Jun 14 2021 All Articles

Boat battery smarts - maintenance and safety advice

Boat battery smarts - maintenance and safety advice

Boat battery* basics - it’s a timely discussion. Did you know that winter is the most crucial time to keep on top of charging your boat battery? In the colder months, batteries can lose as much as 30 percent of their charge.

Firstly, let’s establish how important a functioning battery is. You don’t want to be stuck out on the water with a motor that’s doing nothing but maintaining silence. To avoid that scenario, ensure you choose the right marine battery and then maintain it.

But how do you choose the right battery for your boat? What aspects of the battery need checking before heading out on the water? How best to charge a marine battery and maintain it? Can you use a car battery instead? These are, apparently, common questions according to the Boating & Outdoors website.

The learned people from Boating & Outdoors tell us things to consider when choosing a marine battery include your boat’s power requirements (engine start, electric motors, technology), your battery category that suits your craft (dual purpose, deep cycle, cranking battery), as well as what environmental conditions you will be exposing your boat to.

And yes, funny as it sounds, the question is often asked “can I just use a car battery?” The answer: “All batteries are not created equal. While car and boat batteries have similar purposes and features, a car battery has no place on your boat.”

Now, with that out of the way, let’s address the questions around battery checking and maintenance. The team at Boating & Outdoors advise putting time aside for some basic battery maintenance and safety checks before spending a day on the water. Things to check are:

  • Check and clean the terminals and connecting cables to make sure they are tight
  • Make sure your battery is secure and strapped down before take-off
  • To reduce the possibility of discharge, be sure to clean the top of the battery case
  • Take a look over the terminals, screws, clamps and cables for breakage, damage or loose connections. These should be clean, tight and free of corrosion
  • Check if the battery is fully charged and allow enough time for recharging in case it’s not. A full charged battery should be above 12.5V. Retest the battery after 24 hours to ensure the battery is maintaining a good charge level
  • For added safety, use a battery monitor: This is the easiest way to keep track of your battery’s state of charge and your boat’s starting and charging systems.

Remember there are many parts to a battery that need constant upkeep and inspection to ensure power and performance. Top maintenance tips for this (also according to Boating & Outdoors) are:

  • Always keep the battery in a covered area away from salt spray and water. Think about storing your battery in a specific battery box
  • Use grease to help prevent any damage from corrosion
  • Regular (monthly) testing and inspection will help to maximise battery life
  • Discharging even the best deep-discharge batteries below 50 per cent of their rated capacity will dramatically shorten their life, while regularly flattening the battery can destroy it in a few months. Don’t underestimate the effect of this: over-discharge is the biggest single cause of battery failure
  • Reduce the load: This can be one of the easiest and cheapest ways to extend battery life. It's as simple as not leaving lights on unnecessarily. Low-energy LED bulbs are recommended
  • Always take a spare. Or consider a power back up.

It’s important to also be smart about charging your boat battery. Charging your battery correctly will prolong its performance. To keep your battery in top condition, make sure you use a marine battery charger that meets the manufacturer’s recommendations for your type of battery and its charging requirements. When a battery is left to go flat or partially flat, it will permanently lower the capacity of the battery.

The Boaties Best Mate website wouldn’t be a best mate if it too didn’t supply battery advice. As well as the tips already mentioned, advice includes:

  • Make sure your battery is properly installed. A boat can take a pounding, which means the battery will too. Have the battery securely fastened in your hold 
  • Keep terminals free of corrosion. Check terminal connectors regularly to avoid loss of conductivity
  • Don't mix old batteries with new ones in the same battery bank. Old batteries tend to pull down the new ones to their deteriorated level
  • Trickle charging. If you're not going to be running the boat for a length of time, it's a good idea to set up a small solar charger for your battery - this helps keep it topped up, and in a healthy state. It’s a decent investment to keep more expensive batteries in good nick
  • Be mindful of temperature extremes. A whole range of things such as temperature, humidity conditions and type of battery all affect performance. Batteries don't like extremes of cold or hot weather, and high humidity can affect their charge. So, keep an eye on their charge levels over time, and be proactive about replacing them.

There you go - your battery knowledge base is now fully charged!

*This article is referring to lead acid batteries only.

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