Motorhome Battery – Which One To Choose? 

Recently, caravanning is gaining popularity – a holiday destination, which is traveling in a motor home. Motorhome provides travelers with mobility and comfort, freedom from hotels and travel agencies, the ability to independently choose and adjust routes.

Self-powered Motorhome

For comfortable travel, such cars are equipped with electrical wiring and built-in equipment. Even small drop trailers have, at a minimum, lighting and USB ports for charging electronic devices. In hotel-type campers, electrical equipment is also represented by underfloor heating systems, air conditioners, zone climate control, refrigerators, coffee machines, hair dryers, water pumps, electric ignition stoves, various TV and AV equipment.

Each electrical appliance in the camper needs to be provided with a full-fledged autonomous power supply. Depending on their number and level of energy consumption, electrical wiring may include several electrical networks. The power supply of appliances and equipment in car houses is provided by standard autonomous power supplies for 12, 24 and 48 V.

Types Of Electrical Equipment In A Camper

All consumers of electricity in a motorhome are divided into 2 groups:

1. Automotive – headlights, standard lights, dashboard, interior and engine cooling system, starter, audio system and other types of automotive electronics and electrics.
2. Household – appliances used in the residential part of the camper. These include refrigerators, electric stoves, electric pumps, lighting fixtures, chargers for laptops, smartphones and cameras.

Why Do Household Consumers Need A Separate Battery?

Connecting household energy consumers to a car battery is not an option. Firstly, this will quickly drain the battery, and the remaining charge may not be enough to start the engine. Secondly, starter batteries are generally not designed to operate in a cyclic or buffer mode. They are designed for short-term supply of high starting currents necessary to start the engine.

When used for other purposes, car batteries quickly become unusable. Therefore, only low-power consumers of energy are allowed to connect to them. In other cases, including for autonomous power supply of equipment in a camper, you need to use a separate battery. Moreover, it should not be a starter, but a traction one – capable of long-term energy return.

Such batteries differ from starter batteries both in design and in technical characteristics:

• Less sensitive to deep discharges;
• Designed for intensive use in cyclic or buffer mode;
• Resistant to chemical degradation;
• Are capable of continuously supplying energy for the operation of any electrical equipment, instruments and devices for a long time.

Which Battery To Choose For A Motorhome?

Self-contained power supplies for 12, 24 and 48 volts are effectively used as batteries for campers . They are portable chargers with solid capacity batteries. Such batteries are supplied in a moisture-resistant version, equipped with a built-in protection board and a charger. Portable batteries allow you to feed a variety of energy consumers with a voltage of 12 V, and in the presence of an inverter-converter – and equipment for 220 V.

In terms of price, specific energy consumption and weight, lithium-ion type batteries, in particular, lithium iron phosphate (LFP or LiFePO4), are reasonably considered the best choice. They are:

• Reliable;
• Quickly charged from the outlet;
• Durable;
• With light weight and compact size, they accumulate a large amount of energy;
• Provide efficient power to all kinds of electrical appliances;
• Do not require maintenance;
• Safe to use – built-in protection board prevents overheating and other dangerous situations;
• Work stably in the temperature range from -20 to +50 °C.

Energy Calculation

The larger the battery capacity, the longer it will be able to power electrical equipment without being discharged to a critical level. As a rule, lithium batteries with a capacity of at least 100 Ah are installed in the battery compartment of the motorhome. To more accurately calculate the required battery capacity, you should take into account the power of energy consumers and their battery life on 1 battery charge.

An example of data for calculation is presented in the table:

Depending on the specific equipment of the motorhome with electrical appliances and appliances, it is necessary to calculate their total need for electricity. To do this, the power consumed by the devices is multiplied by the approximate time of their daily operation, and the resulting values are summarized taking into account all the devices used. This calculates the total power consumption per day or other period between battery charges.

Calculation Of The Required Energy Intensity Of The Battery

For example, we got a total energy consumption of 2500 Wh. In practice, energy consumption is higher than the calculated value, so when choosing a battery, it is recommended to take a margin of at least 20%. In our example, the total energy consumption with a 20% margin is 3000 Wh.

To calculate the energy reserve of a lithium battery, you need to multiply its nominal voltage by the capacity and efficiency. The efficiency of lithium batteries is approximately 95%. As a result:

1. For a voltage of 12 volt battery and a capacity of 100 Ah, we get: 12 V x 100 Ah x 0.95 = 1140 Wh.
2. For a voltage of 24 volt battery and a capacity of 66 Ah, we get: 24 V x 66 Ah x 0.95 \u003d 1505 Wh.
3. For a voltage of 48 volt battery and a capacity of 60 Ah, we get: 48 V x 60 Ah x 0.95 \u003d 2736 Wh.

Next, we compare the total power consumption of motorhome devices with the energy intensity of the battery, and select an autonomous power source with suitable parameters. In our example, you can take 2 batteries with a voltage of 24 V and a capacity of 66 Ah.

The Principle Of Operation Of A Battery For A Motorhome

Lighting fixtures and other low-voltage devices in the living space of the motorhome are powered by a separate 12 V on-board power supply with a storage battery. Household appliances are connected to it through low-voltage sockets. Equipment operating from a 220 V network is connected to sockets of another network, which, through the external connector of the camper, is connected to the power supply network of a camping or other stationary object when parked.

An alternative option for powering equipment at 220 V when the motorhome is parked is the use of a fuel generator. It can be portable or built into the camper. In addition, you can get an internal network of 220 V using an inverter-converter by connecting it to an autonomous power source. This option is universal – it is used both in the process of movement and during parking. The inverter power is selected 20% more than the total power of the connected electrical equipment.

Thus, power for a motorhome can be provided by different sources:

1. Rechargeable batteries, in other words – autonomous power sources.
2. Fuel generator or running camper engine.
3. Camping power outlet or other external power source.