Choosing the Right Converter or Charger

What size converter or battery charger do I need?

The correct converter or charger size depends on your battery bank, electrical load demands, and application.

Recommended Sizing

• 35A–55A
• Small RVs
• Single battery systems
• Basic 12V applications
• 55A–75A
• Standard RV setups
• Multiple battery configurations
• Light shop or service applications
• 75A–100A+
• Lithium battery systems
• Large battery banks
• Off-grid applications
• Automotive dealerships and service departments
• ECU flashing and ADAS calibration environments

For automotive applications such as ECU programming, diagnostics, and ADAS calibration, higher amperage output (75A–100A+) helps maintain stable voltage during heavy electrical loads and prevents voltage drops that can interrupt service procedures.

What’s the difference between a converter, inverter, and battery charger?

Converter

Converts 120V AC power → 12V DC power while also charging batteries.

Inverter

Converts 12V DC battery power → 120V AC power for household-style appliances.

Battery Charger

Designed primarily to charge and maintain batteries. Some advanced chargers also provide regulated power supply functionality.

PowerMax Converters products combine:

• Converter functionality
• Smart battery charging
• Regulated DC power supply capability
• Adjustable voltage control

This makes them suitable for RV, marine, off-grid, and automotive service applications.

Can I replace my WFCO or Progressive Dynamics converter with PowerMax?

Yes. PowerMax converters are commonly used as direct replacements for many:

• WFCO 8900 Series
• WFCO 9800 Series
• Progressive Dynamics converter models

In most installations:

• The mounting footprint is similar
• Minimal or no rewiring is required
• Existing DC fuse panels remain compatible

Benefits of upgrading to PowerMax include:

• Adjustable voltage output
• Improved lithium charging performance
• Faster charging capability
• Better charging control versus auto-detect systems
• More stable output for sensitive electronics

Is PowerMax compatible with my RV or vehicle?

Yes. PowerMax products are compatible with:

• RV electrical systems
• Automotive service departments
• Marine applications
• Off-grid power systems
• Lithium and lead-acid battery setups

Adjustable voltage output allows fine tuning for:

• LiFePO4 batteries
• AGM batteries
• Flooded lead-acid batteries
• Deep-cycle batteries
• Specialized service applications

Lithium Battery Charging

Do I need a special converter for lithium batteries (LiFePO4)?

Yes. Lithium batteries require precise voltage control and stable charging output.

PowerMax lithium-compatible converters support:

• Adjustable voltage (13.0V–16.5V)
• Stable low-ripple DC output
• Efficient lithium charging
• Long-term battery maintenance
• Re-bulk charging capability

Unlike many fixed-voltage chargers, PowerMax units allow users to manually set charging voltage based on the battery manufacturer’s specifications.

What voltage should I use for lithium batteries?

Typical LiFePO4 charging voltage ranges are:

Bulk / Absorption Charging

• Approximately 14.2V–14.6V

Float / Maintenance Voltage

• Approximately 13.4V–13.8V

These settings may vary slightly depending on the battery manufacturer.

PowerMax adjustable converters allow users to:

• Optimize charging performance
• Match battery manufacturer requirements
• Improve charging speed
• Maintain batteries safely during storage
• Extend overall battery lifespan

Is adjustable voltage better than auto-detect lithium charging?

Yes. Adjustable voltage provides significantly greater control and flexibility than automatic battery detection systems.

Advantages of Adjustable Voltage

• Precise charging control
• Better compatibility across battery brands
• Improved charging performance
• Greater flexibility for RV, marine, automotive, and off-grid systems
• Ability to fine-tune voltage for specific lithium chemistries

Limitations of Auto-Detect Charging Systems

Some competitor systems rely on automatic battery detection, which can:

• Misidentify battery chemistry
• Fail to properly enter boost mode
• Limit charging performance
• Undercharge lithium batteries
• Create inconsistent charging behavior

PowerMax converters also feature re-bulk charging capability.

If a lithium battery’s internal Battery Management System (BMS) disconnects due to low voltage and later reconnects, the converter can automatically resume charging. Some competing converters may not recover properly after a BMS disconnect event.

Can I leave a lithium battery connected to a charger full-time?

Yes — if the charger supports proper voltage regulation and float maintenance.

PowerMax converters can be adjusted to safe maintenance voltage levels to help:

• Prevent overcharging
• Reduce battery stress
• Maintain battery health
• Keep systems ready for use

After the battery reaches the proper charge state, the converter transitions into a lower float/maintenance stage rather than continuously applying higher bulk charging voltage.