Fred,
Thanks for the reply, I'll try to answer some of your questions below, but
first, I failed to mention the first time around that this is not going to
be a commercial repeater system; actually, it's a Ham repeater system.
Therefore, a handful of others and I are doing the work ourselves; we're
just looking for a little guidance and a few suggestions or ideas from those
who may have walked down this path before.
As for the Vertex repeater, even though there are almost 10 of these
repeaters in service for ham applications in this area alone, I'll be the
first to do any type of experimenting with the backup power option. The
information I provided in my previous E-Mail came from an independent
communications company and from Vertex technical support, but leaves me a
bit confused. From what I gathered the charging circuit is meant only to
float charge the batteries to keep them optimized, not to bring them back
from any "dead" state, such a condition would damage the charging circuit
and or the repeater. In fact, it was the Vertex technician who recommended
that should AC power fail and the repeater runs the DC batteries below the
normal operating voltage, AC power should not be reconnected to the unit
until the batteries have been allowed sufficient time to recharge on a
separate unit. Like I said above, this makes sense in a way, but yet,
confuses me in that how could you stop AC power from coming back on much
less have time to get to the site in between to disconnect the DC power
source?
The computer in this case will not need extended run time as I don't believe
the servicing ISP has any type of extended life on the small UPS that they
own, I'm looking at just a clean way to bring it down at this point, and I
think that a small AC UPS will do the trick for it. One less problem in the
mix.
I think I can answer most of your questions with a quick summary; I'm
looking to get the most I can with what I have. My space requirements are
the bottom of a repeater cabinet, I can get to the repeater pretty much any
time Monday through Friday and other than two flights of stairs and I can
get to the equipment with relative ease.
Does this help any?
--
Justin W. Pauler
E-Mail: [EMAIL PROTECTED]
WWW: http://www.jwpauler.org
> -----Original Message-----
> From: sentto-104168-44263-1100610463-
> [EMAIL PROTECTED] [mailto:sentto-104168-44263-
> [EMAIL PROTECTED] On Behalf Of Fred
> Seamans
> Sent: Thursday, November 18, 2004 7:07 AM
> To: Repeater-Builder@yahoogroups.com
> Subject: Re: [Repeater-Builder] Repeater Backup Power
>
>
> 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
>
>
>
>
>
>
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