stay. You still need a reliable way to recharge it through winter. Use your expected solar conditions and daily consumption together when planning an off-grid system.