50 Amp RV Inverter Charger Replacement: Complete Installation Guide 20

The Rundown

The Magnum MS2812 has a 50A transfer switch rating, which limits it to 30-amp shore power connections, not 50-amp. The unit provides 2800W inverter output with 120A charging capability. Your Tradewinds was likely rated similarly - most inverter/chargers use 30-amp breakers internally while handling 50-amp shore connections just fine. The unit will draw what it needs for charging and pass the rest through to your RV's electrical panel.

However, that 2014 manufacturing date is concerning. At 11+ years old, you're looking at a unit that's already past its typical 8-10 year lifespan, even with light use. For $700 plus $300 for the remote compatibility fix, you're paying $1,000 for an aging unit when modern 30-amp alternatives start around $600-800. Unless you absolutely need 125A charging capacity for large battery banks, this deal isn't as attractive as it initially seems.

Why It Happens

Your 20-year-old Tradewinds inverter failed because that's simply what happens to power electronics after two decades of thermal cycling, capacitor aging, and component stress. Inverter/chargers contain complex switching circuits, transformers, and electrolytic capacitors that degrade over time regardless of usage patterns. The power conversion components are particularly susceptible to failure as they handle the constant switching between AC and DC power.

The shop's offer reflects a common scenario - they have spare equipment that works but isn't necessarily the best solution for your specific needs. The Magnum MS2812 is a quality unit, but age matters significantly with power electronics. Components like cooling fans, relays, and especially electrolytic capacitors have finite lifespans that don't reset just because a unit wasn't used heavily.

The confusion about amp ratings is typical in RV electrical systems. Shore power capacity (30A or 50A) refers to what you can draw from the campground pedestal, while the inverter/charger's input rating refers to how much current the charging circuit can safely handle. These are related but different specifications that often confuse RV owners when shopping for replacements.

Gather These Items

Before making any decisions, you'll need to assess your actual power requirements and available alternatives. Start by measuring your current battery bank capacity and typical charging needs. Check if your batteries are lead-acid, AGM, or lithium, as this affects charger requirements. Document your existing electrical connections, including the DC output cable size and AC input wiring configuration.

Research modern alternatives like the Victron MultiPlus 12/3000/120 (with 120A charging), AIMS Power 3000W, or Go Power! GP-3000HD. These units typically cost $800-1,200 new and include modern features like programmable charging profiles, better efficiency, and smartphone connectivity. Compare their charging rates to your battery bank size - many RVers find 30-amp charging perfectly adequate for typical usage patterns.

Get quotes for complete installation from multiple shops, not just equipment prices. Factor in any necessary electrical updates, mounting modifications, and the cost of compatible monitoring systems. Many newer units include built-in displays or smartphone apps that eliminate the need for separate remote monitors.

Consider the total cost of ownership including warranty coverage. A new unit with a 2-3 year warranty versus an 11-year-old used unit with no warranty represents significantly different risk profiles for a critical RV system.

The Fix

For your specific situation, I'd recommend skipping the used Magnum and investing in a new 30-amp unit unless you have compelling reasons for 50-amp charging capacity. Most RV battery banks charge adequately with 30-amp chargers, and the reliability and warranty coverage of new equipment outweigh the modest cost savings of used gear.

If you decide 50-amp charging is essential, look at the Magnum MS2812 new (around $1,800-2,000), Victron MultiPlus-II 12/3000/120-50 (around $1,500), or the Xantrex Freedom XC 2000 (around $1,400). These provide current technology, full warranties, and proven reliability for high-capacity charging applications.

For installation, ensure your DC connections can handle the new unit's output current and that AC wiring meets current codes. Most inverter/chargers require 4 AWG DC cables for safe operation (check manufacturer specifications for exact requirements). Plan for adequate ventilation and accessibility for future maintenance. If keeping your existing remote display is important, factor compatibility into your selection process.

Consider timing your purchase around RV show seasons or end-of-year sales when dealers often discount inventory. Some manufacturers offer rebates or trade-in programs that can reduce your total investment in new equipment.

Know Your Limits

Installing inverter/chargers involves high-current DC connections and AC electrical work that can be dangerous if done incorrectly. DC short circuits can cause fires or explosions, while improper AC connections create electrocution risks. If you're not experienced with electrical work, hire a qualified RV technician for installation and system testing.

Be honest about your actual power needs versus wants. Many RVers overestimate their charging requirements and end up paying premium prices for capacity they never use. A properly sized 30-amp charger often provides better value and reliability than an oversized 50-amp unit, especially considering the significant price difference.

Don't rush into the first offer, even from a trusted shop. Get multiple quotes and consider online retailers for equipment purchases while using local technicians for installation. The RV power system market has evolved significantly with new manufacturers offering competitive alternatives to established brands like Magnum and Xantrex.