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.

16 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?

  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.

Join the conversation

Your email address will not be published.