The essentials in 30 seconds
- Victron, Mastervolt and MG Energy Systems are not compared on a ranking, but on their architecture: external BMS for Victron, BMS integrated into the battery for Mastervolt, master BMS controlling modules for MG.
- This architecture determines what else must be purchased alongside the battery: a Victron BMS from the correct family, a safety relay and a fuse for an MLI Ultra, a Master LV for MG batteries.
- Victron has the widest ecosystem (chargers, combis, DC-DC, MPPT, monitoring). Mastervolt connects everything via its MasterBus. MG does not manufacture its own chargers and documents compatibilities, notably with Victron.
- The claimed cycles (2,500, about 3,500, over 4,000 at 80 % discharge) cannot be compared: each manufacturer sets its own test conditions.
- The best choice is most often the one that extends what is already on board.
Table of contents
Choosing a lithium bank means choosing an ecosystem: the battery itself, the protection management system (BMS), chargers that know how to obey it, and monitoring. This comparison puts side by side the three brands we distribute, based on their manuals and technical datasheets. It does not replace our guide to electricity aboard a sailboat, which starts with an energy balance, nor the marine lithium BMS comparison.
Our criteria
- BMS architecture: where it is located, what it cuts off, and how it operates.
- What needs to be added to the battery for an installation compliant with the manual.
- Communication: how the BMS stops chargers and alternators, and how it integrates with the rest of the boat’s systems.
- Brand charging sources: chargers, combis, DC-DC converters, solar and alternator regulators.
- Supervision: state of charge, alarms, history.
We did not apply any price criteria (current prices are on the product pages) nor warranty conditions, which are detailed on each manufacturer’s site.
Victron Energy: external BMS, extended ecosystem
Victron lithium batteries come in two families, both LiFePO4: the Lithium Smart (12.8 V and 25.6 V, for example the 12.8 V 100 Ah) and the Lithium NG (12.8 V, 25.6 V and 51.2 V). They balance and monitor their cells but require an external BMS, to be purchased separately:
- for the Smart models: smallBMS, VE.Bus BMS V2, Lynx Smart BMS or Smart BMS CL;
- for the NG models: smallBMS NG, VE.Bus BMS NG or Lynx Smart BMS NG.
The two BMS families are not interchangeable. The Lynx Smart BMS (500 A or 1 000 A continuous) integrates a contactor and a pre-charge circuit, sends charge and discharge authorization signals to chargers and consumers (« allowed-to-charge », « allowed-to-discharge »), and communicates via VE.Can and Bluetooth. The VE.Bus BMS V2 directly controls MultiPlus and Quattro combis.
Charging: 14.2 V absorption for at least two hours, 13.5 V float (28.4 V and 27 V for 24 V systems), recommended current 0.5 C, no charging below 5 °C. House charging sources: Blue Smart, Smart IP43, Skylla-i and Skylla IP65 chargers with lithium mode, MultiPlus-II combis, Orion XS and Orion-Tr Smart DC-DC chargers, SmartSolar MPPT charge controllers. Monitoring: SmartShunt monitors and Cerbo GX marine communication center.
Target users: boats already equipped with Victron gear, or those aiming to build a complete single-brand system with a wide power range. Note: the correct BMS must be selected for the battery family, and each charger must be stoppable by it (remote input or bus), which is not documented for Blue Smart chargers.
Mastervolt: integrated BMS and MasterBus
The MLI Ultra 12/3000 (230 Ah, 3 000 Wh), 12/6000 (460 Ah, 6 000 Wh) and 24/6000 (230 Ah, 6 000 Wh) are LiFePO4 batteries with an integrated BMS: balancing, protections and communication with Mastervolt chargers are handled inside the battery. An external safety relay is still required, mandatory (Blue Sea 7700B-BSS for 12 V, 7702B-BSS for 24 V, per Mastervolt datasheets) and a type T fuse rated at 500 A maximum, with a breaking capacity of at least 15 kA. The MLI Ultra connection kit includes mounting bracket, relay and fuse holder, but not the fuse. The smaller MLI Ultra 1250 models have an integrated relay.
Communication: all communication runs through MasterBus. The battery sends a « Stop charge » event to shut down Mastervolt chargers and cuts alternator excitation via the Alpha Pro III regulator. The manual also mentions CZone integration, but states it requires a major firmware update: confirm availability for your battery before relying on it.
Charge voltage: 14.25 V in absorption and 13.5 V in float (28.5 V and 27 V on 24 V), "PWM" profile on Mastervolt chargers; recommended current of 80 A max for the 12/3000 and 160 A for the 12/6000 (for the 24/6000, 80 A per the manual and 60 A per the datasheet). House charging sources: Mastervolt chargers ChargeMaster Plus and Mass, Mastervolt combis CombiMaster and Mass Combi Ultra, DC-DC Mac Plus, solar controllers SCM, alternator regulator Alpha Pro III, all with a PWM profile. Monitoring: MasterShunt 500 (MasterBus, CZone, NMEA 2000); a MasterBus–NMEA 2000 interface links the two networks.
Target users: boats already equipped with Mastervolt or wired for MasterBus, and those wanting a system where batteries, chargers, and alternators communicate without additional control wiring. Note: the PWM profile of the chargers is designed for Mastervolt batteries; with another brand of battery, it does not apply as-is.
MG Energy Systems: a master BMS for modules
The MG LFP batteries (12.8 V 210 Ah, 25.6 V 230 Ah and 25.6 V 304 Ah) are LiFePO4 modules, each equipped with a slave BMS. They require a master BMS from MG, the Master LV for low voltage (12 V, 24-48 V, and 72-96 V versions) or the Master HV for high voltage. The Master LV integrates the safety contactor (150 A to 1,000 A depending on the model), pre-charge, fuse holders, distribution, and shunt: no external shunt or contactor is required.
Communication: the Master LV controls chargers and consumers via charge/discharge enable outputs or CAN (MG NMEA 2000 protocol recommended by MG, or SMA, or "General BMS"). Its Bluetooth is disabled by default. MG documents compatibility with Victron (GX central required, DVCC regulation recommended) and several CAN charger manufacturers (TC Charger, Micropower, Delta-Q, Cristec, Zivan, among others); it does not mention Mastervolt. The AFC 300 regulator controls alternator excitation based on BMS setpoints, and the SmartLink MX gateway can group up to 15 Masters for a redundant bank.
Charge sources: MG does not manufacture chargers, inverters, or DC-DC converters under its own brand; the CAN-bus chargers sold with the range (TC, Robust) are made by third parties. Target users: large, modular or redundant systems, and custom projects integrated via CAN, particularly with a Victron ecosystem.
Do not confuse: MG’s former NMC-chemistry batteries (HE series) are no longer in the MG catalogue; they used a different chemistry than LFP.
Comparison table
| Criteria | Victron Energy | Mastervolt | MG Energy Systems |
|---|---|---|---|
| Lithium batteries | Lithium Smart and NG, LiFePO4; 12.8, 25.6 and 51.2 V (NG) | MLI Ultra, LiFePO4; 12 and 24 V | MG LFP modules; 12.8 and 25.6 V |
| Where is the BMS | External, specific to each family (Smart or NG) | Integrated in the battery | Slave in each module + mandatory master |
| System shutdown | Lynx Smart BMS contactor, or signals to chargers and consumers | External safety relay mandatory (except MLI 1250) | Contactor integrated in Master LV |
| To add to the battery | A Victron BMS matching the family; a monitor depending on the BMS | Relay, T-type fuse, fuse holder (connection kit) | A Master LV or HV |
| Charger shutdown | Charge enable signals, VE.Bus, VE.Can | “Stop charge” event on MasterBus | Charge enable outputs or CAN |
| Brand chargers and combis | Yes, wide range | Yes, with MLI profile | No (third-party CAN chargers) |
| Alternator | DC-DC chargers Orion XS / Orion-Tr | Alpha Pro III regulator, Mac Plus DC-DC | AFC 300 regulator |
| Supervision | SmartShunt, Cerbo GX | MasterShunt, MasterBus, NMEA 2000 interface | Shunt integrated in Master LV, CAN |
| Claimed cycles | 2,500 at 80 % DoD (5,000 at 50 %), up to 80 % remaining capacity | Approx. 3,500 at 80 % DoD, 25 °C, charge C/3, discharge C/2 | Over 4,000 at 80 % DoD (LFP 304), 25 °C, end of life at 70 % |
Sources: manuals and datasheets from the three manufacturers, listed at the end of the article.
Why not compare cycle counts
The three figures in the last row do not measure the same thing. Victron stops its test when 80 % of capacity remains, MG when 70 % remains, and Mastervolt provides its value for limited currents (one-third of capacity in charge, half in discharge); Mastervolt also publishes, in another document, 3,000 cycles at full discharge and higher current. Ranking these figures would be misleading. What they have in common: the lifespan of a LiFePO4 system depends first on depth of discharge, currents, and temperature.
Limitations and pitfalls
- Mixing Victron families: a NMEA 2000 NG BMS does not manage a Smart battery, and vice versa.
- Forgetting the relay on a MLI Ultra 3000 or MLI Ultra 6000: it is mandatory according to Mastervolt.
- Relying on CZone with a MLI Ultra without checking the firmware version.
- Assuming one bus is enough: two products that speak NMEA 2000 or CAN are not necessarily compatible. Only written compatibilities by manufacturers count.
- Ignoring existing chargers: regardless of brand, each must apply the battery manufacturer’s values and be able to stop on BMS command.
Skysat has not conducted comparative testing of these systems for this article: it relies solely on manufacturer documentation.
Our verdict by situation
- Boat already equipped with Victron (combi, MPPT, Cerbo GX): Victron. Choose the battery family (Smart or NG), then the matching BMS, and ensure each charger can be stopped by it.
- Boat equipped with Mastervolt or wired on MasterBus: Mastervolt. The MLI Ultra, its MLI profile chargers, and the Alpha Pro III form a coherent system; plan for relays and fuses.
- Large modular bank, redundancy, or custom CAN integration: MG Energy Systems, with a Master LV and chargers whose compatibility is documented by MG, often within a Victron environment.
- None of the three if you do not intend to replace chargers and alternator: in this case, it is better to stick with lead-acid than install half-baked lithium.
Sources
Manufacturer documents consulted on 22 October 2026:
- Victron Energy: manual Lithium Smart Battery (rev. 21, 01/2026) and datasheet for Smart batteries; manual Lithium NG 12.8 V (rev. 11, 03/2026) and datasheet for NG batteries; manuals for Lynx Smart BMS (rev. 17, 01/2026) and Lynx Smart BMS NG (rev. 12, 02/2026); datasheets for VE.Bus BMS V2, VE.Bus BMS NG, smallBMS NG, and SmartShunt; datasheet for Cerbo GX.
- Mastervolt: manual for MLI Ultra (rev. 10), quick guide and datasheets for MLI Ultra; manuals for ChargeMaster Plus, Mass, CombiMaster, Mass Combi Ultra, Alpha Pro III, Mac Plus, SCM25, and SCM60; datasheet for MasterShunt 500.
