This product appears in our “Rated Devices” list based on our experience and evaluation criteria. It is not an official approval, certification, endorsement, or guarantee of performance or safety in any specific installation. Safe operation depends on correct system design, installation, and use.
The Waveshare ESP32-S3-POE-ETH-8DI-8RO is an industrial-ish grade 8 channel relay and is one of our “go to” relay devices for campervan use.
Vehicle electrical work can cause fire, injury, or equipment damage if installed incorrectly. This article is provided for general information only and is not a substitute for engineering design, installation instructions, or the manufacturer’s documentation for your specific vehicle. Always use appropriate fusing and cable sizing, follow manufacturer-recommended protection and wiring practices, and consult a qualified auto-electrician if you are unsure.
- Based on ESP32-S3 microcontroller with Xtensa 32-bit LX7 dual-core processor with frequency up to 240MHz
- Integrated 2.4GHz WiFi and Bluetooth LE dual-mode wireless communication
- PoE 10/100Mbp network port, can be powered via Power Over Ethernet
- Good quality relay, contact rating: ≤10A 250V AC or ≤10A 30V DC
- Onboard isolated RS485 interface, for connecting to various RS485 Modbus industrial modules or sensors
- Onboard GPIO pin header interface, for expand other devices such as RS232 / sensor and other functions
- Onboard USB Type-C port for power supply, firmware downloading and debugging
- Onboard power supply screw terminal, supports 7~36V wide voltage input, suitable for automotive applications
- Built-in buzzer, RGB colorful LED, power supply and RS485 TX/RX indicators for monitoring the operating status of the module
- Rail-mounted ABS protective enclosure, easy to install
Summary
If you are not interested in the technical detail of the device, then just read this summary and skip the rest.
This relay is suitable for low to moderate DC loads and general switching. Inductive loads (pumps, motors, solenoids) must use appropriate suppression at the load. High-inrush or mission critical loads should be controlled via an external relay/contactor/solid-state-switch trigger by this relay. The relays are rated at 10A but our goal is always to de-rate and treat it as a max 5A channel.
- Pros
- Well-supported by modern IoT stacks (ESPHome, Home Assistant, Arduino)
- Good power separation between power, IO and comms
- Can be powered from 7-36V DC, ideal for use on a leisure battery
- Cons
- Overcurrent protection is not built in, make sure each channel is fused accordingly
- Dry contact relays, so not silent
- No suppression for inductive loads, this must be added externally
Typically you will install one driver side and one passenger side. The relay can be used to control any low to moderate DC loads and general switching:
- Ball valves for plumbing, e.g. recirculating showers
- Grey waste remote disposal
- Trickle charge on your Victron inverter
Inductive loads (motors, pumps, solenoids) max 5A, add a suppression at the load, e.g a flyback diode to protect from back-EMF, verify start/stall current:
- Water pump
- Roof fans, e.g. MaxAir
- Large fans
Harsh loads, use the Waveshare relay only to drive an external automotive relay or (better) a DC MOSFET switch sized with lots of headroom.
- Large water pump
Can be integrated to Home Assistant
Several Waveshare relay boards exist, so be careful you are buying the correct item. This post is only for the ESP module. The controller uses a ESP32-based dev board which is well supported by ESPHome, Arduino, ESP-IDF, and PlatformIO, so it is very compatible with Home Assistant and definitely fulfills our first requirement.
Suitable for a vehicle
For a van, it’s very suitable as:
- The board has a dedicated ESPHome Devices page with a ready-made YAML config, covering Ethernet (W5500) and all 8 relays + 8 digital inputs, buzzer, RTC, etc.
- Exposes entities to Home Assistant using ESPHome’s native API (api: block), which is the “first-class” way to integrate ESP32 devices into HA.
- Ethernet port, our recommendation is always use wired backbone if possible, but it does have WiFi too.
Power
The unit requires 5V @ up to 1A over USB-C or 7-36V DC on a screw terminal. We recommend always using the 7-36V DC power supply if possible. This is ideal for 12V or 24V leisure-battery vehicle installations. Ideal to connect directly to a 12V or 24V fuseboxe. A step down converter will be required if your leisure battery system is 48V.
Safety guidance (no built-in protection): ensure load matching, external fusing/circuit protection, and suppression for inductive loads to reduce arcing/contact wear.
Temperature range
The official docs list operating temperature around -40 to 85 °C. In a van, interior hardware in summer sun can exceed 60 °C near the roof or windows and in winter can easily go below 0C if heating fails or the van is parked up. So this is a great option for any serious explorer.
Limitations
The relay has a maximum 10A capability. Ideally use the relay for items below this in order to leave a safety margin. Any high current devices will need a specialist high current relay.
Use Cases
Good use-cases for this relay in van automation:
- Ball valves for plumbing, e.g. recirculating showers
- Grey waste remote disposal
- Trickle charge on your Victron inverter
- Control power converters and regulators to reduce idle power loss
Price/Quality
The item typically sells for approximately £61 in the UK at Amazon and we believe that is a fair price for all that functionality and an industrial grade relay.
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Nothing in this article excludes or limits liability for death or personal injury resulting from negligence, or any liability which cannot be excluded under applicable law.