Does my car charge my caravan battery?

In today’s article, we will discuss: Does my car charge my caravan battery? We will explain how you can charge your caravan battery, how much autonomy it has and how to make it last longer.

Does my car charge my caravan battery?

If everything is wired correctly, yes, your car will charge your caravan battery whilst driving. When you start the engine of your car, if the caravan is plugged in, the current of the car (alternator + battery) will recharge your caravan battery. If the cable heats up, the current is too strong and it means that the battery is discharged.

How are caravan batteries recharged?

You can recharge the battery of your caravan:

  1. While driving (thanks to the engine alternator)
  2. By plugging the motorhome into a 220-volt outlet (in a service area for example)
  3. By alternative means such as solar panels, a fuel cell, or even a wind turbine.

Note that ideally, the caravan battery should be recharged from the mains once a month minimum, for 24 to 48 hours to optimize the life of the battery charge.

When we start the caravan engine, the motor automatically charges its own battery and when it is charged, it sends the current to the auxiliary battery in the passenger compartment.

Assuming (as usual) that the engine battery is always charged, the full recharge time of the auxiliary battery is approx. three-quarters of an hour to an hour, (depending on the type of vehicle, the type of battery, the alternator, etc.). and if we have two auxiliary batteries, the time would be about an hour.

It should be borne in mind that if you drive at night it will take a little longer to recharge the auxiliary batteries since part of the current produced by the vehicle’s alternator is spent on the main or population lights, since as we said before, the engine preferentially charges the Its own battery and when it has already been charged, it sends the current to the auxiliary or auxiliary ones.

A second possibility is when we are at a camping site,  that they are recharged with a battery charger installed inside the caravan (there are caravans that have it already installed and if it cannot be installed easily) to use it when we connect the caravan at a camping site.

Now you must bear in mind that these chargers take much longer than the vehicle’s engine to charge them, they are usually 6 or 8 A. So the charging time for a 100Ah battery is 12 to 16 hours minimum and if we have two batteries, double it.

If you want to recharge faster, you must install a special 20A electronic charger.

What is important to know is that the vehicle’s alternator charges the passenger compartment auxiliary battery (s) when the engine is running Provided that these batteries have some charge. 

If for some strange reason they have been completely discharged, there is a Relay that does not open and then they do not recharge, with which you run out of Light inside the caravan. 

It can be a problem because if you are travelling, you have no choice but to enter a campsite and connect the motorhome to 220 V. So that the charger inside partially charges the auxiliary battery, takes a little charge and can with the engine start to continue charging it.

We recommend that you install a manual Bypass, so if this happens to you, it passes through the Bypass for a couple of minutes or three current to the auxiliary battery and you can start the engine and recharge it normally with it.

What autonomy does a caravan battery have?

This is a question that is difficult to answer because the electric autonomy is estimated according to the consumption and the equipment on board.

It is clear that if you have a van or a small motorhome with the basic amenities, without a TV, your heater and refrigerator run on gas, and you drive every day, you are very likely to fall over. never out of power!

How to calculate its consumption?

You need to assess your electricity consumption, depending on your type of equipment, your lifestyle (duration of electricity consumption) and the means you have to cover these needs (capacity of the living area battery). It also depends on whether your gas cylinders supply some of your devices.

How to make your caravan battery last longer?

If the capacity of your battery rises to 100Ah, and your energy consumption is higher (this is the case if you have additional energy-intensive equipment such as a TV, air conditioning, etc.), you will have to review your consumption at lowering or increasing the energy capacity of your motorhome.

Tip: If you want to make your battery last, it is best not to use more than half of its capacity and to fully charge it between two discharge cycles.

How to increase the electric autonomy of your caravan?

It is common practice to seek solutions to have greater autonomy in order to reduce one’s dependence on service areas and campsites. There are various ways to do this.

  • Install LED bulbs: You can reduce your consumption by replacing all of your interior lightings in your motorhome with LED bulbs: in the living room, kitchen, bathroom, bedroom, toilets …
  • Install solar panels: Adding a solar panel to the roof of a recreational vehicle (motorhome, van, campervan) is also a good solution. A 110 Watt panel (like ours for less than 150 euros) delivers between 10 and 40 Ah depending on the level of sunshine.

Obviously, the problem is that in winter or in bad weather, the performance of your panel decreases.

  • Buy an additional battery: You can also install an additional battery with the same technology and the same capacity that you will connect in parallel.
  • Invest in a lithium battery or a fuel cell: This is a significant initial investment because it takes around $1,000 for a Lithium battery and around $1,300 for a fuel cell, but these types of battery have many advantages: they recharge very quickly and the number of cycles is higher. 

Final tips

We advise you to frequently check the condition of your caravan batteries. If you spend a certain time without taking the motorhome, it is recommended to disconnect the terminals so that there is practically no consumption.

 If you do not want to disconnect the terminals, you have to start the engine occasionally and it is important to check that the entire passenger compartment electrical system is switched off.

If you need personalized advice on equipping your caravan, van or converted van with a battery, converter, generator or even a solar panel kit, please feel free to contact us! 

FAQ on Does my car charge my caravan battery?

How long does it take to charge a caravan battery?

The charging time for a 100Ah caravan battery is 12 to 16 hours minimum and if we have two batteries, double it. If you want to recharge faster, you must install a special 20A electronic charger.

What is a booster to charge batteries?

A Booster auxiliary battery charger is electronic equipment capable of taking the charging intensity of the vehicle’s alternator and generating a great load intensity towards the auxiliary battery, the most efficient chargers produce between 25 and 40 Amps PER HOUR direct to the auxiliary battery.

How do you recharge a caravan battery? 

The batteries are recharged automatically thanks to the energy generated by the motor. First, the main battery is charged and when it is fully charged, it sends current to the auxiliary battery.


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