MasterLi BMS – 48

MasterLi BMS is designed to be the Best Lithium Battery System for all kind of 48 V applications. The BMS has advanced software, which is programmed with settings to manage LiFePO4 cells (only) and require no individual programming. MasterLi BMS offer a lot of very unique features, which create the safest and most reliable lithium battery system on the market.

The 48 V versions of MasterLi BMS has the same benefits as the 12/24 V. Designed to handle 16 cells LiFePO4 cells (only) and with a nominal voltage of 53 V (48 V system).

Safest Low Voltage Protection (LVP) on the market

  • The Low Voltage Protection consists of two levels cut off (LVP1 and LVP2), measured at at each cell with accuracy of +/- 0.1 mV.
  • Algorithm ensures that interruptions do not occur in case of voltage drop due to high load.
  • Zero standby current after low voltage protection (LVP) cut off.
  • When LVP1 shutdown the status (SOC) is about ≤ 10% which is much higher than the standard in the market of 1-2% (see comparison).
  • Protects your lithium battery from never being damaged by discharge to critical low voltage, the safest protection on the market.

Warning System

  • Warning system on Control Panel alerts in three steps with LED and buzzer before LVP or extreme battery temperature turns off battery (= blackout which shut down autopilot and all other navigation).
  • Alerts ensure that no blackout occurs suddenly and unexpectedly, which becomes a dangerous situation for boat and crew.
  • MasterLi BMS is designed with regard to boat and crew safety first in mind. For this reason, BMS has built in noise filters to avoid false triggers that could otherwise shut down the battery.

Maximum utilization of true capacity

  • The battery is recommend to built as one unit (Cell Pack). The principle is the same as Tesla builds its batteries, which offers great advantages compared to several 12 V blocks connected in parallel.
  • When a Cell Pack is combined with an advanced MasterLi BMS that also warns before LVP, then about 90% of the battery’s true capacity can be utilized. It corresponds to approx. 115 – 120% of nominal Ah for Winston cells. This is approximate 50% more than other systems in the market, as 80% of nominal capacity is recommendation.
  • For Marine use: True capacity is about 125% x Nominal Capacity – and of this can 115 – 120% be utilized safely, but require advanced BMS.

MasterLi BMS 48 – How it works

  • In a dual system, it’s possible to manage Load and Charge individually.
  • When BMS disconnect chargers (open Charge relay) to protect battery from high voltage, it will be possible to use battery for consumption (Load relay still closed).
  • MasterLi BMS has Charge Relay with multi functions:
    1. Operates as protection of high voltage (HVP) and temperature.
    2. Charge Relay has the function of controlling all chargers with the Charge Management System (CMS)
  • MasterLi BMS has an extra output (AFD) that can be connected to alternator or other charge controllers and safely disconnect. This feature is highly recommended for high performance alternators, which will be disconnected at Field side 2 seconds before Charge Relay open.

Charge Management System (CMS)

Optional connection on BMS unit. MasterLi BMS has a unique CMS feature by disconnecting all chargers when Cell Pack is fully charged.

  • The great advantage of CMS is to avoid float charging which shorten life of lithium battery. BMS is programmed with advanced algorithms that determine when the Cell Pack is fully charged and disconnect chargers from charging the Cell Pack.
  • When the CMS has switched off all charging, the status / voltage will be checked after a certain time. If, after some time, CMS senses that the discharge has occurred and if any charger is still connected, CMS will turn on the charge again.
  • The lithium battery will therefore be close to fully charged with CMS, but not constantly top-charged which otherwise occurs through float charge (increased voltage).
  • CMS improves lithium charge and extends life of the lithium battery.
  • CMS works on all chargers / alternators with or without a controller (bulk / float charging).
  • CMS is based on the same charging algorithms used for charging EV and other pure lithium systems, or simply charge at constant voltage until full then switch off charge voltage. (But difference is for EV to use very fast charging and of this reason controlling the very high charge current. And difference for Marine use is to connect charging back again at certain time / status due to continuously discharging.)

Alternator disconnect (AFD)

In combination with CMS and Charge Relay, AFD can also be connected. The MasterLi BMS with a Aux battery connection is capable of handling transient spikes that otherwise occur when high charge current is interrupted. However 48 V system might not have an aux, but MasterLi BMS has a special AFD (Alternator Field Disconnect) output, which can handle high-performance alternators and chargers and disconnect 2 seconds before Charge Relay. This is the safest way to disconnect high power chargers. The AFD can be connected direct to charger instead of CAN which most often require interface.

Easy to install and no programming required

  • Installation manual included with wiring diagram for different types of boats.
  • No interface required for computer to program settings
  • All existing chargers and controllers for lead / AGM work very well with CMS integrated in MasterLi BMS (i.e LiFePO4 settings are not required).
  • Save money through simplified installation as above and at the same time get a more efficient MasterLi system with no power loss.



managed by MasterLi AB