Deep-cycle battery maintenance


If you want to make full use of the battery, deep cycle battery maintenance is very important. Unfortunately, many people do not know how to maintain their deep cycle batteries, in fact, they will destroy their batteries. Now, they usually think it is a battery problem, but in fact the battery user does not properly maintain and use the battery. To avoid running out of battery, it is important to read this article completely and pay special attention to what you are about to learn.

Deep-cycle battery maintenance

What is a deep cycle battery?

The deep cycle battery is an AGM battery specially designed for deep cycle. In other words, they are designed to be powered off for a period of time and then recharged. The other type of battery is the starter battery, sometimes called the starter battery or car battery. These batteries are designed to provide a large amount of power in advance, but they are not designed to extract power from the battery for a long period of time. This particular article will not discuss car battery maintenance. Instead, it will discuss deep-cycle battery maintenance. There is a big difference between the two battery types and how you maintain them!

The most important thing about any battery is the depth of discharge, which is commonly referred to as battery cycle. If you want to have a long-lasting battery, it is important that you understand the depth of the battery discharge (how much power is taken from the battery) and the frequency of discharge. If you discharge the battery frequently, its lifespan will be shortened. However, if you just remove a little bit from the battery and then fully charge it again, the battery will last longer. Following the deep-cycle battery maintenance guidelines will definitely help you extend battery life.

Don’t over discharge

The absolute worst case is to discharge the battery until it is completely depleted. Many people have done this because it is easy to do. Turn on a light in your caravan without any protection, and the battery will only get flatter and flatter until it drops to zero volts. In fact, a battery is actually flat at 11.8V. That is when the battery is in the “zero” state. You can still take more power from the battery and consume it to 0V, but this will completely drain the battery. For almost all brands of batteries on the market, if you discharge them below 10.8V, you will not be covered by the warranty because you will damage the batteries. This is why it is important to avoid excessive battery discharge and include it in your deep cycle battery maintenance checklist.

What is battery voltage?

Let us explain in a very simple way what battery voltage is. The voltage is basically the full volume of a bucket of water. If your battery is charged more, the voltage is higher. If the battery is not charged, the voltage will drop. The following figure shows the relationship between the state of charge of the battery and its voltage.

battery voltage

Therefore, when the battery is fully charged, its voltage will be between 12.7-13.2 volts. As the battery power drops or discharges, the voltage will drop. For example, if the battery is only charged 75%, the battery voltage is 12.4V. Similarly, if the battery is only charged 50%, the voltage is 12.2V, and so on. Read on to understand the relationship between battery voltage and deep cycle battery maintenance.

Regularly measure battery voltage

One of our most common methods for people who have run out of batteries is that they don’t have any way to measure voltage. For anyone who uses a battery, it is very important to know how to measure its voltage. Deep cycle batteries are maintenance-free, which means you don’t need to add water to them, but it doesn’t mean you don’t need to take care of them. How to measure the voltage of the battery? The easiest way is to use a multimeter. If it is a 12V system, a multimeter is required; this is not an option. At the very least, you need to know what the battery voltage is. Without knowing the voltage, you don’t know whether the battery is charged or dead. Being able to measure battery voltage is essential for deep cycle maintenance. Why? Well, if you don’t know the battery voltage, you won’t know the battery level. In other words, you don’t know whether you should continue to use (discharge) the battery or stop using it to avoid running out of battery power.

An alternative tool that can be used in place of a multimeter is a voltmeter. However, to ensure that you get an accurate voltage reading with the voltmeter, make sure that the wire connecting the voltmeter to the battery is short. If your voltmeter is far away from the battery, you need to make sure that a thick cable is connected between the voltmeter and the battery to determine an accurate voltage reading. This is because if the cable is too thin or too long, part of the voltage will be lost on the way from the battery to the voltmeter, resulting in lower voltage readings of the voltmeter.

Regularly measure battery voltage

Charge the battery as soon as possible

Ensuring that the battery is charged as soon as possible is a key step in deep cycle battery maintenance. Reminder: Do not discharge the battery below 11.80 volts. Even better, when you use the battery, make sure to put the removed items back in place. So, in an irregular situation, suppose you are camping on the beach and your portable refrigerator is running and running out of power. At night, the battery will discharge, so during the day, the solar panels you have need to be large enough to make up for the power lost overnight, while running the refrigerator. Therefore, in most cases, it is important to fully charge the battery as much as possible. Of course, sometimes this is unavoidable when camping. For example, you may be camping in a place with insufficient sunlight, or you may not have solar panels installed. In these cases, make sure to put the battery on the battery charger when you go home.

Choose a charger with 10% battery capacity

battery charger

When purchasing an AGM battery charger, you should choose a battery charger that can provide about 10% of the battery capacity. For example, if you have a 200Ah battery, you should choose a 20Ah battery charger. All AGM batteries, including deep-cycle batteries, are designed to use up to 30% of their capacity. Therefore, if you have a 200Ah battery, the maximum acceptable charge capacity of the battery is 60Ah. In other words, if you have a 200Ah battery, do not use a charger larger than 60Ah. Even if you do this, it is useless because the battery will not exceed 60Ah. The only advantage of using a larger charger is that the battery charges faster. However, in the long run, a charger that is too large will drain your battery, so it is best to stick to the recommended battery charger, which can provide 10% of the battery capacity.


If you want to make full use of the battery, deep-cycle battery maintenance is essential. It is important to understand how to maintain them during and after the charging cycle. We have created these tips for you to use at home, of course, to learn more, please let our friendly experts help you.

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