Observed arrival · 2026-11-15
Two Marstek batteries, one unhappy backup bus
An owner’s technical account of two Marstek Venus E home batteries failing to work together for backup power through a SmartBox DB63S.
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✦Pretty
●Pro
◎Niche
◉Human
⚑Risk
ƒJS
- For
- Marstek Venus E owners and prospective buyers
- Worth noticing
- The owner says a 1% state-of-charge difference was enough to trigger the failure; the logs were sampled about every 10 seconds.
Field notes
The owner traces the setup from the SmartBox's AC-in and Backup buses to each battery's Grid and Backup ports, noting that the units have no communication cable between them. A diagnostic tool built around Marstek's documented local API and Modbus supplies logs; the outage chart is described as recording readings about every 10 seconds. The page also organizes reported issues by wiring, firmware, app and modes, network/API, and support.
Observed signals
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Editorial observations of this landing page, not a rating.
○OpenPublic substance visible
✦PrettyNotable craft visible
●ProPolished or operationally mature
◎NicheUnusually specific use
One card from the complete issue