Water Your Batteries: RV Battery Maintenance

Did you know that you need to water your RV batteries for proper RV battery maintenance?

Let’s just say, it’s story time and ignore this advice at your own peril.

The TL;DR version: regular RV battery maintenance is important! Water your RV batteries!

Why to Water your RV Batteries - RV Battery Maintenance Advice and Tips

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RV Batteries

RV batteries are typically flooded batteries with removable caps.

Over time, the charging process will boil off the water in the flooded cells. Batteries can also lose water through evaporation.

When the water is completely boiled off, it may kill your battery. Routinely allowing the water level to drop below desired levels will shorten the lifespan of your battery due to a process called sulfation.

Thus, you’ll need to regularly check and maintain the water levels in these batteries.

You only want to fill the battery cells until the cell plates are covered. Overfilling can be as dangerous as letting them run dry!

Story Time: Water Your RV Batteries or Else…

The or else – hint: bad things can happen.

Early this summer, I was out RV tailgating with a dear friend of mine for the Georgia Tech baseball regionals. That’s the first round of the NCAA tournament where four teams match up in a double elimination format.

My friend, let’s call him Tom. He’s one of the reasons that I love RV tailgating so much and definitely a big reason why I bought a Tiffin RV. He’s part of my tailgating crew, for both football and baseball. He’s been RVing for years and year and has had multiple different RVs, including a Tiffin that he ordered from the factory.

We arrived on Thursday evening and setup our tailgate. I knew that my RV battery maintenance was due, but didn’t have any distilled water on hand. (I forgot to pick up the water in the grocery store trip prior to the tailgating weekend, but hey, you get a story out of my forgetfulness)

I asked Tom if he had any distilled water on hand. He didn’t.

I told him that it was going to be on my to do list before the game Friday night, to go by the store, get some distilled water and fill the batteries (I have four batteries in my RV house battery bank). We made a plan for breakfast and then I’d continue on to get my water.

Tom made a comment about how he probably needed to check his too, but he’d wait until after the weekend. He said that I worried too much about RV maintenance and should let it go more often.

In other conversations Thursday night, Tom also described some problems he was having with his RV. When he went to pick it up from storage (he can’t keep it plugged in at his house like I can) he found that he was having problems starting the RV – the fridge wouldn’t get cold, his steps were wonky, the lights weren’t very bright, and he wasn’t getting a full charge on the batteries with the generator running. It meant that he had to have the generator all the time, that the inverter wasn’t very useful.

Filling Water on Batteries

[pullquote-right]Get a $5 credit when you use the promo code RVTAILGATE when you sign-up with Lyft for the first time![/pullquote-right]So skip ahead to Friday. After breakfast, it was a quick electronic scooter ride to the grocery store and a quick Lyft ride back to the RV. It would have been quite a site to watch me try to ride the scooter with two gallons of distilled water with me. But I saved you all that story by going with the Lyft ride.

Yes, I was a good friend and got Tom a gallon of distilled water too.

Back at the RV, I filled up the battery cells.

They were definitely low on water and needing refilling. I used about 2/3 of a gallon of water on my battery bank. Yikes!

I left the rest of the water for Tom. He was “pish, posh, it’s not really necessary. But I’ll do it anyways.”

Turns out, his batteries were bone dry! Worse than mine!

No wonder he was having so many problems with the electrical systems in his RV.

Tom used all of the rest of my gallon, plus the other gallon of distilled water to fill up his batteries’ cells.

Tom Gets Picked On

So Tom is older than me, like retired old. (Lucky him, since I still have to work and all)

But since he was picking on me for being so picky about my RV maintenance, it sure was nice to be able to say “I told you so!” when all his systems started working better.

Quientessential RV tailgating scene - the grill with hamburgers a grillingSeriously, like instantly. Batteries were charging. Inverter was working again. Lights were brighter. All systems were go.

All those things that you need working for an RV tailgate? Yep, it worked again. Just because he filled the water reservoirs on his RV batteries.

His wife was not as nice as I was and definitely ribbed Tom – “You should listen to the young whippersnapper!” Ok, not the actual words used but you get the idea.

Maybe next time he’ll listen to the solo woman RVer? Meh, probably not.

Just remember, don’t let someone tell you that you don’t need to take RV maintenance seriously.

I’d rather be overly cautious rather than spend big bucks later because I was peer pressured into ignoring a critical system on my RV.

Other Short Term and Long Term Effects of Not Watering Your RV Batteries

Tom got to experience the short-term effects of not maintaining his RV batteries properly. Systems stopped working, he couldn’t get the batteries to charge, etc.

Other short term effects could include the batteries overheating and setting your RV on fire!

That would also be a pretty big long-term effect that would probably hinder your RV tailgating for the foreseeable future. Let’s not do that.

The most likely outcome though of not maintaining your RV batteries is that you will shorten the lifespan. Some RVers report having to replace their RV batteries every 1 to 2 years.

You really should be able to get 5 to 7 years out of the batteries with proper maintenance.

Americans, not just RVers, but everyone, are so bad at battery maintenance that some 85% of lead-acid batteries die early. Yikes!

And while RV batteries aren’t as expensive as say RV tires, who wants to be spending money on such basic items when you could be spending money on more fun things – like say tickets to more football games!

Tools to Make RV Battery Maintenance Easier

I take the hard way, using that funnel and pouring from the gallon jug.

There are some easier ways:

Flow-Rite Pro-Fill

Flow-Rite Pro-Fill replaces the cell vent covers with ones that connect to rubber tubing and a hand pump.

Then you fill the batteries from one single water source (ie the gallon jug). But you don’t have to pick it up and pour. You just squeeze the bulb in the hand pump kit.

The Pro-Fill system will only fill cells that are low on water, meaning you won’t overfill them. It becomes quite hard to pump water once all the cells are full.

I used the Pro-Fill system on the Winnebago because the RV batteries were so difficult to access for regular RV battery maintenance duties.

Battery Filler

This heavy duty battery filler will still require that you pour the water but it has the same auto-shut off valve that the Pro-Fill system has.

It holds two quarts of water, so if the batteries are really low or you have a lot of batteries, you might need a refill before you are done watering your RV batteries.

It’s also quite a bit cheaper than the Pro-Fill system.

Battery Filler Rubber Bulb

The Battery Filler Rubber Bulb looks and acts like a turkey baster.

You fill it up with water and squeeze it into the battery cell.

Unfortunately, these do not have the auto-shut off valves like the Pro-Fill and the Battery Filler. You can end up overfilling and getting battery acid on the outside of the battery and in the battery compartment.

Over time, overfilling can lead to a shorter RV battery lifespan.

But this is also one of the cheaper options to filling your RV batteries.

RV Battery Maintenance Tips

Here are some more tips to make sure that your RV battery is maintained and you get the full life of your battery:

Use Distilled Water

The reason that I had to go out to the grocery store to get water for the RV batteries is because I only use distilled water when filling the batteries.

Sure, if it is an end-of-the-world situation, I’d use other water. But for standard operating procedures, it’s distilled water only.

Regular tap water or softened water has minerals in it that will react with the electrolytes in the battery acid. This will increase sediments, affect the battery performance, and overall shortened the lifespan and efficiency of the battery.

Check the Water, Check the Connections

We treat our RVs pretty harshly. I mean, have you seen the roads we drive on?

Things are constantly coming loose. Things, including battery cables and connections.

When you check the water levels, you should also check the battery cables and connections to make sure that none of them have come loose. Tighten as necessary.

Two different ways to monitor the DC voltage in the Tiffin Class A 2017 34PA

Never Let 12 Volt Battery Discharge Below 12 Volts

A fully charged 12 volt battery is actually 12.73 volts.

As you use the battery, it will (hopefully) slowly discharge until it falls to 12 volts. I actually prefer about 12.1-12.2 volts.

At 12 volts, the RV battery is at 40% of it’s charge. At 12.1-12.2, the battery is at 50% of its charge.

At 10.5 volts, your chances of permanent sulfation increase dramatically. Permanent sulfation occurs when lead sulfate crystals build up. Sulfation will lead to battery death. So sad….

Reducing how far a battery discharges will increase the battery’s lifespan.

RV batteries should not be fully discharged. Ever. It’s not needed and will do damage to the flooded lead acid batteries.

DC Volt Meters

Many of the newer RVs have DC voltage meters built in somewhere, like on a control panel. If your RV doesn’t have one, then you’ll want to install a DC voltage meter (not to be confused with the AC voltage meter).

You can tap into the DC power with this charger socket, add the DC voltage meter and even get a couple of USB plugs out of the deal!

My RV has the voltage meter in the hallway, across from the kitchen. That’s nice and all, but the longest time period I go without running the generator is when I’m sleeping. I’d like to add a voltage meter next to my bed. I know that the DC lines come through there because there are various light switches on the wall next to my bed.

Monitor the Battery Charge Even When Not Camping

It’s important that you monitor your RV batteries, even when you aren’t actively camping.

Even in storage, your RV is probably pulling on your RV batteries. It is one of the best reasons that I love keeping my RV plugged in at home between trips.

But I know not everyone can do that.

If you are going to be storing your RV for a prolonged period of time, like for winter storage, then it is wise to take the batteries out of the RV and take them to your home. There, you can put them on a trickle charger to maintain their charge during the winter.

Exercise the Generator, Charge the Batteries

If you are storing your RV for a shorter period of time and can’t plug it in, make sure that you turn off everything that you can – fridge, fans, dehumidifiers, inverter, radios, USB plugs, etc. And then hit the 12V disconnect button, if you have one. This makes sure that you have disconnected everything.

You’ll still find that there is a phantom draw. So, during storage, it is important for you to go out there and charge them up. It’s also a great time to exercise your RV generator to prevent problems with it.

Flip the switch to turn the 12V system back on and start up the generator. Be careful that you have proper ventilation for the generator exhaust so you don’t end up sick or even dead.

Run the generator for about half an hour to an hour. Put it under a load too, like running the air conditioner, to properly exercise the generator. And watch the voltage on your RV batteries.

It shouldn’t take too long if you have truly disconnected everything. You should check the batteries weekly, and exercise the generator at least monthly, more often if the battery charge has fallen.

Discharging RV Batteries Is Important Too

It’s important to discharge the batteries during storage to maintain proper health.

For most RVers that leave their RV unplugged during storage, this is rarely a problem.

But if you leave your RV plugged in for long periods of time without actively using the RV, you could be shortening the lifespan on your RV batteries! Gasp!

So at least once a month or so, make sure you unplug the RV for a few hours. Working on the yard on a Saturday, unplug and let the kid watch Saturday morning cartoons inside the RV (if it isn’t too hot). Or run some systems.

Just be sure to plug the RV back in before the RVs discharge too much!

PS Temperatures above 80 degrees Fahrenheit will accelerate the battery’s self-discharge characteristics.

Tip on Selecting Batteries

Purchase the most recently manufactured RV battery to ensure long RV battery lifespanSince exercising the battery is important, you don’t want to purchase a battery that has been sitting on store shelves for a long period of time.

When you are selecting the battery at the shop, make sure you grab the newest batteries.

Batteries will have a stick on the top with the month and year of manufacture. Get the most recent to ensure the longest usable lifespan for your RV batteries.

Don’t Let Batteries Freeze

It can be hard in the winter, but you shouldn’t let your RV batteries freeze.

Freezing results in damage to a battery’s plates and container which will kill the battery.

Keeping the batteries at a high state of charge will prevent freezing.

If you have to store your RV during winter without electric plugins, then pulling your batteries out of the RV is a good idea. Just keep them away from space heaters in your home or garage.

Make sure that you store your batteries fully charged. A trickle charger is a great investment for storing RV batteries in winter.

You should always fully charge your batteries and check the water levels before returning them to the RV.

Clean Any Corrosion Off Batteries

Corrosion occurs when acid meets air. So just about anything outside the battery cell.

In particular for flooded RV batteries, corrosion will occur when the batteries out-gas during charging. Out-gassing is a process where bubbles rise up and burst through the water-acid solution and the acid goes out the vents. You’ll likely find the corrosion near the terminals.

If you don’t have one already, add a metal battery brush to your RV toolkit. This makes it easy to clean the top post and cables.

Our old friend baking soda is also great to help with the corrosion. Create a paste with baking soda and a small amount of water and add to the areas affected by corrosion. An old toothbrush will come in handy for cleaning up. Scrub the corrosion off the battery, then rinse with fresh water and dry with a clean cloth.

Once you’ve removed the corrosion, spray some battery terminal protector on the affected areas to slow the build up of corrosion in the future.

Safety is Important!

If you happen to splash the water into and out of the cells, you can get hit with battery acid.

You should wear gloves and eye protection, as well as old clothes that can be damaged.

You should also disconnect the batteries from use and charging while you are checking and adding water. No use in getting electrocuted during the maintenance process.

Do You Regularly Check the Water in Your RV Batteries?

Why to Water Your RV Batteries and More RV Battery Maintenance advice and tipsChecking and maintaining the water in your flooded RV batteries is an important part of RV battery maintenance.

You should check the water levels at least monthly, until you figure out how fast the water drops in your RV batteries.

Then you might find out you have to check less often, at least until all your systems stop working like Tom’s did.

Just don’t make your RV batteries part of the 85% of lead-acid batteries that die before their time! It just takes a little proper RV battery maintenance.

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  1. I am leaving my 5th wheel on site in Florida for the summer. Will be leaving a de-humidifier with a continuous drain hose attached draining in a nearby sink. I have 50 amp service. .Would it hurt anything to keep my rig hooked up to the 50 amp service. Like the inverter??

    1. Bob,

      Typically, no, leaving things hooked up won’t hurt anything. In fact, by keeping the power on, you can keep the dehumidifier running and prevent problems.

      The biggest issue is the batteries. Typically, you need to check them monthly to see if they need more water. How often do you typically need to add water to your batteries? With very little running and not drawing down the batteries repeatedly, you are likely to be fine. But I would definitely make sure that the batteries are full when you leave them. And be prepared for them to not work when you return.

      Another issue could be power surges. Do you have an EMS/surge protector running on your rig? Especially in the summer, you can have problems with electrical supply as everyone is running air conditioners. And storms pose a risk as well.