Lithium Powered Solar SAILING MACHINE! Installing Lithium Batteries Sailing to Alaska | A&J Sailing

Allison and James navigate their 30-foot sailboat Uintah along the 1,000-nautical-mile passage between Vancouver Island, Canada, and Southeast Alaska while executing an electrical overhaul of the vessel’s primary power systems. Facing the heavy power requirements of onboard electronics and coastal navigation, the crew strips out decades of prior wiring modifications to install a dedicated lithium iron phosphate battery bank.

Operating aboard a 1970s production cruiser through open swells and challenging tidal waters requires reliable direct-current power. On Allison & James, the sailors replace aging components with self-heating lithium technology, integrating modern battery monitoring while preserving a secondary lead-acid bank for auxiliary redundancy.

Stripping 45 Years of Marine Wiring Modifications

Before installing modern batteries, the crew addressed four decades of previous modifications that compromised Uintah’s electrical safety. Behind the bulkheads lay a tangled bird’s nest of inconsistent wire gauges and legacy splices accumulated over 45 years. James and Allison removed the outdated runs to protect against electrical fire hazards and bring the direct-current distribution up to modern ABYC safety standards.

The existing energy generation array consists of three 100-watt solar panels supplying up to 17 amps of solar charging current through dedicated controllers. Supplemental charging comes from an engine alternator driven by the boat’s 14-horsepower inboard diesel engine, which contributes approximately 30 amps while motoring, alongside an alternating-current shore charger for marina layovers. Upgrading to lithium chemistry required building a reliable foundation where each power source feeds into the boat with proper circuit protection.

Paralleling 400 Amp-Hours of LiFePO4 Power

The new house bank comprises two 200 amp-hour LiTime self-heating lithium iron phosphate (LiFePO4) batteries connected in parallel to deliver 400 amp-hours of usable storage at 12 volts. LiFePO4 chemistry provides thermal stability and eliminates the risk of thermal runaway associated with cobalt-based lithium formulations found in handheld tools or scooters. The cells are Grade A units matching standards utilized in modern electric vehicles.

Switching to lithium provides a significant weight reduction. The 400 amp-hour lithium bank weighs 40 kilograms, whereas an equivalent 1,200 amp-hour lead-acid bank would weigh 200 kilograms. With an energy density of 200 to 260 watt-hours per gram compared to 50 to 70 watt-hours per gram for lead-acid, lithium delivers three to five times more energy per unit of weight. Dock neighbor Brian assisted the refit by supplying heavy 2/0 non-tinned copper cable, which normally retails for 15 to 20 dollars per foot, while helping the crew reattach Uintah’s canvas Dodger. Allison and James crimped heavy lugs and applied heat shrink to construct clean parallel interconnects.

Energizing the Bus Bar and Commissioning the Shunt

Allison and James routed the positive 2/0 cable to the primary positive bus bar and ran the negative return through a digital smart shunt to track every milliamp entering and exiting the bank. When energizing the main switch, James observed, “nothing is blowing up yeah so that’s a good sign.” The shore-power charger immediately began delivering 25 amps of charge current, with the smart shunt confirming 24.5 amps entering directly into the lithium cells.

To safeguard the installation, the crew retained their original 200 amp-hour lead-acid battery bank. Because a standard marine alternator produces a native lead-acid charge profile that is incompatible with lithium parameters, the alternator charges the lead-acid bank directly. A dedicated DC-to-DC charger extracts current from the lead-acid reservoir and converts it to a multistage lithium charging profile for the house bank. The lead-acid bank also starts the 14-horsepower inboard diesel and provides immediate system redundancy if the lithium internal BMS ever disconnects. James cautioned that “they’re definitely not drop in replacements for lead acid” because proper wire gauges and overcurrent protection must be engineered throughout the entire vessel.

Technical Comparison: LiFePO4 vs. Traditional Lead-Acid

| System metric | LiTime 400 amp-hour bank | Lead-acid bank | | :— | :— | :— | | usable battery capacity | 400 amp-hours usable | 100 amp-hours usable | | Total battery weight | 40 kilos | 200 kilos | | Rated cycle life | 4,000 cycles at 100% (15,000 at 60%) | 1,000 discharge cycles | | Alternator charging setup | DC-to-DC charger with lithium profile | Alternator charging from 14 hp diesel | | Low temperature limit | BMS cutoff below 0 Celsius with heating pad | Standard cold performance |

Sea Trials to Petersburg and Sub-Zero Safeguards

Following the refit, Uintah departed Vancouver Island on an offshore passage northward, covering 600 nautical miles to reach Petersburg, Alaska, known as Little Norway. The voyage served as an extended shakedown cruise, pushing the battery installation through 25-knot headwinds and rolling downwind seas. The IP65 water-resistant casing proved vital when torrential rain soaked the battery units while the crew carried them down below before departure.

Sub-zero protection protects the battery cells in cold northern waters. The internal 100-amp BMS monitors cell temperatures, triggering built-in heating pads if temperatures fall below 0 degrees Celsius to permit safe charging. A secondary safety cutoff halts all battery discharge if internal temperatures drop below -20 degrees Celsius.

In Petersburg, the expanded battery bank transformed daily shipboard routines. The sailors no longer manage electrical loads with constant anxiety or worry about parasitic drain from inverters and navigation lights. James reflected on their surplus electrical power: “we’re pretty well lit up like a Christmas tree which is hilarious for two people who are eating by candle light for the last 3 years.” With reliable power secured, the crew prepares for upcoming passages through glacial fjords and iceberg fields.

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