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#13381 - 03/06/03 03:05 PM Battery Backup
John Warner John Warner old hand Registered: 01/09/03 Posts: 824 Loc: Port Perry, Ontario, Canada	I purchased two surplus 12vdc sealed lead-acid batteries today in hopes of using them to backup the security portions of my HA system (see previous discussion earlier in this forum). Does anyone currently power their Ocelot, SECU's etc. in this manner, and, if so, how do you keep the batteries charged? In my arsenal of power supplies, I have 13.5vdc 1A unregulated wall warts, 12vdc 1.5A regulated switching power supplies, 12vdc 800ma unregulated wall warts, 12vac 1.5A wall warts, and a couple of 1A motorcycle battery trickle chargers. After playing with them a bit today, I find that the 12v regulated supplies don't show any charge current (I assume 'cause their voltage is lower than the battery (which is around 13 volts))? The unregulated 13.5v supplies charge the battery at about 15v as do the motorcycle battery chargers (no load on the battery). The 12vac wall wart through a bridge rectifier also showed over 14v connected to the battery with no load. Since the Ocelot and SECU's call for 9-12vdc (with some margin to allow for up to 15vdc I understand), I'm reluctant to hook them to this setup. Should I be looking at a voltage regulator to keep things down to 12vdc? Which of these supplies is my best bet? or, Should I turf the whole works and buy a UPS? TIA
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#13382 - 03/06/03 03:38 PM Re: Battery Backup
Guy Lavoie Guy Lavoie Beyond All Hope Registered: 12/21/02 Posts: 6421 Loc: Montreal, QC, Canada	One quick and dirty way to lower the voltage is to put a rectifier diode (like a 1N4004) or two in series with the supply to the Ocelot and modules. Put the anode on the battery side and the cathode (the end with the band) at the module(s) side. Every diode will drop about 0.7 volts so two of them will drop 1.4 volts; you'll be at around 12.5 volts dc at the modules. Just make sure the current rating of the diodes is sufficient enough to power everything, or use one diode (or diode pair) for each module. _________________________ "If you don't know what you're doing, do it neatly..."
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#13383 - 03/06/03 04:16 PM Re: Battery Backup
petec petec active contributor Registered: 02/05/03 Posts: 167 Loc: Hyde Park, NY	there are some (realativly) inexpensive 'alarm system' power supply/charger circuit boards out there . . . just what your looking for . . . this Altronix product is just an example I found on a google search . . . Pete C
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#13384 - 03/06/03 06:07 PM Re: Battery Backup
John Warner John Warner old hand Registered: 01/09/03 Posts: 824 Loc: Port Perry, Ontario, Canada	How's this circuit look? Alarm Power Supply or this one: UPS
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#13385 - 03/06/03 06:52 PM Re: Battery Backup
petec petec active contributor Registered: 02/05/03 Posts: 167 Loc: Hyde Park, NY	sorry John, none of your links seem to work for me ? ? ? . . . but you get the idea, there are power supplies that provide online power (AC to DC) and a trickle charge for your batteries, with autoswitch to battery when the AC goes away . . . (this particular Altronix would require a AC transformer, but this lets them avoid the UL that goes with 120v, and kkep the price reasonable) . . . I have a 10A Altronix PS SMP10 that I run a few ADI and other HA stuff with . . . (no monetary connection w/ Altronix or ADI, though I have been plugging for a ADI T) Pete C
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#13386 - 03/07/03 06:50 AM Re: Battery Backup
John Warner John Warner old hand Registered: 01/09/03 Posts: 824 Loc: Port Perry, Ontario, Canada	Hmmm? on the broken links - they work ok for me? Both are circuits to build a Power Supply like the one you describe. I see what's needed now, the question is can I do it better/cheaper myself with these batteries or does it make more sense to take them back and buy a UPS. I've got $30 invested in the 2 batteries, if I need to invest another $50 or more in a Power Supply (they all seem to want around 20VA 16vac to drive them which I don't have either). Since I'd like to isolate the Ocelot/SECU supplies from the PIR/Sirens, that means I have to do it all twice! :eek: A UPS is only around $100 so is starting to look more attractive...
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#13387 - 03/07/03 07:29 AM Re: Battery Backup
Guy Lavoie Guy Lavoie Beyond All Hope Registered: 12/21/02 Posts: 6421 Loc: Montreal, QC, Canada	A UPS would be overkill if you have no real need for 110 Vac power. The first of the two links shows a good circuit that you could use for your purposes, but if you need no more then about 1 amp then your 13.5 volt unregulated wall wart might be enough too. I would just verify the charging current between it and the batteries to make sure it doesn't exceed the charge rate rating. It might exceed it a bit for a short time (30 seconds to a minute) after connecting the batteries but it should settle down after that. You could then use that series diode(s) I mentioned in an earlier post to bring the voltage to no more then 12.5 volts or so at the modules. When the power fails, the voltage will then drop a bit (0.5 to 1 volt) but that's still within the Ocelot's / SECU16's specs. The circuit shown in the link keep the voltage constant by using a 7812 regulator after the battery/charge circuit but you might not really need that in this application. _________________________ "If you don't know what you're doing, do it neatly..."
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#13388 - 03/07/03 08:02 AM Re: Battery Backup
Brian Raynor Brian Raynor addict Registered: 01/09/03 Posts: 454 Loc: Columbia, SC	Small UPS's can be found for around $39 (look for some of the power strip style ones). They should be able to power the Ocelot for days if not weeks I would imagine. You could probably get by with buying the smallest/cheapest UPS you can find... That's what I'm using to backup my Ocelot, though of course I already had a UPS.
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#13389 - 03/07/03 08:48 AM Re: Battery Backup
John Warner John Warner old hand Registered: 01/09/03 Posts: 824 Loc: Port Perry, Ontario, Canada	Guy: The first circuit calls for a 12v 20va supply with a bridge rectifier. Would my 12vac 1.5a (is this 18va?) wall warts be a better fit than the 13.5vdc 1a ones without the rectifier? The advantage of a cheap UPS I guess is I can keep ALL my existing HA supplies intact and powered. It also provides isolation among devices (I currently power my PIR's/alarms separately from my Ocelot/SECU's and my Waterbug is on its own supply - I'm about to add a SpeakEasy which will also be powered separately). The disadvantage of a UPS is, when its battery dies, I'm looking at a relatively expensive and specific replacement vs the generic sealed lead-acid ones I now have?
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#13390 - 03/07/03 10:31 AM Re: Battery Backup
Guy Lavoie Guy Lavoie Beyond All Hope Registered: 12/21/02 Posts: 6421 Loc: Montreal, QC, Canada	The 20 va requirement of the circuit is probably for that specific application (an alarm system). Don't forget that sirens are usually 12 volts too! I designed my own to provide up to 3 amps (about 36 va). For the purposes of what you;re powering, you can roughly estimate that the va will be the voltage x current since we're not powering largely inductive loads like transformers or motors. You would be ok with the 12 vac 1.5 amp wall wart. Trying to provide backup power is never a clean, simple operation. The types of UPS you're talking about are usually meant to keep a computer going for 10 to 15 minutes, until you realize that the power failure is for real and gives you time to do a proper shutdown, or to give a chance for a generator or other backup system to come on. Full time UPS's cost quite a bit. _________________________ "If you don't know what you're doing, do it neatly..."
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#13391 - 03/07/03 12:16 PM Re: Battery Backup
John Warner John Warner old hand Registered: 01/09/03 Posts: 824 Loc: Port Perry, Ontario, Canada	All I want to do is to run the Ocelot, two SECU's, 8 PIR's (which should draw very little with no detects), the alarm keypad (which holds a small relay while set) and, on an alarm condition, sound the sirens (which are 12vdc) for a couple of minutes. The smallest of UPS's should easily handle that? I do like the idea of a home-brew solution though that uses generic batteries that are cheap and easy to replace! Does anyone have experience with entry-level UPS's? What sort of batteries do they use and how long do they last before needing replaced?
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#13392 - 03/07/03 06:30 PM Re: Battery Backup
Joe Thielen Joe Thielen journeyman Registered: 01/14/03 Posts: 64 Loc: Toledo, OH	[QUOTE]Originally posted by John Warner: [qb]Does anyone have experience with entry-level UPS's? What sort of batteries do they use and how long do they last before needing replaced?[/qb][/QUOTE]I've been using APC UPS's for a few years now, and have been VERY happy. The smaller ones (BACK-UPS 280 or something) can be had for like $50 at Sam's Club now! I bought two for my home. We've been using them at work for years, and I find that I change batteries maybe every 3 years! :eek: I've not done any type of battery backup with my ADI stuff. I do want to look into it, and would love to come up with a home-brew solutions with some big fat car batteries to keep the system running for a while
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#13393 - 03/07/03 06:39 PM Re: Battery Backup
ken-h ken-h active contributor Registered: 01/13/03 Posts: 106 Loc: Calgary, Alberta, Canada	John Most entery level UPS system use Nicad batteries. They last 3 to 5 years. They will last longer if you discharge them on a regular schedule and then recharge and float charge after. _________________________ Ken H To Automate is all right.
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#13394 - 03/08/03 04:38 AM Re: Battery Backup
John Warner John Warner old hand Registered: 01/09/03 Posts: 824 Loc: Port Perry, Ontario, Canada	Guy: How does this circuit: Alarm Power Supply provide 13.5vdc to charge the battery from a 12v transformer? Would my 12vdc 1.5a regulated switching power supply do the same if used with this circuit in place of the transformer and bridge rectifier?
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#13395 - 03/08/03 08:12 AM Re: Battery Backup
Guy Lavoie Guy Lavoie Beyond All Hope Registered: 12/21/02 Posts: 6421 Loc: Montreal, QC, Canada	A 12v transformer produces a voltage of 12vac RMS. The voltage actually reaches a peak of about 17 volts before starting to go down and then reach another peak of 17 of opposite polarity. If you filter it with a capacitor (which is what C1 does in that circuit) then you will measure about 16 to 17 volts dc across the cap. The extra voltage gives the regulator some "working room" to keep it down to 13.5 vdc will regulated. Your 12 volt regulated power supply will not work with this circuit. If you wanted to use a dc power supply and eliminate the rectifier, your dc supply would need to provide at least 15 volts for the regulator to operate correctly. _________________________ "If you don't know what you're doing, do it neatly..."
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#13396 - 03/11/03 02:55 AM Re: Battery Backup
JeffVolp JeffVolp active contributor Registered: 01/26/03 Posts: 177 Loc: St. George, Utah	All the "Entry Level" UPS I am familiar with use sealed lead acid batteries. NiCads would not be cost effective for that application. These batteries will last several years before they need replacement. Maximum running time will deteriorate slowly over that period. BTW, I have a couple of smaller APC 280 (the one that looks like a large power strip) that were used to backup digital clocks and VCRs. I have a single high power UPS circuit in the new house, and can let these go very cheap. e-mail if interested. _________________________ X-10 automation since the BSR days
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#13397 - 03/11/03 03:31 AM Re: Battery Backup
John Warner John Warner old hand Registered: 01/09/03 Posts: 824 Loc: Port Perry, Ontario, Canada	Jeff: As the old saying goes - a day too late ... I bought an APC BX1000 yesterday (1000va). It should be more than adequate to power down my PC gracefully (it comes with software to do so) with lots left to run the Ocelot/SECUS/PIRs, and, (if necessary), sirens, through any power outage! The BX1000 is brand new from APC at an excellent price point (their new XS series). Here's a link if anyone is interested: APC BX1000 UPS
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#13398 - 03/11/03 02:28 PM Re: Battery Backup
gregking gregking newbie Registered: 02/19/03 Posts: 7 Loc: Lewisville,Tx	If you do go with a UPS then stick with a name brand one. I bought a CyberPower UPS a couple of years ago and it barely lasted 3 months before not holding any charge. I have subsequently bought 2 APC units which have been quite pleased. I picked each up a few months apart, but was able to get one for only $10 after a $50 rebate. The latest one was only about $25 on sale at OfficeMax a couple of months ago. These were the small units (I think Model 350) and last about 10-12 minutes for a PC, but that is sufficient for the typical "blips" in power that I get in storms, etc. greg
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#13399 - 03/11/03 02:49 PM Re: Battery Backup
John Warner John Warner old hand Registered: 01/09/03 Posts: 824 Loc: Port Perry, Ontario, Canada	An interesting wrinkle with my new APC UPS... Seems these critters are quite intelligent these days - perhaps too much so! The PC and UPS talk to each other via a USB connection. I have mine set to power my PC down gracefully 2 minutes after a power outage so there's LOTS of power left for my Ocelot, SECU's, PIR's etc. After shutting down the PC though, the darned thing figures it's done its job so goes into "battery sleep mode" to save itself for the next outage! I've got a couple of work-arounds in mind but am hoping APC can tell me how to tell the UPS to stay alive in this situation! :rolleyes:
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#13400 - 03/11/03 03:51 PM Re: Battery Backup
John Warner John Warner old hand Registered: 01/09/03 Posts: 824 Loc: Port Perry, Ontario, Canada	Here's a good one for you Guy: So my Ocelot, SECU's & PIR's are now happily humming away through a power outage... What will happen to all my X10 & IR commands? Obviously, there will be no input commands (although input IR is possible I suppose) but the Ocelot will keep pumping out X10 and IR. Will these be queued and then sent in order when the power is restored? If yes, how many are queued and what happens to the rest? TIA.
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