Leisure Battery
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| Leisure Battery | Electric Hook Up (EHU) | Solar Panels | Generators |
Description
For those who are not aware, the Leisure Battery in a caravan is not the same as a car battery. A car battery is designed to send a large surge of power to the car starter motor in a quick burst. It will then constantly receive a large charge to keep the battery fully charged. This way a car battery will always remain at a high charge. When a car battery becomes flat the charge level of the battery is usually affected.
With a Leisure Battery the structure has been modified to allow a slow discharge so that the battery can become flat without any major loss to its charge level. There will probably be some minimal loss to the battery charge level, but the leisure batteries are supposed to be far more capable of dealing with being completely discharged compared to a car battery.
Power Ratings
Various power ratings are available for a Leisure Battery. These are usually based on how many ampere hours (Ah) the battery can supply over a 20 hour period in ideal conditions. In reality the actual power of the battery will be less than what is quoted. Most Leisure Batteries start around the 60-80 Ah, where more powerful and expensive batteries can be 200 Ah and beyond. The larger powered batteries are also larger in size, so you may find that some batteries do not fit in your battery compartment.
To work out how long a battery will last you, you will need to know what you plan to run off that battery, how much power is drawn and how long you expect to run that item. The example below gives you an idea on how to calculate you usage.
| Equipment | Wattage | Hours | Total Watts |
| Three 8 Watt Lights | 24 | 3 | 72 |
| Water Pump | 50 | 30 Mins | 25 |
| Television | 75 | 3 | 225 |
This gives a total of 322 Watts per day.
Divide this by your 12V battery rating.
322 divide by 12 = 26.8 Ah per day.
On an 85 Ah battery you may be able to run your appliances for around 3 days before the battery is completely exhausted.
Note: That manufacturers may rate the appliances at certain conditions when they are using the most power. In reality the appliance may use less power.
You will usually find the wattage of each appliance on the equipment or within the operating instructions. Failing this it is possible to use a meter to see how much power is being used. This is only recommended if you are competent with working with electrics. Always seek advice from your dealer or a qualified electrician if you have any doubt about this or any other electrical matter.
You should also be aware that a battery will self discharge itself over a period of time. This is usually at a very slow rate so when in use you should not really notice this.
This is a non sealed battery where you can see the caps that unscrew over each cell.
On this model there is a handle for carrying that usually covers the terminals.
Maintenance
There are various technologies in use but most of the Leisure Batteries are constructed in a similar way. Looking at a battery will also let you know if it is a sealed battery (very low maintenance) or if it is a battery that requires some user maintenance. On a battery that requires some form of maintenance from you, there will be caps or covers over each of the cells. These can be removed so that you can check the electrolyte level of each cell (the plates inside are covered with liquid – battery acid). If these are exposed then they should be topped up with distilled / de-ionised water, never use water defrosted from a freezer or tap water. If cells have been left dry for too long then there is a high risk that these have become damaged. Some batteries should be topped up at certain levels so always check documentation or seek advice on your battery.
If the caravan is to be stored for a long period of time it is advisable to remove the battery and store it in a cool well ventilated place. Always check the charge level of the battery every month. You should also clean the battery tray, terminals and connecters yearly and smearing the connecters with petroleum jelly.
The battery charge level can be tested in two different ways. You can either use a digital volt meter (multi-meter), or a hydrometer. Using the digital multi-meter is probably the easiest as you only have to place this on the two terminals of the battery and take the reading. A hydrometer can tell you more on the condition of each cell, but this is not as quick and clean, as you have to draw the electrolyte out of each battery cell. Most batteries will have a charge of 12.7V or over when they are fully charged. If the level drops below 12.4V, usually 50% charged, it is recommended that the battery is fully charged again to avoid any damage to the cells. On most batteries a hydrometer reading of at least 1.27 will be the equivalent to the 12.7V reading on the volt meter, where 1.2 will be equivalent to the 12.4V. If you use a hydrometer then please refer to the batteries documentation, refer to your dealer or the manufacturer as some batteries will have different readings.
It is also possible to take the battery to your dealer or a garage where they should be able to conduct a discharge test. This will show how long that the battery can run for. If a battery does become damaged it may still show as being fully charged by your own tests, even though the length of time to discharge the battery may have been reduced. Your 100 Ah battery could actually on be the equivalent to a 60 Ah battery.
Note: Some warranties can become void if the battery was not maintained as per the documentation that was supplied with the battery.
Safety: Care should always be taken when working with your leisure battery, due to the acid and gas content that the battery holds. Always work in a well ventilated location, beware of splashes from the acid and never smoke around the battery.
Charging
Almost every Leisure Battery should only be trickle charged. There have been quotes that you should never charge the battery more than 10% of the rating of the battery. Where the battery is rated at 65 Ah then you should not charge it above 6.5 Amps. It is always advisable that you check any documentation that you have and / or consult your dealer or manufacturer of the battery.
If you are charging the battery away from the caravan you should remove the caps on a non sealed battery to allow the battery to vent (release gas) properly.
For sealed batteries charging can become more complicated. These batteries can often deteriorate if they are allowed to vent their gas. This usually occurs when the voltage on the cells reaches around 14.1 volts. Specialist charges will usually monitor the voltage of the battery and cease charging when a certain level is reached. Always consult any documentation, your dealer or the manufacturer if you have any doubts about your battery.
Some people leave their caravan connected up to the mains to constantly charge the battery. With modern caravans and proper charges this is possible. Check with the caravan and battery manufacturer to see if your equipment is suited for this method of charging. If you use this method it is advisable to stop the charging once a month for 24 hours to give the battery a rest. This will also aid the battery life.
As stated before, batteries will self discharge at a small rate. On a new battery at room temperature the battery may only lose around 0.2% of its charge per day. If the ambient temperature increases or the battery age increases, this percentage of self discharge will increase. One manufacturer has also stated that their battery loses around 1% for each 1 degree celcius below 25 celcius. So where the battery is operating at freezing point there could be a 25% reduction within its capacity. This is why batteries kept in compartments away from the extremes of temperatures tend to last longer.
If you leave you battery on your caravan for long periods of time, one option could be to use a small panel to keep the battery at its current level. There are several ways to charge the battery whilst it is still in place on the caravan, which some are covered in the Electric Hook Up (EHU), Solar Panel and Generator sections.
WARNING!
All electricity can cause shocks, injuries and damage to your equipment. If you are in any doubt as to your electrical system, always seek professional advice from your dealer, product manufacturer, caravan manufacturer or a qualified electrician.
These pages are designed to give you an idea on how your electrical system works. Any work that you partake on your electrical system is solely at your own risk. We hold no responsibility regarding any action you take based on these pages.
Information here has been researched as best as possible, where over time rules and regulations change which may not be reflected on these pages.