Confused: ElkPD9HC Questions

[DotNetDog]

OK, I am planning on a LOT of input devices. I wired for 47 occupancy sensors (yeah, I know) as well as other inputs. I will actually install them one room at a time and my success rate will determine how many I eventually install. But let's assume that I eventually add all of the sensors. There are various models/brands but it looks like the most amps per device is 43ma...so I'll use that for power calculations.

I'm thinking about using the PD or PD9HC distribution modules. However, looking at the documentation Elk has a nice table at the bottom of page 2 that shows recommended power supplies and number of devices supported per amp requirements. I noticed that the bottom of the table that shows the PD9HC only shows output voltage of 12VDC. My sensors will be 24VDC. The top of the table shows the PD9 as supporting 24V devices.

Is this because the table only shows the PD9HC with the ELK-412 power support, which is 12 volts? Can the PD9HC support a 24V power supply, such as the P624? If so, how do you add back backup to the P624 since Elk only seems to have 12V batteries?

I'm very confused about this Elk power distribution stuff and want to get this down. Any thoughts would be appreciated!
Thanks.

 

[electron]

It definitely supports 24VDC, it all depends on the power supply you use.

 

[DotNetDog]

By the way, if I plan to use the PD9HC to power occupancy sensors, which are not security sensors, could I skip connecting a battery to it? I would simply use the 24v transformer to power the PD9HC and whenever the power goes out I would not have power to my occupancy sensors. That's OK since they are used for lighting control and...well...no power...no lights! :lol: