Projecta IntelliRV Caravan Battery Management System

Test, Check & Rejuvenation Guide

Applicable Systems

This guide applies to the following Projecta IntelliRV systems:

• PM235 / PM235J / PM235J-2
• PM335 / PM335J-2
• PM435 / PM435J-2
• PM335C/ PM435C/PM235C

Purpose of This Article

Over time, caravan battery systems may show inaccurate State of Charge (SoC), reduced charging performance, or unexpected shutdowns.
This guide helps identify and correct common issues caused by:

• Loose or deteriorated cable connections
• Voltage drops
• Incorrect battery settings
• Firmware issues
• Solar or tow-vehicle charging problems

Following this process can often restore the system to original performance.

It is recommended every caravan owner has the following available:

• Multimeter (DC voltage measurement capability)
• Ring spanner or open-end spanners
• Pliers
• Phillips-head screwdriver
• Insulation tape
• Notepad & pen
• Mobile phone (for app access or technical support)

Step 1: Update Firmware (Bluetooth Models Only)

1. Open the Projecta Bluetooth app
2. Go to Settings → Firmware
3. Install any available updates

Important Notes:

• Ensure good mobile reception
• Access to 240v mains supply
• Be inside the caravan during update
• If prompted for a password, check the LCD screen (top-left corner)

Note- Always turn ON 240v Mains supply while doing firmware updates.

Step 2: Verify Battery Type & Capacity

Set Battery Type

1. Open Settings → Type
2. Select the correct battery:

• Lithium (LFP)
• AGM
• GEL
• WET

3. Press Confirm

Access Code: If prompted, enter 7960

Set Battery Capacity

1. Go to Settings → Capacity
2. Enter the correct battery capacity (Ah)
3. Press Confirm

⚠️ Do not change Advanced Settings unless instructed by Projecta Technical Support.

Step 3: Multimeter Setup (DC Voltage)

• Set meter to DC Volts (0–20V range)
• Black probe → COM
• Red probe → V / Ω socket
• ❌ Do NOT use the 10A or 20A socket

Step 4: Check Battery Voltage Accuracy

Measure Voltage at the BMS

1. Remove the metal terminal cover
2. Measure voltage between:

• Pin 4 (+) positive terminal and Pin 6 (–) Negative Terminal   (For PM235, PM335, PM435, PM235J, PM335J)
• Pin 4 (+) positive terminal and Pin 1 (-) Negative terminal    (For PM235C, PM335C, PM435C)

3. Record the reading

Measure Actual Battery Voltage

1. Black probe → Battery negative
2. Red probe → Battery positive
3. Record the reading

Acceptable Difference

• ≤ 0.2V → Normal
• 0.2V → Voltage drop present
• 0.5V → Serious issue (must be investigated)

Step 5: Check Solar Charging Performance

Solar Input Indication

Solar charge current (amps) is displayed on the LCD screen.

Typical Output Example:

• 200W panel → ~8A under ideal conditions

Performance depends on:

• Time of day
• Weather
• Panel angle
• Location (north vs south Australia)

Step 6: Measuring Solar Panel Voltage

Solar voltage is measured as open-circuit voltage.

1. Disconnect the solar negative cable from the system
2. Multimeter:

• Negative probe → removed cable
• Positive probe → solar positive terminal

3. Typical reading: ~18–24V (varies by panel)

Step 7: Tow Vehicle Charging Check

How to Confirm Charging

• Engine running → charging link should show closed
• Voltage should appear next to starter battery icon

If Charging Is Poor

Common causes:

• Undersized cabling
• Poor connections
• Smart alternator behavior

Step 8: Do I Need a DC-DC Charger?

What a DC-DC Charger Does

• Boosts tow-vehicle voltage
• Ensures full battery charging while driving
• Isolates starter battery
• Compensates for smart alternators

Strongly Recommended If:

• You have lithium batteries
• You use IntelliRV systems
• Vehicle has a smart alternator

Step 9: Understanding Voltage Drop

Voltage drop is the loss of voltage between the battery and the power management system.

Causes

• Long cable runs
• Loose connections
• Corrosion
• Undersized cables

How to Test

1. Disconnect solar & tow vehicle
2. Load the system to reduce battery voltage
3. Reconnect mains power
4. Compare:

• Battery terminal voltage
• BMS input voltage

Difference > 0.2V indicates a problem

Step 10: Projecta Shunt (PMSHUNT)

Why a Shunt Is Required

The BMS cannot see:

• Inverters
• Diesel heaters
• Devices wired directly to the battery

Without a shunt:

• SoC readings become inaccurate
• System may shut down early

⚠️ Only Projecta PMSHUNT is compatible.

Step 11: Recalibrating the Shunt

1. Disconnect all charge sources:

• Mains
• Tow vehicle
• Solar

2. Remove the red +B1 cable
3. Wait 30 seconds
4. Reconnect the cable

✅ Status LED should become solid green

If not, repeat or contact Projecta Support.

Step 12: Error Codes                                                                

• Error codes appear in red at the bottom of the LCD
• They must not be ignored
• Refer to the error code table or contact support 📞 Projecta Technical Support: 1800 422 422  

Step 13: Caravan Storage Best Practices

Option 1: Connected to Mains (Best Method)

• Turn off 12V loads
• Allow periodic discharge and recharge
• Check system every 4 weeks

Option 2: Connected to Solar

• Ensure correct panel type (regulated/unregulated)
• Keep panels clean and unshaded
• Check system every 2–4 weeks

Option 3: No Charge Source

• Least recommended
• Check voltage weekly
• Do not allow voltage below:

• 12.3V Lead Acid
• 12.8V Lithium

Option 4: Fully Isolated Battery

• Disconnect battery or use isolation switch
• Reconnect and complete a full charge cycle before use

Need Further Assistance?

If issues persist after following this guide, contact:

📞 Projecta Technical Support: 1800 422 422