When it comes to getting the best marine battery for a trolling motor, its important to highlight that there are two different types of batteries for the different two jobs on a boat. One, cranking the engine, and, two, powering the trolling motor and other electronics.
The cranking battery has more numerous, thin plates designed for the burst of energy needed to engage the starter and is recharged by the alternator within a few seconds. The cranking battery will overheat when used for the trolling motor and, likely, the trolling motor and the control unit will overheat and be damaged or even destroyed. However, deep cycle marine batteries which are best for trolling motors have fewer, thicker plates and provide better output for longer periods of time. The thicker plates of the deep cycle battery are also better able to withstand vibrations of your boat which can damage the battery so it won't charge or will even destroy it. Thicker plates also withstand the higher temperatures that are created when heavy current is drawn down for an extended run time so they provide better power output over a longer period. Simply stated, starting batteries don’t handle long periods of use at low amps. Deep Cycle Batteries can handle longer use at low amps. So, your choice really is a deep-cycle battery. Which type usually comes down to cost and how often you use it.
If you need expert, tailored, no-obligation advice on Marine Batteries for Trolling Motors or Boat/Yacht setups email or call our friendly team on 1800 853 315 or download and print our battery Power Estimator to help you work out the best Deep Cycle Battery for your application. Or Shop our Range of Best Marine Batteries for Trolling Motors all with Australia Wide Delivery.
All batteries use lead plates, separated by spacers, immersed in a solution of approximately 35% sulfuric acid and 65% distilled water. As a battery is used, it generates heat that dissipates the water and exposes the lead plates. Plates that are left exposed are subject to overheating and warping. Deep cycle marine batteries are specifically designed for the depletion and re-charging associated with trolling motor use, and are the most economical choice. They usually last from one to two and a half years and are cheaper to buy. These batteries are very common and handle the frequent draining and re-charging associated with trolling motor use, and are the most affordable option. The downside to these batteries is that they can require occasional maintenance – topping up the water – and they are also prone to vibration and spillage.
We recommend AGM Deep Cycle Batteries for use with all Sounders, lights, bilge pumps, live wells and any fridges or other appliances cycling from the batteries. Any Outboard Motors that require a battery for electric trim/tilt and starting should use an Exide Marine Calcium Flooded Battery for this purpose. We could also mention that we sell a Giant 220Ah Flooded Battery with a 1200CCA Rating. This battery will be too big for most applications. If your on doubt give as a call as we love to help our customers get the best battery solutions for their marine and boating needs.
AGM Absorbed Glass Mat DEEP CYCLE Batteries are great for use as Trolling Motor Batteries
The other option is AGM Batteries. AGM Batteries are completely sealed, generally last longer on a charge and have a longer life-span. While a traditional deep cycle battery might last approximately two years, an AGM deep cycle marine battery should last between three to four years. While more expensive, they are the best choice for longevity and performance out on the water. They also have the added benefit of being 100% maintenance free. Maintenance-Free AGM batteries are sealed and won't spill. There is less corrosion, generally, with a maintenance-free battery because the electrolyte in the cells doesn't get released unless there is a pressure buildup through overcharging. You can't service maintenance-free batteries, except for cleaning the corrosion off the terminals, so when a cell gets low because of overcharging, it stays low.
AGM batteries' internal structure is quite different with fewer, thicker plates so they are also far more resistant to vibration. The cells have thick, high-purity, lead-calcium alloy plates to ensure a lifespan of around 12 years at infrequent discharges as low as 20°C). These are corrosion resistant and the lead-calcium grids have a low self-discharge rate of approximately 3% of the battery capacity per month. Terminals are quality Copper-Silver alloy which means low contact resistance and high corrosion resistance.
Gel Cell Batteries
AGM Batteries are often mistakenly identified as Gel Cell Batteries. Both batteries have similar traits; such as being non-spillable, deep cycle, may be mounted in any position, low self-discharge, safe for use in limited ventilation areas, and may be transported via Air or Ground safely without special handling.
Gel Cell batteries are often mistakenly identified as AGM Batteries. Both batteries have similar characteristics. They are non-spillable, deep cycle batteries which can be mounted in any position. They are low self discharge, safe for use in limited ventilation areas, and may be transported safely without special handling. However Gel Cell batteries are mainly designed for stand-alone power storage, usually attached to a solar system. They are designed for up to a 20 year life and over 5000 cycles. This is far more than you need for a trolling motor; in fact you'd be likely to wear out your motor and even your boat before you wear out the battery!
AGM Batteries vastly outsell Gel Cell. AGM is preferred when a high burst of amps may be required. In most cases, recharge can be accomplished by using a good quality standard battery charger or engine alternator. The life expectancy; measured as cycle life or years remains excellent in most AGM batteries if the batteries are not discharged more than 60% between recharge. In contrast, Gel Cell Batteries are typically more costly and do not offer the same power capacity as the same size AGM batteries. Gel Cell Batteries must also be recharged correctly or the battery will suffer premature failure. The battery charger being used to recharge the battery(s) must be designed or adjustable for Gel Cell Batteries. If you are using an alternator to recharge a true Gel Cell a special regulator will need to be installed.
MCA. Marine Cranking Ampere (MCA) rating refers to the number of amperes a battery can support for 30 seconds at a temperature of 0°C until the battery voltage drops to 1.20 volts per cell, or 7.20 volts for a 12V battery. Thus, a 12V battery that carries a MCA rating of 600 CCA tells us that the battery will provide 600 amperes for 30 seconds at 0°C before the voltage falls to 7.20V. AH. Ampere-hour (Ah) rating defines the capacity of a battery. A typical battery that is rated as a 100Ah battery, at the 10 hour rate of discharge, is capable of delivering 10A for 10 hours before the terminal voltage drops to a standard value such as 1.67 volts per cell, or 10.02 volts for a 12V battery. Similarly, a 50Ah battery would supply a 5A load for 10 hours.
You can think of a battery's amperage hour rating as being similar to the petrol tank of a car. A 100 amp hour rated battery can deliver 100 amp hours of current to a trolling motor. So if a motor is running at low speed and pulling 4 amps, the battery should last around 25 hours. (100 amp hour rating / 4 amps = 25 hours). Similarly, if the motor was running at top speed and pulling 40 amps, the battery would last for 2.5 hours (100 amp hour rating / 40 amps = 2.5 hours). For trolling, we recommend a battery with AT LEAST a 100 amperage hour rating
Charging Batteries
Recharging the batteries puts the sulphate back into the solution, which in turn gives the battery the potential to provide electricity again. Batteries fail for a number of reasons. One is that fishermen choose the wrong one for the
application. Marine batteries are more expensive because of their construction, and on occasion, fishermen pick cranking batteries or deep cycle batteries that are intended for use on land because they can be significantly cheaper. That's false economy, because a battery built for use in a car is simply not strong enough to withstand the rigors of a bouncing ride in a boat. The battery might be able to handle it for a while, but repeated abuse will loosen plates, crack cases and set the stage for failure. Deep Cycle marine batteries, with their heavier plates and stronger internal construction, are built for rough duty and are built to deliver the smaller doses of power required by a trolling motor over a long period of time.
Keeping marine deep-cycle batteries up to scratch doesn't have to be a chore. Avoid totally discharging wet-cell, deep-cycle batteries as well as avoiding quick charges that create more heat than the more desirable trickle charge. Promptly recharging your batteries immediately after use will markedly extend their life. Convenient, on-board smart chargers eliminate the hassle and worry about overcharging. Once you've returned home from a boating trip, you simply plug the charger into a 240- volt outlet and let these smart chargers maintain your batteries without the hassle of personal monitoring.
With the right trolling motor, batteries and charger on your boat, many of the worries of a day on the water are eliminated and you can concentrate on the most important reason you bought your boat for in the first place - having fun on the water.
How to get the most out of your Deep Cycle Battery.
Maintenance-free AGM batteries do not require a lot of maintenance, but they do require some. The most important thing you can do is charge your batteries — regardless of type — as soon as you return from fishing. If you let batteries sit under partial charge for long periods of time, you will see a drop in their performance because of sulphation, and there will be a drop in the longevity of the batteries as well. Another source of battery failure is the buildup of sulphates on the plates of batteries. Charging the battery returns sulphate on the plates to the electrolyte solution, but not all of it leaves the plates. Over time, the sulfates build, and it's this buildup that increases internal resistance and resistance to charging. For wet-cell batteries, you can add a "cleansing agent," to each cell to remove sulphate buildup and thereby extend the life and capacity of the battery.
The second-most important thing you can do is frequently check for the buildup of corrosion on the battery terminals. If signs of corrosion are found it's caused by liquid electrolyte leakage when the battery is overfull, hot or overcharged, or by the gas the battery releases when it's charging. Corrosion will lead to partial charging, and it will also cause a break in the circuit, usually at the worst possible time. Clean off the corrosion by using a solution of baking soda and water, a rag and a wire brush or sandpaper on the terminals. Coat the areas with electrolytic grease. Before you put the battery cable back on the terminal (or when you install a new battery), run a thin bead of silicone around the base of the battery post and install a felt battery washer. Coat everything with the grease to eliminate contact with the battery gas and always connect the positive (red) terminal first to avoid sparking.
On wet-cell or flooded-cell batteries, unscrew the cell caps and check the electrolyte levels before charging. Battery plates should be covered by 1/8 inch of fluid. The fluid level should not extend to the top of the cell but should be approximately 2-3 mm below the splash ring on the mouth of the cell. The gap allows for expansion of the electrolyte when hot. If the cells are down, you will need to refill them using distilled water. Add the water
to the cell slowly so you can judge levels accurately. Don't overfill.
Smart chargers for all sorts of Marine Batteries
The best insurance you can buy to extend both the life of your batteries as well as the power they provide is to use a multistage charger that delivers the power your batteries need at the different stages of charging. The new generation chargers won't overcharge a battery and cause it to overheat or boil. Whether you opt for an onboard charger, which installs in the battery compartment of your boat, or a stand-alone model, be sure to choose the best you can afford. Want to charge your trolling motor batteries while motoring from one fishing spot to another? The right charging system can use either AC power (from an electrical outlet) or DC power (from your outboard) to charge up to six batteries at a time.
Power to the battery.
Charging is where you can make the greatest gains in extending the life and keeping the capacity of the battery high. Leaving the battery discharged will reduce its life and performance. When a battery is discharged, sulphur deposits form on the lead plates. When the battery is recharged, the sulphur dissolves back into the electrolyte. Sulphur oxidizes the plates and can shorten battery life. Also, when sulphur deposits become large enough they can short out the plates and prematurely terminate the battery's useful life. That's why it's important to recharge batteries promptly after use and check water levels frequently so that the sulphur isn't allowed to form and solidify. Letting a battery sit also results in sulphate buildup on the plates so it's important to fully charge the battery as partial charging will eventually lead to reduced capacity.
When charging, unscrew the tops of wet-cell batteries to release heat buildup as well as to ease the off-gassing that will occur. Check fluid levels at the same time. Only use distilled water to protect against the chlorine damage from tap water
To get the most from your battery, you also need to measure the charge you're giving by first checking the battery's charge level. For instance, a 50 percent charge on a 100-amp battery means that the charger should provide 50 amps or a five-hour charge at 10 amps. Too much time on the charger will damage the battery.
Other Tips.
Never put an older battery with a new battery because the older battery will pull down the new battery.
Store batteries in a cool, dry place when you're not using them and hook the battery up to a trickle charger. If a trickle charger is not used, charge the battery at least once per month.
Ensure the tops of the batteries are clean and that the terminals are free from corrosion.
If you're using the trolling motor regularly an AGM battery with a minimum 100AH is your best bet for performance and longer life. If you only use the motor occasionally, a deep cycle, wet-cell battery will cost you less and perform adequately as long as you keep it charged and maintained.
If you need expert, tailored, no-obligation advice on Marine Batteries for Trolling Motors or Boat/Yacht setups email or call our friendly team on 1800 853 315 or download and print our battery Power Estimator to help you work out the best Deep Cycle Battery for your application. Or Shop our Range of Best Marine Batteries for Trolling Motors all with Australia Wide Delivery.
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