Comparison of Battery Types for Camper Vans: Wet Cell, AGM and Lithium

Batteries are very important to every camper van. There are two distinct electrical systems in motorcoaches that you should be aware of: a 120-volt AC system (shore cable plug-in powered) and a 12-volt DC system (battery powered).

Even if you just plug your coach into shore power at RV parks and campsites all of the time, you still typically need batteries to operate some features, such as power patio awnings, leveling jacks, slide-outs, lights, the water pump, the water heater ignition, and even propane-powered refrigerators that need a small amount of battery power. A general understanding of the choices you have in battery types is a good foundation for anyone living the #vanlife. Remember: always seek professional assistance when changing your battery system from what the manufacturer originally designed your camper van to provide. Now, let's dive into battery types.

RV Battery Types

You may be wondering, "what types of batteries do camper vans use?" There are two general types of batteries that most camper vans use to power their 12-volt DC systems:

Deep Cycle Lead-Acid Batteries

Within this type, there are two versions of traditional lead-acid batteries that are most typical:

  • Wet Cell (or Flooded)
  • AGM (Absorbed Glass Mat)
  • Lithium Batteries

    These are the hip, new-kids-on-the-block in the camper van world.

    Can I use 6-volt Golf Cart batteries in my camper van?

    While RV's typically use 12-volt RV/Marine batteries for their 12-volt DC electrical systems, it's also possible to use two 6-volt Golf Cart batteries instead. The 6-volt batteries must be wired in series and used in pairs to provide a similar voltage and higher Amp Hour rating to meet your van's DC electrical system needs. You might consider 6-volt batteries instead of 12-volt batteries for your camper van because sometimes they provide longer usage hours than 12-volt batteries. 6-volt batteries come in both wet cell and AGM versions of traditional lead-acid batteries.

    Which type of battery is best for my camper van?

    When choosing the right battery system to power the coach of your new or existing camper van, there are a number of factors you should consider and weigh in your purchase or replacement analysis:

    Cost

    The difference in upfront cost between traditional lead-acid batteries and lithium batteries is A LOT. Lithium batteries cost about 8-10 times more than wet cell batteries, and about 3 times the cost of AGM batteries. Keep in mind, the old adage of "you get what you pay for" is very true with batteries. Lithium may cost a lot more, but they have a long list of benefits that explain their higher cost. And in the long run, they may be the least expensive option for you when all of the other factors are weighed in.

    Use Frequency

    If you rarely use your adventure van, and most of the time it just sits in your garage, in your yard or in storage, then traditional lead-acid batteries may be the right choice for you due to their much lower cost. AGM batteries are maintenance free, discharge more slowly than wet cell batteries, and don't require the watering service maintenance like the wet cells. They can be a good choice for longer term inactive use of your camper van but with wet cell batteries being so inexpensive, you can easily replace a battery that no longer works due to storage. Wet cell batteries can be a bit forgiving and brought back to life sometimes.

    Depth of Discharge (DOD)

    One of the more complicated aspects of batteries, especially with lead-acid batteries, is the depth of discharge...or how far down you drain the batteries before recharging them. Most lead-acid batteries have a significantly reduced life if they are discharged below 50% DOD. Whereas lithium batteries can be discharged to 80-100% DOD without much of any negative long-term effects. It's typically recommended to go no more than 80% DOD on lithium batteries for optimum battery life.

    Life Cycle

    The life cycle or lifetime of lead-acid batteries compared to lithium batteries, is really where lithium far outshines lead-acid. Lithium batteries can easily last 3-10 times or more charging cycles than a lead-acid battery. Lead acid batteries might be capable of 400 - 1,000 cycles, depending on their quality, maintenance and depth of discharge. Whereas lithium batteries are typically good for 3,000 - 5,000 cycles. If you're living full-time in an RV and charging your batteries every single day, then you'll go through lead-acid batteries a lot quicker than lithium. You might need to replace your lead-acid batteries annually depending on your depth of discharge and maintenance habits.

    Maintenance

    One of the reasons wet cell batteries are so inexpensive is because they require maintenance. You have to regularly check the fluid level, regularly make sure they are charged properly (not overcharged), and they need periodic equalizing to clean the internal plates. Along with occasional cleaning of the battery cables so they do not corrode over time. AGM batteries are sealed and basically maintenance free, but still have the concern of being overcharged. Lithium batteries are the most maintenance free and easiest to own.

    Size and Weight

    A big advantage of lithium batteries is that they weigh about 1/3 of lead-acid batteries and are often a bit smaller in size. Which can really add up when you have 2, 3, 4 or more house batteries in your motorcoach.

    Venting and Installation

    Lead-acid batteries (both Wet Cell and AGM) need to be in a properly ventilated compartment within your RV. Both wet cell and AGM batteries need proper outdoor air ventilation to prevent the buildup of hydrogen gas that can cause battery damage, explosions and poison the breathable air. If you allow hydrogen gas to buildup, even the smallest spark can ignite the air and cause serious damage to your travel van. Wet cell batteries must be installed with their top side vertical, because water can otherwise leak out of them. Lithium have the advantage of not producing hydrogen gas, but they still require ventilation to prevent thermal runaway. If a lithium battery gets too hot, it can reach a critical condition and explode. Lithium batteries can often be installed on their side in more space-restricted compartments.

    Type of Use

    If you typically or always plan to use your camper van at an RV park or campsite where you can plug into shore power, traditional lead-acid batteries are probably your best choice...either wet cell or AGM depending on your ability to properly maintain the batteries. Lithium batteries are most advantageous for boondocking and off-the-grid RVing.

    Stored Energy

    The ability of the batteries to keep their charge and their stored energy when not in use, especially when in storage, is tied to the battery type. Wet cell lead-acid batteries lose their charge the quickest, then AGM batteries, and then lithium batteries.

    Charging Speed

    Lithium batteries charge approximately four times faster than lead-acid batteries. And within lead-acid batteries, AGM charge faster than wet cell.

    Manufacturer's Warranty

    Lithium batteries have the longest warranty of the battery types.

    Weather

    One of the minor drawbacks to lithium batteries, is that they don't handle really cold or really hot weather well. They can't charge in freezing cold weather especially. This problem is typically resolved by providing a temperature-controlled storage compartment so they don't freeze or get too hot.

    Efficiency

    Lithium batteries are the clear winner in efficiency over lead-acid batteries.

    Internal Resistance

    Lithium batteries surpass lead-acid batteries when it comes to the flow of current within the battery itself.

    A few notes when buying new or replacement batteries for your camper van

    It's best to buy coach batteries for your camper van all at the same time in a matching set, so that they all have similar performance characteristics during their lifetime together.

    If you're interested in switching your coach battery system from lead-acid to lithium or vice versa, seek professional assistance. This might require changes to other components of your camper vans electric system, such as a DC-to-DC converter when switching from AGM lead-acid batteries to lithium batteries.

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