The Leisure batteries typically found in caravans (and used to power lights, water pumps, and the like) are usually of the deep cycle variety. A deep-cycle battery is one designed to be regularly discharged right down, then recharged again without damage. Such batteries will last longer if they receive a top-up charge at regular intervals after being partially discharged.
Leisure batteries are vital for your caravan, campervan, or motorhome since they power the essentials in your living area. The lights, refrigerator, and even television are among them. These too must be recharged regularly to be able to function properly and repeatedly.
Caravan Owners are responsible for keeping their batteries charged. It is common practice to use an automatic battery charger for this purpose, although it can be done by using your vehicle’s alternator. If you plan on leaving your caravan unused for long periods, then you’ll need to ensure that the battery is kept charged to prevent damage.
A fully charged battery will hold its charge almost indefinitely and is usually safe to be left unattended for a couple of months. However, it’s still best to check up on it every so often and top up the charge levels if necessary. It may only take a few minutes out of your day to give it a quick 5 or 10-minute charge, but if you forget for several days or weeks, it can be an idea to check that everything is still working properly.
Therefore, to get the best life out of your caravan battery, it should be recharged when it falls to approx 80% discharged. If you are away in your van for longer periods between charges, this will probably mean more frequently topping up charges – perhaps every 3 days or so. This is because modern leisure batteries are designed to be used in this manner.
One of the most popular chargers for caravan use is the solar charger which has the advantage of being automatic, without any intervention required by the user. These units will detect when your leisure battery charge level drops below 80%, then top it back to 100% ready for use.
An alternative unit that is also suitable (and probably cheaper) is the mains-powered battery trickle charger, again equipped with an automatic cutout to prevent overcharging. But, again, if you can find a suitable automatic model, this will suit your requirements perfectly – and will be one less thing to worry about when camping!
You normally choose a slow charger, a fast charger, and an instantaneous charger; the latter is very expensive, so we will ignore this now. The question is, how long does it take to charge a caravan battery from a flat? The answer depends on what you define as being fully charged.
If you want to use your appliances with no worries about being left with a flat battery overnight, you need to be able to use them after about 12 hours on a charge. This is probably best achieved by a cheap slow caravan battery charger often supplied as standard, usually rated at around 2 amps charging current.
These can be either mains powered or run from your car battery kept topped up by a solar panel during the day. Note that using a fast charger may actually shorten your battery life and so I would not recommend this for this purpose. If, on the other hand, you want to leave your van stored for longer periods without having to run it every 2 weeks or so, then you will need a faster charge rate; otherwise, the plates inside the battery will become sulfated and this will destroy your battery.
For a quick overnight charge, you should be able to get one of these chargers for about £35, but beware you do not get what you pay for! It is best to buy them from caravan accessory specialists like Leisure Shop Direct or Westfield Caravans, who sell quality quality brands.
These are either mains or 12-volt models designed for charging leisure batteries without boiling them dry. They are usually quoted in amps; the higher the number, the faster they charge at 14 volts but be careful here because cheaper chargers may also damage your battery if you try to use it at 10 amps charging current, which is somewhat higher than the normal maximum current of 10% of the Ah capacity, for example, an 80Ah battery can be charged at 8 amps.
The most common ones are 3-stage chargers which do a bulk charge followed by absorption then finally achieve float charging to maintain the battery with only minimal power input, like trickle charging in effect. The good news is that you can use any of these chargers on your 12-volt battery; the slow 2 amp type will take 48 hours or more, and a 7 amp charger several hours.
The last one is probably not an issue if left overnight but bear in mind that it may boil dry during the summer when kept outside in hot weather. I have not been able to find a slower one than this, and the only reason I can think of needing such a low charging current is if you have a completely flat battery.
A quick guide to caravan batteries:
– A 100Ah leisure battery will typically take about 10 amps to charge it fully from flat;
– The Ah rating (i.e., the storage capacity of a battery) is always quoted at 20 degrees Celsius, so it may not be as good when used in your caravan;
– Unless you have a solar panel, avoid using cheap 2 amp slow chargers. Use this for topping up only and recommend a 7 amp one instead.
– A mains-powered 16 amp 13-stage charger is the best choice if you want to leave your caravan stored for long periods.
On a concluding note, a caravan battery should be charged as quickly as possible but take care not to overheat it. It is probably best not to use a car charger except in an emergency since this is likely to boil the battery dry and could also damage your starting system.
However, manufacturers constantly update their products, so I have just noticed that Westfield has started supplying a new 7 amp trickle charger with some of their new caravans, which is ideal for overnight charging; I have also noticed that these are now starting to include a battery temperature sensor which is an excellent safety feature that will switch off the power before it can boil dry or overheat.