Introduction to lithium batteries for leisure yachts

In this video, Lars gives an introduction to lithium batteries for leisure yachts. Here you will learn facts about lithium batteries, charging and monitoring as well as advantages and disadvantages compared to other types of batteries.

The video lasts 30 minutes.

Main points in text form

Facts about lithium batteries

  • Voltage: 12.8V
  • Cell-voltage: 3.2V i.e. 4 cells in a “12V” battery
  • LiFePo4 (LFP) has around 4 times more charging cycles than other lithium-ion polymer batteries (LIPO)
  • LFP has a larger temperature range
  • LFP has less current loss during storage
  • LIPO has larger energy density and therefore more unstable and risk of fire

Charging and monitoring

  • BMS – Battery Monitoring System monitor cell/battery voltage
  • Normal “cut out” voltage is 2.80V where all load is disconnected
  • Absolute max cell voltage is 3.75V
  • Defective charger might charge with higher voltage.
  • Battery temperature during charging must be between 5°C and 75°C
  • Cell voltage and temperature sensors are mandatory
  • Beware of hot-spots internally: Buy quality batteries from a well known manufacturer

Pros and cons

Advantages over ordinary acid batteries

  • No blaster gas – the battery can be next to charger, inverter etc.
  • Higher efficiency. I.e. better utilization of charging current/voltage: 90% for lithium batteries against approx. 75% for lead-acid batteries
  • Deep discharge far more than lead-acid batteries
  • Faster charging rate and much higher charging current
  • Lifetime is much longer than lead-acid batteries
  • Example: 500 charging cycles for a GEL battery against 5.000 cycles for a LiFePO4
  • Less weight


  • Higher acquisition price; this is compensated with longer lifetime
  • Risk of fire if the battery is used incorrectly or if damaged (The Phosphorus-cathode in  LFP batteries burn but doesn’t explode. This means that safety is relatively close to normal batteries)
  • Monitoring and BMS is a must
  • In many cases, a DC-DC converter from the generator is also necessary

Learn more about the types of batteries you can use and which ones are right for you

In our online course on batteries, the more common types of batteries are reviewed. Including open and closed acid batteries, GEL batteries and AGM batteries, and a small section on lithium as well.

You will learn about the pros and cons of the different types of batteries,  discharging and charging, and maintanance.

After this course, you are well equipped to choose the batteries that suit you and your boat. At the same time, you learn how to best handle and maintain your batteries.


If you know someone who should see this post, feel free to share it via the buttons below.