It's not just individual batteries - power supplies, jump-starters, torches and many products we use today contain batteries. So it's important to understand at least a little about them.


Battery Safety

When using products with batteries, it is important to consider several key safety aspects to ensure proper usage and minimize potential risks. Here are some important points to keep in mind:

Battery Quality and Authenticity: Always use high-quality batteries from reputable manufacturers. Counterfeit or low-quality batteries may pose safety hazards like leakage, overheating, or even explosion. Purchase batteries from trusted sources and avoid suspiciously cheap options.

Compatibility: Use recommended batteries compatible with the specific product or device. Improperly sized or incompatible batteries can lead to overheating, leakage, or damage to the device.

Battery Handling and Storage: Follow the manufacturer's instructions for properly handling and storing batteries. Avoid exposing batteries to extreme temperatures, direct sunlight, or moisture. Improper storage or mishandling can result in leakage, overheating, or other hazards.

Battery Installation: Ensure correct polarity (+/-) alignment when inserting or replacing batteries. Inserting batteries in the wrong orientation can cause short circuits or damage to the device.

Charging: If the device has a rechargeable battery, carefully follow the provided charging instructions. Overcharging or using incompatible chargers can lead to battery damage, overheating, or even fire hazards.

Charging Supervision: When charging batteries, it is advisable to supervise the process whenever possible. Avoid leaving charging devices unattended for extended periods, especially overnight or when you are away from home.

Battery Damage: Do not use batteries that appear damaged, swollen, or have leaked. Damaged batteries can release harmful chemicals or have an increased risk of overheating or exploding. Dispose of damaged batteries properly according to local regulations.

Child Safety: Keep batteries, especially small coin-cell batteries, out of the reach of children. Ingesting batteries can cause severe injuries or health risks. Ensure that battery compartments of devices are securely closed and cannot be accessed by young children.

Recycling and Disposal: Dispose of batteries responsibly according to local regulations. Many batteries contain hazardous materials and should not be thrown in the regular trash. Check for recycling programs or drop-off locations in your area.

Fire Safety: In case of battery-related incidents, such as overheating, smoke, or fire, exercise caution. If safe to do so, remove the device from the vicinity of flammable materials and use appropriate fire-fighting equipment, such as a fire extinguisher. If necessary, evacuate the area and call emergency services.

Remember, these guidelines provide general safety advice, but it's crucial to refer to the specific product's instructions and warnings for comprehensive information on battery safety.


What should I do if my battery catches fire?

There are a couple of preventative measures and some 'emergency' management in case the worst happens.

  • If the battery is looking rough, consider replacing it. Earlier Lithium compositions had a risk of exploding if damaged - a good drop or decent knock could be enough to cause damage. If in doubt, don't.
  • Don't leave your battery charging unattended - especially if on any kind of 'fast charger' - batteries don't like to be overcharged - and not all battery chargers cut off when the battery is fully charged
  • Make sure the battery (and charger) have adequate ventilation around it. This is often more than people realise - ensure air vents are not obstructed in any way.
  • Always keep a fire extinguisher handy. This is a general 'best practice' suggestion - but especially important if there are large batteries or other potential sources of fire. Ensure you also have an appropriate type of extinguisher for the potential hazards and know how to use it!

Lead Acid Batteries

There are a variety of differences between the two most common types of battery chemistry on the market today. What you purchase is going to be dictated by use and budget.

Lead-Acid is a tried-and-true technology that costs less but requires regular maintenance and doesn’t last as long. Lithium is a premium battery technology with a longer lifespan and higher efficiency, but you’ll pay more for the performance boost.

Flooded Lead-Acid (FLA)

The distinguishing feature of FLA batteries is that the plates are submerged in water. These must be checked regularly and refilled every 1-3 months to keep them working properly. Falling behind on upkeep can shorten the life of the batteries and void the warranty. FLA batteries also need to be installed in a ventilated enclosure to allow battery gases to escape.

Sealed Lead-Acid (SLA)

SLA batteries come in two types, AGM (Absorbent Glass Mat) and Gel, which have many similar properties. They require little to no maintenance and are spill-proof. The key difference between AGM vs. gel batteries is that gel batteries tend to have lower charge rates and output. Gel batteries generally can’t handle as much charge current, which means they take longer to recharge and output less power.

Flooded batteries need water

While many batteries are now sealed and maintenance-free, some Lead Batteries still require regular checking and topping up with water. More importantly, watering must be done at the right time and in the right amount, or the battery’s performance and longevity suffer.

Water should always be added after fully charging the battery. Prior to charging, there should be enough water to cover the plates. If the battery has been discharged (partially or fully), the water level should also be above the plates. Keeping the water at the correct level after a full charge will prevent having to worry about the water level at a different state of charge.

Lithium Batteries

Lithium Batteries are lighter, do not self-discharge, can charge fast and stand up well to repeated charging and discharging. But - we see a few things trip people over when using them.

Avoid storing overcharged or over-discharging

Lithium Batteries are considered 'smart' batteries because they have a circuit board built into them (basically a tiny computer) that controls the battery's performance. This board provides three levels of control - the first is a balancing circuit that manages the charging and discharging of the cells within the battery. The second is a protective circuit module (PCM) that protects the whole system, and finally, a Battery Management System (BMS) that optimises the battery over its life.

In a battery with a balancing chip, the cells are managed to all have the same charge on them. This is important because the PCM is often set up to shut off once a cell gets below or above a certain voltage. If the cells within the battery are not balanced - this could happen when there is still power available in the other cells or the other cells are not fully charged.

The PCM system can cause frustration and confusion for people new to Lithium Batteries.

If a lithium battery gets below a certain threshold, the PCM may go into protect mode, effectively 'switching off' the battery. Once it is in this state - it may not charge back up again unless the correct battery charger, with the ability to 'wake up' the battery, is used.

Concerns with 'Exploding Lithium'

Technology is constantly evolving and improving. The same is true with Lithium Batteries.

Early Lithium Batteries were made from components that, on rare occasions, could allow thermal runaway. This is essentially the battery overheating and going into a cycle that could result in flame-ups - some very significantly.

This was generally the result of the battery taking a significant knock. This could disrupt the composition of the battery internally which can turn into a bit of a domino effect and cause a fire.

Here at Marine Deals, when it comes to the batteries we stock and sell, we prioritize the use of lithium iron phosphate (LiFePO4) chemistry due to its inherent safety features. With LifePO4 you can rest assured that a battery meltdown is not a concern. LiFePO4 batteries possess a chemical and mechanical structure that prevents them from reaching hazardous levels of overheating, which sets them apart from batteries containing cobalt-oxide or manganese-oxide cathodes.

The similarity in physical characteristics between the charged and uncharged states of LiFePO4 ensures remarkable stability of ions, even during oxygen flux that occurs during charge cycles or potential malfunctions. The bond between iron phosphate and oxide is notably stronger than that of cobalt-oxide, meaning that the phosphate-oxide bond remains structurally stable in cases of overcharging or physical damage. In contrast, other lithium chemistries experience bond degradation and the subsequent release of excessive heat, ultimately leading to thermal runaway.

LiFePO4 proves highly effective for the needs of our customers. However, this chemistry may not perform as efficiently when used in small electronic device batteries. In addition, the LifePO4 can result in a slightly larger battery for the power supplied.

Not all battery chargers are the same.

Unfortunately, many of the cheaper battery chargers don't have the ability to charge a lithium battery correctly. For a start - your old lead battery charger likely isn't suitable for charging lithium batteries. They require a charger that specifically can work with Lithium.

In addition, there are chargers that can provide the correct voltage and amperage to charge a Lithium Battery but don't have the ability to detect and adapt to a Lithium battery that has been 'over-discharged' and needs a wake-up.

'Smart Chargers' normally can also test, maintain and sometimes even recondition a battery - so investing in a high-quality charger can be a good choice if you are charging and recharging batteries a lot. They generally work over multiple types of batteries, and some even let you charge multiple batteries at once.

Victron Blue Smart Charger

We use the Victron in the service/testing office, which has allowed us to recover several batteries that were returned 'dead'. These are often batteries that have been used, totally discharged and then put into storage for a couple of months. Different from how we should be storing Lithium Batteries, in particular.

Store them charged - not too little, not too much.

Storing a lead-acid battery at a very low charge can cause crystal formation, reducing capacity. The general rule is that the less the battery is discharged before recharging, the longer it will last.

However, most lithium battery manufacturers recommend storing their batteries within 50 to 75% capacity. This can be a challenge, so some companies even provide devices to allow you to discharge batteries to a certain point, like the SwellPro Safe Discharge Stick.

The important point here is not to completely discharge your battery and put it away without recharging. After a long day out on the beach or the water, plugging in the battery might be the last thing on your mind, but doing so will provide a longer lifespan and fewer issues for your investment.

Should you disconnect your boat battery when not in use?

Like many things, it depends. You should be aware that simply turning off your engine doesn't mean the battery isn't discharging. Depending on your wiring setup, the radio, sounder, bilge pump and other electronics could still draw power. If the boat lives moored up, you might want the auto bilge pump to have power still so it can do its job when you are not there.

However, if the boat is trailered when it's not in use - you may want to disconnect the battery (or turn off the isolating switch if one is installed) to ensure there is no unnecessary drain on battery when the boat is not in use. If it's going not to be used for a significant amount of time - you might also want to consider plugging it into a charger that is able to go into a maintenance mode - this will go into a low-power trickle mode that will ensure the battery is ready for use next time you use it. As always, read the instruction to ensure the charger can do so.

Basic Troubleshooting

Batteries are generally part of a wider electronics ecosystem, so doing a few quick checks before sending back a battery is important. More than once, we have discovered it's not the battery but something else in the system.

Do this methodically - trying to do too much at once can quickly confuse the issue.

Charge Your Battery

Ensure your battery is charged. Part of this is ensuring your charger is the right one for the battery type. In addition - if it's a Lithium Battery and the battery seems completely dead - we need to confirm the battery can actually 'wake up' a sleeping lithium battery. Overnight can be a good idea - but confirm the charger is smart enough to stop charging when the battery is at capacity (some cheap chargers don't and can damage the battery).


Once you are comfortable that the battery should have a full charge, start at the battery end, isolate it, and test it with a multimeter. You are looking for a voltage reading - which potentially will be slightly over or under the expected voltage. Many 12v batteries will show 13.2 volts when freshly charged.

Of course - if it doesn't have a charge - it is possible that the charging device is at fault - swapping it out to try and isolate the fault is a good step (if you can).

If the battery is showing a charge, but you still don't have power to your electronics - you might want to start checking further up the line with the multimeter to try and determine where the power stops being supplied. Fuses, switches, and even cabling can all cause issues.

If you can't determine the issue

Get in touch. We are always happy to help out by getting the battery back and testing here. If it's faulty, then we will happily replace it.