What is the Best Way to Charge Trolling Motor Batteries? Let’s take a look
As we power through the 2020s, boating has never been more popular as a pastime. And with that, trolling motors, used to power boats for fishing and leisure, have never been more used.
And the answer to the question is ‘it depends’. But if pushed, we choose the generator as our favorite method.
Let’s look at the variety of methods that you can use to keep your trolling motor batteries charged.
Table of Contents
Alternator
The first method is to keep your battery charged using the alternator on your outboard motor. While you are using the engine, the alternator inside is charging the battery.
When the starter battery reaches 13.6 Volts, the alternator will charge the deep cycle batteries.
The amperage the outboard will put into your battery bank is typically on the cautious side. This is because the outboard’s internal regulator restricts the output. So you won’t get the amperage you think you will. It is an ultra-cautious way of avoiding frying the battery. The workaround for this is to add an external regulator.
A good example is the Balmar 614. Or the Wakespeed external regulator. These will allow the outboard to push more current into your battery without damaging it. They don’t come particularly cheap, but they are an excellent option to meet your needs.[1]
The other problem with this is that it means that need your outboard motor running. Not always practical or desirable when you anchor.
Let’s look at other methods of charging your batteries without the outboard running.
Shore Power
The most used method of topping up your batteries is shore power, also known as cold ironing. This is a convenient way of topping up the batteries when you don’t want your outboard running. It means that you have access to a source of AC electricity that will meet your needs and save fuel.
It is more cost-effective and sustainable, depending on whether its source is renewable. And oftentimes, shore power is available from a hook-up wherever you berth your boat.
The only problem is that you can only use it when in your berth, so no good if you are out and about. And not all shore power is super reliable. Depending upon the facilities, they can be prone to outages. So you may need to fall back on another energy source.
Generator
Many people choose to rely on a gasoline generator to supply their extra power while they are anchored.
A small but powerful modern generator won’t power your entire boat. But it can power your electrical items or recharge your batteries. We recommend something like a Honda EU2000i – small, portable but still packs a punch. And the more appliances you have, such as freezers, fridges or TVs, the more likely it that a generator will benefit you.
If you go for a direct generator to battery recharge, you can do so using the generator’s 12Volt output, if it has one. It has a 15Amp rated output, which means around 10-12Amps in practice. The other option is to connect the output to your boat’s shore power cord inlet. This simulates the AC current that you would get while berthed.
One of the main disadvantages of the generator is the noise. While foliage muffles the noise in woods, on open water it carries further. So you need to consider any neighbors.
Remember also that gas emissions from a generator can be hazardous. So don’t use it in any closed spaces. It’s not the cleanest, either.
Solar Panels
One of the best ways to top up your battery when at anchor is to use solar energy. Solar makes use of the natural energy from the sun and is a great way for topping up. That way you can increase your time st anchor before going back to shore.
Once you have paid for the equipment solar is a free, handy source of energy. To maintain a 100Ah battery, you need a 5-10Watt solar panel. But if you need more than a top-up for your battery bank you can double up with those or invest in a more powerful setup.
You need to include a solar regulator (aka charge controller) in your setup. This goes between the panel and your battery bank. It cuts off the energy when the battery is full. This will prevent hazardous overcharging which can damage the battery.
But there are some disadvantages of solar panels. While they are an emission-free energy source, their environmental credentials are questionable. This is due to the resources used and emissions created as a byproduct of their manufacture. And safe and sustainable disposal of obsolete or broken solar panels has its own issues.
But from our point of view, the main problem with solar panels is that they cannot generate energy at night. So, if you think you are going to need nighttime energy, you should consider investing in a fuel cell,
Fuel Cells
Another option If you only need an occasional top-up is to use a fuel cell.[2] Fuel cells oxidize chemicals into electricity and heat. They do this using electrochemical conversion. It is usually fuelled by propane or methanol.
One of the top versions available is the methanol battery charger produced by EFOY.[3] They are a quick and handy way to recharge when there is no other method available.
They run on EFOY proprietary fuel – methanol. And users report needing to use around three 10-liter M10 cartridges per year. At the time of writing each cartridge costs around $65. So you can keep that liquid energy handy without breaking the bank.
Each cartridge contains around 1000 Amp hours of capacity in liquid form. And it is ready to come to the rescue whenever you’re stuck.
The methanol fuel cell is also quiet (only 22 decibels), an important consideration. A smartphone can control it, and it also has an auto top-up, so it is a simple matter to keep your battery full.
Other fuel cells include the WATT Imperium fuel cell.[4] It shares some of the functions of the EFOY, but runs off propane rather than methanol.
Best Way to Charge Trolling Motor Batteries – Our Verdict
The ideal method depends upon the circumstances. And in many of those circumstances will be a mixture of those above. However, proper charging of the battery through proper means and understanding its characteristics will ensure a long and productive battery life.
And remember, it could also save you from the situation of running out of charge on the water.
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