A commonly asked question is: Can I replace lead-acid batteries with lithium batteries for my trolling motor?
The answer is yes, there are numerous benefits when replacing lead-acid batteries with lithium batteries in marine applications. Not only will a lithium battery keep your trolling motor running efficiently but, when you reduce weight by switching from a lead-acid to a much lighter lithium battery, you will find that your boat will be easier to tow, and its performance and speed on the water will improve.
So what is the lifespan for a lithium battery that is used for powering a trolling motor?
Lithium deep-cycle batteries are designed to discharge slowly over a long period and to withstand numerous charging and discharging cycles. You can expect up to 5,000 cycles at 50% depth of discharge (DoD), or 2,000 cycles at 80% DoD during the lifespan of a lithium battery. This type of deep-cycle battery is designed to be used with your trolling motor and any battery-powered accessories.
What size battery do I need 12V, 24V, 36V or 48V?
Baintech Whitehaven Marine Series batteries are available in 12V, 24V, 36V, or 48V, and your selection will depend on your trolling motor. Trolling motors with higher voltages have more thrust. Thrust in marine terms means you will achieve better results in windy conditions, allowing you to spot lock, keeping your boat safely in place.
However, the amount of energy stored in the battery, or battery capacity, must also be considered. The capacity is indicated by the amperage-hour (amp-hour or Ah) rating of the battery. The capacity of the deep-cycle lithium battery you require will depend on your trolling requirements and the size of your boat. Different conditions will determine how long your battery will last out on the water. Obviously, if you are trolling in low wind conditions in an inlet, you will draw less power than you would when fishing in higher winds and are dealing with a current.
If you own a 12V electric motor, naturally you will need a 12V battery. Baintech carries a range of 12V batteries from 75 Ah to 225 Ah, and you should consult your trolling motor manufacturer’s specifications for a better understanding of its amp-hour requirements.
For example, if you have a 100 Ah battery, and your trolling motor is drawing 10 A of current then, theoretically, you can run your motor for 10 hours. Drawing 25 A of current you could go for 4 hours, and so on. The basic calculation is: Capacity (Ah) divided by electric current (A) = time (h). This is only an approximate calculation because your power requirements (and hence current) will vary in different conditions. It’s important to note that lithium batteries should only be discharged to 80% DoD to avoid decreasing the longevity of your battery.
Charging Your Trolling Battery
To ensure the best performance of your lithium battery in the long term, it is important to charge it correctly.
AC Charging: A 240V AC charger can be installed onboard allowing you to charge your battery by simply plugging it in after your day on the water.
DC-DC Charging: With a DC-DC charger you can recharge your deep-cycle battery while on the water.
Battery-to-battery waterproof chargers, suitable for specific motors are the:
BBW1212 Sterling Pro Charge B for a 12 Volt Electric Motor,
BBW1224 Sterling Pro Charge B for a 24 Volt Electric Motor, and
BBW1236 Sterling Pro Charge B for a 36 Volt Electric Motor
The Pro Charge B is a fully epoxy encapsulated, plug-and-play battery-to-battery charger. It is primarily designed to be put between the starter battery and a deep-cycle battery (trolling / bow thruster / domestic). The charger puts a load on the alternator and converts that load into a 4-stage charging profile to provide fast and effective charging. The purpose of the charger is to recharge your batteries as you cruise by fully utilizing your onboard alternator.
Note that DC-DC charging from your main boat engine is possible only if the engine charging circuit can carry the overall charge current required.
Are Lithium Batteries the Best Choice for Your Boat?
We’ve gone over the basics of lithium batteries, why they’re safe and effective, and why it benefits you to use them. So, is lithium the right choice for boat batteries?
Choosing lithium over a lead-acid battery means you’ll be switching to a lighter, more efficient power source. Your lithium battery will last up to 7 times longer than a comparable lead-acid alternative, so will need to be replaced less often, reducing costs in the long run. Make the switch and see the difference for yourself!
Do you need a new marine battery?
Take a look at our new Baintech Whitehaven Marine Series to see what Bainbridge Technologies can offer you.
www.baintech.com.au or visit 1224 Lytton Road, Hemmant, QLD, 4174 Phone: 1300 224 683
Published in print January-March 2022
