How much battery capacity do you need, and what type of battery is best? And how do you take care of them?
To answer these questions, you first need to decide what type of motor caravanner you are. If you just get away occassionally for the weekend, and don't watch much TV, or mostly stay in campsites, you'll need less battery storage, and maybe no solar panels. If you are on the road permanently, or for months at a time, use computers as well as the TV, and like to freedom camp for 2 or 3 days at each location, then you'll clearly need much more battery capacity, as well as solar panels, or even a generator. This is even more true if you use an inverter to run the microwave, toaster, washing machine, or hair dryer.
So, the first thing to do is to make a list of all the power using devices that you would normally use while on the road. You might then want to get advice from one of the expert RV Electrical service companies in your area.
THE DIFFERENT TYPES OF HOUSE BATTERIES
House batteries have different operating requirements from your vehicle starting battery, and your motorhome or caravan should come prefitted with ddep cycle batteries that are suitable for their purpose. They don't last forever, and you are fortunate to get more than 5 years if you look after it, and much less if you don't. When it comes time to replace your house battery, it's a good time to review both the capacity and type of battery you should replace it with.
These are cheaper, and commonly used, but require some ongoing maintenance for keeping water levels topped up. If you don't discharge them below 75%m they can have a working life of between 3 and 5 years.
Absorbent Glass Mat (AGM) Batteries
These are completely sealed, and generally have a longer working life, but need the correct charging system with a 'gel' setting. The longer working life or between 5 and 10 years more than justifies their slightly higher cost, especially as the higher spec ones can be discharged down to 50% of their rated capacity.
Rare earth lithium iron phosphate batteries are around 98% efficient (compared with around 95% for AGM and 85% for Lead-Acid batteries). This means they charge more efficiently from solar panels, which is quite an important consideration if your existing batteries take a long time to recharge. They typically have a working life of at least 10 years, even when discharged to 50% of their rated capacity. They are also significantly lighter and take up less room, which can be a factor, especially should you need larger capacity batteries. However, they are also significantly more expensive, and not all RV Electrical Suppliers stock them.
GETTING MAXIMUM LIFE FROM YOUR HOUSE BATTERIES
The most important guideline is to be careful not to discharge your batteries below what is recommended for each battery type. Having an accurate battery monitor installed will more than pay for itself for this reason alone.
House batteries also benefit from regular cycling - so when parked for long periods at home, it's better to turn off your fridge (saves using up your LPG) and allow the solar panels (if you have them) to recharge the batteries after they lose a little capacity overnight. This gives a slightly better battery life than just plugging your motorhome into 230v for months at a time.
If you're using Lead-Acid batteries, don't neglect to keep the electrolyte levels topped up with distilled water.
It's really worth getting good advice from a reputable supplier of motorhome electrical services and make the decisions that are right for your motorhoming needs.