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Wild.Bird - 17 Sep 2023

Interesting reading all the comments on lithium.
I built my own 280Ah 24v ( equivalent to 560Ah at 12v) battery using CATL cells purchased in the USA. I had them shipped to Antigua.
I used a JK 200A BMS with 2A active balance.
The convertion to lithium has been a game changer for us.
The 720w of solar we have used to harvest circa 2kWh per day when connected to our lead domestic bank. That same solar now harvests over 3kWh per day. The simple fact with lithium is that you dont need to get the battery full every day to maximise its life like you do with lead. Infact, keeping the battery below 90% full,  will lengthen the life of lithium. As a result, we can use more battery capacity and keep the lithium battery on bulk charge, rarely floating the battery.
We now do 95% of our cooking on an induction hob. We boil the kettle on the induction hob. We use the immersion heater for hot water and we make water with our 220v watermaker all through a 3000w low frequency inverter.
We added 4x50w flesible panels on a canvas backing that are our roving panels for when anchored. They fold up in to the space of a single 50w panel when not in use. With this additional 200w of solar we are averaging 3.6kWh per day of solar harvest. More than enough to run all our loads electrically.
Our propane consumption is now negligible. We only use the gas cooker at sea, when our portable hob is stowed.
With the increasing number of people moving to lithium there are a few things to note.
24v boats are ideal for lithium. The load limiting factor is the BMS. They are rated in amps. If you are a 24v boat, you half the amp draw off your 24v battery.
Two lithium batteries is the ideal number. This actually needs to match your load but 2 batteries is way better than 4 batteries.
When you install multiple batteries in series, it can be difficult to balance the batteries with each other. This can result in one battery being dominant and taking most of the load. It can cause battery shut down of the highest or lowest charged battery in extreme cases. Parallel is less of a problem but balancing can still be an issue.

I am currently building a second lithium battery of a smaller size. 105Ah. It will use the same JK BMS and it be wired in parallel to the existing 280Ah battery. This will give me resilience should one BMS fail. It will allow me to carry on whilst we replace a BMS, etc.
The additional capacity will allow us to get through a few cloudy days without having to resort to the diesel generator.

Don't under estimate how much rewiring you may need to do to accommodate lithium. There is no such thing as a drop in replacement battery.

Stay clear of cheap lithium batteries.  It is far better to build your own with cells from a known source and a good BMS than buy something in a sealed box that you know nothing about. The cost of building your own battery is about half the cost of a cheap drop in lithium battery.
Building your own battery also allows you to install the battery in a ventilated battery box. If you sail in the tropics, heat is not your friend. Cooling drop in lithium batteries isnt possible. The BMS mosfets make considerable heat when charging and particularly discharging. This heat cannot escape a sealed box. By comparison, a diy battery can easily accommodate forced ventilation.
Lithium and solar were made for each other. Maximise your solar install.
Speak,to your insurance company. Mine were happy for me to install lithium

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SoggyPaws - 5 Dec 2023

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Wild.Bird - 17 Sep 2023

Interesting reading all the comments on lithium.
I built my own 280Ah 24v ( equivalent to 560Ah at 12v) battery using CATL cells purchased in the USA. I had them shipped to Antigua.
I used a JK 200A BMS with 2A active balance.
The convertion to lithium has been a game changer for us.
The 720w of solar we have used to harvest circa 2kWh per day when connected to our lead domestic bank. That same solar now harvests over 3kWh per day. The simple fact with lithium is that you dont need to get the battery full every day to maximise its life like you do with lead. Infact, keeping the battery below 90% full,  will lengthen the life of lithium. As a result, we can use more battery capacity and keep the lithium battery on bulk charge, rarely floating the battery.
We now do 95% of our cooking on an induction hob. We boil the kettle on the induction hob. We use the immersion heater for hot water and we make water with our 220v watermaker all through a 3000w low frequency inverter.
We added 4x50w flesible panels on a canvas backing that are our roving panels for when anchored. They fold up in to the space of a single 50w panel when not in use. With this additional 200w of solar we are averaging 3.6kWh per day of solar harvest. More than enough to run all our loads electrically.
Our propane consumption is now negligible. We only use the gas cooker at sea, when our portable hob is stowed.
With the increasing number of people moving to lithium there are a few things to note.
24v boats are ideal for lithium. The load limiting factor is the BMS. They are rated in amps. If you are a 24v boat, you half the amp draw off your 24v battery.
Two lithium batteries is the ideal number. This actually needs to match your load but 2 batteries is way better than 4 batteries.
When you install multiple batteries in series, it can be difficult to balance the batteries with each other. This can result in one battery being dominant and taking most of the load. It can cause battery shut down of the highest or lowest charged battery in extreme cases. Parallel is less of a problem but balancing can still be an issue.

I am currently building a second lithium battery of a smaller size. 105Ah. It will use the same JK BMS and it be wired in parallel to the existing 280Ah battery. This will give me resilience should one BMS fail. It will allow me to carry on whilst we replace a BMS, etc.
The additional capacity will allow us to get through a few cloudy days without having to resort to the diesel generator.

Don't under estimate how much rewiring you may need to do to accommodate lithium. There is no such thing as a drop in replacement battery.

Stay clear of cheap lithium batteries.  It is far better to build your own with cells from a known source and a good BMS than buy something in a sealed box that you know nothing about. The cost of building your own battery is about half the cost of a cheap drop in lithium battery.
Building your own battery also allows you to install the battery in a ventilated battery box. If you sail in the tropics, heat is not your friend. Cooling drop in lithium batteries isnt possible. The BMS mosfets make considerable heat when charging and particularly discharging. This heat cannot escape a sealed box. By comparison, a diy battery can easily accommodate forced ventilation.
Lithium and solar were made for each other. Maximise your solar install.
Speak,to your insurance company. Mine were happy for me to install lithium

Tim,
Thanks for the description of your LFP install.  It seems everyone does it differently.  A couple of things to note. 
Not all BMSs are internal Mosfet relay rated in amps.  A number are external relay BMSs with few of the internal Mosfet BMS disadvantages you mention.  We used a very well regarded ElectroDacus SBMS0 external relay BMS that does require more wiring, including separate relays for the various charging devices and loads that the BMS can control.  These are commonly available up to about 500 amps each.  Using an external relay BMS greatly expands the amps a BMS can control and without any internal heat issues. 
One battery can reasonably be used for most installs requiring only one BMS instead of two or more batteries, each requiring a separate BMS and having the battery balancing problems you mention.  If you are concerned about a rare cell failure just carry a spare.  We do.
Insurance coverage is a big deal and may get more difficult in the future.  Read your insurance policy for its current requirements, but be aware that they may change in the future.  They are all different right now.  However, the future may require compliance with recently developed ABYC or ISO standards so understanding those is important before starting an install.
We live on solar in the tropics, almost never having to resort to our alts or portable generator for charging.  We designed our system for at least 3 days holdover with no charging.  It doesn't get much better than silent auto charging all day.
And finally using electric for cooking is safer, more convenient and produces far less heat than using LPG.  LFP makes that possible.
Dave McCampbell
SV Soggy Paws