How to Trickle Charge an RV Battery: A Comprehensive Guide

Trickle charging an RV battery is a crucial task to maintain its optimal performance and extend its lifespan. This comprehensive guide will provide you with the necessary technical details and step-by-step instructions to effectively trickle charge your RV battery.

Understanding Trickle Charging

Trickle charging is a method of providing a slow, continuous charge to a battery to maintain its full charge without causing any damage. The charging rate should be around 10% of the battery’s capacity, which helps to prevent overcharging and ensures the battery remains in a healthy state.

Determining Battery Capacity

how to trickle charge an rv battery

The first step in trickle charging an RV battery is to determine its capacity in amp-hours (Ah). This information is typically provided by the battery manufacturer or can be found in the RV’s documentation. For example, a common 12-volt RV battery may have a capacity of 100 Ah.

Calculating the Trickle Charge Rate

Once you know the battery’s capacity, you can calculate the appropriate trickle charge rate. As mentioned earlier, the trickle charge rate should be around 10% of the battery’s capacity. For a 100 Ah battery, the trickle charge rate should be approximately 10 amps (100 Ah x 0.1 = 10 amps).

Selecting a Trickle Charger

When choosing a trickle charger for your RV battery, it’s essential to select one that can provide the appropriate charging rate. Look for a charger that can deliver a constant current of around 10 amps or less, depending on your battery’s capacity. Some popular trickle charger options include:

Charger Model Charging Rate Battery Capacity
NOCO Genius1 1 amp Up to 30 Ah
Battery Tender Junior 0.75 amp Up to 12 Ah
Schumacher SP1-2 1.5 amp Up to 45 Ah

Connecting the Trickle Charger

  1. Ensure the RV is parked in a well-ventilated area, as batteries can produce flammable hydrogen gas during charging.
  2. Locate the battery terminals, typically located in the RV’s battery compartment or under the hood.
  3. Connect the positive (red) clamp of the trickle charger to the positive (+) terminal of the battery.
  4. Connect the negative (black) clamp of the trickle charger to the negative (-) terminal of the battery.
  5. Plug the trickle charger into a suitable power source, such as a 120V AC outlet.

Monitoring the Charging Process

During the trickle charging process, it’s essential to monitor the battery’s terminal voltage regularly. A fully charged 12-volt RV battery should have a terminal voltage of around 12.6 to 12.8 volts. If the voltage remains below 12.6 volts, the battery may not be holding a full charge, and you may need to adjust the charging rate or consider replacing the battery.

Calculating Recharge Time with a Generator

If you need to recharge an RV battery using a generator, you’ll need to consider the generator’s output power (in watts), the battery’s capacity (in amp-hours), and the battery’s voltage. For example, if the generator produces 100 watts and the battery has a capacity of 100 Ah at 12 volts, it would take approximately 20 hours to fully recharge the battery (100 watts / 12 volts = 8.33 amps; 100 Ah / 8.33 amps = 20 hours).


Trickle charging an RV battery is a straightforward process that requires careful attention to the battery’s capacity, the charging rate, and the monitoring of the charging process. By following the steps outlined in this comprehensive guide, you can ensure your RV battery remains in optimal condition and ready for your next adventure.


  1. Charging RV Battery with External Charger – Forest River Forums
  2. How to Effectively Charge RV Batteries While Driving – YouTube
  3. How do you trickle charge the RV batteries? – Page 2 – iRV2 Forums