A leisure battery that is not charging may have no available charging source, a disconnected or protected charging path, unsuitable charger settings, or a battery fault. Start by identifying which source has stopped working: solar, alternator charging, mains hook-up, or all three. That narrows the checks before you buy replacement parts.
Record the battery chemistry, charger models, recent changes, app warnings and whether the problem happens only when cold, parked or driving. Prefer the equipment's status screens and manufacturer troubleshooting instructions for the first checks.
Start with non-invasive checks
Stop if you see damaged insulation, hot or melted connections, swelling, smoke or a repeated protective-device trip. Do not bypass a fuse, BMS or solar controller. Keep mains covers closed and leave live mains measurements to a qualified person. Follow the equipment's isolation procedure before disturbing DC wiring; a battery can deliver a very high fault current.
First: confirm what is actually happening
Check three separate readings where your equipment provides them:
- Charging-source output: is a charger delivering current, or just displaying a voltage?
- Battery current: is the battery gaining energy after the running loads are counted?
- Charge permission and stage: is charging enabled, paused by a BMS, or reduced because the battery is approaching its configured limit?
For example, a charger supplying 15A while the van consumes 20A leaves an approximate 5A deficit at the battery. The battery can discharge even though the charger is working. Compare readings taken at the same time, on the same DC side of the system.
A voltage reading alone is not a precise state-of-charge measurement, particularly for LiFePO4. A monitor also needs correct settings and synchronisation. Avoid declaring a battery “full”, “dead” or a specific percentage charged from one generic voltage figure.
Fault tree by charge source
| What you observe | Start here | Useful evidence |
|---|---|---|
| No charging from any source | Battery protection and the shared battery connection | BMS status, isolator position, common fuse or connection history |
| Solar alone fails | Solar controller status and available sunlight | PV voltage/power, charge stage, error message |
| Charging fails only while driving | DC-DC activation and vehicle-side supply | Engine-detection status, remote enable, input lockout message |
| Hook-up sockets work but battery does not charge | Mains charger status and DC output path | Charger mode, warnings, battery compatibility |
| Some charging, but battery still falls | Compare incoming current with running loads | Simultaneous charger and battery current readings |
| Problem started after a battery replacement | Profile, BMS and monitor configuration | Exact battery model and recommended charging settings |
Step 1: Check for a Blown Fuse
Identify the protective devices in the affected charging path from your wiring documentation: the battery fuse, DC-DC input/output protection and solar-controller battery-side protection. Don't assume that one visible fuse is the only protection in the circuit.
A visual check does not prove every fuse is sound. Only perform an electrical check if you know the correct isolation and meter procedure; never use continuity or resistance mode on an energised circuit. If unsure, ask the installer to check it.
Find the cause before fitting a replacement. Use the specified fuse type and rating, never a larger fuse to prevent further trips. A repeat failure requires investigation, not another reset or replacement.
Step 2: Check the DC-DC Charger Is Activating
Check the charger app or indicators with the vehicle in the operating condition described by its manual. Record whether it reports disabled charging, engine shutdown, input-voltage lockout, temperature protection or another fault.
Remote-enable wiring, engine detection and input thresholds differ between chargers. Don't connect an ignition wire or lower a threshold simply because another van uses that arrangement. For Orion XS equipment, use Victron's troubleshooting and support guidance and the installation instructions for that exact model.
If the charger is enabled but supplies less current than expected, record both its input status and output limit before assuming it is undersized. The DC-DC charger sizing guide explains the planning decision separately from fault finding.
Step 3: Check Solar Panel Output
Start with shade, weather and the controller's status. A controller displaying PV voltage is not necessarily delivering useful charging power. Check the charge stage, output current and any explanation for why charging is off.
Victron's MPPT troubleshooting guide separates low solar supply, battery connection issues, charge settings and load demand. Use the corresponding manual if you have a different controller.
Keep the panels connected through the specified controller and protective arrangement. Do not connect a panel directly to the battery as a test. Panel wiring tests and disconnection need the manufacturer's procedure, suitable equipment and competence; don't unplug PV connectors under load.
For a solar-only problem, continue with solar panels not charging. Record the evidence above first so you can distinguish weak sunlight from an electrical fault.
Step 4: Check Battery BMS (LiFePO4 Only)
Read the battery app or status indicator for an explicit reason charging is blocked. Temperature, individual cell limits and current protection can affect charge permission, but the thresholds and recovery steps are model-specific.
Do not apply a universal “charge below 0°C” or “reconnect above 5°C” rule. Victron's Lithium Smart operation guidance, for example, specifies a minimum allowed charging temperature for that battery family. Your battery's own manual governs your installation.
If a battery shows zero terminal voltage or reports protection mode, contact the manufacturer or follow its documented recovery procedure. Do not bypass protection, force a charging voltage or repeatedly disconnect the battery to try to reset it. Zero volts at protected terminals does not by itself identify the underlying fault.
Step 5: Check Wiring Connections
A charging path includes the positive and negative conductors, fuse holders, isolators and connection points. After proper isolation, look for movement, corrosion, damage or discolouration. Tightening specifications come from the terminal or equipment manufacturer; “as tight as possible” is not a torque setting.
A qualified installer can compare charger and battery voltage under controlled operating conditions to locate excessive voltage drop. Record the current and where each reading was taken. A single universal voltage-drop threshold cannot diagnose every connection or cable run.
Keep a photo of the installation and the exact equipment labels for a support request. That makes it easier to explain what changed after a service, battery swap or new accessory.
Step 6: Alternator Not Charging (Vehicle Issue)
First distinguish vehicle charging from the DC-DC charger's activation logic. Smart alternator voltage can change as part of normal vehicle operation; a brief low reading is not enough to diagnose alternator failure.
If the vehicle has a charging warning, starting trouble or other symptoms, have the vehicle system checked using the manufacturer's procedure. Do not work beside moving engine parts to chase a generic voltage target. Explain to the technician what the leisure charger is reporting and when the fault occurs.
For background, see smart alternators in campervans.
Step 7: Battery Charger Not Working (Shore Power)
Check whether the campsite supply is available and whether other normal mains appliances work. If the whole mains system is off or a protective device trips repeatedly, disconnect as instructed and get the site or installer to investigate.
If the sockets work, inspect the charger's user-facing indicators or app. Is it enabled? Does its charging profile match the battery? Is there a warning or an identified DC output connection problem? A working socket does not confirm that the charger is working.
Don't open the consumer unit or probe live 230V terminals. The Caravan and Motorhome Club's electrical fault-finding advice distinguishes basic checks from dismantling equipment. Use the EHU guide for the connection and pitch-load checks.
Step 8: Battery Has Reached End of Life
If the charging sources and connections check out, arrange a battery assessment. A battery that quickly charges and discharges may have reduced capacity, but changed loads, an incorrectly configured monitor or incomplete charging can look similar.
Use a manufacturer-approved capacity-test procedure rather than repeatedly deeply discharging the battery. Cycle-life figures are conditional ratings, not a guarantee of a fixed number of years in a van. Record age, storage history and previous faults before deciding whether replacement is justified.
Check the plan behind your charging system
Use the free electrical calculator to review daily demand and charging assumptions once any installation or equipment faults have been resolved.
FAQ
My solar controller shows voltage but no charging current. Is it faulty?
Not necessarily. Check its reported charge stage, charge permission, available solar power and warnings. A full battery, restricted charging or a connection issue can all require different next steps. Do not bypass the controller to test it.
My battery monitor shows 12.8V. How full is the battery?
That reading alone is not enough. Chemistry, whether the battery is resting or under load, temperature and recent charging affect interpretation. Use the battery manufacturer's guidance and a correctly configured monitor rather than a universal percentage.
My new LiFePO4 battery shows 0V. Is it dead?
It may be in a protective state, but that is not a diagnosis. Check the manual and contact the supplier with the model and status information. Only use the manufacturer's supported recovery procedure and a compatible charger.
Why did charging stop after changing from AGM to lithium?
Check the battery's supported charging settings, charger compatibility, BMS permissions and monitor configuration. Don't select an arbitrary higher voltage or a lead-acid reconditioning mode to force the battery to charge.
What information should I send to an installer or manufacturer?
Send the battery and charger model numbers, a wiring overview, the exact warning text, relevant app screenshots, what changed recently and whether the problem occurs on one source or all sources. Do not remove protective covers just to obtain a photograph.
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Jack Kennedy is a self-builder who has built two vans. He created Roam Wired to simplify conversion planning and share free tools, supported by affiliate links.
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