Gather context
Battery telemetry, tariff periods, solar forecasts and user choices provide different kinds of input.
Home Assistant + TightWatt
Useful controls. Clear decisions.
Home Assistant connects lighting, physical controls and system monitoring. TightWatt brings tariff-aware planning to battery charging, with protection checks kept separate from price decisions.
Control
One owner for each action
Choice
Lighting settings worth keeping
Feedback
Plans and observed state kept distinct
Care
Bounded recovery where enabled
Follow the signals
Observe, decide, act, check.
A simplified view of the control design. It illustrates responsibilities, not the current state or layout of the installation.
Use the right owner
Charging, lighting and appliance routines have their own rules. A shortcut calls the existing routine.
Request a change
Commands express the desired state. That is separate from confirmation that the equipment responded.
Show uncertainty
Service failures, stale data and protection faults need different explanations and responses.
The office control box
A useful shortcut you can reach.
A twelve-button physical interface brings workspace modes and selected routines together, using the same control logic as the dashboard.
ModeLightSceneRoutineWorkRelaxSaveRestoreSceneRoutineModeLight
Illustrative layout · no real device state or button mapping.
Physical controls, established routines
Select a workspace mode, call an existing appliance routine or restore a saved lighting appearance. Restoring lighting does not imply restarting every connected appliance.
The recorded build includes flashed firmware and a connected message interface. Complete physical-action verification remains a separate step.
See how lighting choices are retained →Everyday use
Keep the choice. Explain the change.
Lighting that remembers
Configured rooms retain selected appearance settings. Temporary modes use defined override deadlines and inactivity rules; they do not all follow one blanket nightly reset.
Illustrative example: choose a warm, dim scene; a later return restores that appearance when the room's rules allow.
Flexible loads, separate charging
Fresh negative-price readings can start eligible discretionary loads. TightWatt remains the charger owner. When the rate becomes positive, the load routine excludes the dishwasher so it does not interrupt a running cycle.
Supporting systems
Connected does not always mean up to date.
Service health and data freshness
System monitoring separates service availability from the age of incoming data. A responding database can still contain stale readings; a plan can exist without proving an action occurred.
Illustrative example: “Service reachable · latest data delayed”. This is an example, not an installation status.
Local communication with UniFi
UniFi-managed addressing gives connected equipment stable allocations. Local communication, internet access and power continuity are separate dependencies. Fixed addressing alone does not establish operation during an internet outage.
Recovery with limits
The configured VenusOS recovery path is opt-in and checks maintenance state, relay availability, cooldown and attempt limits. It is not an unconditional restart loop or a promise of uninterrupted operation.
Small displays, useful context
The companion display and dashboards are another view of the control system. Public examples use synthetic information; private installation screens stay private.
TightWatt · energy decision engine
Plan the energy. Check the battery.
Price-aware charging uses a demand estimate, forecast generation and available tariff periods. The target is an estimate, not a guaranteed deadline or saving.
Estimate the need
Use stored energy, expected demand, solar forecast and the configured target time. Planning gaps are reported separately from protection faults.
Rank eligible periods
Select qualifying periods within the configured price limit. Low-battery and negative-price requests have their own rules.
Check permission
Battery temperature and cell checks, plus configured BMS inputs, can prevent charging despite an economic request.
Compare request and result
One charger decision point compares desired and observed state. A planned window is not proof of measured charging.
ProtectBattery and configured BMS checks
PlanTariffs, forecasts and defined fallbacks
ObserveRequested state and measured response
Software checks support the control system; they do not replace independent electrical protection. Optional session limits and solar thresholds apply to particular charging paths, not every request.
Illustrative decision replay
A plan is only part of the story.
Invented prices and decisions explain the stages: wait, select a window, check permission and compare the response. This is not household telemetry, measured savings or a simulation of a released controller.
A fictional planning day
Illustrative: a selected charging period still needs protection checks and an observed response. JavaScript adds a visual replay.
waitingselectedprotection holdexample target time
Dashboards
Representative system views
These privacy-safe recreations use entirely illustrative data. They communicate the shape of the real controls, energy planning and solar analysis without exposing household names, devices or live state.