Upgrading to lithium batteries & testing an all Mastervolt DC power system

Ben Stein

Ben Stein

Publisher of Panbo.com, passionate marine electronics enthusiast, 100-ton USCG master.

21 Responses

  1. Eric Artman says:

    No solar/wind generation?

    • Ben Stein Ben Stein says:

      Solar is on the list for upgrades. However, I don’t have too much hope of getting the boat to be able to generate all her power from solar or wind. The boat draws enough, primarily because of refrigeration loads, that I doubt I can get enough solar to make all the power I draw.

  2. Carter says:

    Do you still have a separate Lead Acid starter battery?

  3. Charlie McVey says:

    Very interesting Ben. I would like to install Lithium on our next boat possibly.

  4. Gary Warner says:

    Hi Ben – I’ll be very interested in your installation and operating experience with your new high capacity alternator. I did an alternator upgrade 4 years ago to a 180A small case unit with external mounted diodes powered by our Yanmar 6LY2A-STP engine with new pulleys and 10 rib serpentine belt. Our initial install was somewhat problematic as the belt occassionally rode over the water pump pully. Numerous alignment attempts did not solve the problem. Finally the alternator bracket was removed, bolt hole slotted and with the addition of a idler pulley hopefully resolved. So exact pulley alignment is critical and addition of an idler pulley necessary to maintain belt tension. I think a major contributor to the belt overriding problem, along with imperfect alignment, is the low shoulders on the outer ridges of the Balmar replacement pulleys which allowed the belt to easily ride over thos outer ridges. The alternator pulley has higher shoulders and we have never had an override at that pulley.
    I hope your pulley replacement kit has better designed pulleys as that should make for a smoother transition. I’d also seriously consider a spring loaded idler pulley if you have space. We did not and are using a fixed pulley.
    We have eliminated the need for a generator on our boat with the 180A alternator, 400 watts of solar panels and 4 Firefly carbon foam 100 Ahr house batteries. While not year round livaboards, we do cruise our Ellis 36 for 6 month seasons with 2-3 months summer cruise to Maine each summer.

  5. Tim Connolly says:

    Hi Ben,
    Just curious if the Mastervolt system has NMEA2K interface or some other output that would allow for feeding various “power parameters” into a signalK server. I will need to replace my similarly aged Xantrex inverter soon and this will be an important feature so I can consolidate data in one place or on multiple displays around the boat that are being driven by the SIgnalK/Influx/grafana setup.

    Thanks for a great article

  6. Jeff Pernick says:

    Hi Ben. I like your focus on generator time as a game changer. That is exactly the phrase I have used. We are a 24 volt MasterVolt system with (2) Mass Combi and (2) Ultra 25/5000 180AH batteries. On Generator, both chargers run full blast and replenish 24 hours heavy battery use in about 90 minutes.

    And, just wait until you start messing with the power sharing features available for A/C loads. When you have the ability to use batteries to cover short term high amp draws like microwave or coffee maker, it’s just incredible how little amps you need from shore to run and charge the boat. You only need to provide for average load from shore, not peak.

  7. Ben Stein Ben Stein says:

    Mastervolt makes a MasterBus to NMEA 2000 adapter. This has the ability to output almost any of the parameters from MasterBus to NMEA 2000.

    I’m planning to cover those capabilities in a later entry, but here’s a panel from Grafana through my SignalK server:

    Grafana Panel

    -Ben S.

  8. Hamish says:

    I have a Mastervolt installation on my sailing catamaran and I love it. My goal is to minimize battery charging from the alternator as I like the peace of running the boat from solar. In this scenario, I currently have just over 1kW of solar and I plan to increase that to nearer to 2kW and what I have learned from trying to switch to solar power is that you must be able to take all the amps you can get when the solar panels are working at their maximum output. My current panels peak at about [email protected] when the sun is bright and overhead, so I am hoping that my additional panels will increase this to around 150A. Lithium is also a key contributor to weight reduction, which is a hot topic on a sailing catamaran. If all goes to plan, I think I will be able to run my water maker (12V dc, 60A), my two fridges, the small chest freezer, all the navigation gear, washing machine, USB charging for personal devices, lighting etc without ever needing to start the engine to charge the batteries except in cases of extended overcast weather. With the current solar, I can operate in sunny conditions at anchor (we spent three months in a marina in Ecuador where the shore power was very sketchy and we never once needed to do anything to run the boat, but once I start all the navigation gear and autopilot, the system cannot keep up and it can’t handle anything other than very sunny conditions, so I hope that the extra capacity will increase my options and allow me to sail 24/7 without needing to start the engines (I don’t have a generator or AC).

    Looking forward to the rest of your comments about your new system.


    P.s. although it’s quite user unfriendly, the Mastervolt MasterAdjust software is very useful and provides detailed system control.

  9. Yianni says:

    I am wondering if the Mastervolt system has the ability to charge the batteries bases on in/out going current. Not just voltage.

    • Ben Stein Ben Stein says:


      I’m not exactly sure what you mean by in or outgoing current. Batteries accept charge based on their state of charge and the incoming voltage. I don’t believe it’s possible to control the battery cells and tell them to accept more charge at a lower voltage.

      -Ben S.

      • Yianni says:

        Ben, hi
        I think we are both describing the same issue. What I meant to say, up to this point Charging regulators were able to charge batteries based on voltage alone. Recently though companies such as Wakespeed (WS500) have been able to monitor and adapt the battery charging cycle based not only on voltage alone but on the current measured at the battery level.

        • @Yianni,

          Yes, the Mastervolt system is able to do this. With the Lithium batteries you don’t need a shunt as the battery BMS has a built in current measuring system. With non-Mastervolt lithium or any brands traditional batteries you need a MasterShunt.

          With the shunt connected to the charger or charger controller via MasterBus the charging is based on net current into and voltage at the battery, not what is measured at the charger source.

          This is not new: my boat has had it since 2010 and the tech has been available since the mid 2000s.

  10. Yup,

    The integrated nature of the Mastervolt system really works well. The battery tells the charge controller when to stop charging and when to reduce charging. Beautiful.

  11. Joseph Pica says:

    Hey Ben, did lfpo4 13 yes ago with twin victron multiplexes that would charge my bank at 240 max amps. All reduced my genset run time to < 1/3rd from year before. All good. The multipluses had 4 programmable relays and customizable charging profiles. Offer power match supplementing of meager shore power.. which permitted us to cruise in comfort when glomming inadequate power from a garden out or other 15 and source. All cutting edge at that time. I am still a fan but know little about what Mastervolt offers. Currently doing that to my small boat however using Firefly batteries as did know how to control the outboard charging systems. Interested to see the comparison with Ben E. Warmest regards, to you and family, Joe Pica

  12. rareskyfive says:

    Amazing thanx for sharing information.

  13. Keith says:

    Hi Ben,

    I see in your diagram that you don’t have any lead acid batteries as buffer batteries.

    I was told by Mastervolt that you still need these. Was he mistaken? or was it just left out of the drawings?

  14. Abel Vazquez says:

    Thanks for sharing. I have purchase the same MasterVolt inverter charger because of it 160AMP charger and I will be using it ith non-Mastervolt lithium.

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