Wednesday, March 22, 2023


RVelectricity – Watering flooded cell batteries; comparing RV batteries

By Mike Sokol

Dear Readers,

Deep-cycle batteries
Deep cycle batteries from U.S. Battery

For those of you who think I’m fixated on Lithium batteries, let me assure you that I’m an equal opportunity instructor. I now have representative samples of Lithium, AGM and Lead-Acid Flooded Cell batteries in my shop. In fact, thanks to my friends at Tri-State Battery, I now have a pair of U.S. Battery 6-volt deep cycle batteries in my possession for testing.

Why did I ask for old-school flooded-cell batteries? While Lithium batteries are great, there are many RV owners who either don’t want or need, or can’t afford to upgrade to the newest battery technology.

Do I need to spend big bucks on RV batteries?

Battery cycle life chart
Expected battery cycle life vs. DOD, from U.S. Battery

In fact, for casual RVing families who might only take their camper out a few times a year, spending big dollars on a Lithium battery that can do 3,000 to 5,000 charge/discharge cycles doesn’t make economic sense. A pair of 6-volt lead/acid batteries should have a life in excess of 1,000 charge/discharge cycles, as long as you properly maintain their electrolyte levels and don’t discharge them below 50% SOC (State of Charge). Take a look at this chart from U.S. Battery that tells the story.

Why do good RV batteries die young?

I firmly believe the primary reason many flooded cell batteries die an early death is a lack of water. That’s right, you really should be checking your RV battery electrolyte level every month. However, some RV manufacturers locate the house batteries under the steps or in a hidden compartment, which makes checking the water/electrolyte level in your batteries difficult, if not impossible, without removing them first. In their defense, flooded cell batteries can’t be located in your living quarters without some sort of venting system, due to their outgassing during charging.

Cool concept alert!

battery watering system
Flow-Rite battery watering system

When I saw this cool battery watering system from Flow-Rite, I contacted their marketing group and was quickly put in contact with Flow-Rite proper.

Of course they offered to send me a sample product to review, but I thought it would be a better idea to test the concept on a pair of 6-volt deep cycle batteries, which I didn’t have in my lab yet.

So I asked if they could find me a pair of batteries for the review, and voila, yesterday a pair of 6-volt, deep cycle batteries arrived, courtesy of U.S. Battery and Tri-State Battery. Thanks very much, guys. You know how much I love to test stuff!

Coming soon to a media player near you…

Flow-Rite battery watering system
Flow-Rite battery watering system

In the next few weeks I’ll do a formal review of the Flow-Rite battery watering system, which looks like it would solve a lot of battery low-water issues for RVers.

In addition to discussing electrolyte level in flooded cell batteries, this now gives me the opportunity to directly compare Lithium, AGM and Flooded-Cell batteries for things like charging speed, solar panels, DC-to-DC chargers, air conditioner operation from batteries, 3-stage converter/chargers, hybrid inverters, etc.

Stay tuned to this bat channel…

I’m not sure what all I’m going to learn yet, but I’ll be sure to keep you informed on whatever I do find out. So Please Stand By for more knowledge.

So a special thanks to Flow-Rite Controls™, U.S. Battery and Tri-State Battery for providing the test samples. It’s like Christmas in February for me.

Let’s play and stay safe out there….

Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at For more info on Mike’s qualifications as an electrical expert, click here.

For information on how to support RVelectricity and No~Shock~Zone articles, seminars and videos, please click the I Like Mike Campaign.



0 0 votes
Article Rating
Subscribe to comments
Notify of

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Inline Feedbacks
View all comments
Monte Milanuk
1 year ago

Any updates on when we might see that video?

Pete Morris
2 years ago

Mike, have you done any articles or testing of Gel Cell batteries for RV use?
Thanks Pete

Jon Schacher
2 years ago

Mike, be aware that the Flow-Rite system is battery design dependent. I recently looked at purchasing the system for my house batteries. I contacted them regarding a specific battery sold by NAPA and manufactured by East Penn, Marine Master, and found out that it was not compatible.

Mike Sokol
2 years ago
Reply to  Jon Schacher

They sent me the proper Flow-Rite system that matches the U.S. Batteries that were just delivered. But I’ll be sure to let all my readers know. Thanks for the reminder.

2 years ago

Mike, I have used this system (Flow-Rite) for over ten years on two different Rv’s. On my Class A it would be very difficult to use anything else the way the batteries are set.

Mike Sokol
2 years ago
Reply to  Chuck

Looks like a very handy system to have on a lot of RVs.

2 years ago


Can you briefly (again) tell me what the charging profile of AGM’s are vs. lead acid?



Mike Sokol
2 years ago
Reply to  Drew

I’ve got an article somewhere on that topic. I’ll have to look it up.

Tommy Molnar
2 years ago

I’m {bleeped} about checking the water level in my 6-volt batteries. Problem is, I have to remove the propane tanks in order to do it. The older I get, the harder it is to haul those puppies off. Even harder to hoist them back up! But, I’ve had batteries last upwards of 8-9 years!

I will be anxious to see this review/comparison. Hurry up, Mike. 🙂

Kostyal Don
2 years ago

Walmart refused to honor warranty on their best battery (5yr—but now 3 year) after mine (rv chassis battery) went bad after 14 months because I popped the caps to add water (almost monthly). They stood by a statement in their on line info about “the battery should never need water under normal use.” After pointing out it didn’t prohibit adding water, they then tried to say an rv isn’t “normal use.” I then said it is a Ford F53 chassis and is listed in their application tables. They wanted to argue a Ford 53 is not an RV. By now I could be heard over half the store and they gave me a 3 year battery to just leave. This was Idaho Falls Idaho—I had driven 100 miles from the Tetons to replace the dead battery. Bought a new one at Napa and sold the Walmart POS.

2 years ago

I’ve also used the Flow-Rite battery watering system since we went fulltime in 2010 & wouldn’t travel without it. I have a reminder in my Outlook every two weeks on Saturday morning to check the water level. It takes about 2 minutes to top off the batteries I also have a reminder every month to equalize the batteries.

Rick M
2 years ago

I have used this system since 2010 on my 5th wheel batteries. Top off batteries once a month. Finally had to replace them in 2020. 10 years is pretty good for lead acid batteries.

Sign up for the

RVtravel Newsletter

Sign up and receive 3 FREE RV Checklists: Set-Up, Take-Down and Packing List.