What do we mean when we talk about power in a campervan?
Probably one of the biggest misconceptions when buying a campervan is to do with the very modern problem of electrical power. We all need electricity in our lives- some more than others, but when we live in a modern home where electric supply is never an issue, it is far too easy to underestimate how important it is when we are in our vans.
Living in a campervan is not the same as living in our houses. That is one of the main attractions of owning a campervan, but to assume that our van will have the same power capacity of a modern home would be a little foolish. I am happy to say I was that little foolish camper when we had our VW T6 Kombi converted into our beloved campervan- Nelson. I had no idea about how campervan electrics worked or what our requirement from the system would be. After 4 years of van ownership- I am happy to admit that I still have no practical skills in electrical systems, but I do have a good idea of what works, and more importantly does not work when living in a van.
There are two main electrical systems in a campervan, and most vans tend to have both.
The 12v system
The 12v system runs off a leisure battery which is a subsidiary battery to the engine battery. The engine battery powers the engine and the leisure battery looks after all things in the living accommodation- and pretty much never the twain shall meet.
Both are obviously batteries, but they are very different in nature- the engine battery releases very short doses of charge very quickly, the leisure battery releases a lower charge, but over a considerably longer time period.
The 12v system runs all the interior lights, USB/12v sockets in the living area (the engine runs those in the cab area), the fridge, the water pump (if you have a tap) and any fan within a heating system. We have a LPG heater for use in the winter, but it’s fan pulls a surprising amount of battery power. It is fair to note that this is also a well publicised issue with diesel heaters.
The 12v system needs ways to recharge the power held within the batteries. This can be done in three main ways.
Via the engine is the most common way of charging the leisure batteries. In older vans this was done with a split charge relay straight from the engine alternator to the leisure battery. In most modern vans, that have smart alternators, you will require a smart battery to battery (B2B) charger fitted. These clever devices hook into the power generated by the engine when driving and supply it in a consistent way to the leisure batteries.
Many B2B chargers also accept a power input from solar panels. This is a really efficient way to keep your 12v system fully charged. We started with a flexible solar panel on the roof, but it just didn’t serve us well as they are far less efficient than the solid state panels. Once we upgraded to a 150w solid state panel we have never looked back. Our fridge now comfortably keeps ice in the heat of the summer for days on end. Solid state panels do not look as pretty, but they do keep you powered up. We would not be without ours.
Another way to charge the battery is from the mains (via EHU) using a mains charger. We had one retrofitted when we upgraded the solar panel, but to be fair we rarely feel the need to use EHU now as the solar panel is so efficient. A mains charger is useful in the depths of winter when solar struggles with the lack of sun.
The 240v system
240v system runs via an electric hook up (EHU) to the mains supply via an external power cable. It provides pretty much the same system as what you would expect at home via domestic 3 pin sockets. However, when on campsites, and particularly in Europe, you have to be careful of the amount of load that you put on the system- remember that everything originates from a single socket outside the van. If you load it up with kettles, toasters, hair driers and straighteners, you may trip a fuse, just as you would at home if you tried to run everything off one socket.
The 240v EHU system runs all the 3 pin domestic sockets in the van- we have two of these and purposely chose sockets that had integrated USB sockets included which is great when you want to quickly charge phones, etc.
Two added 240v features that we retro-fitted to our van are a transformer to power the fridge directly from the mains supply, and a mains battery charger that keeps the leisure batter in tip top shape when on EHU. This means that the moment we hook up, our fridge runs directly from the mains source and frees up any demand on the leisure battery. In addition, all the time we are hooked up, our battery gets a smart charge from the mains that we can monitor via an app on our phones.
Common misconceptions that we had about electricity in a campervan
When we park up- all the sockets, lights and appliances would run indefinitely, and we could use them just like at home. FALSE- a leisure battery has a very limited capacity- it is not comparable with home. You will need to carefully consider your energy usage to get the best out of your leisure battery. If you have high energy requirements you will most likely need to invest in a larger battery bank.
We can always use the 3 pin sockets when in the van. FALSE- they only come into use when you are using EHU- when you are not hooked up they are obsolete.
LED lights hardly use any battery charge. FALSE- modern campervans do use energy efficient LEDs, but they tend to have far too many LEDs within the van so any saving is negated by the extra lighting.
Modern campervan fridges happy run off leisure batteries. FALSE- although they are so much more efficient than fridges in the past, they remain the biggest load you will probably run off your leisure batttery. Fridges are a constant frustrartion to campervan owners- it took us a good few years to work out what works best for our van.
One leisure battery will be fine for a weekend trip. FALSE- most campervans come with the smallest capacity batteries to save on costs. A 90Ah battery will only provide 45Ah which is not enough to run everything for a 2 night camp. If you have a larger battery this may help. We upgraded to 2x120Ah batteries that give us 120Ah working capacity which looks after us on our more extended trips.
The fridge will run off the EHU at campsites. FALSE unless you have a specific charger fitted that runs direct from the EHU to the fridge. They are not very much to buy and fit, but many converters save costs by not fitting them as standard. Ironically, even when we are on EHU we have to remember to switch the fridge off the 12v system for the mains power to kick in. If we forget, the fridge continues to pull from the 12v system and drains the leisure battery.
The leisure battery will charge when the EHU is used. FALSE- unless you have a mains charger fitted to the EHU system. Most vans do not have this facility which is crazy! We were crazy for a good few years until we understood what we wanted and had a mains charger fitted.
There is loads of power left in the battery- the volt gauge says so. FALSE- modern lead acid leisure batteries can be damaged if you let the charge go too low. Anything below 12v is a risk. That is why the published amp hour capacity on lead acid batteries are not a working capacity. The safe working amp hours is only 50% of the full capacity.
How to keep things efficient day to day
Fridge settings
Set it on it’s lowest setting when parked up.
When driving, ramp up the settings as the battery will take power from the engine.
On a night, turn the fridge down or even switch it off.
Keep the fridge door closed as much as possible.
Keep the fridge full to hold the cold.
Pre-chill the fridge using EHU from home before any trip away.
Lighting options
Ensure that you have your LED lights on separate switches to use as little light as required. A single switch that lights up all LEDs is a power disaster.
Use other light sources such as battery fairy lights, candles, battery lamps as an alternative to van LEDs.
If you have the design option, plan for as few LEDs as you can really mange with. We have some very designer down lighters in our tailgate that we have never used!
Consider a solar option
A professionally fitted solar panel system is not cheap (but also not too expensive!), but will increase your flexibility to run off grid for longer periods of time.
The electric system that we have in our VW T6 Camper Nelson.
Ring Automotive B2B charger. This was one of the very first B2B chargers produced for smart alternators as used in VW T6 vans. It is not ideal as it has a known software issue that requires a soft reset periodically. In an ideal world, with the benefit of hindsight, we would have gone for a Victron solution, but the Ring does works with the periodic resetting required so we are living with it for the moment.
2x120Ah AGM Leisure batteries. We upgraded from just 1 battery and the performance and reliability improvement was significant, although the second battery does take up more storage space.
150v solid state solar panel. The best power upgrade we have made. Beats the flexible solar panel hands down and keeps us topped up all summer long.
Victron Energy Blue Smart IP22 Mains Charger to run off our EHU system. A great piece of kit to keep the battery healthy when hooked up. In reality, now the solar is doing so well for us, we rarely need this charging option.
USB 12v Sockets- 2 sockets and a traditional cigarette lighter socket that we rarely use.
Water pump- needed for the tap but when in use it uses a huge amount of energy.
LED lights- far too many. We have 4 in the main living area, 2 above the hob and 2 in the tailgate. We could light up a runway with these. We mainly use the 2 above the hob for ambient lighting.
Dometic CoolMatic CRX 50L Compressor Fridge. Who doesn’t love a cold beer or ice in their G&T? Expensive yes, but an essential not to be skimped with- don’t even think that a powered cool box can compete- they can’t.
Propex HS2000 12v LPG heater- we love this in the winter and it means that we can use the van throughout the year. Even in sub-zero temperatures it only needs 5 mins to warm up the van. It does however use a surprising amount of battery power to power the fan.
240v consumer box- to keep things safe- I don’t really understand what it does- but you definitely need one.
2x240v plug sockets and 4 USBs on the 240v system when using EHU. A lifesaver for charging laptops and camera batteries that do not have a 12v charging option.
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