Battery Maintenance Tips for Your Deep Cycle Batteries

Written by John Ho on October 22, 2020
Battery Maintenance Tips for Your Deep Cycle Batteries

A deep cycle battery is like an integral part of a solar panel because there is always a deep cycle battery connected with a solar panel to store its energy. So if we will be discussing everything about solar panels on this platform, then we will also have to talk about deep cycle batteries a little more in-depth.

The fact that deep cycle batteries are nothing like car batteries make them complicated.

And while the deep cycle batteries relate significantly less to car batteries, maintaining them is equally important. If you fail to uphold your deep cycle batteries, you can ruin them, and ruining them can give you a pretty bad hit on your paycheck. So, it is always better to learn essential deep battery maintenance tips beforehand. Also, a properly maintained deep cycle battery can sometimes even run you a decade. That is what makes them so durable.

However, to make a deep cycle battery run for a whole decade, you will have to pay close attention to these tips on how to maintain a deep cycle battery and will also have to implement them in their prescribed timelines.

Tips for maintaining a deep cycle battery

Watch out for corrosion

The most common phenomenon which causes people to lose the longevity of their deep cycle batteries is corrosion. Usually, the batteries connected to the off-grid systems sit idle inside a hideout for years. This lack of movement causes these batteries to corrode from inside out.

However, there are some remedies given below, through which you can avoid corrosion from infecting your battery.

  • Put an extra layer of any corrosion preventing material on the top of every metal part of the battery; bolts, wires, terminals, etc.
  • After coating the wire with a protective layer, you can lightly rinse it with water once or twice a year.

Install A Good Capacity Battery

Always Install a battery that can handle more than the load you will throw at it in your home. There are many reasons why a bigger battery lasts longer than a battery, which just gets you through your day.

  1. Often, the load in your home increases after a few years, and if you bought a battery designed to handle your previous load only, the battery would not be able to handle the excess load, which will reduce a few years from its life.
  2. Always buy batteries from reputable brands because their batteries offer the performance they quote during the marketing stage.

Never go for more parallel strings

Always opt for one or at max two parallel strings when you are installing a battery.

In case you are installing a 1000Ah battery, go for two strings of 500Ah batteries or a single string of 1000Ah battery, not more than that.

More than two strings can produce weak cells, which can take off years from your battery bank's life.

There are also some factors which you should keep in mind while installing multiple strings in parallel.

  1. Connect wires in such a way that the current flows evenly through them.
  2. Maintain a decent amount of space between each battery for air to prevent any overheating.
  3. Fully charge each cell at least once a week.

Maintain a decent temperature

Batteries tend to discharge faster and also lose their capacity early at extreme temperatures. So it is better always to maintain a decently moderate temperature around your batteries.

To avoid high temperatures, cover the batteries with a sheet. And in a situation where you have to avoid cold weather, either put the batteries in closed storage where average temperatures are maintained.

Tip: Never put the batteries in front of a heater or any other heat radiating device to maintain an average temperature.

Never overcharge a battery

Overcharging a deep cycle battery can result in permanent damage to battery life. It is better to install an LVD ( low voltage disconnect ) in the DC inverter to prevent the battery from overcharging.

Some people might argue that they do not need an LVD because they are responsible enough to disconnect the battery manually before it starts overcharging. However, I would suggest that one should never rely on human intervention in this case. Overcharging can occur at any time of the day and can cause permanent damage to the battery.

Adjust the temperature

At different temperatures, the battery's behavior changes. For example, at high temperatures, the battery requires a voltage drop to prevent overcharging. During low temperature, the battery requires an increase in voltage in order to charge fully.

And to meet these voltage requirements, you will need a temperature probe for every charging device to connect with the battery.

You can find these temperature probes online or at any electronic store easily.

Fully charge a battery every two weeks

It is recommended to charge a battery to 100% at least once every two weeks. This prevents any weak cell from getting even weaker and also saves the battery from corrosion.

A battery is fully charged once you hook it up with an off-grid system for most of the year. But, if there are any hiccups due to the weather. Do not think twice after it is past two weeks since the battery was fully charged, and connect a generator to charge the battery fully.

To acquire more information about when you should fully charge your battery, feel free to take help from this article.

How to check the true charging of the battery?

Many people live under the delusion that the fully charged bulb on the controller gives the battery's exact reading. However, that is not true. It only gives an approximation that the charge is approaching full. Even when the battery is not 100% charged in reality.

You can also use a voltmeter to check the true charge of your battery, although it does not give an accurate number too due to current, time, and temperature fluctuations.

Apparently, your only best bet to check the actual charge value in a flooded battery is a hydrometer. You can use it to check the charge of each cell. A working hydrometer can easily be scrapped out of an old battery.

Reading a hydrometer is rather simple too. Just follow the instructions given below,

  • After the water is added, the hydrometer will show a dramatically low reading because it takes some time for water to mix in the cell. So, wait for the water to mix.
  • Temperature plays an important role in the reading of a hydrometer. If the temperature is low, the fluid becomes dense. Subtract 3.5 points for every 10F after 70F.

You can also buy a temperature compensating hydrometer to avoid this hassle of subtracting points.

  • It is better to take readings with a hydrometer once the battery is discharging as it tends to give the actual readings of the cells during the discharging process.

In the case of a sealed battery, an amp-hour meter should work fine to measure the actual charge of a battery.

CAUTION: Always wear proper gear when working with batteries, and it is better to contact a professional to get the work done for you.

Add water regularly

In flooded batteries, the plates of the battery must be overwhelmed with water. There is no need to add any special liquid to flooded batteries. Just add normal distilled water or rainwater.

Check the recommended refill timeline of your battery on its manual. Mostly it is in between 6-12 months. Also, fill the battery with the amount of water that is recommended by the manufacturer.

Ensure that you pay attention and refill your battery in the regulated timeline, or else you will end up damaging your battery's health.

Connect a system tracking display

If you connect a display with your batteries, which shows the complete status of your batteries, voltage, current, and every other important detail, keeping track of things could become a lot easier for you.

By using this information, you can figure out if something is off with the batteries or if they need maintenance.

You can install this display anywhere you feel comfortable monitoring your battery status, and if you want more information on what devices you will need to make this possible, head over to this article to learn more about system tracking displays for batteries.


Here are some FAQs.


Deep cycle batteries are the powerhouse of your off-grid system, and if not paid attention to, it will not live by your side for long. However, there is no rocket science in maintaining a healthy deep cycle battery. All you need to do is just pay some attention during the installation process, and some during their lifetime at your disposal. By doing these two things, you can take full potential from your deep cycle batteries, and there is also an advantage to these batteries that is, if you take proper care of them, they can run you a decade or sometimes even more.

And that is what we at Solar Mio are striving to do, trying to make your off-grid systems as efficient as possible.

Article written by John Ho
Our goal is to provide you with comprehensive and thorough solar-energy product guides, which will leave you confident that you have made the right purchase decision for your home.

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