I have a Greenline 40 boat with Quattro & Cerbos GX and after reviewing the manuals I can not figure out how to configure system to maintain the factory-recommended 40-60% SOC for long term storage while still permitting pass through of shore power for boat heaters.
You can set a sustain voltage that will keep the battery at a prescribed voltage level, while still keeping pass through. Part of the solar & wind priority. The setting is on the Advanced tab of VE Configure. We use it with our MP when our RV is in storage, I assume Quattro has this feature too.
There is no setting for this, either use sustain voltage, or search around on here as there are many topics, but you will have to write a Node-RED flow, there are some example flows. Victron does not recommend this for their batteries, which is why you will not find the feature.
This 40-60% percent myth is persistant. No evidence for LFP. They are voltage sensitive for aging, not SoC sensitive.
You need the occasional (~3mths) full charge to keep SoC tracking accurate.
Set the float voltage to 3.32V per cell and repeated absorption to 3.45V per cell, for 2 hours at 30 days interval.
Multiply these with the number of cells in your battery and set the appropriate voltages with VEConfigure.
These voltages will prevent dendrite formation during long periods of inactivity.
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This all is not true. Look e.g. at the specs of EVE cells, e.g. the MB31. They recommend long time storage based on SOC (which has a relation to voltage), but most cells are referring to a SOC state, which is also easier to measure and maintain. Voltage is too fluent as a thing. The only catch there is, is on long time storage the cells might be lower than the BMS things because of the very low consumption of the BMS and not updating the SOC states. In that light a full charge is of course helpful. However, Iâve seen cells with almost no discharge in 6-9 months if not in use. EVE cells produced in march 2025 and still on the shelve measure exact the same Voltage as the capacity report specified in March â25.
Thank you for all your comments. Asking AI (see below) it believes storage at 40-60% is optimal for maximizing the life of the $40,000 of batteries on the boat. As you noted, Victron doesnât make it easy to do this or recommend it. The technical work-arounds (setting maximum charge voltage) seem to have risks of their own around cell balancing and the like, and are beyond my personal comfort level to configure.
I live in a climate where the temperature drops below 40 degrees (when heaters kick in) for only short periods of time so I am leaning toward manually discharging the battery and disabling the charger and then monitoring the need for a charge. I would be nice if Victron could support the recommendations of the battery manufactures for this situation.
Google Gemini AI prompt:
How much will the life of a LiFePo4 battery be reduced by long term storage at 100% SOC?
Impact of Storage at 100% SOC
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Accelerated Aging: A full charge maintains the internal cell components in a higher-stress, less stable state, which speeds up the permanent loss of capacity, a process known as calendar aging.
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Capacity Loss Rates (Approximate):
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At an ideal temperature of 0°C (32°F), a battery stored at 100% SOC might lose around 3% of its capacity annually.
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At room temperature of 25°C (77°F), the annual capacity loss increases to approximately 10%.
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At a high temperature of 40°C (104°F), the capacity loss can be substantial, up to 20% or even 35% annually.
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These losses are significantly higher than the typical annual loss of less than 5% when stored at the recommended partial charge and moderate temperature.
Optimal Storage Practices
To maximize the life of a LiFePO4 battery during long-term storage (more than a few weeks), follow these guidelines:
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Optimal SOC: Store the battery at an SOC between 40% and 60%. This range keeps the internal chemistry most stable and minimizes stress on the cells.
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Ideal Temperature: Keep the battery in a cool, dry place, ideally between 15°C and 25°C (59°F and 77°F). Avoid locations with extreme temperature fluctuations, such as uninsulated garages or attics.
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Disconnect: Physically disconnect the battery from all loads and charging sources to prevent phantom loads from accidentally deep discharging the battery over time.
Victron does support this option, and it is very easy, just one setting. (assuming you have a sustain voltage option in your inverter)
Setting a sustain voltage to what you observe when your pack is at 40%-60% SOC will keep your pack at that voltage and SOC. In sustain mode, the pack will discharge down until it hits that fixed sustain voltage, then the inverter will keep it at that voltage. At that point, any loads will be supplied by the fixed voltage from the inverter, simple. If the temperature is too low/high to charge/discharge, the BMS should handle the disconnect. Works fine on my DIY pack at 60% set to 26.35V.
Itâs also useful so your batteries donât get hit with a full charge every time you plug into shore, yet can be topped up to 100% with a few clicks.
Thanks Paul. I think you are referring to this capability, documented as Distributed Voltage and Current ControlCerbo GX Manual Page 98
The wording in the manual seems to be strong in saying that this has a very narrow application during the breakin of two specific brands of batteries and otherwise is counter indicated (bolding is mine). Have I missed something?
Chris
12.4.2. Limit managed battery charge voltage
Some managed batteries, such as BYD and Pylontech, may require a reduced charge voltage during their initial commissioning period. This helps ensure proper cell balancing in the first few weeks of operation. The Limit managed battery charge voltage feature is designed specifically for this purpose. When enabled, it allows to temporarily reduce the maximum charge voltage, even if the batteryâs BMS normally permits a higher voltage.
⢠Do not use this feature for other purposes. Improper use may prevent cell balancing from occurring, leading to severe long-term imbalance.
⢠If the voltage is set above the CVL (Charge Voltage Limit) from the battery BMS, the lower value will be
Not DVCC, solar & wind priority.
I noticed the link to the HTML says it will 100% charge batteries after 7 days, the PDF version mentions that time is controlled by the charger ârepeated absorption intervalâ (max 45 day).
I set 45 days, I donât recall mine ever charging without my intervention. Could be my interactions playing with beta firmware that resets things, or the manuals need an update. I do have a DIY managed battery that uses DVCC features to charge.
Hi Chris. Welcome to the forum. You mentioned a temperature of 40°F (I presume) and I hope thatâs not the temperature of your batteries. Thing is. The electrolyte inside your battery cells will become more gel-ish when the temperature drops. At that temperature - for me that would be close to 5°C, you can barely charge them. Some cells more than others, but in general they do not like low temperatures. Which is why heating pads came into existence.
Now. You yourself may not (have the intention) to charge them, at that temperature, but may I ask what material your batteries are installed on? Is that metal, wood or polyester? Getting your batteries off of metal would be a good starting point. Next to getting them into a little more cosy temperature spot.
Anyone who want to verify this. Get a prismatic cell. Flip them upside down and back. Note the sound of fluid (electrolyte) inside the cell. Now put one inside a cooler of 5°C get it out after 30 minutes and flip it upside down again. Yeah that sound it different isnât it. And this process starts at 15°C which is why cells must be handled more carefully at lower temperatures.
Ok. Ha. Sorry for the somewhat offtopic post at 6 oâclock in the morning. Getting ready to ship 4000 EVE cells out to customers⌠have a nice day 
Chris, donât be afraid to store at very low SOC states. (why not 30%?) Dahn et all (Dahn is good) recently posted a study regarding the comparison between low, medium and high SOC states. Cycling at low SOC states as well as storage at low SOC states appeared to be the least stressful for the cells and thus the least loss in capacity. The Operation Window of Lithium Iron Phosphate/Graphite Cells Affects their Lifetime - IOPscience.
Thank you, all. This is a lot to digest, even for a reasonably technical boater like myself. Reviewing the posts there seems to be consensus on the following points:
- long term storage is the 40-60% level is good practice
- the current charger configuration on the boat - bringing the battery to 100% and holding it there is not optimal for capacity retention
- cycling at lower states of charge is better, but staying above 20% SOC is probably good
My next challenge is how to implement. I have no convenient user interface on managing SOC on the Victron gear. This is something Victron should do. Even my Chevy Bolt allows me to limit charge to 90% with a slider.
If you look at the voltage range and what they consider to be 0% and 100% aoc you will find many bms manufacturers already limit the voltage range useable to withitn 20% and 80% in the voltage range.
So limiting it further in that range is not really necessary.
What kills cells also in the article to actually cycling, holding cells at any one voltge within that range less so.
Periodice full charging is important for balancing.
Time will tell.
Storage is when the betteries are not connected to anything at all. So not applicable to what you are trying to do.
Many manufacturers recommend at least a charge to 90% whrn being left stored to prevent problems of over discharge on the cell lower end which is damaging. (And i have seen people damage them by not doing this)
I would like to add a few notes. Their pouch cells were small, of a lower capacity, and they used a low current, at a much higher temperature. Next to that they acknowledge a few other results. Contradicting their own findings. Meaning that itâs not that easy to set the same parameters for testing.
Fact is. Everybody knows that temperature and the used C-rate is pretty much detrimental to the health of the cells. And stationary storage and shipping is best done at 40% SOC. Also. Not too many people know this, but the cell efficiency is also relative to temperature and C-rate. And what I have learned over six years in Norway is humidity. Nobody talks about that and completely ignores it, but EV batteries are sealed and contacts are nickel plated. And what do we see on prismatic cells?
Now back to Chris. Low temperature, lower temperature and I donât know how they are installed. I asked but 
Thx for your add-ons ChiefSolar. Yes, they acknowledge other results too, but also show that other tests came to same conclusions on a lot of things. I think at this moment there is no reason to believe that the results of the small cells will differ from that of bigger cells, simply because the chemicals are the same and there have been done more tests which lead to more or less the same conclusion; lower SOCâs are better than higher, for cycling but also for storage.
Regarding the influence of temperature; I knew:-) Yes, lower temp is lower capacity. And regarding the C rates; although less pronoun then with lead accid, itâs still existing with LFP. I think itâs just Peukert what you mean, isnât it?
The exact mix of chemicals is not 100% the same for all LiFePo4 cells. For example. There will be added chemicals in cells which support higher C rates and/or can handle lower temperatures. This to lower the risk of lithium plating. And you wonât need all that, or in a much lower quantity in smaller cells.
Peukert? Ok look at the new MB56 cells. You canât expect the chemical mix to be the same. No. They had to fight lithium plating and did something âextraordinaryâ. That was what EVE execs told us in China. My own batteries are installed in Norway, but my sons have also EVE cells in a much more friendly climate. Which stay somewhat healthier. Yeah. I keep asking them for cells that can handle lower temperatures, and they kept telling that Lithium Plating is still an issue.
The report mentioned that they used a 12 times lower C-rate than the other mentioned researchers. I here have 8 batteries that are being monitored with different temperatures. From 6 manufacturers. And one of those days a new research may be made available from someone in Norway, or at least with the data that they got from these batteries 