Battery Simulator
Safely test dangerous scenarios in our simulator.
This simulator shows why battery type, charge profile, temperature, BMS and critical loads must be designed as one system. The goal is simple: VHF, navigation lights, bilge pump and navigation must never lose power when you need them.
Pick a situation and the consequence is worked out straight away. No prior knowledge needed.
Tick what has to keep working when everything else fails.
Charging is limited and the BMS is used as protection, not as the everyday main switch for the whole boat.
This is what a correctly designed system looks like: lithium performs very well when charging, BMS, protection and critical loads are designed as one system.
This is the baseline. The rest of the page shows what separates it from the next four.
The simulator does not run on opinions. These are the documents behind it, linked straight to the source so you can read them yourself.
Standard
Small craft – Lithium-ion batteries. Requirements for selecting and installing lithium-ion batteries above 500 Wh on board. Published March 2025, replacing ISO/TS 23625:2021, which is withdrawn.
Standard
Small craft – Electrical systems – Alternating and direct current installations, with Amd 1:2022. Replaces ISO 10133:2012, which is withdrawn.
Standard
AC and DC Electrical Systems on Boats, Lithium Ion Batteries og Storage Batteries. American, but widely used as a reference on this side of the Atlantic too.
Regulation
In Norway this regulation covers pleasure craft between 2.5 and 24 metres. The clauses on declaration of conformity and notification do not apply, but the safety requirements do: the installation must not endanger life, health or property.
Manufacturer limit
Manual rev. 21. The charge range is given as 5–50 °C, the cells take permanent damage when charged below 5 °C, and setting a lower limit voids the warranty. Note: 5 °C, not 0 °C.
Read it yourself
The table of contents and scope can be read without buying it. Useful if you want to see what the standard actually covers before ordering.
Lithium is not the right answer for everyone. A boat with moderate consumption and shore power in the marina does perfectly well on a correctly sized AGM or GEL bank and a charger that follows the manufacturer’s profile. And very few systems need a monitoring display of their own. What decides the outcome is how charging, protection and critical circuits fit together – not how much equipment is bolted to the bulkhead.
On a leisure boat the battery is not just comfort. It can supply VHF, navigation lights, bilge pump, navigation, autopilot and other safety-critical equipment. Poor system design can therefore have consequences far beyond low voltage.
A LiFePO4 battery with an internal BMS can disconnect charging or discharge on overtemperature, undertemperature, over-/undervoltage or cell imbalance. If every load sits behind the same disconnect, critical circuits can lose power at once.
Lead-based batteries react differently from lithium. The wrong charge profile, high temperature or overcharging can cause gassing, pressure build-up in VRLA batteries, venting and permanent loss of capacity.
Get the battery, charging, BMS, critical loads, cable sizing, protection and system architecture assessed before the fault happens at sea.
Bulk: Maximum current. Absorption: Constant voltage topping. Float: Maintenance.
SOC: State of Charge (0-100%). SOH: State of Health (Degradation).
Communication between battery and charger. Prevents BMS emergency shutdowns.
The rate of charge/discharge relative to capacity. 1C on 100Ah = 100A.
Lithium Iron Phosphate is thermally stable and does not catch fire if punctured or overcharged.
Describes how a lead-acid battery's capacity decreases the faster it is discharged.
