Compact 110VAC to 12VDC converter with 3-stage smart charging. Compatible with Lithium, AGM, and Lead Acid batteries. 650W continuous output.
The PowerMax PM3-45A is a compact AC to DC converter and battery charger that converts 110VAC shore power or grid power into clean, regulated 12VDC power for charging batteries and powering 12-volt equipment. With a solid 45-amp continuous output (650 watts), this converter provides reliable performance for smaller battery banks while simultaneously powering all your 12V devices.
Featuring advanced 3-stage smart charging technology, the PM3-45A automatically adjusts its charging profile to match your battery's needs: bulk charging at 14.6V for rapid recharge, normal charging at 13.6V for safe completion, and float charging at 13.2V for long-term maintenance. The unit also offers a fixed voltage mode with adjustable output from 13.0V to 16.5V, making it compatible with ALL battery types including LiFePO4 lithium, AGM, gel cell, and traditional lead acid batteries.
As a direct replacement for WFCO WF-9845 converters, the PM3-45A installs easily in RVs, boats, off-grid solar systems, automotive applications, and anywhere reliable 12V power is needed. Its efficient switch-mode design delivers over 85% efficiency with minimal heat generation, while built-in protection against reverse polarity, overload, and thermal issues ensures safe, reliable operation for years to come.
650W continuous power - charges 90Ah battery in 2 hours, 180Ah bank in 4 hours
Automatic charging profile: 14.6V Bulk, 13.6V Normal, 13.2V Float for optimal battery health
Fixed mode with 13.0V-16.5V adjustment - perfect for lithium batteries and custom applications
Works with Lithium LiFePO4, AGM, Gel Cell, Flooded Lead Acid - all battery types supported
Stage 1 - Bulk Charging (14.6V): When your battery is depleted (below 80% state of charge), the PM3-45A delivers maximum current at 14.6 volts to rapidly restore capacity. This "boost" mode brings batteries back to life quickly after heavy discharge. The converter stays in bulk mode as long as the battery can accept the full 45 amps. Stage 2 - Normal Charging (13.6V): Once the battery reaches approximately 80% charge and can no longer accept full current, voltage drops to 13.6V for safe, controlled charging to 100% capacity. This absorption phase ensures batteries are fully charged without overcharging damage. The PM3-45A simultaneously powers all your 12V devices during this stage. Stage 3 - Float/Storage (13.2V): After batteries reach full charge, the converter automatically switches to 13.2V float mode to maintain charge without overcharging. This trickle charge keeps batteries fresh during storage or light use, preventing sulfation and extending battery life. Perfect for RVs plugged in at home between trips. Automatic Mode Switching: The PM3-45A constantly monitors battery voltage and load conditions, automatically transitioning between charging stages as needed. When you turn on appliances that draw power, the converter instantly provides current while adjusting the charging profile. This intelligent system works 24/7 with zero user intervention required.
Small RVs & Pop-Up Campers: Direct replacement for WFCO WF-9845 converters. Powers all 12V lighting, water pumps, awnings, and electronics while charging house battery banks. Perfect for pop-up campers, small travel trailers, and truck campers with 90-180Ah battery capacity. Weekend Boating: Charges marine batteries when connected to shore power at the marina. Powers 12V electronics, navigation equipment, bilge pumps, and cabin lighting while keeping batteries topped off for weekend adventures. Off-Grid Cabins: Converts AC power from small generators into clean 12VDC for battery charging. Works alongside solar charge controllers for faster battery recovery during low-sun periods. Automotive & Emergency Vehicles: Powers emergency vehicle equipment, mobile workshops, and car audio systems. Fast charging between uses means less downtime and more performance. Backup Power Systems: Maintains small battery banks for backup power systems, communications equipment, and critical infrastructure. Float mode keeps batteries ready for instant use during power outages. LiFePO4 Lithium Battery Systems: Adjustable voltage mode (13.0V-16.5V) allows precise matching to lithium battery specifications. Set to 14.4V or 14.6V for optimal lithium charging without battery management system conflict. Telecommunications & Remote Sites: Reliable power for radio equipment, cellular sites, internet equipment, and remote monitoring systems. Converts generator power into clean DC for sensitive electronics.
Certified Electrician Installation Required • Professional Installation Mandatory: All PowerMax converters must be installed by a certified electrician per NEC code requirements. • Ventilation Critical: Minimum 1" free air space required at each end for proper cooling. Do NOT install in zero-clearance compartments. • AC Circuit Requirements: Connect to dedicated 15-amp 120VAC circuit within 36" of converter. Do NOT share circuit with high-draw appliances. • Wire Sizing: Use minimum 8 AWG copper wire for DC output connections. Larger wire recommended for long runs to minimize voltage drop. • Battery Disconnect: ALWAYS disconnect battery positive (+) terminal BEFORE connecting converter to prevent sparks and reversed polarity damage. • Never in Flammable Storage: DO NOT install in compartments containing batteries, gasoline, propane, or other flammable materials. • Proper Grounding: Connect 8 AWG ground wire from chassis to converter bonding lug for safety and code compliance. • Terminal Torque: Tighten all DC connections securely - loose connections cause overheating and fire risk.
In The Box: • PM3-45A Converter/Charger Unit • Built-in 36" AC Power Cord • Chassis Bonding Lug (Pre-installed) • Mounting Flanges with Holes • Reversed-Battery Fuses (Internal) • Owner's Manual with Wiring Diagrams • Warranty Documentation NOT Included (Required for Installation): • 8 AWG or larger DC wiring • Wire terminals/lugs for DC connections • Mounting screws/bolts • 8 AWG chassis ground wire • Professional electrician installation service
Compare the PM3-45A with other models in the PM3 Series to find the right converter for your power requirements.
Estimated time to charge from 50% to 100% state of charge (bulk + absorption phases). Actual times vary based on battery type, temperature, and condition.
Note: Charging times assume battery can accept full 45A charge rate. Absorption phase may take additional 30-60 minutes to reach 100% capacity. Lithium batteries typically charge faster than lead acid due to higher charge acceptance rates.
Why the PM3-45A is Perfect for Lithium: The PowerMax PM3-45A offers adjustable voltage output (13.0V-16.5V) that allows precise matching to your lithium battery manufacturer's specifications. Most LiFePO4 batteries charge optimally at 14.4V to 14.6V, and the PM3-45A can deliver exactly that voltage continuously. The 45-amp output is ideal for lithium banks from 90Ah to 180Ah, providing safe charge rates without overwhelming the battery management system. Setting Fixed Voltage Mode for Lithium: 1. With the converter unplugged, locate the two switches on the side of the unit 2. Move Switch A (right) to "Fixed Voltage" position 3. Plug the converter into 120VAC power 4. Using a voltmeter on the DC output terminals, adjust Switch B (up/down dial) until you reach your desired voltage 5. Common lithium settings: 14.4V (most conservative), 14.6V (faster charging), or per your battery manufacturer's specs 6. Once set, the converter will maintain this exact voltage every time it's powered on Important Lithium Considerations: • Consult your battery manufacturer's charging specifications before setting voltage • Battle Born recommends 14.4V | RELiON recommends 14.6V | Lithionics recommends 14.4V • Ensure your lithium battery has a proper Battery Management System (BMS) that will disconnect charging if cells become imbalanced • The PM3-45A's 45-amp output is safe for most lithium banks 90Ah and larger (0.5C charge rate or less) • Lithium batteries charge much faster than lead acid - expect 50% faster charging times • Monitor first few charge cycles to ensure battery BMS and converter work together properly Returning to 3-Stage Mode: To switch back to standard 3-stage lead acid charging, power down the unit, move Switch A back to "Three Stage" position, power up, and use Switch B to adjust voltage to 14.6V with a voltmeter.
Product Documentation: Download PM3 Series Owner's Manual (PDF) Download PM3 Series Specification Sheet (PDF) Lithium Battery Resources: Using PowerMax with Battle Born Batteries (External Link) Warranty Information: 2-Year Limited Manufacturer's Warranty Covers defects in materials and workmanship under normal use No forms required - call tech support for rapid replacement Replacement unit shipped promptly upon defect confirmation Return shipping arranged for defective unit Company Website: www.powermaxconverters.com PowerMax Converters 5107 Lena Road, Suite 108 Bradenton, FL 34211
A: Yes, the PM3-45A is perfectly sized for pop-up campers and small travel trailers, and is actually the ideal choice for these applications. Here's why it's well-matched: Typical Pop-Up/Small Trailer Power Requirements: Small RVs typically have 90-150Ah of battery capacity and run these 12V loads: LED lighting (5-10 amps total), water pump (8-10 amps when running), furnace fan (3-5 amps), USB chargers and small electronics (3-5 amps), awning motor (12-15 amps for 30 seconds). Total continuous loads are typically 15-25 amps, with brief spikes to 40 amps when pumps or motors activate. PM3-45A Performance: The converter delivers 45 amps continuously, which comfortably handles these loads while charging batteries at 20-30 amps simultaneously. After a weekend of camping that drains batteries to 50%, the PM3-45A can fully recharge a 100Ah battery bank in about 2 hours while powering all your lights and appliances. Why not upgrade to 55A or 65A? For small RVs, the PM3-45A offers the best value. The extra capacity of larger converters won't be utilized in typical use, so you'd be spending more money for power you don't need. The PM3-45A requires only 9 amps AC input (vs 11A for the PM3-55A), leaving more headroom on your RV's 30-amp service for other appliances. When to consider upgrading: Only upgrade to the PM3-55A if: (1) You have 200Ah+ of batteries and want faster charging, (2) You frequently run multiple high-draw devices simultaneously, (3) You have a larger trailer (25+ feet) with more electrical loads. Real-world feedback: Pop-up camper and small trailer owners report excellent performance with the PM3-45A. It's the right-sized converter that delivers reliable power without being overkill for the application.
A: The PM3-45A is a direct drop-in replacement for the WFCO WF-9845 with several meaningful improvements that justify the upgrade. Both are 45-amp converters with the same physical footprint, but the PowerMax offers: (1) Adjustable voltage for lithium compatibility - The PM3-45A has a fixed voltage mode (13.0V-16.5V adjustable) that allows proper charging of LiFePO4 lithium batteries. The WFCO WF-9845 is designed only for lead acid batteries and cannot properly charge lithium. If you upgrade to lithium batteries (increasingly common in small RVs), the PM3-45A is essential. (2) True 3-stage smart charging - More sophisticated charging algorithm (Bulk/Normal/Float at 14.6V/13.6V/13.2V) compared to WFCO's basic charging profile. This extends battery life significantly by preventing overcharging and sulfation. (3) Quieter operation - Temperature-controlled proportional fan adjusts speed based on load and heat. Runs very quietly during typical light use, full speed only under heavy loads. WFCO fans often run at constant speed which can be annoying in small RVs. (4) Better long-term reliability - PowerMax converters have an excellent reputation for lasting 10+ years with minimal issues. WFCO converters, while adequate, have more frequent failure reports. (5) Same installation footprint - The PM3-45A uses identical mounting holes and wire connections as the WF-9845. Installation takes 30-60 minutes and many RV owners do it themselves. Bottom line: If your WFCO WF-9845 still works, the upgrade is optional but recommended for lithium compatibility and quieter operation. If it's failed, the PM3-45A is the superior replacement that will outlast and outperform the original WFCO unit.
A: Yes, absolutely - the PM3-45A works excellently with a single 100Ah Battle Born battery, and this pairing is very common in small RV lithium upgrades. Here's why it's ideal: Charge Rate Considerations: A 45-amp converter charging a 100Ah battery provides a 0.45C charge rate (45A ÷ 100Ah = 0.45C). Battle Born batteries can safely accept up to 100 amps (1.0C) continuously, so the PM3-45A's 45-amp output is well within safe limits - in fact, it's conservative. Your 100Ah Battle Born battery can easily handle the full 45-amp output without any stress on the battery management system. Real-world performance: Starting from 50% state of charge (50Ah depleted), a 100Ah Battle Born battery charges to 100% in approximately 1 hour 10 minutes with the PM3-45A. This is dramatically faster than the 4-6 hours typical with lead acid batteries of similar capacity. After a day of boondocking, plug in during lunch or while doing errands, and your battery is fully recharged by the time you're ready to leave. Voltage Setting: Battle Born recommends 14.4V for charging. Set the PM3-45A's fixed voltage mode to exactly 14.4V using the adjustment procedure in the manual. At this voltage, the converter delivers constant current charging while the Battle Born BMS manages cell balancing and charge termination. You'll never risk overcharging. System Flexibility: If you later add a second 100Ah Battle Born battery (200Ah total), the PM3-45A is still appropriate, providing a conservative 0.225C charge rate that maximizes battery lifespan. The 45-amp output is the sweet spot for 100-200Ah lithium systems - powerful enough for reasonable charging times, but not so powerful that you're paying for capacity you don't need.
A: Yes, absolutely - this is exactly what the PM3-45A is designed to do. Running loads and charging batteries simultaneously is the primary function of RV converters. Here's how it works in practice: Power Distribution: The PM3-45A delivers 45 amps total output, which is automatically distributed between (1) powering your 12V loads and (2) charging your batteries. The converter prioritizes loads first, then uses remaining capacity for charging. Typical RV Scenario: Let's say you're using: Interior LED lights (8 amps), Water pump running (10 amps), Furnace fan (4 amps), Phone chargers (2 amps). Total loads = 24 amps. The PM3-45A delivers: 45 amps total - 24 amps to loads = 21 amps remaining for battery charging. Your batteries receive 21 amps of charging current while all devices operate normally. When the water pump cycles off, charging current automatically increases to 31 amps (45 - 14 = 31). This dynamic adjustment happens instantly and automatically. Peak Load Handling: When high-draw devices briefly activate (water pump startup = 15 amps, awning motor = 15 amps), the converter can momentarily reduce or pause battery charging to ensure loads receive priority. Your devices never experience brownouts or voltage drops. If total load briefly exceeds 45 amps, the battery supplements power for a few seconds without any noticeable effect. Benefits of this design: You never need to choose between "charging mode" and "use mode" - the PM3-45A does both simultaneously. This is standard converter operation and works flawlessly in pop-up campers and small RVs. The 45-amp capacity provides plenty of headroom for typical small RV loads (20-30 amps) while maintaining 15-25 amps of charging current.
A: This is an important distinction - the PM3-45A is fundamentally different from a standard battery charger, and understanding the difference explains why RVs use converters rather than chargers. Battery Charger Limitations: A standard battery charger: (1) Only charges batteries - cannot power 12V loads simultaneously, (2) Must be disconnected before using battery power to run devices, (3) Typically lacks proper voltage regulation for powering sensitive electronics, (4) Not designed for continuous operation (most are designed for intermittent use). If you tried using a standard 45-amp battery charger in an RV, you'd need to: unplug the charger every time you wanted to use 12V devices, plug it back in to recharge, repeat constantly. This is completely impractical for RV living. PM3-45A Converter Advantages: The PM3-45A is a power supply AND battery charger: (1) Provides continuous clean 12VDC power for all devices whether batteries are present or not, (2) Charges batteries while simultaneously powering loads - never needs to be disconnected, (3) Delivers rock-solid voltage regulation (±0.2V) for sensitive electronics, (4) Designed for 24/7 operation - can run continuously for years without issues, (5) Acts as a buffer between shore power and your electrical system, protecting devices from AC power fluctuations. Real-world use: When you plug your RV into shore power, the PM3-45A instantly takes over as your primary 12V power source. Batteries serve as backup for brief power interruptions and provide power when you disconnect from shore power. This seamless operation is why every RV has a converter rather than a simple battery charger. Think of it this way: A battery charger is like a gas station - you visit occasionally to refuel. A converter is like having an onboard generator - it provides continuous power plus keeps batteries topped off as a bonus.
A: The decision between the PM3-45A and PM3-35A depends on your specific battery size and load requirements, but for most small RVs, the PM3-45A is the better investment. Here's the analysis: Choose PM3-35A only if: (1) Your battery bank is very small (70-100Ah) and you want the absolute lowest-cost option, (2) Your 12V loads are minimal (10-20 amps maximum) - basically just LED lights and occasional water pump use, (3) You're in a teardrop trailer, van conversion, or very small camping setup where every penny counts. Choose PM3-45A (recommended) if: (1) Your battery bank is 90-180Ah - the 45A provides ideal charging rates without overwhelming batteries, (2) Your typical loads are 15-30 amps - this is standard for pop-up campers and small travel trailers, (3) You want reasonable charging times - the 45A charges batteries 30% faster than the 35A, (4) You want headroom for future upgrades - if you add another battery, upgrade to lithium, or install additional 12V devices, the PM3-45A won't become inadequate. Cost vs Performance: The PM3-45A typically costs only $15-25 more than the PM3-35A. For this modest price difference, you get: 10 more amps of output (28% more power), faster battery charging (30% reduction in charge times), more headroom for simultaneous loads and charging, better long-term value if your electrical needs grow. Real-world perspective: Most people who buy the PM3-35A later wish they'd spent the extra $20 for the PM3-45A when they realize their loads occasionally push the 35A to its limit. The PM3-45A provides enough extra capacity to never feel constrained, while still being appropriately sized for small RVs. Unless budget is extremely tight, the PM3-45A is the smarter choice that you won't outgrow.