How to Upgrade Progressive Dynamics Converter for Lithium RV Batteries Safely

Bottom Line Up Front

Your 2006 Lance 915 cabover needs a lithium-compatible converter charger to properly charge those SOK 100Ah batteries with your 400 watts of Bouge solar. The original Progressive Dynamics converter is designed for lead-acid batteries and will undercharge your lithium setup, potentially damaging the batteries over time. You'll want to upgrade to a Progressive Dynamics lithium-compatible converter (verify specific model numbers for your application), which are direct replacements designed specifically for lithium batteries. The PD9245LiV runs about $280-320 and should handle your two 100Ah SOK batteries just fine, while the PD9260LiV costs $320-380 and gives you more charging headroom for future expansion.

Root Causes

Your original Progressive Dynamics converter is programmed for lead-acid battery charging profiles, which use a three-stage charging process (bulk, absorption, float) with voltages that don't match lithium requirements. Lead-acid chargers typically float at 13.6-13.8 volts, while your SOK lithium batteries need 14.4-14.6 volts for proper charging and don't use traditional float charging. This voltage mismatch means your batteries aren't getting fully charged and may show reduced capacity over time.

Additionally, lead-acid chargers often have temperature compensation features that actually work against lithium batteries. Your SOK batteries have built-in Battery Management Systems (BMS) that handle cell balancing and protection, but they need the right voltage input to function properly. The original converter also lacks the lithium-specific charging algorithms that optimize battery life and performance.

With 400 watts of solar feeding into this system, you're also not maximizing your solar investment. The old converter can't properly coordinate with your solar charge controller to ensure optimal battery charging, especially during cloudy conditions when the converter needs to supplement solar charging.

Before You Start

WARNING: This procedure involves working with 120V electrical systems. Turn off all power sources and use proper safety procedures. If you're not experienced with electrical work, consult a qualified RV technician.

First, verify your current converter model by checking the label inside your electrical compartment - it's likely a PD9245 or PD9260 based on your Lance 915's typical configuration. Take a photo of the wiring connections before disconnecting anything, as you'll need to match these exactly. Make sure you have a multimeter to verify battery voltages and test the new unit after installation.

Check your SOK battery specifications to confirm the recommended charging voltage and current limits. Check your specific SOK 100Ah battery specifications for maximum charging rates, so either the 45-amp or 60-amp Progressive Dynamics lithium converter will work well. You'll also want to verify that your existing solar charge controller is lithium-compatible - if it's not, you might need to upgrade that too.

Safety preparation is crucial: turn off the main breaker, disconnect shore power, and ensure your propane detector and smoke alarms have backup power during the installation. Have a flashlight handy and consider doing this work during daylight hours. If you're not comfortable with 120V electrical work, this is definitely a job for a qualified RV technician.

The Repair Process

WARNING: Always verify power is completely disconnected before beginning work. Use a non-contact voltage tester to confirm circuits are de-energized.

Start by turning off all power sources - main breaker, battery disconnect, and unplug from shore power. Remove the old converter by first photographing all wire connections, then disconnecting the 12V DC output wires (usually red positive and black negative), followed by the 120V AC input wires (black hot, white neutral, green ground). The converter should lift out after removing mounting screws.

Install the new Progressive Dynamics lithium converter in the same location, connecting the wires exactly as they were on the old unit. The PD9245LiV or PD9260LiV are direct replacements with the same mounting pattern and wire connections. Make sure all connections are tight and torque to manufacturer specifications. The lithium converters have different LED indicator patterns, so familiarize yourself with the new status lights.

After installation, reconnect power sources one at a time and test. With shore power connected, you should see the converter LED indicating bulk charging mode initially, then switching to absorption mode as batteries approach full charge. Lithium-specific converters typically turn off or enter maintenance mode rather than float charging. Use your multimeter to verify the converter is outputting the correct voltage during charging (typically 14.2-14.6V for lithium batteries - check your SOK specifications). Test both with and without solar input to ensure proper coordination.

Lithium-specific converters are typically pre-programmed for lithium batteries, but verify any configuration requirements in the converter manual. Check your SOK battery specifications to confirm compatibility with the lithium charging profile. The new converter should also have improved cooling and efficiency compared to your old unit, running cooler and using less power.

Professional Help Needed

SAFETY WARNING: Working with 120V electrical systems can be dangerous. If you're uncomfortable with electrical work or lack proper tools and experience, always consult a qualified RV technician.

If you're uncomfortable working with 120V electrical connections or don't have experience with RV electrical systems, hire a certified RV technician for this installation. The job involves both high-voltage AC and DC electrical work, and mistakes can damage expensive components or create safety hazards. Expect to pay $150-250 for professional installation on top of the converter cost.

Consider professional help if you discover additional issues during inspection, such as corroded connections, undersized wiring, or an incompatible solar charge controller. A qualified technician can assess your entire charging system and ensure all components work together properly. They can also update any battery monitor settings and verify that your solar controller is properly configured for lithium batteries.

Some RV service centers offer package deals when upgrading multiple electrical components. If your solar charge controller also needs upgrading for lithium compatibility, having both done professionally ensures proper system integration. Get quotes from certified technicians who specifically mention experience with lithium battery conversions, as this requires knowledge of both traditional RV electrical systems and modern lithium technology. Remember that proper installation not only ensures optimal performance but also maintains safety and protects your investment in expensive lithium batteries and electrical components.