If you are planning to go on camping trip in your motorhome or to sail to a distant location, having a high quality battery pack is going to be essential. Your vehicle or boat battery will have to be able to power your lights, pumps, heaters and all the electronics you will want to use.
A deep-cycle battery is designed to discharge between 45% and 80% of its capacity, depending on how it has been constructed. In contrast, starter batteries (e.g. car battery) are designed to deliver short, high-current bursts for starting the engine.
Deep cycle batteries are rated in Amp Hours. For example, if a battery is rated at 100 Amp Hours, it means it can deliver 10 Amps for 10 hours (10 x 10), 5 Amps for 20 hours and so on.
The most common deep cycle batteries are based on flooded lead acid and they come in two types: AGM and gel. AGM batteries use a fiberglass mat which is soaked in electrolyte and gel batteries are filled with lead acid in the form of gel. Both of them are leak proof and virtually maintenance free.
How you discharge and recharge your battery is directly related to how well and for how long your battery pack will perform. AGM and gel batteries should be discharged only to about 50 percent before recharging them back to 100 percent. You can technically discharge your battery to less than 50 percent, but it will shorten its life expectancy, so you should really avoid it.
Since the batteries are rated in Amp Hours, the main thing to consider when choosing the right one is how many Amp Hours you will actually need. That will depend on your every day power consumption as well as how often can you recharge your battery bank. RV batteries are typically recharged with solar panels, your engine's alternator, portable generators and shore power, if available.
Before you do your own research, here we list some of the most interesting products on the market today:
Carmanah 100AH is a sealed non-spillable AGM battery which is also maintenance free. There is no need to add water like in wet cell batteries. It has been specially designed with solar and inverter systems in mind, and should perform well in high power demand situations as found in motorhomes and travel trailers.
Trojan T-105 is a flooded lead acid battery aith 225 AH capacity. It's 6 Volt so it will need to be tied in series with another 6V battery if you want a 12V battery bank. It weighs 62 pounds and measures 10.3 x 7.1 x 10.8 inches. The main disadvantage of this battery is that it needs regular maintenance, such as watering and keeping the charges equal.
This is Trojan's 12V AGM battery rated at 76 Amp Hours, which is maintenance free and leak proof. It measures 10.8 x 6.6 x 8.1 inches and weight 54 pounds.