Gary Hatt
September 25, 2022

Battery Maintenance

Wet cell batteries require maintenance. I have replaced all the batteries in all of my buses at least once and I can tell you that batteries are not cheap. 8D batteries start at $170 each and I need two for my Eagle. Every time I replace them, I am out $340 plus tax and the price is not going down.

In the past, I used six 4D deep-cycle batteries for my house batteries in my Eagle. They are also very expensive. If you leave your bus at a shop, with irresponsible people, and they run them down completely as it happened to me, then you are looking at spending a lot of money. I was not having any luck with 4D batteries and they were also very heavy so I changed my all-electric bus over this year to eight 6V deep-cycle Trojan batteries. I am much happier with those as they are not only lighter but they also hold a much longer charge.

I would like to have AGM batteries that I don’t have to maintain as I had in my Sportsmobile, but the price for these went out of sight a few years ago. Unfortunately, I can no longer afford these. I discovered quickly with lead-acid batteries, that if you do not periodically check the water level, the water level gets low, and that they go bad really quickly.

I always tell everyone to check their water level monthly since you do not want to run your batteries dry. I used to put off checking the water in my batteries as long as I could because they are difficult to get to, they are hard to fill, and it is difficult to check the water level. Some people even have to disconnect their batteries from their system before checking the water level so they have better access. With a battery watering system, you only have to remove your caps once and replace it with the new caps (with hoses on them) then you are finished.

Pop-Up Indicator At Top.
Pop-Up Indicator Low.

In my current bus, my house batteries are on slide-out trays. Thankfully, I can get to them more easily than a lot of folks but it is still a messy job. Also, you don’t want to get battery acid on your clothes which eats them right up as everyone knows.

So, to make the job easier, I bought a battery watering system from An RVer’s Friend at the Quartzsite RV Show in 2018 for a little over $200 for my eight-battery system. It was one of the best investments I made for my bus. Now, I do not even hesitate to go out and water my batteries on the first of every month because it is so easy. I keep a few gallons of distilled water next to my batteries so it is always there when I need it.

It is so easy to stick the end of the hose into one of the bottles of distilled water and using the hand pump, squeeze the bulb until it is hard (which indicates all the cells are filled to the proper level). There is also a white visual indicator on each cell, which pops up when the correct level is reached, so there is no guessing when each cell is filled properly. The competitor's product only has an indicator in the center cell. Most have no indicators at all, so a system with indicators for each cell gives you a much more accurate reading.

This system uses replacement caps that fit right on your batteries so you do not even have to remove the caps to add water. The caps stay in place and come in a set of three for 6V systems. To install the watering system, you simply remove the existing battery caps and replace them with the set of three caps that are already pre-plumbed. Then, you cut a piece of provided hose to run a separate line between the batteries. No matter what your battery configuration is, you can set up the system to work for you with the correct length.

After you run hoses between each battery, you cap the end of the line and attach the filler hose to the last battery in the string. The filler hose has a bulb that you squeeze to add water to your batteries. As noted before, you do not even need to see the batteries to know if they are filled to the correct level since the bulb gets hard when all cells are filled precisely to the proper level. This is extremely helpful to people with batteries that are hard to access.

This is much easier than trying to peer into each cell, to check the water level each time when you service your batteries. It is also much safer since I never liked looking down into a battery cell to check the water/acid level when they were charging. For one bus I even had to use a mirror and a flashlight to see the level in some of my cells which was even more difficult.

This job used to take about a half-hour to remove all the caps and to check the level in each cell. Then, I had to add the correct amount of water one paper cup at a time. It was a messy job and I usually wore disposable gloves since caps can get dirty. It also required getting out a mirror and a paper cup and I had to pour the water into the cup several times until all cells were up to the proper level. This does not include the time it takes to slip on old clothes that you don’t mind getting acid holes in.

Water filler caps installed
Water filler caps installed.

You can also overwater a battery which that can be as bad as not having enough water. This system prevents that from happening by a check valve built into each cell fill cap. The pop-up indicators in each cell allow you to glance at your batteries and tell immediately if the cells need water. Not all cells require the same amount of water so don’t be surprised if one valve indicates to add water and the next one on the same battery indicates it is full.

If you cannot see the tops of your batteries as is the case for many RVs, you can just hook up the pump once a month and try to squeeze it. If any battery needs water, the valves are open and you will be successful at adding water to the cells that need it (the others are shut off). If none of the cells need water, your pump will be very hard and no amount of pressing will be able to force water into the battery as the valves are closed shut.

By keeping your battery water at the correct level, your batteries will hold a charge better and will last longer. Most battery watering companies promise an extra two to three years of battery life with a battery watering system. This is due to the water-acid mixture being in the most favorable filled position most of the time. Properly maintained wet cell batteries will outlast AGM batteries AND they will give you better performance.

With this new battery watering system, you do not need to get anything out except for a gallon of distilled water. Then, you simply put the end of the hose in the jug and start pumping away. The entire effort takes less than two minutes and it is a very clean job and no tools or change of clothes are required.

If you haven’t bought one of these systems yet, I encourage you to go out and get one now. It will make your life easier and it is a much cleaner way to maintain your batteries. It takes about a half-hour to install the system and it only requires a knife or scissors to cut the tube to length between each battery. After that, instead of putting this messy task off, you look forward to filling your batteries monthly with this system.

To purchase one of the best watering systems, visit An Rver’s Friend at the Quartzsite rally in the big tent or call them at (408) 603-0600, send them an email to, or visit them online at

Article written by Gary Hatt

Since July 2012, Gary Hatt has been the Publisher of Bus Conversion Magazine. Gary does most of his own work on his bus with the help of mechanic friends. He has owned tents, truck campers, travel trailers, and stick-n-staple motor-homes until he bought his first bus in 1997 which was a 1972 MCI MC-7 Combo. When he had a chance to buy a 1983 MCI MC-9 Log Cabin bus with larger windows he jumped at the chance. On Thanksgiving of 2014, Gary bought a 1967 Model 08 Eagle and has since been living and traveling full time in that.

You may reach Gary Hatt at

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