Lithium Battery Upgrade for 2018 Georgetown RV - Safe?

Cut to the Chase

Max, yes you can absolutely replace your 2018 Georgetown's original flooded lead-acid house batteries with lithium batteries without damaging your converter, inverter, or alternator - but there are some important compatibility checks and potential modifications needed. Since your Georgetown is from 2018, it likely has a WFCO WF-8900 series converter or similar that uses a three-stage charging profile designed for lead-acid batteries. The good news is that most quality 100Ah lithium batteries with built-in Battery Management Systems (BMS) can handle the 14.4V absorption voltage these converters put out, though you'll want to verify your specific converter model and its charging voltages.

Your alternator will also be fine with lithium batteries - the voltage output (typically 13.8-14.4V) falls well within the acceptable range for lithium charging. The main concern with alternators is actually protecting them from the aggressive charging acceptance of lithium batteries, which can draw high current and potentially overheat the alternator during extended driving. However, with just 100-200Ah of lithium capacity, this is rarely an issue unless you're driving with deeply depleted batteries for hours at a time.

The inverter compatibility is straightforward since inverters don't charge batteries - they simply convert 12V DC to 120V AC. Your existing inverter will actually perform better with lithium batteries due to their more stable voltage output under load. The key decision you need to make is whether to go with one 100Ah battery or two, and whether any converter modifications are needed for optimal performance.

The Why Behind It

Your 2018 Georgetown's electrical system was designed during the transition period when RV manufacturers were still primarily installing lead-acid batteries but were beginning to consider lithium compatibility. This works in your favor because most components from this era can handle lithium batteries with minimal or no modifications. The WFCO converters commonly used in Georgetown models during 2018 typically output 13.6V float voltage and 14.4V absorption voltage, which are within the acceptable range for most lithium batteries.

The reason you can make this upgrade safely lies in how modern lithium batteries are designed. Quality lithium batteries like Battle Born, Victron, or Renogy come with sophisticated BMS units that protect against overvoltage, undervoltage, overcurrent, and temperature extremes. When your converter tries to charge at 14.4V, the BMS will accept this voltage during bulk charging and then internally regulate to prevent overcharging. Some BMS units will even communicate back to compatible chargers to reduce voltage when the battery is full.

Your alternator produces a regulated 13.8V to 14.4V output, which is perfect for lithium charging. The main advantage you'll see is that lithium batteries can accept much higher charge rates than lead-acid, meaning your alternator will charge them faster during driving. However, this aggressive charging acceptance is also why some people add alternator protection devices, though with 100-200Ah of capacity, you're unlikely to stress a modern automotive alternator.

The compelling reasons to upgrade include: lithium batteries maintain voltage better under load (your lights won't dim as much), they're about 50% lighter, they can be discharged to 10% or lower State of Charge (SOC) versus 50% for lead-acid, they charge 4-5 times faster, and they'll likely last 10-15 years versus 3-5 for lead-acid. Since you mentioned limited boondocking experience, lithium batteries will give you much more usable capacity for dry camping adventures.

Prep Work

Before purchasing any lithium batteries, you need to identify your exact converter model and check its specifications. In your 2018 Georgetown, look for a metal box typically mounted in a basement compartment or interior cabinet near the electrical panel. The model number should be printed on a label - common models include WFCO WF-8945, WF-8955, or WF-8975. Once you have this information, verify the charging voltages: bulk/absorption voltage should be 14.4V or lower, and float voltage should be around 13.6V for optimal lithium compatibility.

Next, measure your existing battery compartment dimensions carefully. Standard Group 27 lead-acid batteries measure approximately 12.06" L x 6.81" W x 9.00-9.44" H, while most 100Ah lithium batteries are slightly smaller but vary by manufacturer. Battle Born batteries, for example, measure 12.75" L x 6.875" W x 8.9" H, making them nearly identical in size. Document your current battery cable lengths and terminal types - most lithium batteries use the same automotive-style terminals as your current setup.

Check your battery monitoring system if equipped. Some 2018 Georgetowns came with basic battery monitors that may not read lithium battery state-of-charge accurately. Lithium batteries maintain higher voltage throughout their discharge cycle, so voltage-based monitors may show 100% charge when the battery is actually at 50% capacity. Consider whether you'll want to upgrade to a proper battery monitor with a current shunt for accurate lithium monitoring.

Inventory your current charging sources: shore power converter, alternator, solar panels if installed, and generator. Make note of any battery isolation switches or battery combiners in your system. Most 2018 Georgetowns use a simple isolator or combiner to charge house batteries from the alternator, which will work fine with lithium. If you have solar panels, check the solar charge controller specifications - PWM controllers work with lithium but MPPT controllers are preferred for efficiency.

Step by Step

Start by disconnecting shore power and turning off your main battery disconnect switch. Remove the negative cable first from your existing batteries, then the positive cables, clearly labeling each cable's position and destination. Take photos of the wiring configuration before disconnection for reference. If your batteries are held down with brackets or straps, remove these hardware pieces and set them aside - you'll likely reuse them with the new lithium batteries.

Remove the old batteries from the compartment and dispose of them properly at an auto parts store or recycling center. Clean the battery compartment thoroughly and check for any corrosion on cable terminals or mounting hardware. Replace any corroded terminals or clean them with baking soda and water solution. Inspect all battery cables for damage, cracking, or excessive corrosion - replace any questionable cables before installing the new batteries.

Install your new lithium battery or batteries in the compartment, ensuring they're secured with the original hold-down brackets or straps. If installing two batteries, position them to allow adequate ventilation around each unit, even though lithium batteries don't require the same ventilation as lead-acid. Connect the positive cable first, then the negative cable, ensuring tight connections. If installing two batteries, wire them in parallel (positive to positive, negative to negative) to maintain 12V while doubling capacity.

Before reconnecting shore power or starting the engine, turn on your battery disconnect switch and check system voltage with a multimeter - you should read approximately 13.2-13.4V from fully charged lithium batteries. Reconnect shore power and verify that your converter begins charging the batteries. Most lithium batteries will show rapid voltage rise to 14.4V during bulk charging, then the BMS will regulate charging as the battery approaches full capacity.

Test all 12V systems including lights, water pump, furnace fan, and any 12V outlets to ensure proper operation. Run your inverter under load to verify proper operation with the new lithium batteries. verify it's working properly with the new batteries.ng correctly with the new batteries. If you have a generator, start it and confirm the batteries charge properly from the converter during generator operation. Finally, if your Georgetown has solar panels, verify they're charging the batteries appropriately through the solar charge controller.

Beyond Your Garage

After installation, you'll want to recalibrate your battery monitoring system if equipped, or consider installing a proper lithium-compatible monitor. The Victron BMV-712 or similar shunt-based monitors provide accurate state-of-charge readings for lithium batteries, unlike simple voltage meters. These monitors connect between the negative battery terminal and your DC distribution panel, measuring actual current flow in and out of the batteries.

Consider upgrading your converter to a lithium-specific model if you plan extensive boondocking. While your existing converter will work, lithium-specific converters like the Progressive Dynamics PD9100 series with lithium charging wizard or WFCO WF-8900 series with lithium upgrade kit can optimize charging profiles for faster, more complete charging. These upgrades typically cost $150-300 and can reduce lithium charging time by 30-50%.

If you plan to add solar panels in the future, lithium batteries are excellent candidates for solar charging due to their high charge acceptance rates. A 400W solar array can easily charge 200Ah of lithium batteries on a sunny day, versus requiring 600W+ for equivalent lead-acid capacity. The faster charging also means you can harvest more energy during partially cloudy conditions.

Monitor your alternator temperature during the first few extended drives, especially if you're driving with depleted batteries. While unlikely to cause problems, lithium batteries can draw 50-100+ amps from the alternator compared to 20-30 amps for lead-acid. If you notice excessive alternator heat or plan frequent long drives with depleted batteries, consider installing a Battery Protect device or DC-to-DC charger to limit charging current.

Keep your old lead-acid batteries' charging profiles documented for reference. Some RV techs unfamiliar with lithium conversions may try to "fix" charging issues by adjusting converter settings back to lead-acid profiles. Having the original specifications helps avoid unnecessary service calls. Also, consider joining online forums specific to your Georgetown model - other owners who've completed similar upgrades can provide valuable real-world experience and troubleshooting advice.