How to Test a Deep Cycle Battery?

Testing of any battery whether deep cycle or starting is required when you are facing any of the 2 circumstances mentioned below-

Either you want to get aware of any issues that may be there with the battery before buying it or your battery must have got an electric shock or something and you want yourself to know if it’s still working or not.

Problems may be different but the solutions lies the same.

A battery user always goes through this need of testing the battery at least once in life.

Therefore, it is very much important that we all must know the best and appropriate ways of testing a deep cycle battery.

So, let’s get started….

Methods to Test a Deep Cycle Battery

Voltmeter Testing

For executing this method you must be requiring a voltmeter with prongs.

Open up your battery case to expose the terminals. If it’s a maintenance-free battery then there is no need to open as the terminals are already outside the battery.

Now turn on the battery and hold the prongs on the correct terminals (make sure that you do not make a mistake between the positive and the negative terminal).

The negative of the battery needs to be connected with the negative of the voltmeter and the same is the case with the positive terminal.

In a 12V battery, if you see a voltage greater than 10V, it’s good, and if it’s more than 11V, excellent.

Somehow if you are getting a voltage less than 10V than the battery must be having some defect.

Do not go for a battery that is rated for 12V but is incapable of showing a voltage greater than 10V.

A healthy battery rated for 6V must show a reading greater than 6V and if it’s not so fresh than the voltage should at least be more than 5.5V.

And if the needle of the voltmeter does not show any movement and is stuck at 0V only, then you must check the connections are proper and tight enough.

If it still doesn’t move, then perhaps your battery has short-circuited or died.

Hydrometer Testing

A hydrometer is a tool that checks the specific gravity of the acid or gel that is there inside the battery.

Please note that this method is not meant for non-maintenance batteries as they can’t be opened up.

Just place the hydrometer in one of the cells and check the reading.

A healthy battery should have a reading of 1.225 and if it’s a brand new battery then it should show a reading of 1.265.

Also, you have to place the hydrometer at the lowest and the highest depth and take two readings.

There shall not be a difference of 50 points between the highest and the lowest reading.

Repeat the steps with all the cells for better accuracy and knowledge.

Manual Checking

As the name suggests, this method has to be done manually and does not require any technical tools.

It is best for the ones who can’t afford or who do not have a voltmeter or a hydrometer handy at the moment.

For checking the battery manually, you will have to scan the battery externally (if it’s a maintenance-free battery).

And, both from inside and outside ( if it is not a maintenance-free battery).

For any external damages, look for any cracks or bumps on the case of the battery.

The terminals of the battery should not be loose and should be properly tightened.

If there are any screws then they should also be tight.

There should not be any kind of corrosion on the terminals.

The manufacturing date should be fresh and there shall not be any sign of leakage or spilling.

Also, look for damaged parts if any.

For checking the battery internally, look for any discoloration of the liquid.

Acids or gels in old may be discolored and may also become like a paste.

Again, no sign of corrosion must be seen on the cells or the plates of the battery.

If you notice any weird or bizarre smell coming from the acid then maybe the battery has been kept for a very long time. Do not go for such a battery.

If you do not notice any such kind of discrepancy then the battery is safe and worth enough for buying.

Final Words

I think we have listed and explained the best possible and easiest ways for checking a deep cycle battery.

However, you can try all of them if you are not satisfied after giving a try to one method.

Batteries play a major role in our day to day life and hence they must be bought after checking and looking upon everything.

After all, it’s not a toffee, it’s a battery. Check today, to avoid regretting in the future. Do not be in a hurry man!

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