Upgrading our house battery system, part 2; life is better with lithium

Ben Stein

Ben Stein

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

27 Responses

  1. Wolfgang says:

    Thank you for this follow up of the Lithium installation. Very educative.

    I have LI on my list to replace an older 24V/900Ah traction battery, like you stated, I cannot do this before I upgrade everything elso, to protect the LI battery.
    Same like you, I made the decision for Mastervolt, because they supply the whole chain (generator/alternator, charger, inverter, and so on).

  2. Cam Stevens says:

    Thanks for sharing your experiences Ben! It’s really interesting to read about the process of the upgrade as there are not that many organizations that you can consult with in the upgrade. Often we have found ourselves to be on our own to figure things out. A friend of mine and myself are upgrading my wife’s and my boat, and it’s been challenging at times. We’ve not actually started the build yet, but we hope to begin this Thursday if all the components we’ve ordered arrive. Our system will have a 6 kw system with an integrated BMS. Much thought has to be given to protections, charging parametres, and the various protections for the various systems on board. Love to chat about your install or share our plans with you if you are interested!

    • Ben Stein Ben Stein says:


      I’d be happy to talk about your install. I suspect others would be interested in hearing what you’re thinking as well. So, if you’re willing, I think it would be great for you to share your plans in the Panbo forum.

      -Ben S.

  3. Rob S says:

    Ben, really enjoying this mini-series, as always, thanks for taking the time to learn “real world” technology and then sharing your experiences/results.. I believe LiFePO4 will be/is becoming the goto battery technology for the marine industry and that perhaps the largest initial market for manufacturers will be retrofits on older boats. Very nice to see the technology is starting to be in place to support this for DYI’ers, albeit still at an “introductory” price level..

  4. Tom Reed says:

    Hi Ben

    I’d love to hear how these batteries can output information directly to NMEA2000. I recently installed 6 of the MLI 24/5500 batteries on my boat and they work great, but it would definitely be useful to be able to check on everything from standard NMEA 2000 displays.


  5. Richard R says:

    A very timely article, since I also recently installed lithium batteries in our boat. I took as slightly different route with Battleborn/Victron Multiplus, but my experience has been the same. I especially like that voltage doesn’t drop very much as the batteries discharge, and that they recharge at or near the capacity of the charging device,

    Two things to be emphasized when planning a lithium installation.. These batteries don’t like heat, so don’t install them in the engine room, and because regulators will cut charging abruptly when the batteries reach 100%, alternators need to be protected from voltage spikes.

  6. Marcus says:

    I have 4 MLI 24 180AH batteries, and am trying to setup the right stop charge events to my charger. Do you configure the events only from the master battery, or from both?

    My 24/100-3 charger went through full absorption up to 29.3 volts, and one battery had a reduce charge alarm set, but the stop charge does not seem to kick in until higher I guess. The charger finished, but I am puzzled because the bulk and absorb settings are at 28.5, not 29.3.

    I then attempted to trigger a reduce charge event to a relay module and it did not seem to work. I configured this live, after the event occurred, so maybe I should test again.

    I want to optimize for longevity, so I actually want to stop charging when 28.5 is achieved, then float at 26.8. This is more conservative than stated in the manual. Any advice on the event config?

    • Alfred O says:


      I can send you a .XML copy of a proper configured system with stop charge events. Just load the .XML in Masteradjust and compare the settings with your system.

  7. Austin G says:

    Hi Ben,

    Great articles on your upgrade to Lithium, very practical and understandable. I wonder whether you can give some advice:

    I have two battery banks – 3xAGM which I want to replace with a single lithium and 1xAGM dedicated starter battery which I would like to keep. The starter battery is fully charged almost all the time. I have mostly Mastervolt infrastructure already, including a Battery Mate for split charging the two banks. I have a single engine and alternator.

    So my thoughts are:

    1. I have a Mastervolt Chargemaster for shore power charging, so that’s sorted as it has two independent outputs for the two banks, and they can be set to different battery types.

    2. I will need to install an Alpha Pro III Regulator to control the charge from the alternator.

    3. I would like to split charge from the alternator and solar (and possibly other sources such as wind or fuel cell in future).

    Do you have any advice on:

    1. Can I continue to use my Battery Mate to split charge the Lithium + AGM batteries, even though they are different chemistries?

    2. Assuming yes to #1, as the engine battery will be fully charged most of the time, I’m thinking it is ok for the Alpha Pro to just monitor the Lithium battery, so that Lithium controls when it switches between the 3 charge modes? This also protects the lithium battery, as ALL charging will be stopped by a “Stop Charge” event across Masterbus. The AGM may be over-charged in this scenario, but that’s no different to what I already have.

    3. Should I feed solar / other through the Battery Mate too? If so, how is the Lithium battery protected in a “Stop Charge” scenario, as the Battery Mate isn’t connected to Masterbus?

    Ideally, I would like a Masterbus-aware split charger unit to sit in front of both banks, knowing what battery types each bank has and then I can feed all non-ChargeMaster charge feeds through this, but Mastervolt doesn’t have such a device, as far as I can see?

    Best wishes and thank you for any advice you can give!

    • Ben Stein Ben Stein says:

      Hi Austin,

      I’ll do my best to answer as many questions as I can. But, I do want to warn you that I haven’t used several of the components you’ve mentioned in this application. But, with that warning.. here goes:

      Fo your thought number 1, I was surprised the Chargemaster can support multiple chemistries on the same charger. I went and looked at the manuals and spec sheets for the 12/50-3 and don’t see any way to set separate chemistries per batter bank. Can you point me towards what you’ve found on this? It would be great if a single charger could support multiple battery chemistries.

      Thought number makes sense to me. Thought number 3 seems to beg for a DC-DC converter in one direction or another. This morning there was another conversation about the use of DC-DC converters you might find relevant (https://panbo.com/building-a-diy-lifepo4-battery/#comment-219875). Instead of split cahrging, you would dump your charge sources into one battery and then use a DC-DC converter to sned charge to the other bank.

      For your questions, I think the answer to number 1 is no. The Battery Mate doesn’t have any facility to offer different charge voltages or stage durations based on chemistry so you’d be using the wrong profile for one of the batteries.

      Questions 2 and 3 become moot with the answer to number 1, I think. Instead, you’d be relying on DC-DC converters to control the charge from one source to another.

      I think in several respects, the DC-DC converter is the device you describe at the end, except that it’s attached to one battery and feeding the other. Split chemistries aren’t simple and they’re part of why Lithium conversions, even for only one bank, are truly system upgrades.

      -Ben S.

  8. Austin G says:

    Hi Ben,

    Thank you for the quick answer.

    On the ChargeMaster, I’m not near the boat at the moment so can’t check, but I was sure when I first set it up a few years ago that in the configuration via either EasyView or MasterAdjust, it gave the option to specify each battery type. I am now doubting myself though, especially having also looked in the manual I see no option via DIP switches or Masterbus to configure chemistries separately.

    I do note that the new ChargeMaster Plus series explicitly say that multiple battery chemistries are supported, and that they also incorporate a DC-DC converter, so for new builds that might be a good device to base a system around.

    If this isn’t possible with mine, I guess I either think about replacing my Battery Mate + ChargeMaster with a ChargeMaster Plus, or my current device just becomes another DC charge source…

    I hadn’t considered a DC-DC converter at all, I’ll definitely look further into that idea, it would require a re-architecture of my system but I had expected that to some extent anyway.

    Thank you so much for your help.

    • Ben Stein Ben Stein says:


      Thanks, I hadn’t looked at the ChargeMaster Plus before. It looks like it addresses some of the greatest complexities of multi-chemistry and multi-voltage DC systems. I’m going to have to do some more research on just what all it can do.

      -Ben S.

    • Wolfgang says:

      Hi Austin,

      A DC-DC charge for you starter batteries will be enough, if possible to do. Charge your house battery directly from the supplies.
      Even though I do not have Lithium, but FLA for both types of batteries, the traction battery needs a slightly higher voltage than the starter batteries. Alternators directly charge the house battery (with Alpha Pro regulators, highly recommend them. I have the old version without Masterbus.)
      Starter batteries are charged by Balmar Digital Duo Charge devices, purchased about 20+ years ago via Victron Energy. My starter batteries last about 15 years, before I had to replace them.

      Regards, Wolfgang.

      • Austin G says:

        Thanks Wolfgang, yes on reading more into DC-DC chargers, that definitely seems to be the way forward for my setup.

        I’m actually thinking of doing it the other way around though – the primary charge from all sources going to the starter battery, then DC-DC charging my Lithium house battery from that. Then I don’t need to worry about installing / configuring emergency shutdown from a lot of different charge sources, I can just configure this once on the DC-DC charger and I know my Lithium is protected from all charge sources.

        If I were ever to replace my starter battery with lithium, this would need to be re-thought of course.

  9. Great read!!

    Is or how do you make your install, on any for that matter within ABYC standards. I keep hearing that if there is a fire and these standards are not meet you’re Ins.Co. my not pay the claim.

    I have only found two thing, but I am sure there could be more to this. The Install must meet the manufactories requirements and the BMS must warn you ether visually and/or audially that the BMS is going to disconnect the battery. Which I total understand! You don’t want to be entering a new harbor, docking, in a mooring field and lose power without a warning.

    Thank you!

    • Ben Stein Ben Stein says:

      Hi Paul,

      I strive to make sure my installations are ABYC compliant. As I look at these pictures I believe this installation is ABYC compliant with the exception of split loom missing from the battery cabling. I’ve since added that but don’t have updated photographs.

      ABYC has published TE-13 which is a technical information document and not a full standard.

      Here’s the intent statement from the document:

      This technical information report includes elements the manufacturer/installer should consider in the selection and installation of lithium-ion batteries for boats. Lithium ion system manufacturers should provide sufficient information regarding the owner/operator’s responsibility and proper installation and maintenance of the batteries.

      Much of TE-13 notes that lithium battery systems should be installed in compliance with the manufacturer’s recommendations. The document states things like, all lithium-ion battery systems should have a BMS and that a backup power source should be provided for critical loads powered by lithium battery systems. The document also notes that another lithium battery is an acceptable secondary source.

      TE-13 also notes the installation requirements around temperature ranges (high and low) and the need for the batteries to be properly restrained and protected from water.

      Really the only specific requirements are made by incorporating the existing E-11 electrical standards.

      -Ben S.

      • Ben, is there any way that us boatowners can see those electrical standards without paying the big $$ for the entire thing? I would be interested in the ABYC electrical standards since I do all my own electrical work. I’ve had copies of the NEC (and the low-voltage standard) for years, but they really don’t apply all that well to boats.

        • Ben Stein Ben Stein says:


          I don’t believe there is a way. I’ve recently joined ABYC and in so doing gained access to their standards. But, I’m not yet clear on what’s acceptable for me to share and what’s not. I know that small snippets of the standards can be shared.

          -Ben S.

  10. Thank for for your response! Its this end of my project that I am worried about.

  11. ian says:

    Good evening I love your install and write up.

    I have two batteries on order and the rest of the system in place ready for set up when they arrive.

    I have a quick question on the software to set up.

    is the master adjust software in a installer or dealer mode or are all them settings ect available to the normal user?

  12. Bill says:

    Any pointers to a masteradjust manual? When my new to me boat arrived with all Mastervolt kit, I thought I only saw one battery (I have two clustered). Their interface isn’t that intuitive. I would expect there to be two batteries under one parent rather than one. I wasted a bit of time worried I only had one working battery.

  13. Tom says:

    Hi Ben
    I enjoyed this article series… and to prepare for my Trans Atlantic I added the Mastervolt Combimaster 3KW/ 160amp charger with Easyview 5 and Mastershunt 500 using Masteradjust software… to charge 5 ea Firefly Group 31 batteries. Now that I’ve crossed (we’re in Gibraltar now) I’ve found that the Firefly batteries failed miserably. They were installed in 2019 but the Pandemic left them on float charge for an extended time… The capacity has fallen the less than 10% of the original 580 Ahr. I would love to install LifPO4 batteries but the insurers are highly discouraging of this. I have since successfully challenged the ABYC Marine Electrical Tech exam… I’m looking at the Epoch batteries but not sure how the BMS can possibly interface with Masterbus… I will return to Gibraltar beginning April… Thanks for any comment

  14. Wolfgang says:

    Hi Tom,
    I am also looking for a possibility to connect Masterbus to a BMS (can). Should be possible with the CANopen Interface, but I cannot find any examples. Mastervolt is a much more closed system than for eaxample Victron. That will be trail and error in this regard.
    My next best guess is to use NMEA2000 data. With the CZONE bridge interface you can pass data and events to the Masterbus (and vice versa), which contains NMEA2000 data. The Mastershunt is also available in NMEA2000 version, so it should be possible to go this way.
    For the Orion BMS there is some manual to pass battery data to the NMEA2000 bus, with a CAN 2 CAN interface/gateway. Downside are the many interfaces needed (which increases the possibility of faillures).
    (I have already CZONE and Mastervolt installation, in my case it would just be one additional interface.)
    Please let me know if or weather you find a solution.

    • Thomas N McCoy says:

      A more ideal situation would be to bring the MLI 6000 or similar in a reachable price range perhaps… The Epoch seems to a “work in progress” given the continually changing bulb/Absorb profile recommendations I’m seeing… not sure how different the MV vs Victron BMSs are relative to generic Lifpo4…

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