Data Sheet

6
POWER REQUIREMENTS
The 8-RELAY card requires +5V power, supplied either from the Raspberry Pi expansion bus, or from its
own 2.1mm power jack. The on-board relays are connected to the +5V.
Only one +5V source can be used to power both the Raspberry Pi and the 8-Relay card.
Raspberry Pi 3 current consumption: 250 mA @ +5V
8-RELAY Card current consumption: 10 mA @ +5V (all relays OFF)
750 mA @ +5V (all relays ON)
The USB connector which powers the Raspberry Pi can supply maximum 1.5A.
The jack which powers the 8-RELAY card can supply 3A. We strongly recommend using this jack and a 5V
regulated power supply rated at 3A or higher.
The 8-RELAY card can be stacked up to eight levels. A multi-stack configuration can be powered from
any of the cards. A four stack needs 300 mA for electronic circuits, leaving 2.5A for relays. With some
margin of error, not more than 24 relays can be ON at the same time.
In the rare event that your application uses four 8-RELAY cards and requires that all relays be ON at
the same time, you need a power source that can supply minimum 4A. You also need to split the
power cable and feed the +5V through two 8-RELAY cards.