Changing house bank from AGM to Lithium on an older Outremer 55

[fxykty]

We have a 2003 Outremer 55L, a performance cruising sailing catamaran that we’ve owned for four years. In that time we’ve sailed weekends and holidays locally and had several passages and extended cruising periods in the South Pacific. We are preparing to leave New Zealand this year for extended cruising and have decided to change our AGM house bank to Lithium for three reasons based on our time with the current system:

• Avoid voltage drops due to high loads such as our windlass
• Maximise our solar, wind and alternator generation through better charge efficiency and not affected by extended partial state of charge
• More useable capacity, to enable AC water heating via inverter and an all-electric galley so we can remove propane as primary and fixed-installation cooking fuel (avoiding heat, moisture, danger and hassle of propane)

Note that reducing battery weight is not a factor, but a happy byproduct of our battery chemistry choice.

This thread is intended for people who are considering a change of battery chemistry and may be interested in our conversion. This will be a DIY battery build assisted by professional system design and a licensed marine electrician for key parts of the installation. Questions and comments are welcome.

This first post is to describe our starting point and the new components that we’ve decided on so far. We’re currently about half way through the system design, which is being done by Cameron Murray of Trans Marine Pro https://transmarinepro.co.nz/. TMP is located in Opua, New Zealand. The next post will show the completed system design.

The boat currently has a relatively standard electrical system with not much changed from the time it was built. I’ll only show the battery, charge and AC load components as there won’t be any changes downstream of the DC load bus:

• Lead acid house bank, 6x 110Ah Victron Energy AGM 12V batteries
• Starboard and port 12V start batteries (AGM)
• Generator 12V start battery
• Mastervolt Chargemaster 70/3 charger
• Mastervolt Mass Sine 12/2000 inverter
• Mastervolt Mastershunt 500A
• Mastervolt Masterview Easy monitor, control and display
• GE Mase IS 4.0 AC generator (2.9kW continuous output - added in 2013)
• 2x Leece-Neville 8MR 90A alternators, converted to external regulation for Balmar 614 regulators and a Balmar Centerfielder 2 to manage the two outputs
• Victron Energy Smart Solar MPPT 150/100 regulator fed by 3x 330W panels in series (over the davits)
• Superwind SW350 wind generator with SCR 12V charge controller
• 750W 230V heating coil for water heater
• 16A 230V shore power input (generator output is currently routed via the shore power’s ship/shore switch, as only one AC input is possible with the current charger). Note that shore power is only used when we’re hauled out, as our berth doesn’t have power and we don’t use marinas.

New components already purchased:

• 4x Winston WB-LYP700AHA battery cells. These will be mounted in series to create a 4S 12V 700aH battery Shenzhen Smart Lion Power Battery Limited. These were bought ex-factory from Julia Yu Sky Power International
• Tao Performance BMS https://www.taoperf.com/main-menu/tao-bms/. Bought direct from company director
• Victron Energy Quattro 12/5000/220-100/100 inverter/charger https://www.victronenergy.com/invert...argers/quattro
• Victron Energy SmartShunt 500A shunt https://www.victronenergy.com/batter...-battery-shunt
• Victron Energy Cerbo GX monitoring and control https://www.victronenergy.com/panel-...oring/cerbo-gx
• 2x Balmar Digital Duo Charge DDC-12/24 battery combiner/chargers https://balmar.net/products/digital-duo-charge/