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Author Topic: UPS Battery Backup?  (Read 3225 times)
KI4HNN
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Posts: 63




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« on: September 25, 2009, 03:34:29 PM »

Hello,
I have question that I would like to ask and gets everyone's opinions on. I am looking at purchasing a UPS for my computer and radio equipment. I have 1 Pro-197 base radio, 2 BC895XLT radios and 2 ham radios (IC706 and a FT7800 hooked to a Pyramid PS-52KX power supply) I would like to supply power to these radios in the event of a power outage. I was thinking about getting a 810watt UPS to hook it all to so when the power does go out I don't have to fiddle with hooking everything up to a battery, this way it switches over instantly and I can run everything off the existing transformers as well. In the event of a power failure the computer would be cut off and just the radios would be running. I have been looking at other solution's as well but buying the other equipment I would actually spend more than I can purchase a nice size UPS for. Anyone else using a UPS for backup power? I know that it is not ideal but would work to keep my radios going in the event of a outage for a while anyway. Thought about buying a Super PWRGate, but by the time I purchase that and batterys I have close to $200.00 plus in it, and it states that I cannot use a regular automotive battery with it. (Battery would be outdoors of course). Just wanted to get some thoughts and maybe suggestions. Mostly the radios would be in receive mode, if needed for extended periods of time I can power the Ham equipment from my battery in my truck.

Thanks,
Joey
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WB6BYU
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Posts: 13230




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« Reply #1 on: September 25, 2009, 03:56:47 PM »

Most consumer UPSs are designed to keep a computer going
long enough to shut it down in a controlled manner.  The
power ratings are usually based on how much power it
can deliver for 20 minutes.  Generally that isn't what
we will need for emergency operation.

Inside the UPS is a battery, along with charging and
switching circuits.  If you were to take that battery
out and connect your rig to it directly (this is a
theoretical exercise - you'd need to check that it really
is 12V in the real world) you could run the radio for
longer because you wouldn't have the losses involved with
converting the battery power to 120VAC then back down to
12V in a power supply.

So the first step is to look at the size of the battery
in the UPS:  800 watts for 20 minutes is about 20 Amp-hours
at 12.6V.  That's not a very big battery for emergency
use, especially with mobile rigs that are not designed
for low receive current.  The IC706 draws around 2A on
receive, and allowing for voltage drop (by cutting the
rated capacity in half) this would give you about 5 hours
of listening time on one radio.  That's if you connect
directly to the battery - it might be 3 hours if you
are converting up to AC and back down again.

If you want emergency power, first plan how much capacity
you need to run the equipment (which may include ways
to minimize the current draw).  Then plan one or more
batteries to provide the needed capacity, and some means
to keep them charged.  Yes, it may cost you more than
the UPS does, because you are getting more battery
capacity.
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KE4DRN
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Posts: 3722




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« Reply #2 on: September 25, 2009, 07:27:25 PM »

hi Joey,

you can get a nice used ups instead of a new one,
that will save you big money.  you can get them
at local  hamfests or from a local seller on ebay.

look for apc smartups models, you can auto start
this model without any a/c power available.

find one local, most of the time the seller will
remove the batteries if you ask them to save on ups
or fedex fee.  some ups use 36 or 48vdc for power.

get fresh battery and you are all set for short run.

you will have overhead from a ups and the 12v dc
power supply before the power gets to your equipment.

better way to go is to direct power the gear from
a large 12v sla battery, you can get them cheap from
hamfests, removed from large scale UPS systems.

I've got three 12v 38ah units use them all the time.
they get pulled every five years from the ups systems
and will continue to give you long service life in
your application.

73 james
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KB9YUR
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Posts: 229




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« Reply #3 on: October 01, 2009, 01:58:55 AM »

Joey,

I've been using the APC brand model SU1000 UPS for
backup of my Icom 746 and 275H radios for several
years with absolutely no problems. The UPS also
provides power to other devices like computers and
lights. Most APC smart models of 750VA and above
also provide AC line noise/spike protection and are
AC line sine-wave output vs many modified sine-wave
output inverters. Depending on how long you will need
backup power and specific wattage, you might need a
larger model like the SU1400 or SU2200. Many places
like www.refurbups.com sell refurbished APC models
at a great savings vs new ones.

73,

George ...
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W7QPZ
Member

Posts: 25




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« Reply #4 on: October 01, 2009, 09:49:10 PM »

Joey,

I hooked up a used cheep 1000KV UPS to two 75AHr sealed gel cell batteries
No power problems with the shack including my Computer and Fiber internet connection. Up to 3 days

Lou
W7QPZ
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KC9IFF
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Posts: 16




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« Reply #5 on: October 15, 2009, 06:18:47 PM »

One word of warning--be careful that you don't purchase a unit that's too small.  I have an unused CyberPower 425VA UPS (rated maximum 12A/120V output) that I tried this with, plugging my Astron RS-20A into it and my Yaesu FT-8800R into the power supply.  When the radio transmitted on high RF power, the amperage draw/voltage drop was high enough that the UPS would immediately switch into battery mode, which drained the battery low enough to trigger it to power off in less than 60 seconds.
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N8EMR
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Posts: 234




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« Reply #6 on: October 17, 2009, 05:01:32 AM »

Why go to all the work of converting 110v to 12v then back to 110 then back to 12v to power the radio. drop the power supply out, get a big battery and plug all the radio into that. then get a charger to keep the battery up, or just float the power supply across  the battery.
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KG4RUL
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« Reply #7 on: October 17, 2009, 05:40:36 AM »

Think about the West Mountain Radio, PowerGate.  With an adequately sized power supply connected, it can provide power to the radio and keep your backup battery charged.  The bonus is instantaneous switchover upon power loss!
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KC0VGC
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Posts: 18




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« Reply #8 on: October 26, 2009, 08:07:34 PM »

I think N8EMR has the right idea.  I use an IOTA DLS-55 55A continuous duty power supply / charger with the IQ4 charge controller to maintain a marine-type flooded battery (not the best choice, but relatively inexpensive for the given capacity).  The charger, battery, 12v load, and inverter are in-line.  I've been using this setup for over two years and I have enough power to run my shack for hours or even days if I run conservatively. The charger / power supply is more than heavy enough to carry the load without the battery and with the battery it only supplies what current is necessary to maintain the load.  My setup including the charger, battery, and inverter was about $200.  It's a better UPS than anything else I could buy for the same money.
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KB2FCV
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« Reply #9 on: October 28, 2009, 07:44:48 AM »

As stated, most consumer UPS's are soley designed to safely shut down the PC or allow enough time for the user to shut it down themselves. They are not designed to sustain power for a lengthy amount of time. Many these days run with an agent on the PC that senses a change in the power situation (it's connected via serial, usb or in larger cases - IP). It will then instruct the PC to shut off.

In the case of larger businesses (data centers, etc), Ive seen both total battery solution (less common) and battery / generator (more common) solutions. One brokerage firm I worked for in NYC had banks and banks of car batteries as they were in a sky scraper so a generator was out of the question. It worked OK. It usually failed during its quarterly test and was a maintenance nightmare. The better solutions I've seen involve battery backups and generators. Both my company data center, our office, or even the FD that I volunteer for have this solution. It's usually outside mosts people's budget. More and more people these days are buying small generators for their homes. They usually keep it to run a few lights and maybe the fridge.

Generators keep coming down in price. You can probably pick one up used for a few hundred. I highly reccomend Honda if you do. I've used many in the fire dept and during radio contests and they work GREAT. Not sure what your budget is - but you may be able to get both a 'power sensing/shuts down your compter' UPS and a generator used for under $500? This way, if you're not around when the power goes off, your computer shuts down safely and when you get home / when you can you drag the generator out, power it up, run some extention cords and you're on the air, etc.
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AE5JU
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Posts: 229




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« Reply #10 on: December 02, 2009, 10:09:23 AM »

Imagine the energy wasted in the UPS converting 12 vdc to 120 vac, then in your radio power supply back from 120 vac to 12 vdc.

Don't you think it's better to just feed the radio with 12 vdc (well... 13.8 vdc) directly?

eBay, search for RBC-6.  The ones from Gruber Power Services are good, prices good.  One RBC-6, or RBC6, is a UPS gel battery comprised of 2 battery packs, each 12 v 12 ah.  They are usually used in series to produce 24 v 12 ah to power a UPS, however it is easy to make a wiring harness to run them in parallel for 12 v 24 ah.  

I have two RBC-6 sets, that is, two sets of two.  I keep them on charge with a Battery Tender 800.  You can also use the wallwart type Battery Tender, Jr.  Leave connected all the time for best battery life.

On Field Day, from one RBC-6 set I ran my Icom 718 at full 100 w SSB, and had enough capacity left over to run again the next.  With moderate Tx use, mostly Rx, one RBC-6 set could run the radio several days.

Price is about $45 with $20 shipping.  There are other batteries in the Gruber Power Services ebay store.
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K5LXP
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« Reply #11 on: December 03, 2009, 06:36:48 AM »

> Imagine the energy wasted in the UPS converting 12
> vdc to 120 vac, then in your radio power supply
> back from 120 vac to 12 vdc.

Not as much as you think.  Most converters now are modified sine or PWM generated sine, and are pretty darn efficient.

Consider that it may give you capabilities that operating on DC alone does not offer.  Efficiency isn't the only parameter to consider.

First, it gives you access to Ah you may not otherwise be able to use, due to where the dropout point of the radio might be.  Most rigs are spec'd to 13.8V +/- 15%.  The bottom limit becomes 11.75V, which is about the 50% DOD point of a lead acid battery.  So the radio poops out with half the battery capacity remaining.  Most UPS's however will continue to run and regulate until the batteries are completely depleted, or nearly so.  So while there's a conversion efficiency penalty, effectively your run time is extended significantly.

Second, not everything runs on 12VDC.  Antenna rotators, wall warts for accessories, PC's, you name it can run from the UPS as though nothing happened, and without any reconnecting of equipment.  The UPS also takes care of recharging and floating the batteries correctly, and automatically.

It probably isn't practical to haul this kind of stuff into the field but for a home station it's a tough system to beat.


Mark K5LXP
Albuquerque, NM
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AE5JU
Member

Posts: 229




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« Reply #12 on: December 06, 2009, 08:20:37 PM »

That is a good point, Mark.

And aside... I have a 7 kw generator and a 800 w inverter, too.

Paul
AE5JU
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