Are battery tenders waterproof? The importance of waterproofing revealed

By Arif

Battery tender getting connected on car battery

Battery tenders are a great way to keep your vehicle batteries charged when not in use. But many vehicle owners wonder if battery tenders can be used for charging in rain or when they are dipped in water. So, are battery tenders waterproof?

The importance of battery tenders cannot be underestimated keeping the water element aside. However, having a waterproof feature-rich battery tender could be very helpful in charging the batteries in any season.

In this post, I will tell you about the waterproofing capabilities of battery tenders. You will also learn the importance, benefits, and factors to consider when choosing a battery tender.

In addition, I will also list the 3 best battery tenders that are waterproof and are excellent chargers to help you save time on research and decision-making. So, keep reading!

Are battery tenders waterproof?

Yes, battery tenders are waterproof but not all of them. Some battery tenders come tagged with weather-resistance features which may not define their water-proofing capabilities completely.

It’s important to thoroughly check the manufacturer’s specification manual to determine the water-proofing feature of a particular product.

Waterproof battery tenders are designed to resist certain levels of water due to their body material and power cord compatibility.

While you can use such products in any weather we do not recommend doing this frequently. Watery conditions can damage the device and the battery it is connected to due to moisture elements.

If you want to use waterproof battery tenders ensure to do it in closed doors or under the hood to protect the electrical connections from water that otherwise could be harmful and damaging.

To summarize, if you are looking to use a battery tender that is made of water-proof elements and can be used in any weather conditions make sure to read the instructions manual very carefully before purchasing a product.

Related Read: Are Jumper Cables For Car Batteries Waterproof

The importance of battery tenders and their waterproof element

Battery tenders are devices used to maintain and charge batteries in vehicles, such as cars, motorcycles, trucks, boats, etc. when they are not in use.

Battery tenders are useful in preventing automotive batteries from losing their charge when the vehicles are on a stand or sitting idle for a long time owing to extreme weather conditions.

Under such circumstances, a battery can be isolated from the vehicle and connected to the battery tender to keep it charged.

Car Battery Charger

The waterproof featured battery tenders are made to withstand water levels to some extent. Such battery tenders remain unaffected if they are dropped in water to a recommended level and duration.

Some ‘weather-resistant’ labeled battery tenders also do the job well in rain, and snow provided they are used as per the instructions from the manufacturer.

In short, battery tenders are important to maintain the functionality and health of a battery and extend its overall lifespan from the impacts of challenging weather conditions.

3 best battery tenders for vehicle batteries

Based on the importance here are the top-3 best battery tenders in the market.

These products are well-received, tested, authenticated, and trusted by 1000’s of users and are highly reliable from a weather-resistant perspective:

As an Amazon Associate, we may earn a small commission if you purchase any product by clicking the link without any additional cost to you.

Battery Tender 800 SuperSmart Battery Charger and Maintainer

Deltran’s Battery Tender is a brand known for providing a great family of battery chargers since 1965. There are many superior products in the charging segment and this Battery Tender 800 SuperSmart charger is a fantastic addition to their overall list.

The charger is no bigger than a computer mouse and despite a smaller size like this, it packs an impressive 800 milliamps (amperage) of constant current charging power.

Battery Tender 800 is rugged equipment fully automated with features including spark-proof, reverse polarity protection, and short circuit protection.

As a matter of fact, its weather-resistant capabilities let you use the product in a damp and watery environment without any shocks and vibrations. The interior body is structured with a synthetic epoxy resin material that is thermally conductive and flame-retardant.

The charger is perfect for lead-acid, flooded, or sealed maintenance-free batteries such as AGM and gel cell types used in different vehicles. It can cover 12-volt batteries of ATVs, watercraft, motorcycles, boats, cars, etc.

This charger can also maintain the charge of a battery through its float mode. The mode is helpful in identifying a battery losing its charge and bringing it back to the full charge position.

Battery Tender 800 SuperSmart weighs just 1.65 pounds which makes it easily transportable anywhere.

To conclude, this should be your go-to product if you are looking to charge and maintain a battery irrespective of environmental conditions and the battery’s charging status.


  • Fully automated charger and maintainer for different types of batteries
  • Comes with full-proof protection against various environmental and weather challenges
  • Can withstand a certain level of water
  • Compact yet powerful


  • Low amp ratings mean charging may take longer than a higher-amp rating model
  • May not work efficiently on high-capacity batteries

CTEK-40-206 MXS 5.0 Fully Automatic Battery Charger

CTEK is another well-respected brand in the battery charging segment. The company has a series of battery chargers and maintainers that also includes this specific model CTEX MXS 5.

This product is built to last in all weather conditions. It has a distinguishing feature called RECOND mode or reconditioning mode wherein the charger can revive batteries that have been lying unattended and fully discharged for long periods.

It also has a built-in automatic temperature sensor that is controlled by a microprocessor charger to detect the temperature and adjust the charging process accordingly. With this, you don’t have to worry about your battery getting over or undercharged in any condition.

The product is IP65 certified which means it can efficiently tolerate water splashes and dust and continue charging without any interruption.

From a compatibility perspective, CTEK MXS 5 can deliver charging performance on 12-volt batteries used in cars, motorbikes, small trucks, boats, tractors, etc.

The charging process works on simple steps of plug and play and the charger automatically detects reverse polarity and alerts the user. Additionally, the unit is spark-proof, and short-circuit-proof so that you remain protected from any electrical hazards while charging.

The product is fully automated with advanced 8-step charging and battery-detecting modes to accommodate AGM and lead acid batteries.

CTEK MXS 5 is just 1.79 pounds in weight and hardly takes up any space due to its compact size. All in all, it’s a win-win situation for vehicle owners buying this product.


  • IP65-certified splash and dust-proof charger to work in tough weather conditions
  • The simple plug-and-play operation makes it very easy to use
  • The 8-step charging process and modes for all types of battery makes it compatible and versatile
  • Sturdy, compact, and lightweight makes it easy to carry


  • Connecting cables is short which means spending extra cost on additional cords
  • Comparatively expensive

NOCO Genius5 5A Smart Battery Charger

NOCO is a reputed and dependable brand in producing high-quality charging products. The company has been offering products in this segment since 1914 which makes them reliable and trustworthy.

There are multiple NOCO battery chargers on offer but this Genius 5 model stands out for its advanced automated features in charging and maintaining vehicle batteries.

The Genius 5 has a 5 amp charging speed and comes in 6 and 12-voltage options to serve almost all types of vehicle batteries. The product can be used on automotive, marine, and light truck batteries as well as smaller units such as motorcycles, ATVs, lawnmowers, etc.

When it comes to charging, it produces 5A rapid charge/maintaining modes for standard AGM, gel, lithium-ion, maintenance-free, and deep-cycled batteries.

In terms of automation, Genius 5 is well-equipped with automatic detection of battery voltage to adjust the charging mode. The unit will spontaneously stop charging and shift to maintain mode when the battery is fully charged.

In addition, the product is equipped with an integrated thermal sensor that adjusts the charging based on fluctuating temperatures. This feature is instrumental in maintaining the battery charge according to hot and cold temperatures which is a great option to avoid over and under-charging scenarios.

The product comes with LED lights to show different modes depending on the type of battery and charging you want.

The overall structure measures close to 8 inches and weighs only 1.59 pounds which makes it very compact and lightweight to carry.

The unit is spark-proof, shockproof, and detects reverse polarity efficiently. What makes it worth buying is the weather-proof and water-proof capabilities which means you can use it all around the year.  

All in all, NOCO Genius 5 is an all-in-one product with hardly any loose ends.


  • Fully compatible and versatile to serve different types of batteries
  • Comes with built-in automated features on charging, maintaining, and desulfation processes
  • Can be used in different weather conditions and can survive in watery elements
  • The product is easy to use and carry


  • Low power unit with only 5 amps charging speed
  • It gets seriously hot on long periods of charging

The benefits of battery tenders

Here are the 5 primary benefits you get from keeping them in your storage:

Prolonged battery life – When the battery is left discharged for long periods of time, a sulfation process begins which can damage its overall substances and chemical liquids.

It is therefore important to keep the automotive battery charged and to do this constant charging is required which you get with the help of battery tenders.

One of the main benefits of using a battery tender is that it helps prolong battery life by maintaining constant charge and preventing the sulfation process.

Safe – Battery tenders are normally very safe to use and do not pose a risk of any electrical hazards.

The devices are designed to perform a slow and steady charge and come equipped with an auto shut-off feature that stops the charging process when the battery is fully charged.

This eliminates the risk of overcharging and damage to the battery.

Easy to use – The process of using a battery tender is very easy. The equipment works on simple steps of connecting the battery tender with the battery and plugging it in.

Once properly connected, the device will automatically take care of the charging and maintain the battery at the optimal level.

The shut-off feature will automatically stop the charging process giving you complete peace of mind from monitoring and the risk of overcharging.

Battery Charger

Versatile – Battery tenders come in a variety of designs with varying levels of features. The device can be used on a wide range of batteries including those used in cars, boats, motorcycles, ATVs, lawnmowers, tractors, etc.

Battery tenders are very versatile and also come with weather-resistant and waterproofing features to be used in different weather conditions.

Save time and money – Lack of charging and sitting idle for too long increases the discharging process making batteries vulnerable to damage and expiry.

In such a scenario, repairing or replacements are the only options that could be time-consuming and expensive.

A battery tender helps save time and money by reducing the need to replace batteries frequently. It keeps the battery charged and healthy which avoids the cost of buying a new battery and the inconvenience of a dead battery.

Factors to consider when choosing a battery tender including the waterproofing feature

There are certain factors you must consider while choosing a battery tender. Here are a few of them to make your selection easier:

Compatibility – The compatibility feature is very important considering the type of battery you have.

Some battery tenders are designed specifically for lead-acid batteries and some for lithium or gel batteries.

Make sure to choose a battery tender that suits the type of battery your vehicle has. Prefer to have a product that is compatible with all types of batteries to avoid buying multiple battery tenders.

Battery voltage – Voltage compatibility is another important consideration when choosing a battery tender.

Most vehicle batteries are 12 volts which should match the voltage capacity of a battery tender.

A lower-voltage battery tender may not be able to deliver the right current flow which could prolong the charging process.

Ensure to choose a product that is compatible with the right amount of voltage

Amperage rating – Amperage rating will define the charging speed of a battery tender. A high amperage rating will suffice for quick charging but also increases the risk of overheating.

A lower amperage rating means maintaining the battery charge over a longer period which also increases the charging duration.

For typical-size vehicle batteries, an amp rating of 2-4 amps should be enough to do the job. Choose the battery tender amps that suit the type of charging and the type of battery you have.

Safety features – Look for a battery tender that comes with advanced safety features. You don’t want to spend time monitoring and testing the battery again and again.

So, ensure the battery tender has overcharging protection, short-circuit protection, and reverse polarity protection features.

More importantly, the product should have smart technology to maintain the battery charge to the optimal level and shut off automatically.

A few battery tenders offer specialized modes to desulfate a completely dead battery and bring back its power. Similarly, some of them come with a jump start mode to jump-start a vehicle.

Again, evaluate your requirements and finalize a product

Size and portability – Battery tenders are something that you may need to carry along in your vehicle if necessary.

It is therefore important to choose a product that is the right size, compact, and easy to transport. Battery tenders are available in different sizes so, choose the one that can easily fit in your vehicle as well as designed for stationary use.

Waterproofing – The waterproofing feature should be on your list if you plan to use the battery tender in wet or damp conditions.

Such products also come in handy to be used under rain or snow with proper protection. Ensure to choose a model that is waterproof or at least weather-resistant.

Price – Because of the size, features, and compatibility battery tenders are offered at different pricing.

It is better to invest in a reputable brand and high-quality model that can pay off in the long run rather than choosing a low-quality cheap product.

Consider the price of the battery tender and ensure it fits within your budget and requirements.

How to use a battery tender correctly for charging?

Using battery tenders correctly can be achieved by simply following the manuals or instruction guides from the manufacturer.

You can make use of some additional cords, wires, adhesives, etc. to make the charging process safer, more secure, and risk-free.

Generally, most battery tenders work on the following steps under common usage:

  • First, make sure the battery you want to charge is compatible with the battery tender. Another important point is to check the condition of the battery especially if it was left on for long periods unattended. Ensure there are no signs of leakages or damage that can make charging useless.
  • Now, connect the cords of the battery tender with the battery terminals. Make use of the provided cords, hooks, and clips with your battery tender. Check the wires are connected to the right terminals and are secured and tight.
  • If the battery tender wires are not long enough to connect with the battery use the additional cords to achieve a proper connection.
  • Once all the connections are in place, select the appropriate mode of charging. Check the user manual to perform this step.
  • Next, turn on the battery charger. This may happen automatically through an LED indicator/light depending on the type of battery tender you have.
  • Leave the battery tender connected to the charger until it reaches full charging. This may take several hours based on the battery condition and size.
  • Once the battery is fully charged, the battery tender will display a different LED indicator prompting you to disconnect the charging.
  • Disconnect the clamps from the battery terminals in the reverse order and test the battery voltage with a voltmeter if you want to cross-verify the charging volts.

Here is a small video to help you understand the connection and charging process using the Battery Tender 800 model:

Tips to maintain a battery tender

Battery tenders do help you maintain your vehicle batteries charged up however they do require some maintenance from your end to continue doing their job.

Here are some of the tips for maintaining a battery tender in good condition:

Proper usage – To make the most out of a battery tender it is important to use it according to the settings, and method provided in the manufacturer’s instructions.

Ensure the battery used for charging is covered under the conditions of battery tender such as the type, condition, voltage, amperage, etc.

Keep it charged – When a battery tender is not in use keep it plugged in to maintain its charge. This will ensure the unit is ready for the next use.

Use the automatic shut-off feature for charging a battery tender or follow the manufacturer’s guidelines on charging the unit appropriately.

Keep it clean – Ensure performing periodic cleaning on battery tenders using a soft and damp cloth.

Remove any dust, or dirt to keep the unit dry, damage-free, and always usable condition.

Store it correctly – When storing a battery tender ensure the place is dry and away from direct sunlight.

Keep the unit cool and avoid exposing it to rain or harsh weather conditions even if it’s a weather-resistant product.

Are battery tenders and trickle chargers the same?

No, battery tenders and trickle chargers are not the same but they have similar functionalities.

A battery tender is designed to fully charge a battery and then maintain it at a full charge as and when the battery starts losing charge. This ensures the battery is fully charged but not overcharged.

On the other hand, a trickle charger is helpful in providing a slow and steady charge to the battery over an extended period of time. However, because they perform constant charging there is a risk of a battery getting over-charged.

To summarize, while both battery tenders and trickle chargers are used to charge a battery, battery tenders are generally considered to be more advanced, safe, and effective at charging and maintaining a battery’s health over the long term.

Can you use a battery tender in the rain?

Some battery tenders are designed to be used in a variety of conditions including rain. If you have a battery tender that is weather-resistant and waterproof you can use it in rain to some extent.

However, it is not recommended to use a battery tender in the rain as it may pose safety hazards due to electrical connection exposure to rain.

Is it safe to leave a battery on the tender?

Yes, it is safe to leave a battery on battery tenders/maintainers. These devices are specifically designed to keep the battery charged and ready for use without overcharging or damaging the battery.

The safety features such as automatic shut-off when fully charged, temperature, and voltage detection are really helpful in keeping your vehicle battery safe from damage.

How much do battery tenders cost?

Battery tenders typically cost between $20 to $150 or higher. The pricing factor can vary depending on the brand, model, and features.

It is best to research and compare different options to find one that fits your needs.


Battery tenders have been in existence for a long time and there are reasons behind them.

These devices have more pros than cons and when it comes to charging and maintaining a battery (all types) they do their job really well.

Battery tenders work in different weather conditions to keep discharged or unused batteries fully charged. What’s more is, they monitor the charging fluctuations automatically and recharge the batteries maintaining their charge to the fullest extent.

Some battery tenders automatically detect the temperature levels and battery voltage to adjust their charge. Some even work in watery conditions as waterproof units.

To conclude, you must always keep your vehicle batteries well-maintained and keeping them properly charged is one of the essential requirements. The best way to achieve appropriate charging is to keep a battery tender handy.

The usage of battery tenders differs according to the type, voltage, and condition of vehicle batteries so do your research before finalizing a product.

If you are too confused or not sure about any particular product then refer to our list of best battery tenders that are reliable, trustworthy, and weather/water-resistant.

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I am the founder of TheCarPlus. As a passionate car owner and enthusiast, I offer practical solutions and insights from my own personal experiences combined with extensive online research.

The purpose of creating this website is to empower fellow car owners and motorcyclists like 'YOU' with knowledge and practical solutions to enhance your vehicle's performance and aesthetics.

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