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Yikes! Replacing the Corroded Battery Lugs of an RV’s House Batteries

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Recently, I replaced the house batteries on a Class C motorhome. What would normally be a routine maintenance item turned into a miniature masterclass on RV battery maintenance. Here is the Spark Notes version:

My customer wanted to upgrade his flooded RV/marine lead-acid batteries to modern AGM deep-cycle batteries. He’d be the first to admit that he’d neglected his old house batteries, and as you can see in the pictures below, the batteries were certainly showing their age. Like many RVers, he usually camped while connected to shore power, so the house batteries were rarely taxed except during transit.

Heavy corrosion on an RV house battery terminal

What Causes RV Battery Lug Corrosion?

It’s a common misconception that the white-green powdery or flaky stuff on the battery terminals is just normal corrosion. That’s not exactly true. When copper oxidizes in the atmosphere, it forms a protective greenish patina (think of the Statue of Liberty). But that powdery stuff is actually some blend of other oxidative compounds like copper sulfate, and it’s formed when the copper reacts with escaping hydrogen gas or leaking sulfuric acid from the batteries. Translation: The copper gets actually eaten away. 

One response to “Yikes! Replacing the Corroded Battery Lugs of an RV’s House Batteries”

  1. tirod3

    Imagine you are a counterman at an auto parts house installing batteries in customer cars. I saw this weekly, peaking in early winter and again in spring. No maintenance. As a AAA wrecker guy as a 20 year old, same thing, just rubber cases back then, and we often scraped off the black oxide on the post and it would crank up on it’s own.

    I would try to gently suggest that modern maintenance free batteries didn’t mean the terminals. I also found that Optimas were much worse about it, had to clean mine every 30-60 days the few months I had one. Sold it fast and went back to normal ones.

    A lead on that terminal crimper, I found what looked like a whackamole apparatus sold on Amazon, the instructions said use a C clamp or other high pressure device, no hammering. I then found a video online and yep, hammering won’t do it. Kept it tho as a bench vice will clamp them down tight. Saved the cost of a hydraulic unit. That video suggested a properly crimped terminal will have at least 1200 pounds of pullout, when cross sectioned there were no voids or gaps, solid copper. I don’t know of any bolt on battery clamp that can do that. Learned something new.

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