Modern fishing on a boat is unthinkable without the use of navigation electronics, which takes on the search for fish and laying the route. However, even the most perfect sonar is useless without a stable source of energy that can ensure its operation throughout the day. The issue of autonomous power is especially acute for owners of inflatable PVC boats, where the weight and dimensions of equipment play a critical role, but metal boats require a competent approach to the organization of the electricity grid.
The main problem that fishermen face is the wrong calculation of capacity or choosing the wrong battery chemistry, which leads to discharge at the most inopportune moment. Many people make the mistake of trying to use starter car batteries, which are categorically not designed for long-term return of low-power current. In this article, we will examine all the nuances of creating a reliable power system for your navigator, so that fishing depends only on the stick, not on the battery charge.
Well-chosen feed-in Not only does it keep the device running for a long time, but it also keeps expensive electronics from running out of power, and the proper layout of the knots in the boat avoids unnecessary wires that can get tangled under your feet or get caught in gear, so let's take a closer look at what types of batteries exist and what is best to choose for your operating conditions.
Battery types: LiFePO4 vs. AGM and Gelev
There are several core battery technologies on the market, each with its own advantages and disadvantages when used on water, traditionally with lead-acid batteries to power sonars, but lithium technology is rapidly gaining popularity due to its specifications, and understanding the difference between them will help avoid unnecessary costs and disappointments.
Lead-acid batteries, including technology AGM and GELThey're heavy, which can be a plus for the stability of the boat, but a minus for carrying, especially when it comes to high-capacity models. They're afraid of deep discharge: if you drop them to zero, the resource will be reduced by many times, and in some cases, recovery will be impossible.
Lithium-iron-phosphate (LI)LiFePO4) batteries are a modern alternative, free of many of the disadvantages of lead, are much lighter, can discharge almost completely without loss of life and have a built-in protection board BMSDespite the higher initial cost, their lifespan is 5-10 times higher than that of lead counterparts, making them cost-effective in the long run.
- ⚡ Weight: Lithium is 3 times lighter than lead at the same capacity that is critical for light PVC boats.
- 📉 Depth of discharge: LiFePO4 can be discharged up to 90-100%, whereas AGM can only be discharged up to 50% for resource conservation.
- ❄️ Temperature: Lead batteries work better in the cold, lithium requires heating when charging below zero.
- 💰 Price: The initial lithium investment is higher, but the cost of the charge cycle is significantly lower.
⚠️ Warning: Never charge lithium batteries below 0C without a special heating system, this can cause irreversible cell damage and fire.
The choice between these technologies depends on your budget and operating conditions, and if you fish infrequently and your budget is limited, a quality AGM is a reasonable trade-off. LiFePO4 is the leader of the world. modern market.
Capacity calculation: how many ampere hours are needed per day
Determining the battery capacity you need is a mathematical problem that depends on the comfort of your fishing. Many beginners buy a battery by eye, which often leads to a situation where the sonar is turned off an hour before the end of the fishing, and to avoid this, you need to know the power consumption of your particular device.
The average sonar carplotter with a screen diagonal of 5-7 inches consumes from 0.3 to 0.5 Amps at normal backlight brightness. However, this value can increase if GPS tracking is turned on, the Wi-Fi module is running or a high frequency scanning sonar arrow is used. Also, it is worth considering that over time the capacity of any battery falls, so a margin of 20-30% is required.
To calculate, use a simple formula: multiply the current consumption of the device (in Ampere) by the planned fishing time (in hours). The result is the minimum required capacity. If you use a lead battery, the resulting figure should be doubled, since it is not recommended to discharge it by more than 50%.
Consider an example: your sonar consumes 0.4 A and fishing lasts 8 hours. The minimum requirement is 3.2 AH. For a lithium battery, a 5 AH model is enough, and for a lead one, you should take 10-12 AH. Remember that in winter the capacity of lead batteries drops by 20-30%, which also needs to be considered when planning.
| Type of device | Medium current (A) | Consumption in 8 hours (Ah) | Recommended AGM (Ah) capacity | Recommended LiFePO4 (Ah) capacity |
|---|---|---|---|---|
| Base sonar (3-4) | 0.2 - 0.3 | 1.6 - 2.4 | 5 - 7 | 3 - 5 |
| Carplotter (5-7) | 0.3 - 0.5 | 2.4 - 4.0 | 10 - 12 | 5 - 7 |
| Multibeam sonar | 0.6 - 1.0 | 4.8 - 8.0 | 18 - 24 | 10 - 12 |
| System with sonar and GPS | 0.5 - 0.8 | 4.0 - 6.4 | 15 - 20 | 8 - 10 |
Always leave a small supply of containers in case of unforeseen delays on the water or search for fish in hard-to-reach places.
Connection schemes and organization of wiring in the boat
The quality of the connection directly affects the stability of the sonar and the safety of the entire system. Poor contact can cause sparking, a voltage drop and even wiring fire, so installation should be approached with the same care as assembly of electricians in a car.
To connect, use only copper wires with a cross section of at least 1.5 mm2 (for currents up to 5A) or 2.5 mm2 (for currents above). Aluminum wires are categorically not suitable for a boat because of their brittleness and oxidation. All connections should be protected by thermal shrink tubes, and ideally, they should be made with soldering or high-quality crimping terminals.
Make sure to set the fuse in the break of the plus wire as close to the battery as possible, this will protect the wiring from short circuit in case of damage to the insulation. The distance from the battery to the device also matters: the longer the wire, the greater the voltage drop, so for distances greater than 3 meters, the wire section should be increased.
☑️ Verification of wiring installation
If you have an electric starter motor or an electric trolling motor in the boat, you better power them with a separate battery, start the motor causes a voltage drawdown, which can lead to a reset of the sonar or damage to its electronics, and separation of power circuits is the golden rule of safety on the water.
⚠️ Warning: Lay the wires away from places where they may be interrupted by a paddle, hit by spinning or damaged by sharp corners of the transom. Use a corrugated tube for additional mechanical protection.
Protection from moisture and proper installation
Water and electricity are dangerous combinations, so tightness of the joints and proper battery installation are priority number one. Even splashes of salt water can quickly destroy contacts and cause terminal corrosion, so all the elements of the power system must be securely protected.
The battery must be placed in a special box or box that will protect it from direct water and mechanical damage. For lead batteries, the box is also mandatory for safety, since they can emit explosive gas when charging. Lithium batteries are less demanding, but they also do not interfere with protection from shocks.
Use waterproof connectors such as XT60 Or specialized marine connectors that are not afraid of oxidation, the usual windings of tape on a boat will not last long, check the condition of the terminals regularly and when white plaque appears, clean them with a special spray or soda solution.
Treat battery terminals and joint sites with lithium lubricant or contact spray – this will create a water-repellent film and prevent oxidation.
The battery box must be rigid. In PVC boats, the box can be attached to the squirrel board or floor with Velcro straps and slings, but so that it does not shift when rolling. Metal boats often use regular handoos, but you should make sure that there is good ventilation if you use a lead battery.
Charging and maintenance in the off-season
Battery life depends not only on the cycles of discharge, but also on how you store and charge it. Incorrect charging can kill an expensive battery in a few seasons. So it is important to use chargers that are appropriate for the type of battery you have.
For AGM and GEL batteries, use chargers with automatic mode switching and desulfation function. Lithium batteries require chargers with appropriate charge profile CC/CV Don't leave the battery on charge longer than necessary, although modern BMS systems protect against overcharging.
The battery should be sent to the storage fully charged. Lead batteries should be kept in a warm room in winter (garage, apartment), as in the cold the electrolyte can freeze if the battery is discharged. Lithium also prefers room temperature, but will not get critical damage from the cold when turned off.
How to store the battery in winter?
Lead batteries need to be recharged every 2-3 months during storage, because they have higher self-discharge. Lithium batteries can be stored for up to 6 months without recharging, but it is better to control the charge level once a season. The ideal level of charge for long-term storage is 60-80%.
Regularly wipe the battery body with a dry cloth, removing dust and dirt. Mud on the surface can create conductive bridges between terminals, leading to accelerated self-discharge. Visual inspection of the case for bloating or cracking should be a mandatory procedure before every fishing.
Typical errors and troubleshooting
Even experienced anglers sometimes make errors in the organization of food, which lead to malfunctions in the sonar, and analyzing the most common problems will help you avoid them in the future and save time on diagnosis.
One of the most common mistakes is to use thin wires to keep them out of space, which causes the sounder to become jammed, the fish arch becomes intermittent, and the device can spontaneously shut down when a powerful emitter is turned on, and another mistake is to ignore the fuses, which can cause the wiring to burn out if it accidentally closes.
- 🔋 False savings: Purchase of used or refurbished batteries of unknown origin.
- 🔌 Bad contact: Use cheap Chinese terminals that oxidize quickly.
- 🌡️ Temperature shock: Charge the frozen battery immediately after application to the heat.
- 🔌 Mixing of types: Attempt to connect batteries of different capacities or chemicals in parallel.
⚠️ Note: If the sonar starts to show interference or "noise", first check the reliability of the power connection and the state of the battery terminals, not the sensitivity settings.
If you notice that your running time has decreased, don't rush to buy a new battery. Run a test discharge and charge. Maybe the problem will be solved by properly charging low-power current or reducing cycle (for lead). For lithium, a sharp drop in capacity often indicates a problem with the balance of cells inside the BMS.
The sounder’s stable operation depends on 90% of the connection quality and battery status, not just the settings of the device itself.
Frequently Asked Questions (FAQ)
Can I use a car starter battery for sonar?
Technically possible, but highly discouraged: Starter batteries (SLIs) are designed for short-term huge current returns and do not tolerate deep discharge. After several cycles of use with a sonar, such a battery will lose a significant part of its capacity and fail.
Do I need a separate box for a lithium battery?
Strictly speaking, LiFePO4 does not require a box to be safe because it does not emit hydrogen, but a box or bag is used to protect against water, impacts and short circuit terminals, and it will prevent a heavy battery from sliding down the bottom of the boat.
Why does the sonar turn off when the sonar is turned on at full power?
It's probably the battery's overcurrent protection, or the wire section is missing, and when the pulse is strong, the consumption increases dramatically, and check if the contacts are oxidized, and try replacing the wires with thicker ones.
Which battery is best for winter fishing?
Lead acid batteries (AGM/GEL) are better suited for winter, as they are less sensitive to low temperatures when discharged. Lithium batteries in extreme cold can lose capacity dramatically or be turned off by a BMS board if they do not have built-in heating.
How to properly dispose of an old battery?
Throwing batteries into regular garbage is strictly prohibited because of the toxic and heavy metal content. Dispose the spent batteries to special reception points, electronics stores or service stations where there are containers for recycling.