12V bus and relay control
Posted: Tue Jun 09, 2015 9:46 am
I have a lot of 12V AC-DC power supplies connected to tank hardware -- one for a Reef Octopus DC skimmer pump (which, though it shares the same form factor as the Jebao, unfortunately doesn't work with the Jebao harness), two for Jebao DC return pumps, one for a filter manifold DC pump, other smaller wall-wart types for various Reef Angel expansion modules (2x 16 channel PWM), one old laptop power supply for ventilation fans, etc. etc. etc. Some of these are controlled by relays (the skimmer), but most are powered on all the time (with some relying on PWM signals to turn off, like the return pumps).
I thought it might make sense to obtain a larger (but still fanless) 12V power supply (like this one at Amazon), and use it as a 12V power bus for all the 12V devices (except those needing galvanic isolation, like the ORP expansion, and the Salinity expansion). This would reduce clutter, waste heat, and if a higher-efficiency power supply, electrical power.
This would be easy enough for those devices that don't require independently addressable on/off control, but for those that do (like the skimmer), it would be nice to be able to connect them to the bus with a relay and control the relay from the Reef Angel (either through the ATO pins, or the I/O module, or even the 12V Power Control Expansion module).
As I understand it, the ATO pins could only be safely connected to a relay with a very low coil current, but I wonder if the I/O module could generate more? As a last resort, the 12V Power Control Expansion module can generate 500mA per channel (and could itself draw power from the 12V bus), which should surely be enough even for a cheap automotive 12V relay?
Has anyone done anything like this? Does anyone know of a 12V relay with a very low coil current that would suffice to power a 2.5A 12V Reef Octopus skimmer pump?
I thought it might make sense to obtain a larger (but still fanless) 12V power supply (like this one at Amazon), and use it as a 12V power bus for all the 12V devices (except those needing galvanic isolation, like the ORP expansion, and the Salinity expansion). This would reduce clutter, waste heat, and if a higher-efficiency power supply, electrical power.
This would be easy enough for those devices that don't require independently addressable on/off control, but for those that do (like the skimmer), it would be nice to be able to connect them to the bus with a relay and control the relay from the Reef Angel (either through the ATO pins, or the I/O module, or even the 12V Power Control Expansion module).
As I understand it, the ATO pins could only be safely connected to a relay with a very low coil current, but I wonder if the I/O module could generate more? As a last resort, the 12V Power Control Expansion module can generate 500mA per channel (and could itself draw power from the 12V bus), which should surely be enough even for a cheap automotive 12V relay?
Has anyone done anything like this? Does anyone know of a 12V relay with a very low coil current that would suffice to power a 2.5A 12V Reef Octopus skimmer pump?
