What Barnex does

Solar surplus goes to useful loads

Inverter data is read over Modbus (TCP, or RTU over RS485), read-only: the firmware never writes to the inverter. The regulator recalculates the surplus every second. The solar-heating window is 08:00-18:00 by default. Barnex does not deliberately import from the grid or discharge the battery into a heater. Lite polls the inverter every 2-4 s and notices a load change within about 5 s.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Battery-aware

Battery reserve is 20%. The "discharge from" threshold defaults to 95% (range 50-100): above it, battery discharge is ignored when trimming and only real grid import cuts power. "Battery full" mode starts at 99%. The algorithm mode (with charge forecast, or probing upward) is chosen automatically on every step.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Mode for inverters that cannot export

If the inverter cannot export, any current on the grid input is treated as import and the load is reduced.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

You decide who gets the sun first

Surplus sharing is configurable: boilers and the EV work at the same time, or the EV goes first and the boilers after it. Between the boilers there are also two options: one after another, or all at once.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Smooth boiler regulation

SSR control by burst-fire (whole mains cycles), with a step of about 1%. Loads set to "relay" type (heat pump, AC, pump) get only 0 or 100%. Lite controls a boiler through the boiler node; so do DIN and Power.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): Yes

Several boilers with priorities

Several boilers heat either one after another (the first to 100%, then the next, a full boiler is skipped) or all at once when the sun is enough: up to 10 boilers heating simultaneously.

Limits: up to 10 boilers

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Built-in power output

An SSR for smooth control and a parallel contactor that closes after 2 s at 100% so the SSR does not heat. A heatsink temperature sensor caps the power at 50% at 85 degrees held for 60 s.

Which models: Barnex Lite: No · Barnex DIN (Planned): No · Barnex Power (Planned): Yes · Boiler node (In development): Yes

Smart heating in the boiler node

A DS18B20 tank temperature sensor, a thermal model that learns from your data, a night top-up to the target temperature, a weekly heat to at least 60 degrees against legionella, and standalone operation without a coordinator.

Which models: Barnex Lite: No · Barnex DIN (Planned): No · Barnex Power (Planned): No · Boiler node (In development): Yes

EV charging from the sun

Modes: Auto (solar surplus), Manual, Until a set time, Off. Current from 6 to 32 A, default maximum 16 A, in 2 A steps. Battery-top charging starts at SOC at least the threshold plus 3%, PV power from 500 W and import up to 150 W, at 6 A. OCPP 1.6J and the other chargers on the compatibility list are supported. Up to 4 chargers, single-phase mains.

Limits: up to 4 chargers, single-phase mains

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Own CT clamps

Planned for DIN and Power: own CT clamps detect a load change in under a second and work with any inverter. Lite takes consumption data from the inverter.

Which models: Barnex Lite: No · Barnex DIN (Planned): Planned · Barnex Power (Planned): Planned · Boiler node (In development): No

Main-breaker protection

The limit is set in watts and converted to current (W/230), with a 3% margin. Boilers are trimmed first, then the EV charger, by exactly the excess. It also applies over manual mode and schedules. Without a valid grid measurement heating is forced off. A "saved from tripping" counter is kept on the device.

Limits: single-phase mains (L1)

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Safe behaviour on failures

The boiler node switches heating off if no command arrives for 45 s. The coordinator watchdog is 20 s. After 5 consecutive crash reboots the device enters safe mode with loads off and leaves it after 60 minutes.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): Yes

Tariff optimisation

The Ukraine-wide tariff is loaded automatically and can be edited by hand. EV charging and boiler heating are optimised against the tariffs.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Night schedules

Up to 4 named windows per boiler: 100% from the grid through the contactor, ignoring the day window. Up to 4 windows for EV charging with a set current. The main-breaker limit still applies.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Weather-based planning

The planner is off by default. It uses the Open-Meteo hourly cloud-cover forecast, calibrated on 7 days of your own generation history. Without internet it uses the history only, and without a history a simple battery threshold. The evening battery target defaults to 80%.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Works without internet

Modbus, the Wi-Fi link to boilers and the local interface do not need internet. Internet is needed for remote access, Telegram alerts, the weather forecast and tariffs. Schedules need NTP time.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): Yes

Inverter auto-discovery

Local-network discovery from the cheapest method: mDNS, UDP broadcast, ARP scan, then a TCP scan. You can enter an IP by hand. The inverter is identified by MAC and serial number, so a DHCP address change recovers by itself.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

New inverters via a JSON map

A register map in JSON with up to 48 registers, TCP or RTU. Loaded locally, from the cloud or from the bobyk/barnex-maps repository. A bad map rolls back to the previous one after 5 failed polls.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Telegram alerts

On by default: breaker protection, night tariff, grid loss and return, critical battery, stuck relay, a daily digest at 08:00. Optional: EV sessions, boiler, device offline.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Local web interface

A web app on the device itself at coordinator-XXXX.local, a first-run wizard with Wi-Fi setup through an access point, picking the inverter, boiler and breaker limit. The interface is Ukrainian only for now.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): No

Home Assistant directly

In Home Assistant mode the boiler node works through MQTT Discovery with your broker on the local network (Home Assistant 2024.12 or newer). Entities: heat switch, power in percent, tank temperature, power, energy, SSR temperature, faults and a firmware update.

Which models: Barnex Lite: No · Barnex DIN (Planned): No · Barnex Power (Planned): No · Boiler node (In development): Yes

Safe firmware updates

The device checks for updates every 6 hours over HTTPS. Firmware is verified by an Ed25519 signature and SHA-256, with two slots. If the new version does not restore the cloud link within 15 minutes, the device rolls back to the previous one.

Which models: Barnex Lite: Yes · Barnex DIN (Planned): Yes · Barnex Power (Planned): Yes · Boiler node (In development): Yes