Motorhome battery

Reading time: 10:27 min

Laptop, smartphone, refrigerator and lighting - anyone traveling by motorhome today depends on a reliable power supply to operate and charge electrical devices. But globetrotters don't always want to spend the night at campsites. In order to have an unrestricted power supply available even in the great outdoors, a supply battery in the motor home is essential.

With many years of experience in the industry, FraRon has proven itself to be a reliable partner for all aspects of mobile and self-sufficient energy supply in motor homes, cars or on boats. We carry a range of different supply batteries for caravans in our assortment. You decide which one to use for your purposes according to your needs. In this guide, we have summarized the most important information about caravan batteries for you.

What are the types of batteries in the motorhome?

In the motorhome, we basically distinguish two types of batteries: the starter battery and supply batteries. In all motor vehicles, the starter battery is responsible for supplying electrical energy for the engine starter. It also fulfills other important functions by ensuring emergency lighting when the vehicle is stationary and supplying energy to various consumers, from the control unit to the clock and radio. When the engine is running, the alternator recharges the starter battery. This is either a standard wet cell battery or an AGM lead accumulator.

In contrast to the starter battery, the supply battery in the motor home has the task of supplying the connected consumers with energy. If you are not at a campsite where you can use shore power, the motorhome battery is particularly important. Because without its energy, the lights stay off, the refrigerator stays warm and the smartphone battery is empty. Depending on the requirements, different types come into question as a supply battery. And you also have different options for the type of charging, from the socket at home to the use of solar modules to generate electricity from the power of the sun.

What does the on-board battery have to do?

We place high demands on a motorhome battery, because without it the energy supply for our consumers outside the pitch infrastructure is not secured. It must

To meet all these requirements, it is important to pay attention to quality when buying a motorhome battery. Here at the FraRon online store, we only carry high-quality rechargeable batteries, for example from Victron Energy, Bulltron or our own brand.

Cycle stability - crucial for long battery life

If you want to buy a new motorhome battery, the cycle stability is a decisive value in the selection. It indicates how often the battery can be discharged and recharged without a specified loss of capacity. The higher the cycle stability, the longer the service life. The number of possible charge cycles is directly related to the depth of discharge. The following example illustrates the dependency:

Manufacturers of lithium batteries, for example, state that the battery can be discharged 2,000 times before the original capacity is no longer reached during the following charge. However, this specification refers to an 80 percent discharge, which does not occur permanently in practice. If you recharge the RV battery when its capacity is still at 50 percent, the charging cycles are almost doubled.

In the supply batteries for motor homes, boats and other vehicles, we distinguish four types: Wet batteries, AGM batteries, GEL batteries and lithium batteries. We have bundled general information, details on the properties as well as advantages and disadvantages for you in the following paragraphs.

1. Wet batteries

Conventional wet batteries contain the electrolyte in liquid form. This brings with it some peculiarities in handling. Older models in open design (with screw caps) must be maintained, which specifically means that you should regularly refill distilled water. If the highly explosive gases cannot condense in the housing, a hose is included to lead them outside. Due to the danger of the gas and the non-spill-proof design, open wet batteries are no longer used in the interior of motor homes. They are still sometimes used in outdoor storage compartments with good ventilation.

2. AGM supply batteries

The long-life AGM supply batteries with 12 V are available from FraRon with capacities between 14 and 220 Ah. The low self-discharge guarantees a functioning battery system even during longer periods without use. At the same time, AGM batteries can be safely installed in all positions in the motorhome and are completely leak-proof. The supply batteries for all motorhomes are equipped with a micro glass mat in which the acid is located and bound (AGM: absorbent glass mat). This technology is not very sensitive to cold, so that nothing stands in the way of a camping trip to the far north. AGM batteries also work well in expedition vehicles because they are vibration-resistant. The battery type is fast-chargeable and excellently suited for high-current discharge. We therefore recommend it in conjunction with powerful inverters. AGM batteries are characterized by their freedom from maintenance: The batteries do not gas and you do not need to refill water. However, make sure to use the appropriate charging technology.

3. GEL supply batteries

Silica binds the sulfuric acid tightly in this type of battery, so that the electrolytes thicken and a gel is formed. This makes the GEL supply batteries absolutely leak-proof. At FraRon, you can get the RV batteries with a voltage of 12 V and in capacities between 60 and 220 Ah. In its properties, the GEL supply battery is similar to the AGM supply battery. It is also only slightly self-discharging and can also be mounted lying on its side. The design makes it maintenance-free. GEL supply batteries for caravans are characterized by a particularly long service life. Unlike AGM batteries, however, they are not designed for high-current applications (powerful inverters), but rather for endurance and reliability. A particular advantage is that GEL batteries can reach a high depth of discharge without suffering direct damage. However, this requires them to be recharged as quickly as possible.

4. High-End power supply with lithium batteries.

RV batteries made of lithium or LiFeP04 (lithium iron phosphate) use technology comparable to that used for charging smartphones. Significantly smaller and with a greater current storage capacity than AGM and GEL, they can be easily stowed in motorhomes or boats. They are completely maintenance-free and even an unintentional complete discharge cannot harm them. The integrated battery management system (BMS) protects the cells from damage due to overcharging, deep discharge and overtemperature. Lithium batteries have significantly more usable energy available: While an average depth of discharge of 50 percent is applied to GEL and AGM batteries, up to 90 percent of the energy can be used in RV batteries made of lithium. This makes it possible to design the battery system much smaller, which not only offers space advantages but also significant weight benefits. The high-quality supply batteries for motor homes score points with their fast charging capability and up to 3000 charging cycles. In addition, they are suitable for both high-current draw and micro appliances.

Characteristics of motorhome batteries


The nominal capacity in Ah differs depending on the model of the RV battery. You can find it in the respective product description here in the FraRon online store. In addition, there is another important parameter: information on the reference time from C1 to C20. The background is that the higher the current drawn, the lower the available capacity. C1 therefore means that the total capacity is used within one hour. C20, on the other hand, describes that the battery is completely discharged in 20 hours.

Charging end voltage:

The end of charge voltage must not be exceeded while charging the RV battery, otherwise the grid corrosion would cause the battery to gas. The overcharging can not only damage the energy storage, but also become very dangerous due to the formation of oxyhydrogen gas. Normally, a wet battery can handle exceeding the end-of-charge voltage for a short time. However, AGM and GEL supply batteries are very sensitive to this. For them, the value is 14.2 to 14.6 V, while for wet technology it is usually 14.4 V.

Float voltage:

The float voltage counteracts the self-discharge of the RV battery. It comes into effect when the battery is fully charged and is 13.5 to 13.8V for all lead-acid based battery types. For lithium batteries, mostly between 13.2 and 13.5V.

End-of-discharge voltage:

The final discharge voltage must not be fallen short of when discharging the motorhome battery, because then there is a risk of deep discharge. Depending on the battery type, this can cause damage and irreversible loss of capacity. In lithium batteries, this is prevented by the battery management system (BMS).

Batteries for solar panels in motorhome

A special solar battery does not exist, because they are always normal supply batteries for the motorhome. Only their use is special, because such an accumulator should not be charged exclusively through the socket on campsites, but also fed with solar energy. For this purpose, AGM batteries or lithium battery are best suited. Of course, the cylken strength plays a major role. However, it is also important that the battery does not have too much internal resistance. For this reason, GEL supply batteries are also only partially recommended for use with solar modules. This is because, due to the construction, the internal resistance of GEL is higher compared to AGM or LiFePO4. Since the current generated by photovoltaics is often low, a GEL supply battery would hardly be able to be charged with the energy of the sun at a state of charge above 80%. With AGM supply batteries, the process is more effective. It is optimal with lithium batteries, since these absorb the full current almost up to 100% state of charge.

Buying advice: How do I find the right battery for my motorhome?

In order to select the appropriate RV battery, you must first determine your individual consumption, and secondly, determine the appropriate battery type. You should ask yourself the following three questions:

  1. How much power do I need?
    This is how you determine what capacity the battery must have. By connecting several batteries in parallel, large capacities can be realized.

  2. Which energy sources do I use?
    This determines which battery technology is best suited to your requirements. If you often want to stand outside the campsite and use self-sufficient photovoltaics, you are better off with AGM and lithium than with GEL. The same applies to powerful inverters. Lithium batteries are ideal for all requirements.

  3. How much money can/do I want to spend?
    Your budget also has an influence on the decision, because the high-end lithium camper batteries are not affordable for every caravan fan.

The following table clarifies for you the most important facts about the three significant types of RV batteries at a glance:

How do I determine my electricity needs in the motorhome?

Before you can buy a new RV battery, you need to know how much electricity you need in the first place. Therefore, balance your consumption as accurately as possible. To do this, you need to write down the power consumption values of the devices you use and multiply them by the time they are normally switched on. It is best to write down the numbers on several days and average the result. Don't forget to take into account consumers you take for granted, such as lamps, which you may not even notice at first glance. You may even be able to identify potential savings by replacing old halogen lights with energy-efficient LED technology, for example. If you are not only on the road in the summer, you should not neglect to balance your consumption in the winter, because here the electricity use is often much higher due to heating and lighting.

Which motorhome battery is best for me?

If you know your consumption and also whether your motorhome battery will be supplied by shore power most of the time or you will be largely self-sufficient with your own solar system, there is only one decision left: Wet, AGM, GEL or Lithium LiFeP04 battery? We give you the following recommendations:

Wet batteries are outdated because of the maintenance required and the danger posed by gassing. You should therefore not consider converting to wet technology. AGM and GEL supply batteries are the best solution for most normal consumers. GEL batteries are considered to be a bit more durable and reliable, and are therefore suitable for all motorhome fans who mainly spend their time in the caravan on weekends and vacations. AGM supply batteries charge well from solar panels and are designed to work with high currents and powerful inverters.

The lithium supply batteries are the top of the modern RV batteries as the best energy storage currently available on the market. The many positive features come at a price, which is why the purchase is hardly worthwhile for occasional campers. However, anyone who hibernates in their caravan, tours often and for long periods of time and stays far away from the nearest power outlet or needs a lot of electricity, takes full advantage of all the benefits of the lithium battery.

FraRon tips around the supply battery

To ensure that you benefit from the longest possible service life for your motorhome battery, we have put together the best tips for charging and caring for the energy storage unit for you. Because even the best battery can quickly suffer damage if used improperly and take the joy out of the freedom adventure.

Charge battery correctly

There are five different ways to charge the RV battery:

  1. with shore power: use a modern battery charger with IUoU characteristic to apply the correct charging procedure with the appropriate charging end voltage. As soon as you connect the cable to the socket on the pitch, the on-board battery is automatically charged with the standard household shore power.

  2. With power generator: It is noisy and therefore very annoying - both for yourself and for their environment. Therefore, power generators are not a perfect solution to charge the supply battery. Another disadvantage is that the device can often provide little more than 12 volts, so the battery will never be full.

  3. with solar power: when the sun shines, you can get the electricity you need directly from the bright rays. To do this, you only need solar panels on the roof of your motorhome or a mobile version to set up.

  4. Via the alternator: While driving, the alternator not only recharges the starter battery, but also your supply battery(ies) thanks to the isolating relay or charge booster. If you are at the campsite all day, however, this charging option is not available.

  5. with a fuel cell, this generates the energy by burning methanol. The units run very quietly and produce almost no exhaust fumes.

Note: Be sure to use the right cables with a suitable cable cross-section, so that resistance and voltage drop are not too large.

Maintain battery properly

How long the life of the motorhome battery really is depends greatly on proper battery care. Therefore, avoid deep discharge for all types of batteries. Even if the type can cope with being completely drained for a short time, it is better to refill the reserves in good time. However, you can take care of your battery not only during the caravanning season, but also during winter storage to maintain its cycle stability. Before you put the vehicle into storage, fully charge all batteries. When doing so, be sure to disconnect the energy storage unit from both the battery management system and all consumers. If the battery is not used for a very long time, an intermediate check and, if necessary, a short recharge is recommended. AGM and GEL batteries place higher demands on winter storage: GEL supply batteries should be fully charged, then disconnected and recharged every two months at the latest. AGM supply batteries can be left connected directly to the charger after being fully charged, so that the float voltage takes over.

Buy camper battery at FraRon

In FraRon's online store you will find the right RV battery for every need. In addition, we carry everything you need for the power supply of island systems, such as battery cables and inverters. Whether AGM, GEL or Lithium - we are happy to advise you and answer your questions! Just give us a call or send us an e-mail. If you wish, we can also install your new supply battery in your motor home. Simply use our installation service.

Selected for you

Show all