How to Charge a Deep Cycle Battery Properly

Written by John Ho on November 13, 2020
How to Charge a Deep Cycle Battery Properly

Deep cycle batteries are commonly used in RVs, marine vehicles, off-grid systems, and some other areas. The primary purpose of a deep cycle battery is to provide current steadily to the connected appliances in order to make the devices run at a smooth pace. But, a deep cycle battery can supply steady current only if it has a sufficient amount of current juiced up in its storage. And if the battery of your land or water vehicle is not fully charged, then your camping or any other recreational activity can go down the drain, and you definitely do not want that to happen.

That is why I have dedicated this whole article to this subject. And further, you can expect every necessary detail to charge a deep cycle battery. So continue reading and learn how to charge a deep cycle battery properly like an expert.

How To Charge A Deep Cycle Battery Properly Like A Pro

Here is the complete guide to charging a deep cycle battery like a pro.

Pick A Compatible Charger

A charger is the only accessory that is required to charge a deep cycle battery from a conventional grid system. If you mess up with this accessory and buy a charger not compatible with your deep cycle battery, then you will not be able to charge your battery.

So the first step of this guide is to make sure that you buy the right charger that is compatible with your specific deep cycle battery to charge it smoothly.

Follow The Instructions Given On The Manual

There are a lot of factors that come into play in charging your deep cycle battery. So to avoid any of these factors from disrupting your charging process, follow the instructions given on the manual of the deep cycle battery closely.

The Weather Effect

The weather has a significant impact on the speed of charging of a battery. In cold weather, the battery requires a high voltage to charge. While in the hot weather, you can charge your battery at the normal voltage.

However, it is essential to know that you cannot provide high or low voltage to the battery by yourself. Because the battery can get damaged if you supply a voltage too high from the required voltage of the battery, so to tackle the weather effect, I would suggest you read the weather prerequisites from your deep cycle battery's manual. Suppose you cannot find these weather prerequisites in your battery's manual. Then Google might be your best bet. You can easily find the specific voltage you should charge your deep cycle battery at by doing a little research.

Tip: If you cannot find the exact weather prerequisites for your specific battery model, then you can search for the prerequisites of a similar battery that is famous.

Different ways to charge your deep cycle battery

You can choose your deep cycle battery in different ways. Like if you want, then you can charge your battery while it's still in your RV, boat, or whatever. And if you're going to charge your deep cycle battery outside of your vehicle,  you can also take it out and then charge it. It really depends on your preference and situation as to how you want to juice up your battery.

Don't overcharge

Many people might not consider this when charging their deep cycle batteries. However, one should know that overcharging is not suitable for battery health and can reduce the life of the battery.

The reason why this happens is that a lot of heat is generated inside the battery when it is overcharged. And in case you did not know, excessive heat is not good for the battery and causes permanent damage to the battery in the long run.

Keep an alternative charging source

It is good to keep an alternative charging source on your boat or RV for your deep cycle battery. A solar panel is an ideal alternative to charge your deep cycle battery. You can stack it up with your deep cycle battery, and it will keep juicing it you go short on power during a trip.

One great advantage of a solar panel is that it uses solar power and does not require any external electrical source.

Standard procedure for charging a deep cycle battery

Here is the standard procedure that you should follow when charging a deep cycle battery smoothly and safely.

Step 1 - How to Charge a Deep Cycle Battery Properly

Remove the battery from the RV or boat if there is a risk of any electrical mishap in the place during charging.

Step 2

Make sure that there are no leakages in the battery and follow the instructions given on the charger.

Step 3

Check for any dust or other debris on the terminals of the battery and, if found, remove it before moving on to the next step.

Step 4

Once you are done cleaning either terminal of your battery, attach the red wire to the positive terminal (+) of the battery and the black wire to the negative (-) terminal of the battery.

In this way, you will connect positive to positive and negative to negative. Your deep cycle battery should be ready to be charged now. The charging process is given in the next step.

Step 5

Now connect the charger to an electrical grid. Set the voltage suitable for your battery, or it can cause permanent damage to the battery.

Reminder: Although I have already told this to you before but here is just a reminder that you should make sure that your charger and deep cycle battery are compatible with each other when buying one.

Step 6

Turn on the outlet to begin charging your battery. See if your charger stops charging once the battery is fully charged to avoid overcharging. If this feature is available, then you are well off, leaving your deep cycle battery unattended. But, in case this feature is absent from your charger, then make sure that you manually disconnect the charge from entering your battery once it is fully charged in order to avoid overcharging, eventually leading to permanent damage.

Step 7

Once you disconnect your battery from charging once it is charged, it's now time to put it back into your boat or RV in case you removed it for charging.

How to speed up deep cycle battery charging

I would not suggest anyone do this with their deep cycle battery unless in desperate need of charge in an emergency-like situation because the manufacturers do not recommend using this method.

However, if you are stuck in a situation where you need to charge your battery as soon as possible, then you can follow this little trick.

Bump up the ampere rating at which you usually charge your deep cycle battery by 5 amps. In this way, the battery will charge at an abnormally high speed.

Warning: using this method on a regular basis will decrease the longevity of your deep cycle battery.

The age of the deep cycle battery

Many people might not know this, but as your deep cycle battery gets older, its efficiency also decreases. For say, the battery that you have owned for 5 years will not discharge at the same rate as the battery that you just bought. With the passage of time, batteries start struggling to produce power effectively.

So keep this thought in mind when you are charging an old battery. It will take more time to charge and will also discharge faster compared to when it was new.

Do not leave your battery idle

Leaving your battery idle for too many weeks can make it go bad. So even when the deep cycle battery is not in your use, make sure to charge it regularly to keep it alive.



Deep cycle batteries can even last for a decade if you take proper care of them. One of the factors that decide the longevity of your battery is how you charge it. If you ruthlessly charge your battery, then the chances are that it's not even going to last for 5 years. So pay close attention to the method that you are using to charge your battery in order to ensure its longevity.

If you follow the method that I have stated above, then you will be able to sustain your battery and also charge it efficiently and safely.

In case any new questions pop up in your mind regarding this topic, you can list them in the comments below, and I will try to answer them all individually.


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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