What is the best battery for metal detectors?

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batteriesMany metal detecting enthusiasts are wondering what the best batteries for metal detector are.

You should have asked this question at least once. Because we have to replace the detector’s batteries frequently.

A metal detector is not like a remote control where you only have to replace the batteries once a year.

Depending on the detector and the batteries, you will have to replace them after 20 hours of use.

In this article, I will compare three common types of batteries: alkaline, heavy-duty and rechargeable batteries.

We will list their advantages and disadvantages and see whether they can be used to run a metal detector or not. So that you can choose the best one for you.

Alkaline batteries

The manufacturers of metal detectors always recommend using this type of batteries.

It has a self-discharge rate of 0.3 % per month. This means that if you remove the battery from any device and you store them, they will lose 0.3 % of their charge per month.

This is why it has a long shelf life. Depending on the quality of the battery, it can keep it charge between 5 and 10 years.

The nominal cell voltage of an alkaline battery is 1.5 V. They come in different sizes and shapes: C, AA, AAA, N, and 9V

80% of the batteries manufactured in the US are alkaline batteries compared to 60% in the UK and 47% in the European Union.

They have a good capacity (measured in mAh) and a good output curve (stays close to 1.5 until it dies).

It is a single-use battery. And the crushing majority of them are not rechargeable.

Some models of alkaline batteries are rechargeable. But it can only be used for a few cycles and its capacity decrease after every charge/discharge.

Do not try to charge ordinary alkaline batteries. Because they may explode.

The new models (since 1996) of the alkaline batteries have no mercury. So they can be disposed of with normal domestic waste without a problem.

But, some states do not allow that. You have to check the laws of the state where you live.

Heavy-duty batteries

They are an improved version of the good old zinc-carbon batteries that used to leak its liquid and to ruin your devices.

And by heavy duty, they mean they are 50% better than zinc carbon batteries that were sold 50 years ago! (What an achievement!)

The term heavy duty is nothing more than a misleading marketing term to make you think this type of batteries is a hotshot, so to speak.

It is a single-use battery. And it delivers 1.5 volts. They have a short shelf life. It should be stored at room temperature.

Do not use this type of batteries with a metal detector. They are not recommended by almost all the metal detector makers.

Rechargeable batteries

The new generation of rechargeable batteries can keep their charge for months. And charging them is very cheap (doesn’t cost more than a nickel).

If you want to buy one of these batteries you should consider its initial capacity, how much this capacity deteriorates after few charges, how long does the charge last when the battery is used and when it is stored.

To cut the long story short, if you are looking for a good rechargeable AA battery, pick the Panasonic Eneloop AA 2100.

Of course with rechargeable batteries, you need a battery charger.

Don’t buy these chargers that claim they “quick”. Because some of them are not really quick. Charging a battery may last for hours.

Second, quick charging will reduce the life of the batteries. After every charge, the battery will lose a little bit of its capacity.

You can check this Panasonic charger. It has four slots. It is suitable for any brand and for the sizes AA and AAA batteries.

You can even mix AA and AAA batteries from different brands without a problem. You don’t have to use all the slots.

This type of batteries is good for landfills. You don’t have to dispose of a lot of used alkaline batteries in the environment.

But, they take a long time to recharge and they will only last for a short period after being charged.

Do you have to replace the batteries before they are completely dead?

To answer this question, we have to find whether the battery level affects the metal detector performance (depth range, sensitivity) or not.

Metal detectors run on a much lower voltage than that what is supplied by the batteries.

So the detector will be fully functional up to the batteries are completely dead.

But the volume of the onboard speakers may get lower as the batteries get weaker.

This means that you only have to replace the batteries only if they are fully discharged.

Tips extend battery life

Use headphones to slightly extend the battery life. Most of the metal detectors are fitted with ¼ inches headphone jack

Carry some spare batteries with you.

If you choose not to use the metal detector for a long period, remove the batteries from it.

Putting batteries in the refrigerator does not prolong their life. Alkaline batteries lose 2% of their charge per year if stored at room temperature.

At a higher temperature (85° F) they will self-discharge at a faster rate (5%). Freezing the battery will help keep the charge by a tiny worthless amount.

Don’t overcharge batteries. If you forget to unplug them they will recharge more than they should (if the battery charger isn’t automatic). And their life will be shorter.

Don’t mix old batteries with new ones. This may cause battery leakage or rupture. Replace all of them at the same time.

Store them in a dry place at moderate temperatures. If the alkaline or heavy-duty batteries are dead. Don’t recharge them because they may leak dangerous liquids and may explode.


The best batteries for your metal detector are alkaline batteries. They are more expensive. But they last longer. They have a longer shelf life.

Their output voltage stays close to 1.5 volts until it dies. They are available and they are not that expensive.

Moreover, all the manufacturers of metal detectors (as far as I know) recommend using this type of batteries.

Another option could be to use alkaline disposable batteries and rechargeable ones.

If you are going in short hunt use rechargeable batteries and if you are going in long trip use alkaline batteries.

Tell me in the comments section below, which one do you prefer?

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