Inhero GmbH

Inhero MR-2 – Solar Mesh Repeater Board (Multi-Chemistry, MPPT, RED/CE-tested)

SKU:MR2-SET-OE

€119,00 EUR

Sale Sold out

Taxes included. Shipping calculated at checkout.

In stock

In stock – delivery within 2–4 business days

Configuration Battery cable with bare wire ends Battery cable with LiFePO4 protection module Battery cable with Li-ion protection module

Inhero MR-2 – Solar Mesh Repeater Board

Supports Li-ion, LiFePO₄, lithium titanate (LTO) and Na-ion batteries, including low-temperature charge-current limiting
INA228 coulomb counting provides measured SOC values (essential for LiFePO₄) and remaining-runtime forecasts for periods of bad weather
Auto sleep/wake-up on undervoltage to prevent brown-outs
Universal solar input 3.6–24 V, automatic panel voltage detection, buck/boost, MPPT
BME280 environmental sensor and RV-3028-C7 RTC on board
Quiescent current: 6.0 mA at 4.2 Vbat / 7.7 mA at 3.3 Vbat
0.98 Wh energy consumption per day in real repeater operation (24-hour measurement)
Firmware: currently MeshCore only (ready-made builds available) – Meshtastic support is planned but not yet available
Always included: solar connection cable, battery cable, mounting screws and BLE adhesive antenna
CE-certified

Description

The Inhero MR-2 is a LoRa mesh repeater board based on the RAK4630 (nRF52840 + SX1262) with an integrated solar charge controller. It is populated with a BQ25798 buck/boost charge controller with MPPT and JEITA temperature management, an INA228 coulomb counter, an RV-3028-C7 real-time clock, a BME280 for temperature, humidity and barometric pressure, and a TPS62840 step-down converter for the 3.3 V rail. Connectors: two U.FL sockets for LoRa and BLE, USB-C for service and firmware updates, JST-PH 2.0 for battery (3-pin with NTC) and solar (2-pin). Dimensions 45 × 40 mm, four M2.5 mounting holes.

The solar input accepts 3.6 to 24 V with a maximum open-circuit voltage of 25 V. The MPPT operates autonomously; no adjustment to the panel voltage is required. Buck/boost charging works even when the panel voltage is below the battery voltage. Consumption in repeater operation averages 12.3 mA at 3.3 V, measured over 24 hours with typical radio traffic; that corresponds to 295 mAh or 0.98 Wh per day. At full duty cycle under EU868 g3 the calculated figures are 19.8 mA and 1.57 Wh/day. In Central Europe, 2 Wp with vertical south-facing mounting and no shading is reliably sufficient; built-up or partially shaded sites require 3–5 Wp. Some MR-2 units even run year-round on 1 Wp at exposed, vertically south-facing locations.

The battery chemistry is set once during installation via the CLI (set board.bat) and defines the charge cutoff and sleep voltages. If the battery voltage drops below the chemistry-specific threshold, the INA228 triggers a hardware interrupt. The board enters a deep sleep below 500 µA; the charge path remains active, and the real-time clock wakes the board hourly to check the voltage. Restart only occurs 200 mV above the shutdown threshold.

The state of charge is determined by the coulomb counter rather than estimated from the battery voltage. The MeshCore app calculates percentages from a Li-ion discharge curve, so the firmware reports the measured state of charge as an equivalent Li-ion voltage. As a result, the app shows the correct value even for LiFePO₄, LTO and Na-ion. This requires the battery capacity to be stored during installation (set board.batcap) and a one-time full charge as the 100% SOC reference point.

For Li-ion and LiFePO₄, the charge controller limits the charge current as a function of temperature via an NTC; in freezing conditions the charge current is reduced or blocked entirely. The repeater itself continues to be powered from solar – only the charge current is limited.

Available via the CLI: real-time telemetry (battery voltage, current, temperature, state of charge, solar voltage and current), the energy balance over 24 hours, 3 and 7 days, the estimated remaining runtime, the MPPT share of the last 7 days, the charge controller status and an I²C self-test of all ICs. The same values are transmitted as telemetry via MeshCore.

→ Full documentation: docs.inhero.de
→ Firmware downloads (MeshCore builds for the MR-2)

Choosing your configuration

The MR-2 always ships as a complete set: solar connection cable, battery cable, mounting screws and BLE adhesive antenna are included with every variant. The only choice is the battery cable version – there is nothing to add and no compatibility to check.

Battery cable with bare wire ends – if you assemble protection module and cell yourself
Battery cable with LiFePO4 protection module – for LiFePO₄ cells, cutoff at 3.75 V and 2.1 V
Battery cable with Li-ion protection module – for Li-ion and LiPo cells, cutoff at 4.275 V and 2.8 V

Both protection module versions include a temperature sensor matched to the MR-2 and come fully soldered and tested – you only connect the cell.

What's in the box

Included with all variants:

1× Inhero MR-2 board (hardware rev. 1.1)
Short connection cables with bare wire ends and JST sockets (board side)
4× stainless steel A2 mounting screws, Ø 2.5 × 4.5 mm, T8 drive
1× solar connection cable, JST-PH 2.0 2-pin, 20 cm
1× BLE adhesive antenna 2.4 GHz, U.FL, 10 cm
1× battery cable, JST-PH 2.0 3-pin, 20 cm, in the chosen version (bare wire ends or with pre-soldered protection module)

Not included with any variant: battery, solar panel and 868 MHz LoRa antenna. Matching solar panels are available in the shop; the BLE antenna covers only the 2.4 GHz service link, not the LoRa radio.

Firmware & software

The MR-2 is currently supported by MeshCore only. Ready-made, tested MeshCore builds are available for download. Meshtastic support is planned, but no Meshtastic firmware for the MR-2 exists yet. If your network runs on Meshtastic today, please check before purchasing whether MeshCore is an option for your use case.

The MR-2 ships exclusively with the OTAFIX bootloader. No application firmware is pre-installed by design – you flash the firmware yourself. No programming adapter is required.

To flash, press the reset button twice in quick succession (double reset). The board then enumerates as a USB drive on your computer; copy the firmware onto it as a .uf2 file via drag and drop. After copying, the board restarts automatically.

Ready-made MeshCore builds for the MR-2 are published as releases, currently Inhero MR-2 v1.16.0 based on MeshCore v1.16.0. The releases contain three build variants – repeater, repeater with RS232 bridge, and sensor node – each as .uf2, .hex and .zip with SHA256 checksums, plus quick-start guides in German and English.

→ Firmware releases for the Inhero MR-2

Inclusion of MR-2 support in the official MeshCore project is being prepared. Until then, please use the builds linked above. As soon as Meshtastic support becomes available, we will announce it here and in the documentation.

Technical specifications

Radio module: RAK4630 (nRF52840 + SX1262)
MCU: nRF52840, ARM Cortex-M4, 64 MHz
LoRa frequency range: 863.1–869.9 MHz
Bluetooth Low Energy: 2.402–2.480 GHz (service mode only)
Charge controller: BQ25798, buck/boost, MPPT, JEITA
Solar input: 3.6–24 V, max. open-circuit voltage 25 V
USB charging: 5 V via USB-C (shared input with solar)
Charge current: 50–1500 mA, configurable via CLI
Power monitor: INA228, coulomb counter, 100 mΩ shunt, max. 1.6 A
Real-time clock: RV-3028-C7
Environmental sensor: BME280 (temperature, humidity, barometric pressure)
Step-down converter: TPS62840, 3.3 V, max. 750 mA
Battery chemistries: Li-ion 1S, LiFePO₄ 1S, LTO 2S, Na-ion 1S
Firmware support: MeshCore (available), Meshtastic (planned)
Consumption in repeater operation: 12.3 mA at 3.3 V = 295 mAh/day = 0.98 Wh/day (24-hour measurement, typical radio traffic)
Quiescent current, active idle: 6.0 mA at 4.2 V / 7.7 mA at 3.3 V
Deep sleep: < 500 µA (charge path active, RTC wake-up)
Interfaces: 2× U.FL, USB-C, solar, battery. (UART/I²C and SWD as solder pads on the rear)
Dimensions: 45 × 40 mm
Mounting: 4× M2.5 holes, 35 × 40 mm spacing
Bootloader: Adafruit nRF52 OTA-Fix, UF2-capable

Delivery & shipping

Shipping within Germany via DHL Paket (insured, with tracking)
Delivery time: usually 2–4 business days

⚠ Important safety notes

No reverse-polarity protection: The board has no hardware reverse-polarity protection on the battery or solar input. Reversed polarity causes immediate, irreversible damage. Always check polarity before connecting.
Mind the cell chemistry: The cutoff thresholds of LiFePO₄ and Li-ion are not compatible. Choose the battery cable version to match your cell.
NTC required: For Li-ion and LiFePO₄, an NTC must be connected or the solder jumper for the onboard NTC must be closed. Otherwise the charge controller blocks charging.
No short circuit on the solar input while USB is connected: Both share the same input via a Schottky diode.
LTO 2S: An external balancer is required for continuous operation; the board does not balance.
ESD-sensitive assembly – handle only with appropriate ESD protection.
Always connect an antenna when operating the LoRa/BLE transceivers.

Compliance (RED 2014/53/EU)

The hardware has been tested for conformity with the EU Radio Equipment Directive (RED 2014/53/EU) by an accredited test laboratory and is CE-compliant. The final transmission characteristics (transmit power, frequency, duty cycle) depend on the firmware installed by the user and the antenna chosen. The operator is responsible for configuring transmit power and antenna gain so that the applicable EU limits (EN 300 220, ERC/REC 70-03) are met.