Justin: First, Your Vertex rep. is full of it! Look at the power consumption
on the Vertex repeater between AC and DC, especially the Stby/Rec mode. Now
to your question; You have a lot of unanswered questions that need to be
decided before any design can be considered. As a retired engineer I can
list a few for you.
1. What is the expected duty cycles of each piece of equipment when the
power fails?
2. How long do you want emergency power to be operational? 1, 2, 6, 12, 24
hours or days?
3. Is there a physical space limitation on the installation?
4. What type of maintenance is available?
5. Are there any accessibility problems?
6. What are the budget constraints? Are they firm or adjustable?
7. What do you mean by overboard?
8. What level of reliability/redundancy do you want in the emergency system?
These are just the beginning of a long list of questions that should be
answered before any design is considered. Depending on your answers, there
are alternatives that may be considered that will effect price, space
requirements and reliability.
I can see one difficulty now; the computer requires AC stby power while the
other equipment could use either.
I would hope that you are not one of the managers that wants the caddy for a
chevy price.
Since you are not sure about what you need, I would urge you to hire a good
technician or engineer to design a system that meets your requirements.
Fred
W5VAY
----- Original Message -----
From: "Justin W.Pauler" <[EMAIL PROTECTED]>
To: <Repeater-Builder@yahoogroups.com>
Sent: Sunday, November 14, 2004 4:10 PM
Subject: [Repeater-Builder] Repeater Backup Power
>
>
> Hello All...
>
> I am finally in the process of finishing up an install on a personal
repeater system and I've come to a dead end, I'm hoping this group might
have some answers. My goal is to provide emergency power for all of the
equipment in my cabinet for as long as possible, without totally going
overboard or over budget.
>
> First off, here's the equipment that I have:
>
> Vertex VXR-7000 UHF Desktop Repeater @ 50W
> AC PWR: 1AMP @ 120VAC (TX) .5AMP @ 120VAC (STBY/RX)
> DC PWR: 7.5AMP @ 12V (TX) 1AMP @ 12V (STBY/RX)
>
> Alinco DM-330MV 35AMP Power Supply
> AC PWR: 120VAC (Unknown AMP/Watt Draw)
>
> Pentium II 233 Personal Desktop Computer (No Monitor)
> AC PWR: 150W PS @ 120VAC
>
> Connected to the Alinco Power Supply I have two UHF mobile radios and a
repeater controller, the total draw, even while in transmit, is less than 5
amps. At my disposal for this project right now is an Automatic Transfer
Switch from West Mountain Radio, Two 100A/Hr gel-cell batteries and a AC UPS
that will accept external batteries (through a slight modification).
>
> So, what is the best method of powering all of this equipment?
>
> My first thought would be to buy a completely separate UPS to power the
computer and then connect the two batteries to the Vertex Repeater and other
DC items through the Automatic Transfer Switch. However, this creates a few
concerns. First, Vertex is telling me that powering the repeater from DC is
not only inefficient, but if done incorrectly, could cause numerous problems
(including severely damaging the repeater). I was told in most cases, if the
power goes out and you drain the batteries, you do NOT want to reconnect the
A/C power to the repeater until the batteries have been fully recharged, the
on-board charging circuit cannot handle the load. A low-voltage cutoff
switch might work in this situation, but I've done some research and most
are out of my price range for this project. The other complicating factor
here is the fact that the Vertex repeater produces a slight charging voltage
meant to maintain the batteries, not recharge them, I doubt that the low
voltage disconnect circuit or the Automatic Transfer Switch would like
voltage going the other direction.
>
> The other alternative is to power everything off the UPS I acquired,
running everything continuously on A/C. However, I'm also hearing that this
process would be inefficient going from DC to AC and in some cases, back to
DC. I also doubt that I would be able to get much life from a UPS (even with
the two 100A/Hr batteries connected).
>
> So, does anyone have any suggestions?
>
> Justin W. Pauler
>
>
>
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/Repeater-Builder/
<*> To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
