Thursday, June 20, 2013

Like Horses, Batteries Need To Be Watered Too!

Battery Drawer RIGHT of Main Entry
    Like most everyone, my RV has LEAD ACID batteries to power the stuff inside the "house" portion of the coach. Things like lights, the furnace fan, 12 Volt sockets and the refrigerator control panel (and inside light) all draw from the house battery or batteries. Since my RV is small, I have a limited space to store the batteries. At most I can fit two reasonably sized ones. Since I don't have a giant surplus of stored power (not including my solar charging system!) I always take good care of my batteries. The main maintenance chore is making sure they have the correct amount of water in each cell.

There are a few kinds of batteries installed in RV's these days. Mainly they fall into two categories:

Flooded Lead Acid - These are what I have and most folks have as well, they REQUIRE some maintenance.
Absorbed Glass Mat (AGM) - A pricier and slightly more efficient technology. They require almost no maintenance and cannot usually be "topped off" with water as they are sealed.

There are other technologies that can be used. I am currently (and have been for some time) researching Lithium Iron Phosphate (LiFePo3) batteries. As soon as I can get these at a reasonable price AND they can be charged correctly, I will upgrade.

My Battery Storage Drawer
Bear in mind, there are 2 main types of Lead Acid Batteries: DEEP CYCLE, which is what should be used for your HOUSE batteries and Regular START batteries, these are for your engine and the CHASSIS electrical needs of your RV. The main difference is the thickness of the lead plates inside the case. Thicker is better for house batteries. They allow longer, slow amperage discharges and recharges without damage where START batteries are designed to supply large amperages (current) for very short periods of time, then recharge quickly. Marine/Deep Cycles are a hybrid of the two with slightly thicker plates. I always use "true" deep cycles since I like to have as much power available as I can get.

One Cover Removed
OK, start by turning off your charging system if you can. Just to  make sure the batteries aren't outgassing (or boiling) and to avoid having any acid spray on you. Wearing gloves and protective glasses would be a good idea too! Trust me, it's no fun! You should remove all jewelry and watches since you'll be working near the battery terminals and could get a NASTY surprise. Next, access your battery storage area. Look for a way to access your water fill opening. Some batteries have individual caps and some (like mine) have covers over multiple openings. Use a wide blade screwdriver to gently lift the covers. Put them upside down on a clean towel to stop crud from being picked up and transferred INTO your battery! Look down into the openings (you may need a flashlight and or mirror to see in them all.

Each battery manufacturer uses a slightly different way of determining whether the battery has the proper amount of water in each cell (opening). Mine have a plastic extension the reaches down about 2 inches into the cell. I fill them so the water just touches the bottom of this plastic protrusion

You MUST use distilled water. Water with any contaminants will shorten the life of you battery. Besides, it's cheap and available at any supermarket in gallon jugs.

Funnels Make This a MUCH Easier Job
Fill each opening until the correct level is reached. One of my batteries is much harder to fill. It sits behind the other one and makes life more difficult. I have a long reach funnel that just fits, making it much easier to fill. Getting the covers back on is another thing entirely!  I found that re-arranging the wiring a bit allows me to get the covers on the back battery much easier. Not smoothly mind you...but way better than the first few times I tried to return them to their proper place. Insert your funnel in one of the openings and dribble water in it a little at a time. Removing the funnel between dribbles. Overfilling is just as bad.

Now is also a good time to check the battery terminals (where the wires connect!) for corrosion. This mostly happens when the batteries out-gas and small amount of acid vapor is released. The terminals will show a bit (or lots!) of greenish blue corrosion. Clean this off with a wire brush. Corrosion will prevent current from flowing efficiently and make your charging system work harder as well. I remove the wires connected to the battery terminals to do this, but if it's not really bad, you can just clean it up with the brush.  Clean the little bits of the corroded material off the top of the battery with a rag or slightly damp paper towel.

MAKE SURE NOTHING FALLS INTO THE BATTERY OPENINGS!!  That would be bad. Enough corrosion in your battery and it will short out severely shortening it's life.

Some very bright folks wrote in to let me know a Turkey Baster also works well for this process. I agree. I just wouldn't recommend using it for actual Turkey basting afterwards!

Close the covers or caps after making sure all of them are properly filled. Your chassis/engine battery will need the same basic maintenance if it isn't one of the sealed types. I check that right after tending to the house batteries. That's all there is to it. Following these simple steps will make sure you have battery power when you need it and will likely extend the life of your batteries.

Be Seeing You, Down The Road...

Rich "The Wanderman"


  1. OR, to make life simpler, purchase a Qwik-Fill watering cap kit to replace your existing battery caps, then it's simply a matter of hookup up the squeeze ball line, sticking it in a jug of distilled water and squeezing till the ball becomes firm (The caps have floating valves that close automatically when the battery reaches the right water level).

    Did this with all three of my deep cycles, watering now is a matter of five minutes with a jug.

    1. Matt,
      Yup, looked into that too. a bit pricey for a 10 minute job, you need several bits and pieces to make it work AND it has to fit in the compartment.

      Great concept, but if you already knew about know you have to water them in the first place!!


      Rich "The Wanderman"

  2. Rich,
    A very important safety item you did not mention is a person should wear gloves, goggles or face shield when working with batteries. Also take off jewelry and wristwatch if wearing any. The automatic battery system are good to use if your batteries are hard to access. I have a 94 Avion 5th wheel that have batteries mounted above the generator, while they are on a pull out draw it is impossible to add water without removing the batteries. Even with the batteries are pulled out there is less then 2" of clearance to check and add water too them.

    1. Chuck,
      IMPORTANT Safety tip. Great idea Chuck, I added it to the text.

      Rich "The Wanderman"

  3. A garden sprayer pump tank and wand really help. Cut the wand off about 2 inches out of the handle. That is all you need for batteries that are accessible. For those that are behind and under the compartment, a 90 degree plastic fitting, or short flexible plastic tube do it. No more holding flashlight, mirror, funnel and jug all at once.

    1. Anon,
      That's a really cool idea...

      Rich" The Wanderman"

  4. I am not trying to hijack your blog but one of the replies (Chuck) has almost the same trailer as I do and I want to get in touch with him.

    Chuck: Please email me if you're interested in sharing info about your trailer. I have a '91 Avion 5'er.

    Bob F:

  5. Another easy way to add water to the batteries is by using a turkey baster. I find that when it comes time to add water to my batteries, I stick the turkey baster down into the distilled water jug and suck up a baster full of water. It usually works out that each cell will take about a baster-full of water.

    Gene Bjerke

    1. Gene & Jean,
      That is an OUTSTANDING idea! I will update the article to include it.

      Probably not a good idea to use it as a turkey baster afterwards...

      Rich "The Wanderman"


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