How To Maintain & Equalize RV Batteries

TheRVgeeks Annual Maintenance, Electrical, Maintenance, Miscellaneous 4 Comments

We demonstrate how to properly service, maintain and equalize the 6-volt deep-cycle golf cart batteries in an RV.

The “house” batteries are one of the most misunderstood systems on any RV. The proper care and maintenance of your battery bank will help it perform better and last longer.

Flooded, lead-acid batteries are the most common type of battery used in an RV. Keeping them clean and the water level correct should be part of your routine maintenance.

During the normal operating process, the batteries discharge and re-charge over and over again. This can cause sulfation, which is the process of sulfates in the electrolyte (acid) coming out of suspension (suspended in the liquid electrolyte) and attaching to the lead plates instead.

Equalizing the batteries solves this problem by “boiling” the batteries at higher voltage to break the sulfate loose from the lead plates, and putting it back into suspension, where it belongs.


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Comments 4

  1. Hey guys!

    I’m a regular purveyor of your website and YouTube videos. My wife and I are on month 6 of our fulltime lifestyle, and I’m taking a bit of time to catch up on all of the projects I need to stay on top of. I have 1120w of solar panels and 8 Crown 6v 240ah batteries wired series/parallel. I have a watering system on the batteries that I use to top them off every 2 weeks or so. How often should I check with a hydrometer and equalize my batteries? Right now, I’m not a heavy user of solar, as we are in an RV park, and will be for the next 9 months; but we have lots of boondocking planned for next summer as we follow some of the places that you, Technomadia and Wheeling It have written about. Thanks for what you do, and I’ll keep following your exploits.

    1. Post
      Author

      Hi David! Thanks for the note, and congratulations on becoming full-timers! You’ve got a sweet battery/solar setup. We’re jealous of those numbers. ;-)

      In general, being hooked up with the batteries trickle-charging, and a watering system, you’re as close as possible to a hands-off situation. When not discharging/re-charging, like during a boondocking period, the batteries sulfate less, and use less water. We’d recommend checking the battery condition visually on a monthly basis, especially if they’re prone to building up corrosion.

      If you take hydrometer readings, you’ll likely find that the specific gravity does not go down much, if at all, due to less sulfation occurring during continuous float charging. The way you know it’s time to equalize is when the specific gravity of the batteries (at rest) won’t reach 1.278, even when fully charged.

      Note: Make sure the batteries are “at rest” prior to taking any hydrometer readings. To do that, be sure to turn off shore power and solar panel inputs, and put the batteries in “store” mode, making sure no power is coming into or out of them. Let them sit like that for a little while (maybe an hour) and your batteries are now “at rest” and ready for accurate hydrometer readings.

      If they’ve been siting on float charge for a day or more (so you know they’re full), and have now been resting for an hour or so, every cell’s specific gravity should be at about 1.278. If you check your readings after sitting for one month, and they read at or near 1.278, they’re probably good to sit that way for 6 months without any more attention that making sure they stay on charge and stay watered (always above the top of the plates, but never above the bottom of the filler tube).

      It’s when the at-rest readings on one or more cells cannot rise to 1.278, even when fully charged, that equalizing needs to happen. When we had lead-acid batteries years ago (we replaced them with AGMs about 5 years ago, and highly recommend that next time you need batteries), we would sit for three months fully hooked up some winters, and never need to equalize. As soon as we’d go back to dry camping, with its cycle of draining/charging/draining/charging over and over again, that’s when equalizing was needed. Since you have such a large solar setup, your batteries may need very little equalizing… maybe only once every six months or a year. But generally, don’t do it unless the hydrometer readings are low, since excessive, unnecessary equalizing can shorten battery life.

      We’d suggest that you consider this…. a few days before you’re about to hit the road again, equalize once, even if you haven’t seen low hydrometer readings. Then you’ll start your dry camping season with the least amount of sulfation possible, giving you the best performance available from your batteries.

      Hope this helps. Safe Travels!

        1. Post
          Author

          Hey Brad. Sorry about that… we tend to blur those two (since they’re so close). We meant a specific gravity of 1.278 (which, ironically, tends to correlate to a battery-at-rest voltage of about 12.8V… or 12.78V if you have a REALLY accurate voltmeter, LOL!).

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