Do I actually need a 12v battery in my caravan?

[Carouseller]

My leisure battery needs replacing. That got me thinking. Haven't been off-grid for years - always use an EHU and I don't have a mover... So do I actually need a battery installed in my 'van? Is there a technical reason to have a 12v leisure battery connected? Or can I remove the battery and just rely on the onboard charger/transformer to supply 12v to pump, lights etc.? I'd be saving some £££, some weight and the faff of keeping it charged between trips.

My unit is an elderly but much-loved folding Gobur Carousel and the owner's manual isn't entirely clear. I have contacted Gobur by email but they aren't replying.

Cheers!

 

[Tobes]

Generaly - Yes. The 12v battery is a buffer between the charger and the 12v items that use the power. Some items (like the pump) may have (relatively) large startup current draw that the power supply may or may not be able to deliver.
In practice, you may get away with it, but it may shorten the life of the power supply.

 

[Jaydug]

My leisure battery needs replacing.

You don't need a 12volt battery - but it's best to have one to smooth the output from the PSU. But also you don't need a leisure battery if you don't go off grid. I use a diesel starter battery which copes with my mover very well. Buy a small petrol-engined 12-volt battery for around 45quid. See https://advancedbatterysupplies.co.uk/product/heavy-duty-063/
With five cars in our family plus the caravan, I use the company I've mentioned. They are sound! (Hope I'm not breaking forum rules)

 

[Hutch]

As the others have said, yes, but you could get away with the smallest one, maybe not a motercycle on but check out the cheapest ones at Halfords.

 

[Lutz]

Unless UK caravans have different electrics then surely one can do without because their Continental counterparts don‘t have batteries as standard and get by like that.

 

[Hutch]

Unless UK caravans have different electrics then surely one can do without because their Continental counterparts don‘t have batteries as standard and get by like that.

A friend of ours who, lives in Lille, France but we get together near to Vermenton, near Chablis bought a Bailey after he inspected our Coachman with the rear Bathroom. He could not believe what the Brits fitted into the vans.
Le Grand Dolls Vans.

 

[Pfcmike]

I’ve got a Sprite Major (2018) and I used this on electrical hook up without a leisure battery for the whole of last year with no issues.
I had a motor mover fitted last month so have had to fit a battery to operate it.

 

[ProfJohnL]

As you can see you have received differnt and opposite answers. It all depends on what type of 12 charger has been fitted, There are three generic types, and it will depend which country the caravan was built for, and when it was built. I am not sufficiently familiar with Gobur caravans to know exactly which they had.

The oldest and most basic are half or full wave rectified unregulated units. These are basically 2A battery chargers, and must be used with a battery to provide a load and reservoir to enable higher current appliances like water pumps to be used. If used without a battery, the supply might not have enough current capability to run higher capacity products, or other appliance's may not run or could be damaged by the un smoothed output. Another problem is the output is a series of pulses at line or twice line frequency, which will reach a pal voltage of about 21V. If left connected to a battery with current being used for long periods in storage, they will overcharge and permanently damage the battery. Some batteries might explode, I know having had to deal with caravans damaged in this way.

The second type of charger is the same as the first but with a regulator to prevent excessive voltage generation, These are less likely to damage batteries but its not unknown, and they also typically only had a 3 or 5A output.

The third type is called a (linear) DC power supply, and it usually has a greater smoothed output current capacity of 5 to 7A and the output is also clamped to 13.8V, sufficient to charge a battery continually. They can be used without a battery, but they might only run a few lights or may be small water pump. They are better used with a battery

The most recent systems use Switch Mode Power Supply (SMPS) architecture. These don't have a heavy conventional line frequency transformer, instead they use a high frequency converter to keep size and weight and self heating low and to increase efficiency. These can provide much higher regulated output currents, and in many cases are sufficient to run the internal caravan appliance's without a battery.

In the absence of knowing exactly what type of charger/power supply you have already, its impossible to say it would be safe not to fit a battery.

 

[Raywood]

I have always been told you need the battery to smooth out the power and the Prof has explained the reason very well. As Tobes says though if you are always on a hook up the battery is only smoothing out the flow so the smallest cheapest one will manage although it would be best to take that off and make sure it holds it charge in Winter.
We did have a battery fail when in France on one visit there some years back and were able to complete the holiday without it , but I would not want to rely on that long term.

 

[RogerL]

I have always been told you need the battery to smooth out the power and the Prof has explained the reason very well. As Tobes says though if you are always on a hook up the battery is only smoothing out the flow so the smallest cheapest one will manage although it would be best to take that off and make sure it holds it charge in Winter.
We did have a battery fail when in France on one visit there some years back and were able to complete the holiday without it , but I would not want to rely on that long term.

There was a time when the output of the onboard power supply was insufficient to run all 12v items at the same time so needed the battery to make up the shortfall and then be recharged later when demand dropped - but modern power supplies have more power so not so affected.