Home Shack Backup Power

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Rob_K

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I wasn't sure where to put this. Its an ongoing project but I guess it is a picture of my power for my current shack...

This thread is a continuation of these threads that I was participating in:
http://forums.radioreference.com/electronics/219715-12v-car-battery-emergency-power.html
http://forums.radioreference.com/live-audio-administration/220014-hurricane-irene-impact-live-audio.html

I've been doing a lot of work on my backup power for the shack and house in general. I got lucky and purchased a generator off Craig's list about 6 weeks before Irene. Got a decent deal on a 5kw Honda.

For the shack itself, I'm building something very similar to KB0NLY (Shack!). The only thing I don't have is the power supply/conditioner. I want to keep my radios, scanners and feed thin client going on battery power since when the weather gets bad, I'm usually out on fire calls. A few hours would be nice until things slow down and I can get home to fire up the generator.

My Firewall, switch and cable modem are in the basement and powered off a 500va UPS. I get about 40 minutes of run time. I wanted to extend that to the 4-8 hour range. During Irene, my ISP crapped out after 8 hours.

I thought about trying to find a 1500va UPS to get longer run time but the more I thought about it, it seemed silly to purchase something that large when all I need is battery; not power for a large load. I started to do some research on how to get more capacity off the UPS. I found a pretty funny article here: Upgrade your UPS! (with some car batteries...).

Before I went and purchased anything, I wanted to do some testing. At work, we swap the batteries in our backups every 3-5 years (depending on what it does) so I grabbed a tray of batteries from a 3000va UPS. It had 8, 12 volt batteries in it (2 groups of 4 batteries in series for 48 volts). They are over 5 years old but they still hold a decent charge. I re-wired them to all be in parallel so instead of 1, 12 volt battery in my UPS, I have 8.

This is only a trial so, my wiring isn't the greatest.


So far its working out pretty well. I'm trying to decide if I'll go with a larger UPS still (750va - 1500va) that would use 24v batteries. I've read that these smaller UPS might not like to run their DC-AC inverters for very long. The only downside with 24 volts is that I'd need two batteries. An advantage is that the 750va and up usually have a plug on the backside to connect an external battery.

I'm thinking I'll use a car battery because I won't be discharging and charging very often. They'll just be on standby should I lose power. The shack has an Optima battery since I'll run on batter a bit more often.

I'm not sure if anyone has any feedback.

To be continued.

Edit: My cable modem, firewall, Vonage and a gigabit switch draw about 2.7amps. I left this on battery for just over 2 hours and the batteries were still at 12.2v or so. I think I may have a winner here.
 
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SCPD

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Something you may consider. (as what I play with)

I use a motorcycle battery for a Ninja 250 for outdoor applications. This battery's about three pounds.

Car battery for home use (like you state), look into a battery tender, they're about $30 on the web. They'll charge any 12v source at about 750mah rate. And you can keep it on your battery 24/7 and not worry about spillage.

Just a tid-bit, I'm acutally collecting car batteries for this same idea!

Awesome Wiring plan too! It looks much better than what I can do!
 
K

kb0nly

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Cool... I like that big box of batteries you got there. And if they are old but free, well free is always good! If you can get some use out of them then so be it!

Just put any 12v DC items on battery and the rest on the UPS. I assume thats the plan? The UPS does a pretty good job of charging the batteries, you add more battery and it just makes the charge time go up, the 24v units are a bit more efficient and yes the 12v units are what i would call intermittent duty, they don't like running for hours and hours. Most of the smaller ones i have tested with larger external battery banks would run a couple hours but get so hot you would smell that nice hot plastic smell from them. Repeated long use of them i am sure would kill them quickly.
 

Rob_K

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Cool... I like that big box of batteries you got there. And if they are old but free, well free is always good! If you can get some use out of them then so be it!
Yes, for sure. The tray is what came out of the UPS. Once the wiring is said and done, I can throw the cover back on it.
Just put any 12v DC items on battery and the rest on the UPS. I assume thats the plan?
That's correct. In the shack, the scanners, amateur radio and thin client are all running off DC.

The UPS does a pretty good job of charging the batteries, you add more battery and it just makes the charge time go up, the 24v units are a bit more efficient and yes the 12v units are what i would call intermittent duty, they don't like running for hours and hours. Most of the smaller ones i have tested with larger external battery banks would run a couple hours but get so hot you would smell that nice hot plastic smell from them. Repeated long use of them i am sure would kill them quickly.
This little 500va unit chargers the bank of 8 batteries pretty quick.

I'm going to check out our "grave yard" today and see if we have any larger UPSes sitting over there. Might play around with a larger unit.
 

Rob_K

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Lost power at 2019 tonight. Had the generator up within 15 minutes but see how long before the ISP craps out this time.

Will be shutting generator down when I go to sleep. See if the batteries last through the night.

First test of this setup!

Edit: And my 100th post!
 

Rob_K

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ISP went out in less than 5 hours. Ran on battery overnight for just over 8 hours and I still had about 12.03 volts. Looks like I reached my 8 hour goal; too bad Cox couldn't do the same.
 

yamaha769

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Just remember when you charge a bettery that is vented you create hydrogen gas. You put the gas in a room filled with electronics things could get a little crazy and we could hear your address over the scanner for a structure fire. Thats why all UPS systems use a sealed battery.
 

jim202

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ISP went out in less than 5 hours. Ran on battery overnight for just over 8 hours and I still had about 12.03 volts. Looks like I reached my 8 hour goal; too bad Cox couldn't do the same.
Yup, the cable companies don't care much for long time power outage support. They figure the power is out so you can't watch the TV.

On your gell cell batteries, over time they loose the internal resistance and also start to swell or bulge out the sides when they start to go bad. People don't pay much attention to the UPS units around my company until they start to beep an alarm. By that time the individual cells or batteries have grown and you have a hard time getting the trays out of the UPS units.

\
 
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power outage

I have cablevision and the tv channels worked just fine ,so the power was out and their network was up !
Pretty cool huh?I used a power inverter for powerr amd left the car on.
 

Rob_K

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Update to this thread and my setup.

While it looks the same, swapped with a newer tray of batteries, put the lid back on and cleaned up the wiring. There is a power pole connection between the UPS and the batteries so I can easily swap what I'm using for batteries


This setup powers the Internet for my house. On battery is the cable modem, PIX firewall, WiFi and Dell Switch. Vonage, cable tv drop amp and Cisco PoE adapter are on the surge only side. (I need a set of Dies for my crimper so I can clean up the CATV coax)


In the shack, I had a brand new Optima battery that I was using. I took this battery tailgating a couple of times to power an inverter and it got dropped. Needless to say my sealed battery is no longer sealed and now sits in the garage unused.

I took batteries from an add-on battery pack from another UPS. These were re-wired to be 12v. I re-used the large powerpole connectors that tied the batteries to the UPS to connect the batteries together. Power poles connect to my Iota Power supply. The left battery also has a set of power poles so I can plug it in to my other UPS, should I need to. (Been 4 years since I painted, guess I should put that cover back on the radiator)


The rest of the shack power supply (once again, modeled off of KB0NLY's setup). I didn't realize how many stray wires I had until the flash lit them up. This is mounted under the desk.


I'm not sure what is next. I started another thread about changing from a thin client to a netbook or notebook for my feeds if I can find one that can be powered direct to 12v.
 

Bellingham_Scanner

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I don't see any fuses on your batteries.:eek::confused:

YOU NEED fuses on your batteries.

Even the little 7.2Ah batteries can produce dangerous amounts of current when shorted, instantly vaporizing the insulation.

Trust me on this one I work for a UPS manufacturer and have seen and even started my share of battery fires.

For your setup a 10 Amp fuse would be plenty, go to any auto-parts store and get an inline fuse holder
 
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