Caravan batteries cool your food in transit and keep your van’s interior cosy, away from mains power. Therefore, we must understand what they are and how they work to make the most of your camp. Today, we’ll discuss the most common type found in new and second-hand vans—the lead-acid battery—usually in an AGM Deep Cycle configuration. So check out our AGM Deep Cycle battery tips below.
The 12V battery in your tow vehicle differs to what’s in your caravan, which stands to reason given they work in different ways. A starter or ‘cracking’ battery will deliver a high output to start the vehicle’s engine until the alternator takes over the role.
‘Dual purpose’ and ‘deep cycle batteries,’ however, can sustain 12V camping appliances for longer, with deep cycle batteries able to withstand frequent discharging.
Caravan batteries come in a choice of chemistries, with AGM batteries (also known as GEL) ideal for travel as the material within them are semi-solid.
Batteries charge differently according to their composition. Thankfully, good deep cycle battery chargers and solar charge controllers adjust (manually or automatically depending on the unit) to your battery’s chemistry. But check your chargers’ settings first.
We measure a vehicle’s deep cycle lead-acid battery in Amp-hours, where the rating measures the total Amps the battery can deliver. In theory, a 100Ah battery will provide 1 Amp for 100 hours or 5 Amps for 20 hours or 20 Amps for 5 hours.
In practise, though, lead-acid battery sustain damage if they’re fully discharged.
Mark writes that we should aim to discharge your lead-acid battery to no less than between 40 and 50 percent of its rated Amp capacity. Thankfully, we can easily (and automatically) manage this depth of discharge (DOD) by watching our voltage.
Although caravan appliances run on 12V system, your battery will reach 12.75 Volts once it’s fully charged. A lead-acid battery discharged to 50 percent is approximately 12.06 Volts and will reach 10.50 Volts when flat says Mark Ray from R&J Batteries.
To protect the battery, we can set a voltage limit on the battery monitor or a low voltage disconnect device (LVD). Mark recommends it somewhere between 11.9 to 12.10 Volts.
Although your deep cycle battery is full at 12.75 Volt, it requires more (around 14.4 Volts) to charge it effectively. A good multi-stage battery charger will sort you out when you can access mains power. A solar charge controller will automatically adjust the voltage coming from your solar panels at camp. While a DC-DC charger near the battery lets you tap into the vehicle’s alternator power as you drive.
To care for your lead-acid batteries, store them in a fully charged state, says Mark Ray of R&J Batteries. Otherwise, the sulphur within them hardens and won’t convert to electrolyte, essential for storing power. This process is called sulfation. Most lead-acid batteries experience sulfation over time but can power at camp for years to come.