Choose the right batteries, from 12v to 240v, and understand inverters, mains power and portable power before you GO away.
Car Camping and Caravanning
Requires a Car battery or a
Caravan/Motorhome with a leisure battery
Will power mid output items for long
periods of time.
- Coolers & Fridges
- Air & Water pumps
- Lighting & TV’s
Will power heating items but to a limited
degree and for a limited time
12 volt appliances can be connected to any of the
following power sources:
- Fitted with two crocodile clips an appliance can be connected direct to a car
or leisure battery.
- Fitted with a cigarette lighter plug an appliance can be connected direct to a
- Fitted with one of an array of caravan plugs an appliance can be connected
direct to a caravans 12 volt supply. Such plugs can be flat or round pin with 2 or 3 prongs.
How long will a 12 volt battery last?
That depends what you are running from it, so a few equations are needed!
- Firstly, all batteries are measured in Amps, so you need to know that
- Now divide this by the number of Amps the device uses. Remember if you are
running more than one appliance you’ll have to add all the Amps u.
How do I know how many Amps my appliance uses?
If it doesn’t say so on the packaging, use this formula:
How do I charge my battery from the mains?
There are 3 type of battery charger:
- Trickle Chargers (Float Chargers) - A 12 volt battery will
perform better if it is kept fully charged when not in use. A trickle charger is designed to be
left on to top the battery up and will then switch off automatically. Trickle chargers are better
at maintaining the life of the battery.
- Standard Charger - These will charge the battery faster but
have to be switched off manually. To work out how fast they will charge divide the amp rating of
the battery by the amp rating of the charger, like you do to work out how long an appliance can be
- Combination Chargers - These will perform both of the above
functions, but are more expensive.
How do I get electricity into the caravan?
If the caravan does not have either a consumer unit or a Zig unit, one must either be installed or see the instructions for getting electricity into a tent. Caravans with pre-installed electrics will have a consumer unit, which incorporates a fuse-board (to limit the current drawn, so as not to fuse the campsite) and a circuit-breaker (to cancel the current if an appliance short-circuits). These can be hooked up to the campsite electrics with an inexpensive hook-up cable (three pin circular setup).
Zig units are quite rare – not all caravans with 12v sockets are Zig-wired. They too have consumer units, but an on-board transformer converts the output to 12v DC, allowing caravan-specific appliances to be plugged in. These may also be hooked up with an inexpensive cable. The power provided by most campsites is around 10 amps, although they will vary from around 5 amps in smaller sites to around 20 amps provided by larger sites, with the purchase of an upgrade. This will affect the appliances you can use as some appliances, particularly those producing heat, have much larger wattages and will therefore pull more amps. It is preferable to use camping-specific appliances that are designed to use 5 amps or less. A further alternative is a leisure battery – see the relevant section. How do I get electricity into a tent? For this a mobile mains kit is necessary, as campsites will not allow any other method of hook-up.
This is a portable consumer unit, that provides a water-resistant plug-in point. One-socket adaptors are less expensive than three-socket adaptors, and there is nothing to stop you plugging in a ‘bank’ or splitter to allow more appliances in. However, be aware that if you withdraw more than 10 amps, you will trip your fuse-board, as this is their amp rating. Will it work abroad? Yes, but you may need the appropriate plug-adaptor. Polarity Testers are also essential. On the continent, there are no strict rules regarding how to wire a plug, as there are in the UK. If the polarity tester indicated the socket is wired differently, all appliances you use MUST be re-wired accordingly.
PLEASE NOTE : Be aware that many continental sites will not have an earth socket – if a conductive appliance short-circuits, there will be no mechanism for disposing of the charge. REMEMBER: Voltages may differ abroad, so some appliances may be unsafe to use (especially those producing heat). Transformers are available.
There are two types of battery:
1. Shallow-Cycle batteries (vehicle batteries) a. Which are designed to give large amounts of current, but only for short time. These require constant charging (usually via the vehicle’s alternator), and if flattened are irreparable, as the plates are quite thin and can bend.
2. Deep-Cycle batteries (leisure batteries, gel cells) a. Which give lower currents, but can do so for far longer. They can be discharged and recharged many times, as their plates are more robust.
What is the difference between leisure batteries and car batteries? Car batteries are designed to give large amounts of current for short time and then recharged (usually via the vehicle’s alternator) and if flattened are irreparable. Leisure batteries give lower currents, but can do so for far longer. They can be discharged and recharged many times.
Leisure batteries are used primarily for powering 12v appliances in caravans or tents, they can also be used as starter batteries on boats to power engine spark-plugs. How do they work? • Lead plates are dipped in either sulphuric or hydrochloric acid. As the metal dissolves, it releases ions, which cause a flow of charge. The more concentrated the acid, the higher the voltage. • When electricity is run through the battery, the process is reversed, and the dissolved metal ions join up-again with the plates. How long will a battery last? This depends how many amps you draw. All leisure batteries produce 12v.
See the problems section below, as these rules can be affected by other factors. The same formula as before can be used: wattage/voltage = amps Example: 12v Car Kettle: 120 watts Voltage from all leisure batteries: 12 volts 120/12 = 10 amps Batteries are listed with the amount of amp-hours of power they have. This means if you draw 1 amp per hour it will last for that many hours under optimal conditions. • 85 amp-hour batteries will last for 85 hours if drawing 1 amp per hour • 110 amp-hour batteries will last for 110 hours if drawing 1 amp per hour Then use the formula: amp-hours/amps = hours
Using the 12v Car Kettle from before: Amp-hours: 110 amp-hours Amps: 10 volts 110/12 = 11 hours If a 110 amp-hour battery is running the 12v Car Kettle at 10 amps it will last for 11 hours.
This is however only under optimal conditions. In reality, you are not going to use a 12v Car kettle for 11 hours so what does this really mean? Let’s use the following example to expand
If you add up the total watts used e.g. 240 + 120 + 25 + 500 = 885 watts To work out the total number of amp hours you divide by the voltage (12v) 885 watts /12 volts = 74 amp hours.
HOWEVER, in reality you would not get this performance for the following reasons: 1. If you run a leisure battery to total discharge it would not be as effective. 2. Amp hour ratings given to batteries are based on new batteries and in ideal conditions PLEASE NOTE: Never recommend totally discharging a battery ever, ideally you would never let it go below 50%.
Preserving the life of your battery
There are a number of ways to keep your battery working longer.
1. Switch off all appliances when they are not being used
2. Avoid using high drain appliances such as televisions etc
3. Keep your battery regularly topped up.
4. Consider a battery charging device. A guide to caravan voltage meters If your caravan has a volt meter fitted, if not a simple volt meter will suffice, you can check your batteries condition using the following guide. Even though batteries are rates at 12v a fully charged battery will give out nearer 13v (see guide below) Voltage shown on voltmeter Guestimate of battery condition 12.7v or higher Fully charged 12.5v Three quarters charged 12.4v Half charged 12.2v A quarter charged 12v or lower Empty Winter lay up Advice is to remove your battery from your caravan when you lay up your caravan. Make sure you keep it charged over the winter to ensure it is in good condition next time you want it. When removing your battery always disconnect the negative lead first (black) and then the positive lead.
Connecting your battery you should connect the positive terminal first and then negative. Always switch everything off first to prevent sparks etc. Battery Charging There are a number of devices on the market that will trickle charge your battery. The most environmentally friendly versions are solar powered or wind powered. Other alternatives are a generator or to use the power in your car battery. Although be careful not to drain your car battery - so it is only really advisable to do this while the car is being driven.
There are several ways to charge a leisure battery:
- Plug caravans into mains at a site. This will charge the battery through the switchboard in your caravan.
- Trickle charger:This delivers smaller currents while the battery is in use. These maintain charge only and will never fully charge the battery
- Split Charge Relay: This is inexpensive but must be professionally fitted. It runs from the alternator, and delivers the charge to the leisure battery until it detects the vehicle battery is fully charged. o It can only deliver 1 amp, so functions as a maintenance charge only, and will not re-charge a battery from flat.
- Solar powered power packs
What can damage a battery?
Temperature extremes will affect the chemical reactions. Leisure batteries only last for around 2000 cycles (one cycle is a full charge followed by a full discharge) Even when not in use, the battery must be charged every month. Failure to do this, or storing the battery when flat leaves phosphorus deposits on the plates which prevent the reaction taking place. The damage is usually permanent .
Mishandling. The casing is only plastic, and can crack is roughly treated. The contents are high concentration acid – do not get this anywhere near yourself, textiles or furniture! • Overcharging o Leaving the battery on a high charge over a week or more can damage it. Some chargers will have automatic cut offs to ensure this doesn’t happen.
What precautions should I take? Charge in a well ventilated area (in caravans, a hole should be drilled through which the charging hose should be threaded). When charging, batteries produce either sulphur or hydrogen gas, one of which is toxic, the other explosive! • Check the water levels – open up the caps with a coin, and make sure the liquid level is above the metal plates. If they are low, top up with distilled water, available at most garages.
REMEMBER: Always store vertically, as if tipped they will leak acid.
REMEMBER: It is a criminal offence to improperly dispose of an unwanted battery, as the chemicals are highly toxic. Most battery suppliers dispose of all lead-acid batteries by incineration.
Portable power stations
What do power stations do? They allow vehicle batteries to be jump-started if flat. This is not a permanent solution, and the vehicle battery should be replaced immediately. The power-station merely allows the battery to power the spark plugs until the alternator takes over.
REMEMBER: that each power-station has an on-board lead-acid battery. This MUST be charged every month, even when not in use, and MUST NEVER be stored flat, as both of these will cause irreversible damage to the battery. Inverters and Transformers Inverters are used convert 12v to 240V and vise versa, they enable 12v appliances to be powered by a 240V mains source and mains appliances to be powered by a 12v socket. Inverters and transformers won’t work for every device, they will not power appliances with transformers (e.g. laptops), as transformers require analogue Alternating Current, whereas the inverter produces digital Alternating Current, as it is doing so from a direct current appliance (i.e. a battery). They also will not work on appliances that produce heat, as they use current to generate warmth by friction, which the inverter is incapable of supplying. How can I convert 240v to 12v? A Rectifier is required. The inexpensive models only permit a few amps to be drawn, so are unsuitable for high-power appliances.
What is an inverter?
- An inverter will step up 12 volt battery power to 230 volt mains power
enabling you to run a normal home appliance off a 12volt battery source.
What will an inverter power?
Every inverter will have two wattage ratings. The operating wattage of the appliance
you are wanting to run must not exceed the lower of the two ratings. If you don’t have the wattage
of an appliance you can work it out using the following equation;
If the appliance has a peak output wattage (e.g. most TV’s) this must not exceed the
higher of the two ratings.
How do I get mains power into my tent?
A mobile mains kit allows you to run household appliances in your tent, provided
mains hook-up is available.
How do I get mains power into my caravan?
A mains cable allows you to power your caravan 12 volt electrics from the mains,
provided mains hook-up is available.
Car Camping and Caravanning
Requires a Caravan or a Camp site with main
Will power med/high output items
Note - Site supplies
are limited so high powered heating units may cause your supply to be switched off!
Can I run anything I like when hooked up to mains at a camping or caravan
- Site mains hook-ups are usually restricted to about 10 amps, if you try to
draw more that 10 amps your supply will cut out.
- The most likely appliance to cause a cut out will be a heating appliance (e.g.
kettle, heater). We sell low wattage mains 230 volt appliances of this type that will help to
avoid the problem of cut outs.
- You may find it useful to rely on gas appliances for your heating and cooking
Catalytic heaters are designed to provide powered heat in order to increase the internal temperature of the caravan.
Catalytic Heaters are designed to be compact enough to fit into any caravan with ease.
They work by using gas, and can burn without a naked flames.
They are very safe and the only gas heater to be recommended for use on boats as well as caravans. The other benefit of catalytic converters is that they do not produce condensation and that they only produce a very small amount of carbon monoxide.