Every battery only has a limited number of times it can be used, or discharged and then charged back up – which is known as a ‘cycle’. Whether it’s your phone battery, your car starter battery or an AGM Deep Cycle battery, every battery has a number of cycles before it’s suggested to be replaced. The reason it’s so important to choose the right battery for the right application is because cycling your battery daily will use one of those cycles from your battery and take away from the total amount of cycle that the battery can provide. Plus, the further down you discharge your battery, the less cycles you’ll get.

First if you’re thinking about using a typical car starter battery to run your fridge instead of a deep cycle battery then forget it! If you only used 20% out of your car battery and left 80% of the capacity still in the battery, you’d get around 300 ‘cycles’ before the battery needed to be replaced. If you used your car battery even more and regularly cycled down to 50% state of charge (or 50% capacity remaining) then you might only get 120 cycles out of it! If you were running your fridge every day your battery would only last about one third of a year before needing to be replaced. On the other hand a deep cycle battery would be able to provide around 1500 cycles if you only used 20% of your total capacity, or 500 to 600 cycles under the same conditions if you used 50% capacity every time. In that sense, a Deep Cycle Battery can provide you up to 5 times more cycles and a much longer life time than an equivalently sized starter battery.

Why does using more of your battery capacity affect the amount of cycles? Well, it’s due to a couple of factors – some you can control and some that are just a fact of life when it comes to battery chemistry. Number 1 is that it means you need to charge your battery more fully in order to get it topped up and charging and the associated heat can over time degrade a battery. With a flooded battery you can counter this by maintaining the battery and topping it up with water / electrolyte when required, which can be a bit of a hassle and tricky to get exactly right. The great thing about Adventure Kings AGM Deep Cycle Batteries is that they’re maintenance free which means you never need to top them up and while they’re charging more than 99% of any gasses created by the charging process are simply recombined into the battery ensuring it’s charged correctly and avoids losing capacity unnecessarily. 

Number two is that by discharging your battery to a low level you’re causing sulphation this happens to all batteries, but it’s less of an issue in an AGM Deep Cycle. Batteries release energy when the acid inside reacts with the lead plats, sulphation is a situation where lead sulphate crystals form on the battery’s internal lead plates during the discharge process. Unfortunately the higher proportion of lead sulphate on the lead, the less surface area of lead the battery has to react with the electrolyte resulting in a loss of capacity. The condition occurs during discharge and when a battery is left at a low state of charge for any length of time (which is why charging your batteries with solar is so important – you can charge them up daily, before they can sulphate too much). You can reverse the process through charging the battery back up, but it’s never fully successful and you will lose some surface area and associated reaction permanently. Eventually some batteries with thin internal plates will fully degrade and can ‘drop a cell’ or simply lose so much possible power capacity that it will quickly kill the battery overall. This is another reason Deep Cycle batteries are so important when shopping for a camping power solution – they typically have thicker plates that are able to withstand those deep discharges without a worry.

There’s another issue that AGM Deep Cycle Batteries avoid too – because they’re completely sealed and leak proof there’s no worry of tipping your battery and losing capacity – plus in an AGM Battery, the liquid electrolyte is completely suspended or absorbed in the glass matting that surrounds the lead plates meaning they’re always in contact. In a typical flooded battery, the electrolyte is a liquid and can slosh around – if you’re parked on a hill for example, the battery liquid may not be contacting half of the lead – prolonged time in that position can affect the cells of the battery. Similarly if you let it leak out and don’t refill the electrolyte you’ll permanently affect the battery capacity. An AGM deep Cycle Battery means you don’t need to worry about leaking which can damage your vehicle interior, or damage the battery capacity! It just means you need to ensure you’re looking after your AGM Battery a little more so it can keep looking after you – and all that needs is a proper charge that suits the AGM chemistry!

It’s so important to charge an AGM battery correctly because they require a higher charge voltage in order to get back to 100% full. Unless a battery gets up to 100% full there is always the chance of sulphation. Similarly if you’re not using your battery and plan to store it, you should charge it up before it’s put away OR even better you should keep it on a constant trickle charge as the constant charge is better for the battery than discharging and possibly sulphating. Most AGM Deep Cycle Batteries need around 14.6V to fully recharge, but it is worth checking for each battery! An easy way to ensure your battery is getting a good full charge is to use a portable solar kit daily – allowing the battery to charge right back up after being used overnight to run your camping fridge etc. The absolute best way though is with a DC-DC charger – these charge your Deep Cycle Battery while you’re driving (and with Solar if you choose the right model, like the Kings 25A DC-DC) they’re able to output the right voltage, unlike your car alternator and they adjust the charge to look after the battery whether it needs a lot of power or just a trickle!