Frequently Asked Questions

1. What is the Projecta PM535 Intelli-GRID?

Answer:

The PM535 is an integrated 12V power management system designed for caravans and motorhomes.

It provides:

• Service battery charging from AC mains.
• MPPT solar charging.
• Built-in 30A vehicle DC-DC charging.
• Starter battery maintenance charging.
• Battery voltage, current, capacity and time-remaining monitoring.
• Low-voltage battery protection.
• Battery isolation and load control.
• Control of caravan DC loads.
• Control of up to two water pumps.
• Monitoring for up to four water tanks.
• Bluetooth connection to compatible displays, sensors and the Intelli-GRID app.
• Support for compatible Projecta inverters, solar controllers, DC-DC chargers, batteries and shunts.

2. Which displays are compatible with the PM535?

Answer:

The PM535 supports the following Intelli-GRID displays:

• PMD-BT4C — 4-inch Bluetooth display.
• PMD-BT7C — 7-inch Bluetooth display.
• PMD-BT10C — 10-inch Bluetooth display.

The display is used to:

• View battery information.
• Control connected loads.
• Operate water pumps.
• View water-tank levels.
• Change battery and charging settings.
• Configure compatible accessories.
• Pair wireless switches.
• View system alarms and operating status.

The functions available may depend on the display model and connected accessories.

3. Can I control the PM535 using a mobile phone?

Answer:

Yes. The Intelli-RV GenII phone app can be used with a compatible Bluetooth display and system configuration.

The app can be used to:

• Monitor battery voltage and state of charge.
• View charging and discharging current.
• Check remaining battery capacity.
• View solar, AC and vehicle charging status.
• Control lights, pumps and other configured loads.
• View water-tank levels.
• Configure compatible Intelli-GRID accessories.
• Check system alarms and operating information.

The phone must be within Bluetooth range of the connected display or communication device.

4. Which charging sources can the PM535 use?

Answer:

The PM535 can receive charging power from:

• 240V AC mains.
• Solar panels.
• The vehicle alternator through the built-in DC-DC charger.

The charging priority is:

• AC mains and solar: Both sources may contribute.
• AC mains and vehicle DC: AC mains has priority.
• Solar and vehicle DC: Both sources may contribute.

The AUX or Solar LED may flash slowly when the input is available but AC mains is currently controlling the charging process.

5. Which battery types are supported by the PM535?

Answer:

The PM535 supports the following nominal 12V service battery types:

• AGM.
• GEL.
• WET or flooded lead-acid.
• LFP or LiFePO4 lithium.

The selected battery type must match the battery installed in the caravan.

Incorrect battery selection may result in:

• Incorrect charging voltage.
• Poor charging performance.
• Inaccurate battery monitoring.
• Reduced battery life.
• Battery protection operating unexpectedly.
• Possible battery damage.

6. How do I select the battery type?

Answer:

Battery type should normally be selected through the compatible display or app.

The PM535 also includes DIP switches for direct configuration.

Battery-type DIP-switch settings

• WET: Switch 3 ON and Switch 4 ON.
• LFP lithium: Switch 3 ON and Switch 4 OFF.
• GEL: Switch 3 OFF and Switch 4 ON.
• AGM: Switch 3 OFF and Switch 4 OFF.

Charging voltages

WET

• Absorption: approximately 14.7V.
• Float: approximately 13.7V.

LFP lithium

• Absorption: approximately 14.2V.
• Float: approximately 13.5V.

GEL

• Absorption: approximately 14.1V.
• Float: approximately 13.5V.

AGM

• Absorption: approximately 14.4V.
• Float: approximately 13.5V.

The most recently used configuration method may override an earlier setting. After changing the setting through the display or app, confirm the displayed battery type is correct.

7. How do I set the charging current?

Answer:

Charging current can normally be configured through the compatible display or Intelli-GRID app.

For conventional lead-acid batteries, the default charging current is generally based on approximately 10% of the selected battery capacity.

For lithium batteries, the maximum charging current may be set at approximately 30% of the selected battery capacity, subject to the battery manufacturer’s limits.

DIP-switch charging-current settings

Switch 1 ON and Switch 2 ON

• AC charging: 10A.
• Solar charging: 20A.
• Lithium AC/solar charging: 30A.

Switch 1 ON and Switch 2 OFF

• AC charging: 15A.
• Solar charging: 30A.
• Lithium AC/solar charging: 30A.

Switch 1 OFF and Switch 2 ON

• AC charging: 20A.
• Solar charging: 30A.
• Lithium AC/solar charging: 30A.

Switch 1 OFF and Switch 2 OFF

• AC charging: 30A.
• Solar charging: 30A.
• Lithium AC/solar charging: 30A.

Always follow the maximum charging-current limit specified by the battery manufacturer.

8. What do the PM535 charging stages mean?

Answer:

The PM535 uses a five-stage charging process.

Soft Start

Charging begins gradually when the battery voltage is very low.

Bulk

The charger supplies a higher current to raise the battery state of charge quickly.

Absorption

The charger maintains a controlled voltage while the battery completes charging.

Float

The battery is fully charged and maintained at a safe voltage.

Recycle

The charger periodically checks and maintains the battery during extended connection.

If a new AC mains or solar source is connected while the charger is in Float mode, the charger may return to the Bulk stage.

9. What do the CHG LED indications mean?

Answer:

The green CHG LED indicates the service battery’s charging or discharging condition.

• Solid ON: Battery charging in the Float stage.
• Slow flashing once per second: Battery charging in Bulk, Absorption or vehicle DC-DC mode.
• Quick flashing twice per second: Battery is discharging.
• OFF: Service battery is disconnected.

A quick-flashing CHG LED does not necessarily indicate a fault. It normally means the battery is supplying power to connected loads.

10. Does the PM535 charge the vehicle starter battery?

Answer:

Yes. When AC mains or solar charging is available, the PM535 can provide up to approximately 3A of maintenance charging to the vehicle starter battery.

Maintenance charging normally begins when:

• The starter battery voltage falls below approximately 12.4V.
• The low-voltage condition remains present for approximately 30 minutes.

Charging stops when the starter battery reaches approximately 12.8V.

This function is intended to maintain the starter battery rather than rapidly recharge a heavily discharged vehicle battery.

11. How does the built-in DC-DC vehicle charger operate?

Answer:

The PM535 includes a built-in 30A DC-DC charger.

Without a D+ or ignition signal, vehicle charging normally begins when:

• The starter battery reaches approximately 13.2V.
• The voltage remains above the threshold for approximately four seconds.

Charging normally stops when:

• The starter battery falls below approximately 12.8V.
• The voltage remains below the threshold for approximately five seconds.

The DC-DC charger provides controlled charging to the service battery rather than directly connecting the service and starter batteries together.

12. Is the PM535 suitable for vehicles with smart alternators?

Answer:

Yes. The PM535 DC-DC charger can be used with smart or variable-voltage alternators when the D+ or ignition input is correctly connected and configured.

A D+ signal tells the PM535 that the vehicle ignition or engine is operating.

The D+ connection may be obtained from:

• Pin 12 of a suitable 12-pin trailer connector.
• A suitable vehicle ignition circuit.
• Another approved ignition-controlled signal.

Vehicle and D+ wiring must be completed by a qualified auto electrician.

13. What happens when the D+ ignition wire is connected?

Answer:

When the D+ ignition wire is connected, the PM535 can use the ignition signal to control DC-DC charging.

This allows the system to operate with vehicles where the alternator voltage may not remain high enough to trigger voltage-only charging.

The PM535 will generally:

• Start vehicle charging when the ignition signal is active and the starter battery voltage is suitable.
• Continue charging while the engine or ignition signal remains active.
• Stop charging when the ignition signal turns off or the starter battery voltage becomes too low.

The exact start and stop voltage may depend on whether a service battery is connected and how the system has been configured.

14. What solar input can be connected to the PM535?

Answer:

The PM535 has a built-in MPPT solar controller.

The main solar-input limits are:

• Maximum solar open-circuit voltage: 42V DC.
• Maximum solar charging current: 30A.
• Maximum solar supply current: 30A..

The solar array’s open-circuit voltage must remain below 42V under all operating conditions.

Panel voltage can increase in cold weather, so the panel arrangement must be checked using the manufacturer’s maximum open-circuit voltage specification.

15. Can the PM535 operate without a service battery?

Answer:

Yes. When no service battery is connected, the PM535 can automatically operate as a DC power supply.

The nominal output is approximately:

• 12.8V DC.
• Up to 35A total continuous output.

When operating from AC mains, the PM535 can provide up to approximately:

• 30A for battery charging.
• 5A for connected loads.

Battery-monitoring and battery-dependent functions will not operate normally when no service battery is connected.

16. How does low-voltage battery protection work?

Answer:

The PM535 automatically disconnects controlled loads when the service battery becomes excessively discharged.

Default lead-acid settings

• Disconnect voltage: approximately 10.5V.
• Reconnect voltage: approximately 11.5V.

Default LFP lithium settings

• Disconnect voltage: approximately 11.6V.
• Reconnect voltage: approximately 12.2V.

The default disconnect delay is approximately 60 seconds.

Class D constant-supply loads remain active and are not disconnected by the low-voltage protection.

17. How are the PM535 load outputs grouped?

Answer:

The PM535 system provides 14 fused load outputs and a separate Class D constant-supply circuit.

Class A5

• Two relay-controlled and fused outputs.
• Protected by the main battery and load switches.
• Normally used for water pumps.

Class C2

• Ten fused outputs.
• Protected by the main battery and load switches.
• Suitable for lights, ventilation fans and similar equipment.

Class C3

• Two always-on outputs.
• Protected by low-voltage battery protection.
• Suitable for refrigerators, security alarms and similar loads.

Class D

• One constant-supply output.
• Not protected by low-voltage disconnect.
• Suitable for breakaway systems, sway controllers and radio memory.

Class D equipment can continue drawing current even when the main load switch is off.

18. What is the maximum current available from the Always On output?

Answer:

The separate Always On output is intended for equipment that must remain powered independently of the normal controlled load outputs.

The manual identifies the Always On output as a high-current constant-supply connection and warns against overloading it.

The total continuous current connected to the Always On circuit must remain within the specified system and installation limits.

Typical applications include:

• Breakaway systems.
• Sway controllers.
• Radio memory.
• Other essential constant-supply equipment.

The output must not be used as a general connection point for multiple high-current appliances.

19. How does the manual battery switch work?

Answer:

The PM535 has a manual ON/OFF switch on the side of the unit.

When operating from the service battery:

• Switching it ON powers the PM535 and controlled battery outputs.
• Switching it OFF disconnects the PM535 from the service battery.

When AC mains is connected:

• Switching the manual switch OFF may also turn off the display and charging operation.

The manual switch must be ON before the optional remote battery switch can operate.

Turning the manual switch off also disables DC-DC vehicle charging.

20. Will solar charging operate when the manual battery switch is OFF?

Answer:

Yes. The manual states that solar charging can continue when the PM535 power switch is OFF.

This allows the solar system to wake and charge the service battery during storage.

However:

• DC-DC vehicle charging is disabled when the power switch is OFF.
• The display and normal load outputs may remain off.
• Class D or direct-to-battery loads may continue drawing power.
• Solar charging still depends on suitable sunlight, panel voltage and battery condition.

21. How does the optional remote battery switch work?

Answer:

The remote-switch terminals are located near the load-output connections.

The remote switch performs a similar function to the manual battery switch.

For correct operation:

1. The manual switch on the PM535 must be ON.
2. The remote switch must be connected to the correct terminals.
3. The external switch must provide the required open-and-closed contact.
4. The two remote-switch terminals must be bridged when no remote switch is installed.

Removing the terminal bridge without installing a remote switch may prevent the PM535 from operating normally.

22. How does the PM535 measure battery state of charge?

Answer:

The PM535 contains a built-in current-measurement system.

It can calculate:

• Battery voltage.
• Charging current.
• Discharging current.
• Remaining battery capacity in amp-hours.
• Battery state of charge.
• Estimated time remaining.

Only current passing through the PM535 measurement path is included.

Loads connected directly to the battery may not be measured unless a compatible external shunt is installed.

For high-current equipment such as an inverter, a PMSHUNT or compatible Projecta battery management connection may be required.

23. What is the PMSHUNT used for?

Answer:

The PMSHUNT is a compatible 500A battery-monitoring shunt.

It is used when high-current equipment is connected directly to the service battery and cannot pass through the PM535 load outputs.

Typical equipment includes:

• Inverters.
• Large DC loads.
• External solar controllers.
• External DC-DC chargers.
• Other direct-to-battery equipment.

The shunt allows the Intelli-GRID system to measure the current entering and leaving the battery so that the displayed state of charge remains accurate.

24. What do the Reset and Calibration functions for the PMSHUNT do?

Answer:

The PMSHUNT configuration includes Reset and Calibration functions.

Reset

Use Reset after replacing the battery.

The system estimates an initial state of charge based on the measured battery voltage.

For the most accurate result, fully charge the battery before completing the reset.

Calibration

Use Calibration when the battery is fully charged but the displayed state of charge does not show 100%.

Calibration updates the displayed battery state of charge to 100%.

25. What does Night Mode do?

Answer:

When Night Mode is active:

• The display backlight turns off.
• The cooling fans operate at a reduced speed.
• Charging current is reduced to approximately half of the selected rate.

Battery charging may take longer while Night Mode is active.

Turn Night Mode off when maximum charging performance is required.

26. Which water tank probes are compatible with the PM535?

Answer:

The PM535 can monitor up to four water tank probes.

Compatible probe types include:

PMWS200

• Side installation.
• Suitable for tanks deeper than approximately 200mm.

PMWS400

• Side installation.
• Suitable for tanks approximately 300mm to 400mm deep.

The system can normally monitor:

• Fresh water tank 1.
• Fresh water tank 2.
• Tap water tank.
• Waste water tank.

Confirm the tank depth and probe installation arrangement before ordering.

27. How much ventilation clearance is required around the PM535?

Answer:

Maintain at least 50mm of clearance on each side of the PM535.

The installation compartment should provide suitable airflow around the unit.

The manual recommends a ventilation opening of approximately:

• 144mm wide.
• 54mm high.

Do not:

• Cover the ventilation openings.
• Install the unit in a sealed compartment.
• Position stored items directly against the unit.
• Install the PM535 beside another major heat source.
• Continue operating the system if the enclosure or terminals become excessively hot.

28. What battery-monitor maintenance is recommended?

Answer:

To maintain accurate battery-monitor readings:

1. Fully charge the service battery from AC mains approximately every two weeks while the system is in use.
2. Complete a full AC mains charge at least once every three months.
3. Continue charging until the CHG LED is solid or the display shows Float.
4. Confirm the PM535 manual power switch is ON during AC charging.
5. Confirm the installed service battery is a nominal 12V battery.
6. After replacing the battery, fully charge it from AC mains to the Float stage.
7. Confirm direct-to-battery loads are measured through a compatible PMSHUNT or battery management system.

AC mains charging is recommended for calibration because solar and vehicle charging can vary.

29. How should the PM535 be prepared for storage?

Answer:

For storage without an external power source:

1. Fully charge the service battery.
2. Turn off unnecessary loads.
3. Turn off the manual or remote battery switch.
4. Identify any Class D or direct-to-battery loads that remain active.
5. Confirm whether solar charging will remain connected.
6. Follow the battery manufacturer’s storage instructions.
7. Fully recharge the battery at least once every three months.

Turning the manual switch off reduces PM535 current draw to less than approximately 1mA, but direct-to-battery and Class D loads may continue discharging the battery.

30. How do I pair a wireless switch panel?

Answer:

The PM535 includes built-in RF communication for compatible PMWSW4 wireless switch panels.

Follow these steps:

1. Open Engineering Settings on the display.
2. Enter the engineering password shown in the manual: 1999.
3. Select the plus symbol to add a wireless panel.
4. Press a button on the wireless panel twice slowly.
5. Select the corresponding on-screen button.
6. Select the function to assign to that button.
7. Repeat the process for the other buttons.
8. Select Confirm.
9. Select OK when pairing is complete.

Keep the wireless panel close to the display during pairing.

31. Which additional Intelli-GRID accessories can be connected?

Answer:

Compatible accessories may include:

• PMD-BT4C, PMD-BT7C and PMD-BT10C displays.
• PMWSW4 wireless switch.
• SC520, SC540 or SC550 external solar controllers.
• PMDCS30, PMDCS60 and PMDCS30-20 DC-DC chargers.
• PMTPMS tyre pressure monitoring system.
• PMLVL levelling sensor.
• LB-HD lithium battery systems.
• INVCHR2 or INVCHR3 inverter/chargers.
• PMSHUNT 500A battery-monitoring shunt.
• PMWS200 and PMWS400 water tank probes.

Connected accessories must be enabled and configured through the appropriate display or app settings.

Troubleshooting Questions and Answers

The PM535 front-panel LEDs identify AC input, vehicle input, solar input, charging status and system faults.

1. Why does the PM535 have no display or no DC output?

Answer:

Check the following:

1. Confirm the service battery is connected.
2. Check that battery polarity is correct.
3. Measure the service battery voltage.
4. Confirm the side-mounted manual switch is ON.
5. Confirm the remote switch is ON where installed.
6. If no remote switch is installed, confirm the remote terminals are bridged.
7. Check the display communication cable.
8. Confirm the LOAD function is switched on.
9. Check the output fuses.
10. Check whether the red Fault LED is illuminated or flashing.

If the battery voltage is below the low-voltage disconnect threshold, controlled loads may remain off until the battery is charged above the reconnect voltage.

2. Why is the Mains LED flashing quickly?

Answer:

A quickly flashing Mains LED indicates an abnormal AC input.

Follow these steps:

1. Disconnect the PM535 from AC mains.
2. Inspect the AC cable and IEC connector.
3. Check for visible damage, overheating or loose connections.
4. Check whether the circuit breaker or safety switch has tripped.
5. Confirm the AC outlet is approximately 240V and correctly earthed.
6. Reconnect the unit to a known suitable supply.
7. Check whether the Mains LED becomes solid.

Stop using AC charging if the Mains LED continues flashing.

Fixed 240V wiring must be inspected or repaired by a licensed electrician.

3. Why is the AUX LED flashing quickly?

Answer:

A quickly flashing AUX LED indicates a vehicle battery or DC-DC input error.

Follow these steps:

1. Disconnect the caravan from the towing vehicle.
2. Inspect the trailer plug and vehicle connection.
3. Check for damaged, loose or corroded terminals.
4. Confirm the positive and negative vehicle connections are correct.
5. Measure the starter battery voltage.
6. Check the D+ or ignition signal where fitted.
7. Reconnect the vehicle and start the engine.
8. Check whether the AUX LED returns to solid or slow flashing.

Arrange inspection by a qualified auto electrician if the AUX LED continues flashing.

4. Why is the AUX LED flashing slowly?

Answer:

A slowly flashing AUX LED normally means:

• The vehicle or auxiliary input is available.
• AC mains is currently charging the service battery.
• AC mains has priority over the vehicle input.

This is generally a normal operating condition.

If vehicle charging does not begin after AC mains is disconnected, check the vehicle voltage, D+ signal and DC-DC configuration.

5. Why is the Solar LED flashing quickly?

Answer:

A quickly flashing Solar LED indicates an abnormal solar input.

Follow these steps:

1. Isolate the solar input using the approved procedure.
2. Measure the solar-array open-circuit voltage.
3. Confirm the voltage is below 42V DC.
4. Check the solar polarity.
5. Inspect the solar fuse.
6. Check the panel connectors and extension cables.
7. Inspect the panels for damage.
8. Reconnect solar only after the cause has been corrected.

Solar panels can remain electrically live during daylight.

6. Why is the Solar LED flashing slowly?

Answer:

A slowly flashing Solar LED normally means:

• Solar input voltage is available.
• AC mains is currently controlling battery charging.
• The solar input is waiting or contributing according to the PM535 charging priority.

This is generally a normal operating condition.

The Solar LED should become solid when solar is actively charging the service battery.

7. Why is the CHG LED flashing quickly?

Answer:

A quickly flashing CHG LED normally means the service battery is discharging.

Check the following:

1. Identify which loads are operating.
2. Check the displayed discharge current.
3. Turn off unnecessary appliances.
4. Confirm whether AC, solar or vehicle charging is available.
5. Monitor the battery voltage.
6. Test the battery if it discharges unusually quickly.

A quick-flashing CHG LED is not itself a fault indication.

8. Why is the red Fuse indicator illuminated?

Answer:

A solid Fuse indicator means an output fuse has blown.

Follow these steps:

1. Turn off the affected load.
2. Identify the failed fuse.
3. Inspect the connected appliance.
4. Check the wiring for a short circuit or damaged insulation.
5. Confirm the connected load does not exceed the output rating.
6. Correct the cause of the fault.
7. Replace the fuse with the same type and rating.
8. Reconnect the load and confirm the fuse does not fail again.

Never replace a fuse with a higher-rated fuse.

9. What does a solid red Fault LED mean?

Answer:

A solid red Fault LED indicates a short circuit.

Follow these steps:

1. Turn off the controlled DC loads.
2. Disconnect recently installed or suspect equipment.
3. Inspect the output wiring.
4. Check for damaged insulation, trapped cables or reversed polarity.
5. Check the affected fuse.
6. Correct the fault.
7. Reconnect loads one at a time.

Do not repeatedly replace fuses or restart the system without finding the cause of the short circuit.

10. What does one flash of the red Fault LED mean?

Answer:

One flash indicates service battery undervoltage.

Follow these steps:

1. Turn off unnecessary loads.
2. Connect AC mains, solar or vehicle charging.
3. Measure the service battery voltage.
4. Check the battery terminals.
5. Allow the battery to charge above the reconnect voltage.
6. Test the battery if the voltage falls again quickly.

Default thresholds

Lead-acid

• Disconnect: approximately 10.5V.
• Reconnect: approximately 11.5V.

LFP lithium

• Disconnect: approximately 11.6V.
• Reconnect: approximately 12.2V.

Stop using a battery that is swollen, leaking, venting or excessively hot.

11. What do two flashes of the red Fault LED mean?

Answer:

Two flashes indicate service battery overvoltage.

Follow these steps:

1. Isolate the charging sources where safe.
2. Measure the service battery voltage.
3. Confirm the correct battery type is selected.
4. Confirm the charging-current setting.
5. Check the solar-array voltage.
6. Check the vehicle charging input.
7. Arrange qualified inspection if the battery voltage remains high.

The PM535 may disconnect the charger and controlled loads during an overvoltage condition.

12. What do three flashes of the red Fault LED mean?

Answer:

Three flashes indicate heatsink overtemperature.

Follow these steps:

1. Reduce the connected electrical load.
2. Turn off high-current appliances.
3. Check that the PM535 ventilation openings are clear.
4. Confirm there is at least 50mm clearance on each side.
5. Check whether the cooling fan is operating.
6. Allow the unit to cool.
7. Restart the system only after the temperature has returned to normal.

Arrange technical inspection if the fault returns under normal load conditions.

13. What do four flashes of the red Fault LED mean?

Answer:

Four flashes indicate a Bulk charging timeout.

The battery has remained in the Bulk charging stage longer than expected.

Follow these steps:

1. Turn off unnecessary DC loads.
2. Check the service battery terminals.
3. Inspect the battery cables.
4. Confirm the battery type is correct.
5. Confirm the battery capacity is correct.
6. Check the charging-current setting.
7. Fully test the service battery.
8. Restart charging after the fault has been corrected.

A battery with a failed cell or reduced capacity may remain in Bulk charging for an excessive period.

14. What do five flashes of the red Fault LED mean?

Answer:

Five flashes indicate abnormal DC-DC vehicle charging.

Follow these steps:

1. Turn the PM535 off and restart it.
2. Disconnect the caravan from the towing vehicle.
3. Inspect the vehicle connector and trailer plug.
4. Measure the starter battery voltage.
5. Check the D+ or ignition signal.
6. Check the vehicle positive and negative cables.
7. Reconnect the vehicle and start the engine.
8. Check whether the AUX LED becomes solid.

Arrange inspection by a qualified auto electrician if the fault returns.

15. What do eight flashes of the red Fault LED mean?

Answer:

Eight flashes indicate that the PM535 unit temperature is too high.

Follow these steps:

1. Turn off high-current loads.
2. Reduce the charging current where appropriate.
3. Check for blocked ventilation openings.
4. Confirm the installation compartment has suitable airflow.
5. Allow the unit to cool.
6. Restart the PM535.
7. Check whether the fault returns.

Do not continue using the system if the casing, cables or terminals remain excessively hot.

16. What do nine flashes of the red Fault LED mean?

Answer:

Nine flashes indicate overheating in the PCB or load circuit.

Follow these steps:

1. Turn the load switch off.
2. Disconnect high-current appliances.
3. Check the output current used by each load.
4. Inspect the output terminals and cables.
5. Check for loose or heat-damaged connections.
6. Check for undersized cables.
7. Allow the PM535 to cool.
8. Reconnect loads individually.

Arrange qualified inspection if the fault returns or there is evidence of melted wiring.

17. Why is the service battery not charging from the vehicle?

Answer:

Check the following:

1. Confirm the vehicle engine is running.
2. Measure the starter battery voltage.
3. Confirm the AUX LED status.
4. Check the trailer plug and vehicle connection.
5. Inspect the positive and negative vehicle cables.
6. Confirm the PM535 manual power switch is ON.
7. Check the D+ or ignition signal where fitted.
8. Confirm vehicle charging is enabled in the display or app.
9. Check whether the starter battery voltage reaches the DC-DC start threshold.
10. Have voltage drop and cable capacity checked by a qualified auto electrician.

DC-DC charging is disabled when the PM535 manual power switch is OFF.

18. Why does vehicle charging repeatedly start and stop?

Answer:

Repeated DC-DC cycling may be caused by:

• Low starter battery voltage.
• Excessive voltage drop in the vehicle cable.
• An intermittent D+ or ignition signal.
• A loose trailer plug connection.
• A weak starter battery.
• An undersized positive or negative cable.
• The alternator output falling below the turn-off threshold.
• Excessive service battery charging demand.

Have the voltage measured at both the vehicle battery and the PM535 input while charging.

19. Why does the remote battery switch not work?

Answer:

Follow these steps:

1. Confirm the side-mounted manual switch is ON.
2. Check the remote-switch wiring.
3. Confirm the wiring is connected to the correct remote terminals.
4. Check whether the external switch opens and closes correctly.
5. Inspect the terminal bridge.
6. If no remote switch is installed, confirm both terminals are bridged.
7. Check for an active low-voltage or fault condition.

The remote switch cannot operate while the manual switch is OFF.

20. Why is the displayed battery percentage inaccurate?

Answer:

Follow these steps:

1. Confirm the selected battery type is correct.
2. Confirm the configured battery capacity is correct.
3. Identify loads connected directly to the battery.
4. Identify chargers connected directly to the battery.
5. Confirm heavy loads are measured through a PMSHUNT or compatible battery management system.
6. Fully charge the battery from AC mains.
7. Continue charging until the display shows Float.
8. Use the PMSHUNT Calibration function where applicable.

Only current passing through the PM535 or compatible external shunt is included in the battery-monitor calculation.

21. Why does the battery discharge during storage?

Answer:

The battery may continue discharging when:

• The manual or remote battery switch remains ON.
• Class D constant-supply loads remain connected.
• Equipment is connected directly to the battery.
• The breakaway system remains powered.
• A sway controller remains powered.
• The PM535 remains in standby.
• The battery is not periodically recharged.

Follow these steps:

1. Fully charge the service battery.
2. Turn the manual or remote switch off.
3. Identify constant-supply loads.
4. Check for direct-to-battery equipment.
5. Measure the storage current.
6. Confirm solar charging is operating where it will remain connected.
7. Recharge the battery at least once every three months.

22. Why will the water pump not operate?

Answer:

Follow these steps:

1. Confirm the manual battery switch is ON.
2. Confirm the LOAD function is ON.
3. Check that the correct pump output is enabled through the display or app.
4. Check the pump fuse.
5. Inspect the pump wiring.
6. Confirm the battery voltage is above the low-voltage threshold.
7. Check the pump pressure switch.
8. Check for a seized or damaged pump.
9. Confirm the pump is connected to a Class A5 output.

Repeated fuse failure may indicate a seized pump, damaged cable or short circuit.

23. Why is a water tank showing the wrong level?

Answer:

Follow these steps:

1. Confirm the actual tank level.
2. Confirm the correct tank is selected on the display.
3. Inspect the probe connection.
4. Confirm the probe is connected to the correct tank input.
5. Check the probe cable and extension cable.
6. Inspect the probe for contamination.
7. Confirm the probe is suitable for the tank depth.
8. Check the probe installation angle.
9. Restart the display and PM535.

Incorrect probe selection, installation or wiring can cause inaccurate tank readings.

24. Why will the mobile app not connect?

Answer:

Follow these steps:

1. Confirm Bluetooth is enabled on the phone.
2. Confirm the compatible Intelli-GRID display is powered.
3. Move the phone closer to the display.
4. Close and reopen the Intelli-GRID app.
5. Confirm the app has Bluetooth and nearby-device permissions.
6. Confirm another phone is not already connected.
7. Restart the display and PM535.
8. Remove the saved Bluetooth connection and pair again where required.
9. Check that the app and display firmware are current.

Connection procedures may differ between Android and iOS devices.

25. Why will the wireless switch not pair?

Answer:

Follow these steps:

1. Confirm both CR2032 batteries are correctly installed.
2. Replace the batteries if their condition is unknown.
3. Move the wireless panel close to the display.
4. Open Engineering Settings.
5. Enter password 1999.
6. Select the plus symbol.
7. Press a wireless-panel button twice slowly.
8. Assign the required function.
9. Select Confirm.
10. Repeat the procedure for each button.

The wireless switch is intended for indoor installation and its operating range may be reduced by walls, metal structures or electrical interference.

26. Why is a connected accessory not appearing in the app?

Answer:

Follow these steps:

1. Confirm the accessory is compatible with the PM535.
2. Check the communication cable.
3. Confirm the accessory has power.
4. Open the Intelli-GRID configuration page.
5. Enable or activate the accessory.
6. Select the correct connection mode.
7. Confirm the accessory quantity where required.
8. Restart the PM535 and display.
9. Check whether the accessory appears after the system restarts.

Some accessories must be activated before they can be monitored or configured.

Safety Warnings

• Disconnect the 240V AC supply before making or breaking battery connections.
• Connect the battery before connecting AC mains.
• Connect the charger only to an earthed AC outlet.
• Fixed AC wiring must comply with applicable national wiring rules.
• Do not use a damaged AC cable.
• Do not charge a frozen or non-rechargeable battery.
• Use only the correct battery type and charging-voltage setting.
• Keep flames, sparks and ignition sources away from batteries.
• Provide adequate ventilation during charging.
• Do not expose the PM535 to rain.
• Solar panels may remain electrically live during daylight.
• Do not replace an output fuse with a higher-rated fuse.
• Keep button and coin batteries away from children.
• A swallowed lithium coin battery can cause severe injury and requires immediate medical attention.
• Stop using a service battery that is swollen, leaking, venting, excessively hot or physically damaged.

When to Contact Projecta Technical Support

Contact Projecta Technical Support when:

• The same fault returns after completing the recommended checks.
• The Mains LED continues flashing with a suitable AC supply.
• Vehicle charging does not operate after the D+ signal and wiring have been checked.
• The PM535 repeatedly overheats.
• Fuses continue to fail.
• The display cannot communicate with the PM535.
• The Bluetooth app cannot connect after the system has been restarted.
• Battery overvoltage continues after charging sources are isolated.
• The PMSHUNT or another accessory cannot be detected.
• Wiring, connectors or the PM535 show evidence of heat damage.

Provide:

• Product model: PM535.
• Display model.
• Battery type and capacity.
• Measured service battery voltage.
• Measured starter battery voltage.
• Charging sources connected.
• Mains, AUX, Solar and CHG LED status.
• Fault LED flash count.
• Details of connected loads and accessories.
• Vehicle make, model and alternator type where relevant.
• Photos of the installation, wiring and connectors where safe.
• Proof of purchase where warranty assessment may be required.