RV Solar Battery Charger Tips



The rv solar battery charger is tailored to re-charge correctly any type of RV batteries. A good charger will extend the useful life of your batteries and will keep the batteries in a good shape

12V RV Batteries Basics

Not all RV batteries were created equal, although all are supposed to be deep cycle batteries, there are different types. The types most in use are:

  • Flooded lead acid batteries are either lead calcium maintenance free, or lead antimony (the ones that has caps and to which you need to add water periodically). The maintenance free (sealed) batteries are not really deep cycle batteries and won’t last long after a small number of more than 50% discharge. Lead antimony has higher tolerance for deep discharge; however their self phantom discharge current is larger. Weighing all factors, lead antimony batteries are more suitable for RVs.

  • An improved type, the Gel Cell since the electrolyte won't leak. They are mostly replaced with the AGM battery.

  • AGM (absorbed glass mat) is a flooded lead acid battery, but instead of gel, it uses a fibrous pad soaked in the electrolyte. It is sealed hence maintenance free, and the electrolyte is confined and can’t leak out even under vibrations. The AGM battery, although more expensive is the battery of choice for the RVer.

The Requirements from RV Solar Battery Chargers

A good RV solar battery charger is the one that matches the deep-cycle batteries’ needs. The service life and the performance level of the deep-cycle battery is dependent on correctly and timely re-charging the battery. The charger should match the voltage rating and the current storage capacity of the battery. Smart modern battery chargers are equipped with “smart” settings to fit the battery type (flooded lead acid, gel cell or AGM) and will reduce gradually the charging current as the battery charges up by using their smart battery voltage sensor. Batteries are susceptible to either overcharging or undercharging. Overcharging (charging current too high) causes the electrolyte to bubble and the battery to heat up excessively. Under current (charging current too low) or letting the battery to discharge deeply before re-charging causes the battery to develop lead sulfate on its electrodes.
Keep the following rules to ensure a longer life to your battery.

  • Do not wait for the battery to discharge deeply and don’t leave a battery waiting for re-charge. Re-charge immediately after a one day use.

  • Use a charging current that is 10A to 20A per 100Ah of battery capacity (AGM batteries can tolerate higher charging currents)

  • Keep an eye on the battery during the time it is charged up, watch for overheating

  • Pay a bit more to get that added smartness from your RV solar battery charger. A good solar power battery charger will monitor the battery voltage and maintain the correct current charge, will provide an automatic shut-off capability on elapsed charging time or when the battery is fully charged.

A Solar Battery Charger Is Different than A Solar Battery Maintainer

A solar battery maintainer charges with a trickle current, obviously a much lower current than what is required. It lucks the smartness of the RV battery charger, it employs a simple diode reverse current protection.

The solar panel of the battery charger must be large enough to provide the charge current. 10A at 12V equates to 120 Watts net, in essence you need to look for a battery charger with a solar panel of at least 180 Watts production capability.

Additional Solar Reading

The following pages on my site provide more information on related topics:

  • click here to view a background information on solar panels

  • More RV travelers use AC appliances and therefor need solar inverters to convert from DC to AC. View this page for more information on off-grid pure sine wave inverter


click to view my solar energy Home Page