Choosing a power source for a boat is often a stumbling block for boat owners and PVC boats, especially when one battery is no longer enough for all needs. launcher It's zero after an overnight night with the sonar on, familiar to many aquatic motorists, and it's to solve this problem and create a universal power system on board that uses a start-and-traction battery that combines the functions of starting the engine and powering on-board electronics.
Unlike classic two-block schemes, the combined variant saves space and weight, which is critical for small craft. AGM or GEL The right start-and-traction battery will ensure that the engine starts confidently even after long fishing with powerful energy consumers.
In this article, we will discuss the technical nuances that will help you not to go wrong when buying and operating. Cold scroll current (CCA) is not the only important parameter. So, for mixed-use, and how to extend the life of a battery in vibration and pitching, the smart way to power is to be safe and comfortable on the water.
Design features of the starting-traction batteries
The main difference between a starter and a conventional starter battery is the design of the plates and the chemistry of the electrolyte. If the starter battery is designed to give a huge current in a few seconds to rotate the starter, the traction battery must give off energy for a long and uniform time. Combined models try to combine these qualities using thick plates with the addition of antimony or calcium, which allows you to withstand deep discharges.
In modern conditions, the most common batteries manufactured by technology AGM They have an electrolyte in a bound state, absorbed into fiberglass mats, making the hull completely sealed and safe for rolling boats, capable of producing high initiation currents comparable to classics, but with high cycling resistance.
⚠️ Note: Using conventional starter batteries (WETs) as traction batteries will cause the wafers to fail quickly, not designed to discharge below 50% and may lose up to 80% of capacity after 10-15 deep cycles.
Gele (Gel)GEL) analogues are also popular due to their vibration resistance and ability to operate in any position, but they are more sensitive to charging parameters. cyclicity These batteries can be measured in hundreds of charge-discharge cycles, whereas conventional batteries can only withstand dozens, making them ideal for boats where the motor is used not only for moving, but also as a generator for trolling.
Technology comparison: AGM, GEL and Lithium
When you choose a power grid, you have to ask the question of manufacturing technology, each type has its own advantages and disadvantages, which directly affect the cost of ownership and usability, and let's look at the basic specifications so you can weigh the pros and cons.
- 🔋 AGM batteries: Optimal balance of price and quality, withstand high currents of charge and discharge, are not afraid of short circuits, but have a limited cycle life (about 500-600 at 50% discharge).
- ❄️ GEL batteries: They have maximum vibration resistance and better tolerate a deep discharge, but they require a very accurate charge voltage and are afraid of overheating.
- ⚡ LiFePO4 (Lithium-Iron-Phosphate): A revolutionary solution with a weight of 3 times less than lead and a resource of 3000+ cycles, but requiring a BMS and a special charger.
Lithium batteries, despite their high initial cost, are becoming the standard for serious anglers, giving away 100 percent of their capacity, while lead batteries only give 50 to 60 percent of their efficiency to keep them from degrading. tension at the terminals of lithium is kept stable almost to full discharge, which ensures a constant speed of the electric motor.
When you switch to lithium, it's important to keep your temperature in mind. If you're planning to keep your boat in an unheated room in the winter, LiFePO4 You can't charge batteries in the cold without a built-in heating system, and lead is more forgiving, even though they don't like extreme temperatures.
Calculation of capacity and power consumption
The right capacity calculation is to ensure that you don't end up with a broken sonar in the middle of a body of water, and to start with, you have to add up all the electrical appliances you use, the sonar, the navigator, the lights and, most importantly, the electric motor, all of them into a single load.
Consider a rough calculation for a typical fishing trip: Suppose you have an electric motor with a consumption of 20 Amps at an average speed, the sonar consumes 0.5 A, and the navigator 0.3 A. In 5 hours of fishing, the total consumption will be a significant amount that the battery should cover without compromising the start of the ICE.
Formula for calculating the required capacity
Total current (A) × time (h) = consumption (Ah). Then divide by 0.5 (for lead) or 0.8 (for lithium) to get the desired nominal capacity.
Below is a table showing how fast a battery of different capacities goes down under different loads. Note that for lead batteries, we only count 50% of the value so as not to kill them.
| Type of load | Consumption (A) | Capacity of AKB (Ach) | Working hours (h) |
|---|---|---|---|
| Echoer + Navigator | 1.5 | 100 (AGM) | 33.3 |
| Electric motor (medium) | 20.0 | 100 (AGM) | 2.5 |
| Electric motor (max) | 50.0 | 100 (AGM) | 1.0 |
| Combined | 25.0 | 100 (LiFePO4) | 3.2 |
As you can see from the calculations, for a full day on the water with active use of the motor, one "hundred" can be a little bit small if you rely only on lead. In such cases, experienced captains recommend looking towards batteries at 150-200 Ah or switching to a battery at 150-200 Ah. lithium-iron-phosphate technology where almost all of the declared capacity is available.
Connection schemes and circuit separation
Boat wiring requires special attention to safety and reliability of contacts. Even the most expensive battery will not work efficiently if thin wires or oxidized terminals are used. For start-and-track batteries, a circuit with an insulator or mass switch is often used to separate the circuits.
There are several ways to connect, and the easiest way to do this is to use a dual-use battery directly to all consumers, and the more complicated and the right way to do this is to install it. charge-separator A diode insulator that allows two different batteries to be charged from a single generator but discharged independently.
☑️ Checking the connection system
When installing, be sure to use copper tin tips and thermal shrinkage. Aluminum power circuit wires on the boat cannot be used because of their low plasticity and susceptibility to oxidation in a salty environment. It is also important to install a master mass switch that will completely de-energize the boat when put into storage.
⚠️ Warning: Never directly connect the starter and traction batteries of different technologies (for example, WET and GEL) without a smart relay interchange, this will lead to the flow of currents and the failure of one of the batteries.
Charging and maintenance rules
The durability of a start-and-traction battery depends on the quality of charging. Boil-in-car chargers are strictly prohibited for sealed batteries. You need a smart charger with a multi-stage algorithm that matches the type of battery you have.
The charge process usually consists of three stages: the main charge by direct current, absorption (overcharge) by constant voltage and maintenance mode (float). AGM It is critically important not to exceed the voltage of 14.4-14.7 V, otherwise gas formation will begin and the pressure relief valves will open, which will irreversibly dry the battery.
If you leave the boat for the winter, be sure to remove the battery, fully charge it and store it in a cool place, periodically (every 2-3 months) recharging up to 100%.
Check the terminals regularly. Even on unmaintained batteries, contacts can become oxidized due to salt air. Simple prevention, such as lubrication with technical vaseline or a special spray lubricant for terminals, will prolong the life of the entire electrical system.
Typical errors in operation
Many boat owners make mistakes that shorten battery life by many times, the most common being trying to rock a new battery or, conversely, a deep discharge to zero, and running a starter on a dead battery is guaranteed to send it to recycling.
Another mistake is to ignore the temperature coefficients: in winter, the capacity of the lead battery drops almost by half, and in summer, at high temperatures, chemical reactions of corrosion accelerate. Temperature compensation Charge is a feature that you must definitely look for in a good charger.
Also worth mentioning is vibration. Although modern batteries are considered vibration-resistant, rigid mounting of the hull is mandatory. A battery that hangs at the bottom of the boat is a risk of short circuit and physical damage to the hull on the side or trawler.
Compliance with the rules of charging and avoidance of deep discharge increase the service life of the starting-traction battery by 2-3 times.
FAQ: Frequently asked questions
Can I use a battery instead of a normal car?
Yes, you can, if its starting current (CCA) meets the requirements of your engine, but for pure starter tasks (start only), a specialized starter battery is better suited, since it is cheaper and lighter.
Which battery is better for an electric motor: AGM or Lithium?
For an electric motor, Lithium (LiFePO4) is definitely better. It's lighter, gives off all the capacity and lasts 5-7 times longer. AGM will suit as a budget option, but you'll only use half of its capacity.
Why does the battery warm up during charging?
Heating above 40-50 degrees indicates a malfunction (internal circuit) or improper charging mode (too high current).
Do I need to add water to the starting-traction battery?
Water cannot be added to sealed batteries (AGM, GEL) and is technically impossible without violating the integrity of the housing; in serviced lead batteries (WET) - you need to control the electrolyte level with distilled water.