RC7-GS Inverter AGM Battery Settings: Complete Setup Guide

The Quick Answer

For your AGM batteries totaling 210Ah capacity (assuming two batteries of approximately 105Ah each), set your RC7-gs charger to the 125Ah setting rather than AUTO. While this is slightly lower than your actual capacity, it will provide appropriate charging current (around 25 amps) and proper voltage profiles for your AGM batteries without overcharging. The AUTO setting's reset behavior when the low voltage cutoff trips makes it unreliable for your setup. Your generator start issue common causes include either incorrect wiring connections to the generator or the AGS (Automatic Generator Start) feature not being properly enabled in the RC7 programming menu.

What's Causing This

The RC7-gs inverter/charger is designed with preset charging profiles based on battery bank capacity ranges, and your 210Ah total capacity falls between the 125Ah and higher settings. The AUTO setting is problematic because it attempts to "learn" your battery characteristics but resets this learned behavior every time the low voltage disconnect activates, which happens regularly in RV use.

Your AGM batteries require a specific charging profile: bulk charge at 14.4-14.6V, absorption at 14.4V, and float at 13.0-13.3V (verify exact specifications with your battery manufacturer). The 125Ah setting will limit maximum charging current to approximately 25 amps, which is well within the acceptable range for your AGM batteries (they can typically handle 0.3-0.4C charging rate, or about 63-84 amps for your setup, though check your specific battery manufacturer's specifications).

Generator start failure common causes include: the AGS feature isn't activated in the RC7 programming, the generator remote start wires aren't properly connected to the RC7's terminal block, or the generator doesn't have the proper remote start capability enabled.

Tools You'll Need

• Digital multimeter for voltage testing
• Screwdriver set for accessing RC7 programming buttons
• Wire strippers and electrical tape
• Generator manual for remote start wiring diagram
• RC7-gs installation and operation manual
• Flashlight or headlamp for working in tight spaces

Step-by-Step Fix

WARNING: Always disconnect AC power and turn off the inverter before accessing wiring connections to prevent electrical shock.

Setting the Correct Charger Capacity:

1. Access the RC7-gs programming menu by holding down the "Setup" button for 3 seconds until you see "SETUP" on the display
2. Navigate to the "CHARGER" menu using the up/down arrows
3. Select "BATT AH" (Battery Amp Hours) setting
4. Set the value to 125 (the closest available setting below your 210Ah capacity)
5. Navigate to "BATT TYPE" and ensure it's set to "AGM" for proper voltage profiles
6. Exit setup by pressing "Setup" button again and confirm settings are saved

Troubleshooting Generator Start Issues:

1. First, verify the AGS function is enabled in the RC7 setup menu under "AGS ENABLE" - set this to "YES"
2. Check the RC7's terminal block connections - you should have two wires from your generator's remote start terminals connected to the AGS terminals on the RC7
3. Consult your generator manual to ensure remote start is enabled (many Onan and Cummins generators have a remote start switch that must be in the "REMOTE" position)
4. Test the generator's remote start independently by temporarily connecting the remote start wires together - if the generator doesn't start, the issue is with the generator, not the RC7
5. Set appropriate AGS parameters in the RC7 menu: start voltage (typically 11.5V), start delay (usually 5-15 minutes), and stop voltage (typically 12.6-12.7V for AGM batteries)

When to Call a Pro

Contact a certified RV technician if the generator still won't respond to remote start commands after verifying all wiring connections and settings. This could indicate internal generator control board issues that require specialized diagnostic equipment. Additionally, if you're uncomfortable working with 120V AC wiring or if the RC7 displays error codes that persist after following these steps, professional diagnosis may be needed.

Consider professional help if you notice the AGM batteries aren't reaching full charge (should read 12.8V+ at rest after charging) or if the charging current seems excessive (over 40 amps). While the 125Ah setting should work fine for your 210Ah bank, improper charging can significantly reduce AGM battery lifespan, and these batteries represent a substantial investment that's worth protecting with proper setup.