10 HSM100s How much power?

[Koviak]

How much power do I need to supply to 10 HSM 100s running in always on mode? We will say there is an average of 50ft of cable running to each device from a central location. I am currently running 4.5v @1.2amps. It is not working. (random motion signals, not sending data, erratic behavior, etc...) - Josh

[rmasonjr]

I believe a 50' run will give you some degree of voltage drop. You might have to compensate with a slightly higher voltage. After you drop the runs, check the voltage at the end to make sure it's enough.

[Ericryherd]

Each one looks like they draw less than 50mAmps from my measurements. A 500mA supply should just be enough to power 10. But that depends on the length/resistance of the wire and the voltage drop. You also might be getting noise coupled in from somewhere else like a fan or even the AC line.
You might be better off using a couple of small supplies closer to their destination than trying to use 1 supply for them all.
The tiny USB supplies for cell phones work fine for me (they are +5V at 500mA). Be sure the supply is regulated and not just a diode and a cap or the voltage might be too high.

I think I only have 3 running of 1 supply at most though but the wires are pretty long (50ft maybe). I used the old wires from the wired security system to power the HSM100s.

[rmasonjr]

I actually ordered my first HSM-100 today from HS I plan on hard-wiring mine as well from my wiring closet, so my run will be probably 25' or so. I have the luxury of a variable-output power supply so I can accomodate the voltage drop.

[Wadenut]

In case of noise, previously mentioned, you guys could consider an electrolytic capacitor inside the battery compartment of each unit. 100 microfarad should be enough.

[Koviak]

I wasn't aware that noise could affect power distribution. I figured a watt was a watt. (AC and DC of course) So is it possible that I am getting unclean power to the units? I thought noise related to data transmission. The data is transmitted via z-wave. The power right now is originating out of a Rack mounted UPS - then to the power supply. I am sure there are AC lines running across the Alarm lines at some point. I am going to look into Wadenut's suggestion. That may become a standard practice for my company in the future. Perhaps Homeseer should consider adding an electrolytic capacitor to their units. Also, I am getting the full 4.5 volts at the end of each run.

[Koviak]

What are the exact specs of the electrolytic capacitor I am looking for? 4.5v 100 microfarad? What would be the result of just leaving batteries installed while it is hard wired?- Josh

[Wadenut]

I wasn't aware that noise could affect power distribution. I figured a watt was a watt. (AC and DC of course) So is it possible that I am getting unclean power to the units? I thought noise related to data transmission. The data is transmitted via z-wave. The power right now is originating out of a Rack mounted UPS - then to the power supply. I am sure there are AC lines running across the Alarm lines at some point. I am going to look into Wadenut's suggestion. That may become a standard practice for my company in the future. Perhaps Homeseer should consider adding an electrolytic capacitor to their units. Also, I am getting the full 4.5 volts at the end of each run.

You may well have a clean supply then. I only mentioned it because someone earlier had talked about noise; which is entirely possible given a long run like that. At any rate, the cap won't hurt anything and is the simplest form of filter.

Actually, any length of wire can act either as an antenna (picking up noise) or as a transmitter (creating it), or both. Noise would be defined as any unwanted waveform on a conductor.
If you have access to an oscilloscope you can see exactly what's there.

[Koviak]

I am a little ignorant in the capacitor area, Can you post a link of the capacitor I need? Thanks - Josh

[Wadenut]

This one from Radio Shack would be just the ticket.
http://www.radioshack.com/product/in...ductId=2103625

Just connect it across your power supply at each unit. Ideally across the original battery terminals. Turn off the power supply first or you may see a small spark, which is harmless.
Caution: These are polarized, which in effect means, if you connect it backwards you're liable to destroy it. The negative terminal is always labelled with the ( - ) minus sign.
The 50V in this case is the component maximum DC voltage rating.

[Wadenut]

What would be the result of just leaving batteries installed while it is hard wired?- Josh

Not a good idea, even if they're rechargeable batteries, and especially if they're not. The batteries could burst or even explode.

[Koviak]

Thanks Wadenut, I will let you all know how it works out. - Josh

[Wadenut]

No problem

[dschoppe]

Also, I am getting the full 4.5 volts at the end of each run.

Did you measure the voltage with the load connected or open circuit?

Don

[Koviak]

With all 10 units powered up I am pulling 4.63 volts at one of the units that is giving me trouble. - Josh