Learn how marine batteries work, and how to save money with proper battery monitoring!

I’m sure every boat owner ask himself at least once (daily) in what condition his ship’s batteries were. Unlike car batteries that are charged and discharged daily, marine batteries often take weeks or even months between uses. Besides, marine batteries are many times more expensive than the ones for an ordinary car, so that the damage that can occur due to improper and irregular maintenance can be very high.

Maintaining marine batteries is very simple and can be summarized in just one sentence: the battery should always be fully charged. Boat owners are mostly aware of this and always before leaving the vessels check and charge the batteries. The batteries are, frankly,  in a period of non-use, exposed to the greatest risk; as a consequence of chemical process comes to the battery self-discharge (2-3% capacity per month) but often, also parasitic currents that empty them slowly but surely.

Sometimes the reason for battery discharge is much simpler. Show me a boat owner who has never left the main breaker on before leaving the vessel 🙂

sense4boat charging app

If the battery is not used for a long time, crystalline deposition occurs sulfate on lead plates. We call this process sulfation and it is sulfation responsible for the most common irreversible battery capacity reduction. The longer the battery is in the empty state, more crystals precipitate on lead plates, which then progressively shrinks battery capacity.

battery charging

How to properly maintain batteries?

It would be ideal, for batteries to continuously charge over chargers, solar panels, or wind turbines. Unfortunately, this is often not possible for safety or other reasons, so the next best solution is periodic charging at the shortest possible intervals. To know when it is necessary to recharge our batteries, we need information about their current voltage. Battery voltage is crucial for proper maintenance. However, often we only have this information on board, and we are there hundreds of miles away from our vessel.

sense4boat dashboard app

How to measure battery voltage remotely?

There are many devices on the market that make this possible. Most often they are complicated and expensive microcontroller systems with a central unit, 3G / 4G modem, and SIM card. The installation of such systems is demanding as well requires professional and authorized staff.

In recent years, however, sensors have appeared on the market which uses Internet of Things (IoT) technology, which allows us to network “things” simply and affordably. With the development of IoT technologies, we got smart refrigerators, smart water heaters, or even smart toasters (I guess someone needs that too). So why not have the smart ship’s battery? Why not make our ship’s battery smarter to let us know what is its condition, and when should it be recharged? This is the exact solution we are offering you right now!

How do our sensors work?

Our sensors use the Sigfox IoT technology. Sigfox is the largest IoT network in the world, with millions of networked sensors and guaranteed signal quality throughout Europe. It has been 3 years since, thanks to the Sigfox concessionaire (IotNet Adria), this network is also available in Croatia, and the sea is especially well covered by the signal.

Using Sigfox technology, we developed a special monitoring sensor for marine batteries, taking into account all the specifics of the manner and conditions use of this sensor. Our sensor periodically (every 10 min) measures the voltage battery and registers any change since the last measurement. Measurements are sent via the Sigfox network to our systems and services that store and process these messages.

For the needs of monitoring and control of sensors, we have developed a special mobile application through which we provide the user with an insight into the current battery situation, but also all stored measurements in the required time. Through this mobile application, the user can independently manage the sensor, define limit values ​​for individual alarms (low or critical voltage) or other relevant battery statuses (start or end of charging). For each of the alarms, the user determines if and how he wants to be informed (email, push, SMS).

smart battery sensor
smart battery sensor installed

How to charge batteries safely?

Battery voltage information is extremely important to determine the current situation and deciding at what point to start the charging. However, to ensure the safe charging of your battery, we also need battery temperature information. To be exact, during the charging, the batteries raise their temperature; only slightly with the healthy batteries, while with defective batteries in extreme cases it can come to the so-called “Battery cooking” and a potentially dangerous situation. This is the exact reason, why our sensors are also equipped with a temperature reading, that detects each temperature change and alarms in case of potentially dangerous situations. By measuring the voltage and temperature of the battery, we can guarantee a safe battery charge at all times.

Organized charging service

Our sensors simply connect to the home marina/port in which the vessel is located or with a boat-care firm that takes care of the vessel. The purpose of such a connection is for the organized charging services from the side of the marine/boat care companies. Most often, the owner is unable to get to the ship on their own and charge the batteries, so more often than not,  will order that service at their local hosts. Especially now in the time of the global pandemic and limited movement this service has proven to be extremely useful and sought after. Such a way of organized battery charging has been provided for several years in Marina Punat, and right now it is introduced in numerous marinas and services on the Adriatic and Europe. This service can be easily set up in any marina or port on the Adriatic, so we hope that this service will eventually become a standard and integral part of the service of each marina.

sailor charging boat

Ready for the purchase?

purchase the battery sensors with one click and ensure all the benefits of our smart monitoring system.


or contact us for a more info and special offer for your boat !

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