RV Straight Talk with Jeff Johnston​


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Q: “We’ve read some about using a smart battery charger to help the battery last longer so we’re wondering if that’s true, and for that matter, what is a smart charger? Wouldn’t our RV already have one? – Dawane Jones.”

A: If your trailer’s converter has a standard “non-smart” charger, it produces, for example, about 14.2 volts at full amperage to charge the trailer battery. That’s the charging current regardless of the battery’s state of charge, from almost full to fully depleted. If the charger keeps pumping that juice into a fully-charged battery it leads to overcharging, plate sulfation, boiling out the battery water and permanent damage. A smart charger has variable charging currents depending on the battery needs. These charging levels are known as bulk, absorption and float. Bulk is the strongest and helps a deeply-discharged battery get back to fully charged, and at the top end, float is like a trickle charge that’s just enough to keep a full-charged battery up to snuff without damaging it. The charger automatically senses the battery state of charge and applies the best current level as appropriate, thus, the “smart charger” name.

You can determine what kind of charger you have, which is an integral part of your converter, by checking the converter manufacturer and model data on the manufacturer’s website. Replacing an older style converter with a new smart model is always a good investment in keeping your battery in good shape. – JJ