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Disclaimer
The information in this article is not all inclusive of what you will need to know in order to safely modify your RV, travel trailer, 5th wheel or any other item with a 12 Volt electrical system. Similarly, we do not claim nor guarantee that all the information presented in this article is correct, and the information is only provided to share the research and information we learned from personal experience while modifying our 5th wheel. We are not certified electricians or electrical engineers. We are only RV enthusiasts and hobbyists. 12 Volt batteries are dangerous if not handled properly. Failure to follow the correct procedures with your batteries can lead to shock, shorts, mishaps, overload, acid spills, sparks, battery explosions, fire and many other serious incidents. Working with and modifying the wiring and electrical system on your RV is potentially hazardous and can lead to shock, shorts, mishaps and the possibility of fire, injury or other serious consequences if not done correctly. Similarly, modifying or adding batteries or modifying or working on your RV electrical system can lead to damage of your RV’s electrical system and electrical components if not done correctly. If you plan to work on your RV batteries and/or electrical system, you should consult an experienced electrician and/or your local RV dealership’s qualified technicians to make sure that you are following the local electrical codes and proceeding safely with your modifications and not voiding your RV warranty. Similarly, it is important to follow all manufacturers’ instructions for the batteries or electrical items you purchase and intend to use. BigBoyToysOnline, LLC will not accept responsibility for any mistakes, mishaps, injuries or deaths that occur as a result of anyone trying to make modifications to their RV, travel trailer, 5th wheel or any other item based on the information in these articles. This is SERIOUSLY DANGEROUS stuff. Please proceed carefully and safely!
Mounting Your New Batteries Properly
The batteries in your RV are the heart of the entire 12 Volt power system. If you haven’t planned accordingly and at least tried to approximate how much battery power you will need, then most likely you won’t have sufficient power and you are sure to drain your batteries to unacceptably low levels which will reduce their lifespan and abilty to recharge properly. However, let’s not get off on a tangent. I will leave that discussion for another article. This article is about how and where I mounted the batteries in my RV.
It is important to find a means for mounting and storing the batteries in your RV safely and effectively. You need to make sure that the batteries are accessible so you can maintain them properly and that they are mounted properly so they are not bouncing around. Similarly, different types of batteries have different requirements for safe storage; so be sure to do your homework. Remember that standard lead acid and gel cell batteries are prone to gassing while charging. This means that they will be emitting harmful gasses while they are being charged and they cannot be installed in closed locations where people may be breathing the same air. Simply stated, they need proper ventilation and airflow.
Originally my RV came with a single lead acid, deep cycle battery installed. Since I was planning on installing solar panels and an inverter to run all the electronics that I planned to install, I knew that it meant I would have to upgrade the RV batteries in order to make sure that I had enough power to run all my electronics, lights, TV, etc, as well as store all the power that my solar panels were generating during the day. The goal was to be able to live off of battery power as often as possible so that we did not have to run the generator and create noise and pollution. Nothing can ruin the quiet of a beautiful forest quicker than they constant hum of a generator which is also belching fumes into your campsite.
When I finally finished all of my calculations and estimates of the power we would need, I settled on 6 Lifeline AGM golf cart batteries (model GPL-4CT). Now I just needed to determine how and where I could mount them safely. The original battery compartment in my RV was only capable of holding 2 batteries. Clearly this space was not going to work so I had to come up with another solution. Since I was using AGM (absorbent glass mat) batteries I had the option of mounting them almost anywhere. AGM batteries are completely sealed (which means they do not give off dangerous gasses like other batteries and can be mounted indoors if needed), they can be mounted in any position (upside down if you want), they are non-spillable and are even shock and vibration resistant.
(Original battery compartment capable of holding two batteries)
Fortunately, my RV had the perfect space to locate the six new batteries. In the very front compartment next to the generator was a large space meant for storage that was perfect for the six batteries that I had in mind. Similarly, the space was located behind the original battery compartment and most of the wiring that I needed to relocate near the new batteries already traveled through this space and into the original battery compartment. The inverter and solar charger which I had planned on installing in the basement storage compartment of the RV was located right behind the rear wall of what would become my new battery compartment, so cutting a hole and running wires to the inverter and solar charger would be easy. Now it was just a matter of determining how I could mount the batteries properly.
(Location of basement, original battery and new battery compartments)
(Front compartment with storage to left and generator to the right)
Since this space was not originally meant to hold six batteries, I knew that I would have to come up with a custom solution. I was also concerned about the weight of the batteries. Each of the batteries weighted 66 lbs which meant that I would be putting a total weight of 396 pounds into this compartment not including the battery mount that I would fabricate. Since the compartment only had a thin sheet metal floor that was spot welded in a few locations, I was uncomfortable putting 400 Lbs into the compartment without making some modifications to handle the weight. I didn’t want to be driving down the road one day and have over $1000 worth of batteries drop out of the front compartment and splat all over the road. Needless to say, that would not only be messy but could also create a hazardous situation for my fellow motorists. Imagine the liabilty of the situation alone...Geez!
Fortunately for me, the main structural cross beam at the back of the compartment had a wide lip that was strong, the front of the compartment had a narrower but sufficient lip off the front structural beam and the sheet metal although spot welded in most areas was completely welded to the structural beam along the left side of the compartment. Since I knew that the base of the battery box that I was building would be constructed of a strong piece of ¾ inch plywood that would span the entire base of the compartment, I knew it could sit comfortably on these metal lips for structural support. The only remaining side I had to worry about was the right side where there was only the thin sheet metal at the bottom of the compartment to support the base.
(Picture of the thin sheet metal floor w/spot welds and metal lip on rear structural beam)
On the right hand side of the compartment was another structural bar that was welded to the main structural bean at the back of the compartment and ran all the way to the front beam. It was there to provide structural support and also used for mounting the generator box that took up the right side of this large front compartment. In order to create a lip that I could use to support my battery holder I secured two pieces of angle Iron to this bar. The only reason I chose to use two pieces instead of one contiguous piece was because of a spot weld that was used to hold up the bottom sheet metal. With the spot weld in place (located between the two pieces of angle iron in the picture), the angle iron would not mount flush against the bar. Once the angle iron was in place, I now had a strong lip around the whole perimeter of the compartment that I could use to support my new battery base.
(A picture of the angle iron I secured to create a lip to support the battery base)
The next step in the process was to cut out a piece of ¾ inch plywood that would serve as the base of the battery box. This piece of plywood covered the entire bottom of the compartment and sat on the lip around the edges so as to not put pressure directly on the thin sheet metal floor. Similarly, you can see that I drilled a few holes in the base. This was to accommodate the sheet metal screws that were sticking up through the thin metal floor and supporting item hanging underneath the trailer such as the generator exhaust pipe. Since some of the screws still stuck out above the plywood once it was in place and in some instances were located right where I needed a battery, I had to replace the screws with shorter ones so they did not stick up higher than the plywood.
(Plywood base w/holes)
Once I had the plywood cut out and properly sized I covered it with aluminum flashing. This is an extremely important step especially if you are using conventional lead acid batteries. If there was a spill of any kind from the batteries, it would quickly eat through the wood and compromise the integrity of your battery box. Even though I was using non-spillable batteries, I wanted to make sure that this installation would last so I went the extra mile. Additionally, it looks like a much neater and cleaner install then just leaving the plywood uncovered.
(Plywood base clovered with aluminum flashing)
The next step was to created battery holders on the base of the battery box so that the batteries did not slide around. After measuring carefully and determining the proper layout so the batteries would fit into the compartment without hitting or rubbing anything, I started creating the holders. I did this using 1 inch angle iron with precut holes for easy mounting to the base. I mounted them to the base using stainless steel wood screws. Where I could, I put spaces between the batteries. However, because of the layout of the compartment I could not put a space holder between the front two batteries.
(Completed battery base with angle iron and straps used to hold batteries in place)
In order to assure the batteries did not jump out when I hit a bump or during emergency stops, I also created and fashioned a strap for each of the batteries to hold them in place. I did this using standard nylon strapping and parachute buckles. These are just like the straps used to hold the top of a plastic battery box that are commonly used on the outside of a travel trailers. You can find these materials at most craft stores. In my case, I was able to find them at JoAnn's fabric and craft store (chances are your wife knows where to find a JoAnn’s or similar craft store).
(Picture of the nylon strap and buckle purchased from JoAnn's)
Now that the battery box was completed the only thing left was to mount them in the RV. Below is a picture of the completed battery holder and what it looked like once all the batteries were in place outside of the RV and a picture of the batteries installed in the new compartment.
(Batteries mounted on the base outside the RV)
(Batteries mounted inside the the new battery compartment)
