No Bluetooth BMS? Here's How to Track Your Lithium Bank | PYS Tech Talk
July 17, 2026 · 6 min · 1K views
What this video covers
Monitoring the state of charge of a lithium battery bank without a Bluetooth-enabled Battery Management System (BMS) requires installing a shunt-based battery monitor.▶ 0:00 Lithium batteries maintain a steady voltage throughout most of their discharge cycle, making it impossible to accurately infer remaining capacity from voltage readings alone, unlike lead-acid or AGM batteries.▶ 3:02 To capture all current transactions, the battery bank must be electrically isolated from the charging sources and DC loads.▶ 1:20 Install a dedicated battery busbar for the lithium bank and a separate charging busbar for solar arrays, alternators, and chargers.▶ 1:13 Place a shunt between these two busbars to act as a single choke point for all energy entering or leaving the system.▶ 0:52 The battery monitor connected to this shunt tracks the net current, providing an estimate of the bank's capacity.▶ 1:11 This configuration ensures that all power draws and charging inputs are accounted for, regardless of the BMS capabilities.▶ 5:09
More from Pacific Yacht Systems
From Pacific Yacht Systems — see the channel’s boat, crew, and every analyzed video.
The Sailing Directory Newsletter
One email with the fleet's best finds — the moments, boats, and stories worth your watch time. Enter your own address to get your own copy.