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matthias-nagel avatar image
matthias-nagel asked

Recommendation for "small" (100Ah-200Ah) 12V LiFePO4 battery: Type? Manufacturer?

I am considering replacing 12V lead-acid battery with a LiFePO4 battery on a yacht. The capacity should be somewhere between 100Ah and 200Ah. Everything above would be superfluous luxury.

Space constraints are paramount. The yacht does not provide a dedicated engine room, but rather a engine "box" below the cockpit. In other words, compact solutions are a must.

I had a look at Victron's Compatibility Page, but except for Victron's own batteries all other listed products seem to target large ESS installations. Correct me, if I missed something.

While googling and browsing several online shops, the Liontron batteries keep popping up. I like that they seem to be designed modular, i.e. one can replace broken cells, the BMS and the Bluetooth communication module individually. However, the BMS is autonomous and does not communicate with the Cerbo GX. Even though Liontron provides detailed current and voltage settings as part of their manual, it seems that the SoC measured by the Cerbo GX (via its SmartShunt) becomes out-of-sync with the actual SoC, see this tread as an example. Hence, I am unsure about that. I don't know anything about the general quality of Liontron and maybe there are alternatives which provide proper communication with the Cerbo.

What "small" (i.e. 100Ah-200Ah) LiFePO4 battery systems do you recommend?

Important aspects are general, overall quality, sustainability/maintainability/serviceability (i.e. can broken parts be replaced individually) and integration with VE.

Lithium Battery
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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

For 12V you won't find many batteries with CAN communication.
If I remember correctly than "Super B" has that.

But for a simple RV or boat installation thats not really needed.
Just use a normal "drop-in" lithium battery like Liontron or Ultimatron and you are good to go.

Install a SmartShunt if you want to see the SOC on a GX device and only use the battery app if you have problems.

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pwfarnell avatar image
pwfarnell answered ·

The issues with drop in batteries on a boat is if you use the engine alternator to charge the battery. There are 2 potential issues.

1. If the lithium battery gets full and its BMS disconnects charge the alternator may generate a voltage spike which could damage the alternator.

2. The lithium battery can accept a much higher charge rate than lead acid and may run your alternator very hard overheating it.

The usual way around this on small installations is to make the alternator charge the engine start battery alone and then have a battery to battery charger such as an Orion drawing current from the starter battery to charge the lithium house battery. The battery to battery charger is set up so that it only charges the lithium house battery when a charging voltage is detected on the engine start battery, or the engine ignition is on. This prevents the engine battery from being depleted.

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matthias-nagel avatar image matthias-nagel commented ·
The question was not about the starter battery. While all what you say is totally correct, it is off-topic.
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kevgermany avatar image kevgermany ♦♦ matthias-nagel commented ·
Where does it say starter battery?
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matthias-nagel avatar image matthias-nagel kevgermany ♦♦ commented ·
The question of this thread was about replacing the house battery of a yacht by a LiFePO4 battery. The answer by @pwfarnell refers to problems regarding the engine and alternator, i.e. the starter battery. But that's not what the question was about.
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pwfarnell avatar image pwfarnell matthias-nagel commented ·
No, it answers some points of fitting a drop in lithium house battery, it has nothing to do with starter battery problems. This is a public forum and people try to help, sometimes the help is superfluous because the person posting the questions knows the issues. However, the depth of a persons knowledge is not always clear so sometimes the advice is not useful. The polite thing is to then pass on by.
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kevgermany avatar image kevgermany ♦♦ pwfarnell commented ·
Fully agree.
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