Your boat battery health guide

Batteries are are a vital component of any powerboat. Not only do they start your outboard, they also power all those electrics on board like your VHF, electric winch, bilge pump, lighting and fish finder. A poor performing battery is not only frustrating, it’s also dangerous, especially if you’re going out wide. That's why it’s good to be aware of the warning signs that your battery may be on its last legs.  

Four signs that your boat's battery needs replacing
Here are some common warning signs to look out for:​

• Change in starter motor speed: When you crank the motor for 10 seconds and the engine doesn’t turn over at the same rate - i.e. it slows down. 
• Your electrics are not powering up your instruments effectively i.e. they’re cutting out or it’s taking longer to power them. 
• The battery is bulging, i.e. the edges look rounded, not square. This means excessive acid build up and which causes the lead acid plates to wear which creates a loss of voltage.
• There are broken or corroded terminals or cracks in the case. This will generally lead to a drop in voltage and therefore power to your instruments or starter motor.

 
If you're experiencing any of these issues, it's time to invest in a new battery.
 
Have you made changes to your boat lately?
Whenever you make any changes to your boat consider how this will affect the draw on power.  For example, if you’ve recently added a new Fish Finder, lighting or even re-powered with a bigger engine, find out how many amps it will draw and adjust accordingly.
 
Think of battery power like a bank account. The more you’re going to draw on it, the more you need in it! Every electrical item you turn on will withdraw funds from your account. You can deposit money back into your account by running the outboard. For example, say you have $100 in your account, if you use two lights and a pump on you’ll draw 12 dollars every hour. After three hours your bank account will be down to $64. When the outboard is running it deposits $20 every hour.
 
"Think of battery power like a bank account. The more you’re going to draw on it, the more you need in it."
 
Choosing the right battery for your needs
Once you’ve determined that you need a new battery, how do you choose the right one? Firstly, the size of your engine will dictate how big your battery needs to be. A larger engine will require more power to turn over the starter motor. Your outboard’s specifications will tell you how many amps are required to start your engine, or ask your marine mechanic to check this.  As a guide, for a carburetted 2-stroke you need a 550CCA (cold cranking amps)/55AH (reserve capacity). That means you can take roughly 5amps for 10 hours before the battery goes flat. As a rule of thumb, nav lights, fish finder and a stereo will draw 5 amps per hour. In contrast, a fuel injected 2 or 4 stroke will require a 680CCA/70AH.
 
Then there's other considerations such as the physical constraint of the battery well/cavity - obviously it needs to be able to fit in the boat! 
 
Lastly, it's important to factor in how you like to boat. For example, if you spend a lot of time with the engine off and electrics on (bilge pumps, radio etc.) then you’ll need a battery that can cope with this power draw. What tends to draw the most amps is live bait tanks and wash down pumps. Any water pumps on board will generally use 5-7amps per hour. Stereos will use around 5amps.
 
It’s a good idea to talk to a professional, who'll can make calculated recommendations based on the voltage your boat requires. We generally recommend using the biggest battery that’s suitable for your boat.
 
How to prolong the life of your battery
Once you’ve found the right battery, here’s how to make sure it goes the distance.

• In a dual battery set-up, stick to one type of battery only and always replace both batteries at the same time, otherwise the old battery can reduce the effectiveness of the new battery. 
• Keep your battery fully charged and if your boat is likely to go unused for a long period try a trickle charger so that it doesn’t run flat. Leaving a boat battery partially charged can damage it and reduce its lifespan.

• Keep terminals clean and free from corrosion.

• Ensure that your battery is installed safely and securely in an acid proof box or tray and a cover to avoid anything falling on it. This not only avoids damage to your battery, but it also prevents hazards like a spill or fire.

• Keep batteries clean, cool and dry.

 
​Don’t let a simple battery issue affect your boating enjoyment and safety. Talk to us about checking your battery requirements and finding the right battery for your needs today.