↓Episode 44 – RV Deep Cycle Battery Storage

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battery↓There can be a fair amount of confusion about the best way to store an RV Battery during the off season. In this episode I break it down to simplify the process and make some nice product recommendations along the way. In most scenarios the RV’er is storing his battery during the cold winter months and typically not during the hot summer months. The methods can adapted to either situation, hot or cold. The summer heat can damage a battery as much as poorly stored battery during the cold months.

↓The bottom line is to keep the battery case and posts clean and keeping the battery properly charged during the storage process . If your battery is going to be stored in the RV during the winter months you will want to make sure that it has a full charge and this will prevent it from freezing. Some have said that an RV Battery will freeze if left in the RV during storage and that is not true unless the temperature drops way below Zero.

↓If you decide to store the battery in the RV, make sure the battery is disconnected from any electrical source that good drain the battery during storage. It might just be best to physically disconnect the battery cables altogether. If you are unsure of how to hook the battery cables up later then you could take a picture or draw a diagram. It is important that battery gets hooked up the same way it was connected was, assuming it was correct to begin with.

↓I would opt to store the battery in a garage or some place that has power to run a Trickle Charger. The stored battery should be fully charged prior to storage and then the charge should be maintain during the storage period. Today there are plenty of Hi Tech battery chargers available and I recommend to purchase a battery charger that will go into float mode after the battery is charged. If your charger has this capability your can leave it hooked up to the battery and plugged in for the off season with no harm being caused to the battery.

↓It is best to store the RV Battery away from any source away from sparks or open flames. Although today’s batteries can be stored on a concrete floor it is best to store it on a piece of wood, work bench or similar. Make sure the surface is protected if it is a nice surface you care about. It is pretty simple to store a battery for the off season.

I recommend Battery Tender and Noco battery chargers to maintain All of your  Batteries. Click here for more information about both brands and to purchase from Amazon.

Bonus Content: The below content was briefly explained in the podcast. You can consider this some bonus content if you are thinking about changing to a different battery type.

Gel Cell vs. AGM (glass mat) batteries. 

What Is A Gel Battery?
Before you can determine the pros and cons of a gel battery and how they will affect you, it’s important to understand what exactly a gel battery is. A gel battery is very similar to a traditional lead-acid battery with the addition of silica to the electrolyte to create the gel like substance. This thickening of the electrolyte means that gel batteries can be installed in a variety of positions and don’t emit as many fumes.
Pro Tip: This allows for gel batteries to be used in applications where ventilation is limited.

How Does It Work?
A gel battery (often referred to as a gel cell battery) is a lead-acid battery that is valve regulated. When the electrolyte is mixed with sulphuric acid and silica, it becomes a relatively stationary gel substance. This gel mixture allows the battery to utilize the acid and electrolyte in the same way it would with a traditional lead-acid battery, just without the added maintenance.

The Pros:
Maintenance Free: Because the batteries are comprised of gel instead of liquid, there is little to no maintenance to keep the battery working properly.

No Leaks: Even though wet cell batteries are sealed in a plastic encasement there is still the chance that it will leak. Gel batteries are also sealed but with a valve that removes excess pressure. This means that between the gel substance and the removal of pressure, there is nowhere for the mixture to go.

Install Them Anywhere: Gel batteries have the advantage of being able to be used in virtually any position, because they don’t leak and are generally maintenance free. This greatly increases the number of applications gel batteries can be used for.

Minimal Risk: When damage occurs to a traditional lead-acid battery you are faced with a massive and dangerous clean up (not to mention the impact on anything the battery acid may come into contact with during the process). Gel batteries will not leak out if the casing becomes damaged, so there is a reduced risk of harm coming to the equipment and clean up hazards.

Vibration Resistant: One of the biggest complaints with wet cell batteries is that they are very susceptible to extreme vibration and other impacts. Gel batteries absorb the impact and vibrations, making them great batteries for items such as four wheelers.

No Fumes: Because these batteries are comprised of a gel substance there are minimal fumes created as a result of use. This means that there is a reduced need for ventilation which increases the potential applications gel batteries can be used for, as well as making them easier to charge anywhere.

Resistant To Discharge Death: When using a wet cell battery it’s important that you don’t allow the battery to discharge too much. Otherwise, it will never recharge. Gel cell batteries aren’t that way. They are deep cycle batteries  which means that they can discharge more and still be recharged like new.

The Cons:
The Price: While the benefits of a gel battery are pretty hefty, so is the price tag. Many people looking to switch from wet cell to gel batteries see this as the biggest drawback.

Charging Challenged: When charging your gel battery, you’ll want to plan on giving it extra time. Slow charging cycles are pretty common with these batteries, but you can’t walk away and leave it. Because it’s a gel instead of a liquid you’ll need to take it off the charger as soon as it’s complete. To leave it on could cause voids with the electrolyte which is irreversible damage.

Heat Control: This is truly a drawback with most batteries and gel cell batteries are no exception. Heat is one of the fastest ways to cut the lifespan of your battery short. By controlling the batteries exposure to heat, you can lengthen the life cycle and keep your battery running like new.
Pros and Cons provide by Northeast Battery.

What is an AGM Battery? AGM technology became popular in the early 1980s as a sealed lead acid battery for military aircraft, vehicles and UPS to reduce weight and improve reliability. The sulfuric acid is absorbed by a very fine fiberglass mat, making the battery spill-proof. This enables shipment without hazardous material restrictions. The plates can be made flat to resemble a standard flooded lead acid pack in a rectangular case; they can also be wound into a cylindrical cell.

AGM has very low internal resistance, is capable to deliver high currents on demand and offers a relatively long service life, even when deep cycled. AGM is maintenance free, provides good electrical reliability and is lighter than the flooded lead acid type. While regular lead acid batteries need a topping charge every six months to prevent the buildup of sulfation, AGM batteries are less prone to sulfation and can sit in storage for longer before a charge becomes necessary. The battery stands up well to low temperatures and has a low self-discharge.

The leading advantages of AGM are a charge that is up to five times faster than the flooded version, and the ability to deep cycle. AGM offers a depth-of-discharge of 80 percent; the flooded, on the other hand, is specified at 50 percent DoD to attain the same cycle life. The negatives are slightly lower specific energy and higher manufacturing costs than the flooded, but cheaper than the gel battery.

Most AGM batteries are mid-sized and range from 30 to 100Ah. They can also be found in UPS, big and small for stationary and deep cycle use. They are commonly built to size and are found in high-end vehicles to run power-hungry accessories such as heated seats, steering wheels, mirrors and windshields. NASCAR and other auto racing leagues choose AGM products because they are vibration resistant.

AGM is the preferred battery for upscale motorcycles. Being sealed, AGM reduces acid spilling in an accident, lowers the weight for the same performance and allows installation at odd angles. Because of good performance at cold temperatures, AGM batteries are also used for marine, motor home and robotic applications.

AGM is making inroads into the start-stop function of cars. The classic flooded type is simply not robust enough and repeated cycling causes a sharp capacity fade after only two years of use. (See BU-806a: Heat, Loading and Battery Life.)

As with all gelled and sealed units, AGM batteries are sensitive to overcharging. A charge to 2.40V/cell (and higher) is fine; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell); a direct replacement with a sealed unit could overcharge the battery on a long drive. (See BU-403: Charging Lead Acid.)

AGM and other sealed batteries do not like heat and should be installed away from the engine compartment. Manufacturers recommend halting charge if the battery core reaches 49°C (120°F). Table 1 spells out the advantages and limitations of AGM.

Pros:
Spill-proof through acid encapsulation in matting technology
High specific power, low internal resistance, responsive to load
Up to 5 times faster charge than with flooded technology
Better cycle life than with flooded systems
Water retention (oxygen and hydrogen combine to produce water)
Vibration resistance due to sandwich construction
Stands up well to cold temperature
Less prone to sulfation if not regularly topping charged
Has less electrolyte and lead than the flooded version
Cons:
Higher manufacturing cost than flooded
Sensitive to overcharging (AGM has tighter tolerances than gel)
Capacity has gradual decline (gel has a performance dome)
Low specific energy
Must be stored in charged condition (less critical than flooded

Here is what I think!
Unless you have a specific need for a Gel Cell or AGM Battey I would probably sick with a regular old flooded battery. You can get them anywhere and they are a few bucks cheaper and as you read, easier to maintain. I would go with Interstate Batteries as well.

About the author, Eric

I have been a hands on DIY'er since childhood, yeah since childhood with the idea that the job has to get done. My job (not a career) history is not the typical job history. I have run successful multi-million dollar companies, I have started RV related businesses from ground up. Over the years I have acquired many skills, some self taught and taught by others in a hands on environment. Today everything I have learned over the decades has come together and now I love to help others and keep myself involved in my favorite industry, Recreational Vehicles! This is not even close to being finished......