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Post by fishfever on Jan 10, 2010 21:44:49 GMT -5
This might be of some interest to anyone that experiences power outages from time to time and was considering a UPS purchase to keep things running during a blackout. On Black Friday I purchased a couple of UPS (Uninterruptible Power SUpply), mostly to replace some aging ones I had for computer backup but since the sale price was so good I ended up getting 2 spare ones. I wanted to try one out for aquarium back-up power to run at least 1 filter in my tank when power is lost. The model I got was an APC 550VA/330W; it just so happens that one of the larger aquarium supply businesses also sells this model for this purpose (I can't recall who now) but I didn't know this at the time of purchase. Anyway I've been experimenting a bit with it off and on when I have spare time. As a reference, I used a 40-watt lamp as my first test. To test the UPS, it must be fully charged (overnight) then unplugged from the wall to simulate power loss. The 40-watt lamp lasted exactly 90 minutes which was pretty good. Next I tried some air pumps and HOB filters each by themself to isolate each test load. The results weren't nearly as good. Of the 3 air pumps I have only one ran normally. The other two did not run or the output dropped to virtually nothing. I also have 3 HOB filters and only one ran completely normally. One ran acceptably but seemed a little erratic and one did not run.
TEST ---- 40-watt lamp - ran 90 minutes no-name small air pump that came with 3g hex tank - did not run TopFin (Petsmart brand) 60g air pump - did not run Whisper 10 air pump with 2.2-watt motor - ran normally for 65 minutes Aqueon 10 HOB - ran, forgot time but seemed to have trouble starting at first so had to cycle power manually Aqueon 30 HOB - did not run, made clicking noises Via Aqua Vitalife 200 HOB with 8-watt motor - ran normally for 60 minutes
Although we generally have reliable power here and it's rare to lose power for more than a few hours, I thought this would be a nice addition to my setup; it also has surge protection built-in (it has surge-protected outlets that are not battery-backed) so it may help pro-long the life of other things (heater, UV sterilizer, etc.). You may be wondering why the run times (for those that ran normally) are so low, especially compared to the 40-watt lamp which would appear to be a much bigger load. Without getting too technical, this particular UPS (and most of the cheaper ones) when on battery backup attempts to synthesize the normal household waveform (sinusoidal) instead of generating a true sinusoid. This can play havoc with some kinds of loads (motors in particular). Other possible problems that could reduce motor efficiency are harmonics and low power factor but I suspect the main problem here is the approximated sinusoid output (which can increase harmonics as well). I also tried piggybacking my spare UPS to see if I could get double the run time but the second UPS would make clicking noises every few seconds when I unplugged the first UPS from the wall (meaning it was confused by the non-sinusoid output and was switching back and forth between normal and lost power mode). It should be noted that if you are wanting to run a resistive load like a heater with a UPS it should be fine (although I can't see the need for this since temperature drops rather slowly).
I know Carl sells an air pump that uses a dc motor and built-in battery. Because it's a dc motor (all of the above are ac motors) it should run off it's internal dc power supply when power is available and off the internal battery when power is lost. There is no power conversion necessary in power loss mode so it should have a high efficiency and much longer run time than a pump with an ac motor plus UPS backup (if the motor will even run with the cheaper non-sinusoidal UPS). If my power situation was really bad I'd definitely consider that over a UPS. I ended up leaving my Via Aqua Vitalife 200 HOB plugged into one of the battery-backed outlets and plugging everything else into the surge-protected only outlets (no backup). So on a power loss, everything will shut off with the exception that the HOB will run for 60 minutes then shut down. I figure this is somewhat better than everything shutting down on full power loss.
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Post by Carl on Jan 11, 2010 11:09:33 GMT -5
Interesting post fishfever This is subject that I have actually had a lot of experience in, in part dating back to the 1980s to find a way to protect my clients tanks from power failure where I designed my own DC pumps with electric switches (I purchased at Radio Shack) to hold the circuit open while plugged into House Current (loss of power closed the circuit) Later as I became an avid RV camper I experimented with Inverters (which convert DC to AC power), in the late 90s this became a necessity as my son was severely ill and required a machine/monitor be connected to him 24/7. A breakdown by my wife and the consequences that followed convinced me (& others) that I needed to"take a break", I researched and found a good modified sine wave inverter (after an attempt with one that claimed a modified sine wave but appeared to be a square wave). We used this system to take a camping trip where eveything worked well, although the medical equipment failed one day, but my inventive brother in law (who met us 2/3 through the trip) made a "fix" with parts on hand. We still ended up cutting our trip a little short when the charging system for the batteries began to fail (the alternator still would charge the batteries, plus we had a 4000 watt generator), so we were fine to get back home safely we just could not charge well while stationary/camping and running a generator 24/7 is considered rude to other campers nearby. The first "cheaper" inverter (rated at 400 watts) although claiming to be a modified sine wave inverter, could not run many pieces of equipment such as drills and motors. The second model although rated at 400 watts too (800 surge) had no problem loading up to its rating. Both were connected to Deep Cycle batteries in parallel; by parallel, this means placing the batteries in connection in such a way that keeps the batteries at 12 volts, but nearly doubles amp output versus in series which would make the output 24 volts (4 1.5 V 'D' Batteries in series would be 6 V). By using the same energy source, I knew this ruled out the lack of energy since you (for example) cannot connect a 1500 watt inverter to one standard auto battery. I know true sine wave inverters are available, but according to reviews I have read from RV Journals, these give little more than the modified sine wave but for the most delicate of electronics, which your aquarium equipment does not qualify as. What I do not know is why the more costly (triple the cost) heavy duty inverter worked better than the cheap one when the ratings were the same, but I suspect that the claim of a modified sine wave was not true, as it behaved more like a square wave inverter. My suggestion is to get one or two deep cycle batteries and connect a good modified sine wave inverter to them, your run time will be vastly longer. In fact in 2000, I used a couple of series 24 Deep Cycle RV Batteries and a 800 watt inverter for my Aquarium Store. We had a major blackout in 2001 and were able to run all our electronics (cash registers, etc.), pumps, lights (no heaters, air though, but then it was summer in LA). This ran fine for a few hours with a full load when power returned. What was interesting is that mobile 24/7 radio reporter for LA station KFWB was driving down the street we were located on and noticed our business was still functioning while others were in the black, and interviewed an employee of mine who showed them our system. BTW, the Azoo continuous run pump I sell has an AC motor (at least it appears so when I took it apart since it uses a vibrator motor which require alternating current to function), so this pump is essentially an inverter as opposed to a converter (or DC switch). I should note that I only took apart the pump part, but I think this is a safe assumption. Fishfever, please understand that some of my explanations are for others who might read this thread not familiar with this subject, as I figure you (& others) likely already know much of what I stated, I just wanted to explain further. Carl
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Post by fishfever on Jan 12, 2010 7:29:45 GMT -5
Hmmm, now that I know the Azoo also uses an integral inverter, it's really making me more curious as to why my run times are so low compared to that Azoo pump... even my small Whisper (I think the model 10 is the smallest and probably doesn't put out as much as the Azoo although I haven't checked the specs) only runs a little more than an hour with a reasonably beefy UPS (it weighs about 13 lbs which is mostly the battery). I'm sure Azoo did some design work to match the UPS to the motor. But it's still a bit baffling that it would be more than a 10 to 1 run time advantage over a randomly paired UPS and pump. I'm going to pull out my scope and look at the UPS waveform in more detail, maybe this weekend. I also have an old inverter in my pickup truck that I rarely use that I will compare the output to. I like the idea of using the marine batteries with a good sine inverter. Add a simple DPDT relay and it will automatically switch to inverter mode when the power drops out.
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Post by fishfever on Jan 17, 2010 10:16:07 GMT -5
I was out of town for a few days but had a few minutes this morning to capture some waveforms. I used an old scope and a simple resistor network to divide the voltage down to something that wouldn't overload/damage my scope. This is the way our normal 115vac right from the wall appears or when the UPS is plugged into the wall. As you can see, it's not a perfect sinusoid (could be to the various loads on it) but it's pretty close to a pure sinusoid: i558.photobucket.com/albums/ss25/fishfever/Normalhouseholdsinusoid.jpgThis is the output of the UPS when unplugged from the wall and using it's internal battery-powered inverter: i558.photobucket.com/albums/ss25/fishfever/APCES550UPSonbatterypower.jpgI also had an old Tripplite inverter in my pickup truck so I hooked it up to a 13vdc power supply and looked at it as well: i558.photobucket.com/albums/ss25/fishfever/Tripplite300wPowerInverterconnected.jpgAs you can see these inverters are nowhere near sinusoidal output. They call them modified sine but the approximation is really, really poor. I was expecting (or hoping to see) small stair-step approximations but this is only slightly better than a square wave. The only thing that makes this slightly better than a square wave is the duty cycle (amount of time waveform is not zero per cycle) is a lot lower than 100%. It is no wonder that the ac motors don't like to run well off of these inverters. I understand from talking to APC tech support that they make a SmartUPS series that has sinusoidal output (but is also pricier). I think I can do better by getting my own sinusoid UPS and battery combination; I'll report back when I get around to this... But in the mean time, I'd steer clear of general run-of-the-mill UPS types for aquarium back-up power as it's likely to be a big waste of money and time.
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Post by Carl on Jan 17, 2010 11:29:26 GMT -5
Although I have never "scoped" mine (I do not have one, but my Dad does, so maybe he can check his someday), I have not had issues with my Tripplite heavy duty modified sine wave inverter that is hard wired into my camper. I did have problems with a cheapie one purchased at Walmart than connects to a cigarette lighter or clips to the batteries. My understanding is that the modified sine wave is more like the square wave when scoped than the true sine wave. Please see this article from an online RV Blog I subscribe to: RV Doctor – Should I Install an Inverter in My RV?Carl
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Post by fishfever on Jan 21, 2010 21:53:25 GMT -5
Carl, my old Tripplite inverter is just a cheapo small unit that plugs into the cigarette lighter when we need portable ac power so it's just the modified sine output - I probably paid no more than $40 or $50 for it. I think we have used it maybe 3 or 4 times over the years, mostly to charge a laptop (12vdc to 115vac back to low-voltage dc, doesn't make a lot of sense but didn't have a dc adapter cable). I will check out the link as I haven't picked out a sine wave inverter yet; I'm looking for a low-wattage model with as low a drop-out voltage as possible. Once I get it I can measure the dc current (which should be fairly constant since the filter pump runs at one speed and the load should be fairly constant also). Then I can use that information to spec out the battery size (amp-hours) I'm after. I'd like to have my Vitalife HOB run for a minimum of 5-6 hours, preferably even up to the double digits if the battery doesn't get too large.
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Post by Carl on Jan 22, 2010 10:25:25 GMT -5
Likely there are differences in quality, as I had similar issues with the cheapie Walmart inverter of similar cost to yours. Where as the heavy duty hard wired unit cost me $400 (although this price has come down since I purchased as most electronics have)
Carl
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Post by parker002 on Jan 23, 2010 0:52:42 GMT -5
I take it nothing running in the aquarium requires any power conditioning? I have two UPS' but they're for computers. I could run my aquarium off of one of them, but I wouldn't think of running my servers off of a homemade DC inverter.
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Post by fishfever on Jan 23, 2010 9:41:22 GMT -5
Power conditioning is always better than none and is easily provided using an inexpensive passive wall strip to distribute power when there is no power outage. The sine wave output inverters we are talking about are not homemade; however they are more expensive than the cheaper modified sine versions (which is really just a square wave with the output suppressed to 0 for a period as it crosses through 0). You may find that if your UPS is not sine output (most aren't) your motorized things like pumps will either run for a lot lower time than their power consumption would indicate or not run at all (about half the stuff I tried did not run). For computers and other electronics with switching power supplies the waveform type is not critical. A switching power supply rectifies and filters (converts AC to high-voltage DC) before chopping this DC at a much higher frequency than the 60 Hz line input. So it really matters little whether the waveform starts off as a sinusoid or not since it's immediately converted to DC. But many/most AC motors are not going to run right and/or run inefficiently with the non-sinusoidal power.
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Post by Carl on Jan 23, 2010 11:39:31 GMT -5
This is almost the exact description my Dad gave me a few years back when I was first experimenting with different inverters for my camper (so as to take my son and his medical equipment camping) and for my business. I asked this question after noting that the first inverter I purchased would run electronic equipment, bu not a power drill what was well under the wattage output of the inverter.
BTW, my father is an electronics engineer (I do not say this to brag, only to provide some background as to why I asked these questions of him)
Carl
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Post by fishfever on Feb 10, 2010 20:52:44 GMT -5
Carl, I'm an EE as well... I've been trying to find an pure sine inverter/battery/charger combination that was relatively affordable but it looks like this is a fairly expensive proposition for just one tank (but very cost effective if you have many tanks in close proximity or maybe a fish store). The cheapest sine inverter I was able to located was a 150w with a cigarette lighter plug for about $100 (was on sale, normally over $200). But once you price a reasonably sized battery, charger and misc items (such as relays for auto-switching, wiring, terminals, enclosure/cover) it is easily well over $200 and probably more like $300. APC makes several pure sine inverters in the 750VA class and up. The list is about $320, although Best Buy currently has one on sale for about $250 not including shipping/tax. By being patient, I happened to run across one of them (open box with 1-year warranty) for $50 (including shipping!). A deal I couldn't pass up. I have it plugged in now and charging but in the mean time I went ahead and scoped the output on battery power and briefly ran one the filter pumps that would not run at all on the "modified sine" inverters (the 30g Aqueon that only clicked on modified sine power). The good news is this pump runs just fine on the pure sine wave which looks like this: i558.photobucket.com/albums/ss25/fishfever/APCSmartUPSoutputonbatterypower.jpgIt actually looks better (more sinusoidal) than our house voltage AC power (probably due to the various heavy loads like HVAC, refrigerator and other appliances). Over the next week or 2, I'll be repeating the tests I did on the modified sine to see how long a run time I get (after all, this is the main reason for upgrading, to get sufficient run time in case of a long power outage). I am expecting (hoping) I'll get far more than the roughly 1 hour of run time I got from the modified sine inverter. Will post the results (good or bad) here.
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Post by fishfever on Feb 13, 2010 17:47:05 GMT -5
Well I've made good progress on the new UPS testing and have learned/discovered an awful lot... a lot more than I can post here without getting into rather technical stuff and boring everyone to death. LOL Anyway this new UPS I bought charges up much faster (about 3.5 hrs from fully drained to fully charged) so I was able to run a number of tests in a fairly short while. One thing I discovered is this is more than an open box UPS - it has probably been in use for about a year. I found this out when I downloaded some software from APC's web site so I can monitor and tweak some settings (for example I don't want to hear it beep every 30 secs when power is lost). There are tons of things you can monitor and/or change (like internal temp, battery voltage, etc.). One parameter was the battery installation date which was Nov 2008. Another giveaway that this is used UPS is some sticky residue on the case where someone pulled a label off the case. This is probably where someone put the user name/password needed to log into the UPS because this is also where I put my label with my created user name/password. ;-) So a used UPS means the battery has some degradation from age and use. Batteries have a shelf/usage life and generally age faster at warmer temps. This UPS does not have an internal fan since it's a low-end model (the smallest pure sine UPS that APC makes). The monitor screen showed the temp at 36.9 C after it had been on a while so I clipped a tiny CPU fan (maybe 1-watt) over the ventilation holes and the internal temp dropped to 24.3 C (about room temp) after a while. This should extend the battery life going forward but whatever degradation has occurred in the past can't be reversed. The battery terminal voltage also increased from 24.57 to 26.59 volts after the unit cooled down (good sign). I ran a test with the same 40w incandescent lamp I used with the previous (modified sine) UPS. I also tested it with all my filters/pumps. Every one of them runs just fine (not surprisingly) with the pure sinusoidal power. Here are the results: TEST, 750VA/500W Pure Sine UPS ------------------------- 1. 40-watt lamp - ran 93 minutes (this is somewhat low compared to the APC run time calculator so this can probably be associated with not having a brand new set of batteries installed, APC estimates 126 minutes for a 40-watt load) 2. no-name small air pump that came with 3g hex tank - runs fine, did not time run length by itself 3. TopFin (Petsmart brand) 60g air pump - runs fine, did not time run length by itself 4. Whisper 10 air pump with 2.2-watt motor - ran normally for 4 hours, 17 mins 5. Aqueon 10 HOB - runs fine, did not time run length 6. Aqueon 30 HOB - runs fine, did not time run length 7. Via Aqua Vitalife 200 HOB with 8-watt motor - ran normally for 3 hours, 48 mins 8. Ran tests #2, #3, and #7 simultaneously - all ran normally for 2 hours, 40 mins 9. Nothing connected to UPS - shut down after 3 hours, 44 mins So the revelation here is that the UPS itself with NO LOAD has a finite run time similar to a small load. Why is this? The reason is the UPS inverter itself consumes power EVEN IF THERE IS NO LOAD. This is why if you compare tests #4, #7, and #9 you will see it doesn't seem to matter if a filter/pump is connected or not - the limiting factor in the run time is UPS itself! (It is a little odd that the Whisper 10 actually increased run time over nothing connected at all but there is probably a good bit of variance repeating runs, I didn't bother to explore this.) Only when I connected several filters/pumps as in test #8 did the run time drop substantially from the rest of them (in other words, now the load is big enough to have a bearing on the run time). Here is the efficiency curve of my UPS from APC's web site (copyright APC): i558.photobucket.com/albums/ss25/fishfever/UPSEfficiency.jpgThis confirms that the efficiency (effective power transferred to load) drops substantially when using it at the low end of the load range. In fact with a small 8-watt filter like the Via Aqua, we are only at 1.6% loading (8/500) which is actually off the chart (well, well below 50% efficiency if you examine the slope of the curve which intersects with zero efficiency at 0% load). So this explains why it almost doesn't matter whether the filter is plugged in; almost all the power is being consumed within the UPS! Although I'm satisfied for now with nearly quadruple the run-time with this new UPS (I think it would be closer to 5 hours or more with new batteries), this is still not the optimum solution for emergency run power. One could go to a higher VA/watt UPS as long as the batteries were actually higher amp-hours and not just a larger inverter (and hope the UPS low-end efficiency does not consume too much of the battery). But a better (and much smaller, less expensive) solution for a single tank or small number of tanks would be a smaller inverter that was sized just big enough to run the emergency filter/pump. This would shift the whole efficiency curve to the left AND allow more reasonable sized batteries (i.e. smaller) to run your filter/pump. Unfortunately I don't know of anything like this out there because most who would buy a UPS are trying to run high-power equipment so this would be kind of a niche product. The closest thing is probably the Azoo UPS pump that Carl sells but it would be nice if instead of the dedicated air pump they made one with just an outlet where you could plug your own small low-power filter or pump into (limited to maybe 10-15 watts). For a large number of tanks with lots of filters/pumps the larger inverter/custom battery solution is a no-brainer. I'm of the opinion that the sine versus modified sine is primarily a factor for whether your motor runs or not based on the data I collected. It is much less a factor for determining how well the motor runs (i.e. length of run time, motor efficiency). So you can probably get away with a cheaper UPS (modified sine) if you are sure your filter/pump can run off a modified sine or are able to test your filter/pump on a particular UPS before purchasing it.
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Post by fishfever on Feb 16, 2010 18:34:10 GMT -5
Two additional tests I forgot to post for completeness:
1. Ran original modified sine (APC 550VA/330W) without any load. It shut off after 64 minutes. 2. Ran Via Aqua VA302PF with modified sine (APC 550VA/330W) and it ran fine (did not time it).
Test #1 means that the modified sine UPS runs for about an hour regardless of whether there is a light load or no load (in other words all the things that did run on it made little difference on the run time). This is why I drew the conclusion that the pure sine versus modified sine output is only to determine whether a filter/pump can be used with a modified sine and does not have much effect on run time. Since both Via Aqua brand devices worked with modified sine, it's possible that the whole Via Aqua line will work with the cheaper modified sine output.
This evening I may have run across the "holy grail" for getting a long run-time cheaply... I had already come to the conclusion that a low standby current (no load or very light load) was necessary for the inverter. This is more likely with a low wattage inverter which should shift the efficiency curve to the left (consume less power by itself). I measured about 0.6 amp standby current for my cheapo Tripplite 300w inverter which is too high. I was looking at Cobra (the same company that makes radar detectors) and found a mobile inverter but after looking at the manual the specs say less than 0.45 amp standby. I happened to click on another manual and found the standby was less than 0.1 amp! It was the only one they had that was anywhere near this low. I found a new one on amazon.com and promptly ordered it. It was about $25 including free shipping, hard to beat that. I know the output will be modified sine, but I have already verified that my Via Aqua Vitalife 200 runs fine with that. I'll post my results once I've done some more testing but I'm pretty sure I'm on my way to double digit run hours with this inverter and a reasonable sized battery...
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Post by Carl on Feb 16, 2010 19:06:27 GMT -5
Your tests are really educational and informative (even for non aquatic applications)
What is still curious to me is that my hard wired Tripp Lite inverter, which is a "high end" modified sine wave inverter will run everything I have plugged into it from lights, to pumps, drills, even a vacuum cleaner. My low end would not, yet it too is a modified sine wave inverter. I have to suspect that not all modified sine waver inverters/UPS are created equal.
Since my inverter is hard wired to a pair of deep cycle 12 V batteries (wired in parallel, not series), which each have a 160 minute reserve at full 25 amp DC output, I suspect days, not hours of use for low wattage loads (I know the kids have watched DVDs/TV all day and I have tested the batteries at 70% charge)
Carl
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Post by fishfever on Feb 17, 2010 18:32:47 GMT -5
Carl, probably the only way to tell is to scope it while switching the load on to see if the waveform collapses or distorts heavily with problem loads as compared with loads that work. Also many inverters don't like a heavy load on them when starting up; it's best to connect battery/turn the inverter on for a few seconds before connecting the load or switching the load on.
For this application my goal is a simple, inexpensive, compact design with the smallest, cheapest battery I can get away with. The stand below the tank where this stuff will end up is already quite crowded with all the frequently used items such as food, maintenance items, etc. so the "emergency power generator" should be smaller than a shoe box roughly. (I also plan to build a second one for my fry tank that is on another floor once I've finalized everything.) Because my only load will be very light (the Vitalife HOB) and I know the load works fine with the modified sine, I want a small efficient inverter that does not use significant power just to keep 115vac at the output terminals. So although paralleling additional batteries will surely increase run time and easily overcome any inverter losses, I'm trying to get away with a compact, inexpensive sealed lead acid battery, maybe at most 10AH or so to get double digit run hours. I'm pretty sure the Azoo UPS pump that you sell uses a similar design concept (small, efficient UPS and battery capacity just large enough to get decent run times).
I guess an analogy would be like taking a cross country trip with only 2 people (the load) travelling. I could rent a small compact car (small inverter) and get to the destination using minimal gas (small battery), or I could also make the same trip by renting a huge bus (large inverter) and use tons of gas (large battery) to get to the same place.
By the way, I really dislike the term "modified sine" that the industry has adopted. It never started out as a sine wave; it's really a modified square wave but that would probably turn off people since they know sine is what the power company provides. "Approximated sine" would be better, but even that is misleading because it's such a rough approximation.
When I get the new UPS, I'll pull a fully charged battery out of my spare UPS to run some tests which will include running a cycle with the Vitalife HOB and a cycle with no load. I'll also measure the dc current being drawn by the battery with the Vitalife connected so I can calculate how many amp-hours I'll need for the final battery selection to reach at least double digit run hours.
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Post by fishfever on Feb 25, 2010 12:39:11 GMT -5
Here's the latest from my "UPS blog", my personal quest for cheap, small, automatic emergency backup power for my tanks. I'm pretty much done with my research and now know it's very achievable to get double digit run hours for your modest-sized primary tank filter for a lot less than a $100 one-time investment. To me that is a small price to pay for fish "health insurance". By the way, I don't know how long a tank can safely go without some sort intervention before the fish undergo excessive stress but here is a web site in the UK that tries to lay this out: www.thinkfish.co.uk/article/Dealing_With_Power_Cuts/It tries to give guidelines for various length power outages. Of course much depends on the livestock (overstock and/or hardiness of stock). Even though it's likely the fish (unless very sensitive species) will probably "survive" even lengthy power outages, the stress may make them susceptible to disease in the days and weeks to come. So IMHO it's a good idea to have some sort of plan for power outages, especially if you live in an area with frequent power outages or potential power cuts. I am thinking the summer may be the worst time if you live in a hot area with strong storms and/or lightning. With room air conditioning cut off, the tank temperature will gradually rise which I believe reduces the available oxygen. This will be even worse with no power and nothing to disturb the water. If the tank is on the highest floor like my fry tank, the temperature will rise more than tanks on lower floors. I travel fairly often, so my solution needs to be automated. Although I started this as a "UPS blog", I can pretty much say this is NOT an effective solution (either run time or cost-wise). Most, if not all computer UPS systems are designed to support much higher loads and are very inefficient running small motors found in filters and pumps. For example in the popular APC line, the smallest and cheapest UPS they have that would give high run times (double digit hours) is nearly $900 (without shipping), weighs over 100 lbs and takes up an enormous amount of space. I'm not even sure the run-time calcuator works with small loads well since the efficiency is approaching zero. Some time back when I abandoned the UPS idea, I started researching inexpensive inverters that would have decent efficiencies with light loads (these inverters are NOT going to work with large loads but I am dedicating the inverter for aquarium use so it doesn't matter). I purchased a small unit from Cobra which in the online manual claimed less than 0.1 Amp standby current. When I received it I connected it up to the UPS battery that gave me about 1 hour run time. I measured 0.3 Amps which drops off somewhat to 0.2X amps once it gets warm. I called Cobra tech support to see if this unit was defective or was this manual in error? It took a few days, but they confirmed the manual was incorrect. So I plan to return it. But while I was waiting for their answer I went ahead and ran two tests because 0.3 Amps standby is still better than the bigger Tripplite inverter I have and probably tons better than the APC UPS. Here are the results using a fully-charged battery from the APC UPS, a 7 Amp-Hour 12-volt battery: Whisper 10 air pump ran for over 22 hours (same battery in UPS only ran 65 mins) Vitalife 200 HOB ran for over 12 hours (same battery in UPS only ran 60 mins) I measured the current draw from the battery with both loads and the Whisper 10 looks roughly like a 1-watt load while the Vitalife 200 HOB looks like a 4.5-watt load. Using these numbers and assuming the new inverter on order is going to meet spec or better (I discussed this with their tech support before ordering) I can estimate using the same battery I can achieve as much as 45-65 hours run-time with the Whisper 10 (fry tank) or as much as 17-19 hours with the Vitalife 200 HOB. Of course sizing the battery up and paralleling more batteries can greatly increase this time. More than 1 filter/pump can be supported (as long as they work with a modified sine) with a corresponding drop in run time (if the battery stays the same). I'm probably going to stick with a 7AH battery because the size is very manageable (less than 6 lbs and about 6"x3.5"x2.5"). I also noticed an interesting effect when running the Vitalife HOB from the inverter. Since the inverter generates it's own 60-Hz that is slightly different in frequency from the AC line, with the house very quiet and my ear positioned close I can hear a faint "zero beat" between the Vitalife motor running off the inverter and the air pumps running off the ac line. I verified this by unplugging the air pumps and listening then unplugging the Vitalife HOB and listening; in both cases you no longer hear the "zero beat"! In the next week or so I'll have the new inverter checked out and will put together the finished unit and will try to take a picture or 2...
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Post by goldenpuon on Feb 25, 2010 17:41:39 GMT -5
This is some great research you are doing here! Though I'm not familar with a lot of this stuff technical wise, it is definitely interesting and very informative to read!
Great work!
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Post by Carl on Feb 28, 2010 13:09:32 GMT -5
If I read correctly, you are achieving these run times with only a 7 AH Battery?
If my numbers are correct my 160 minute reserve batteries are rated at 75-80 Amp Hours (AH), so this is quite good times for this size battery
I looked at the site link you provided, here are a few thoughts in response to this site; *I am surprised that they do not mention Inverters or UPS.
*As well I have never had an issues adding hot water (from tap) to heat an aquarium provide the water is run for a few minutes prior to use (maybe in the UK their pipes are in terrible shape with a lot of corrosion build up)
*I also have suggested to customers that do not have a generator, emergency pump. UPS, etc to simply gently agitate the water by hand. Although this can be a lot of work, I have had countless clients save their fish after long power outages with this procedure
Carl
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Post by fishfever on Feb 28, 2010 22:30:14 GMT -5
Yes Carl, this is the 7AH battery I pulled out of the APC UPS which was only delivering about an hour or so of emergency power when in the UPS. But using it with an inverter that has a much higher efficiency at the low end of the range I'm getting well into double digit run hours... by going higher in AH and/or paralleling additional batteries I could conceivably run without mains power for days, weeks or even months. But double digit run hours should cover me for just about any power outage. I think the worst we ever had was about 10-12 hours when someone (or some utility company) accidentally cut through underground cables. The agitation idea is good too but for me I want to feel safe even when I'm away on a trip or vacation. If the main tank filter is able to run without interruption automatically even through an extended power outage the stress on the fish should be minimal.
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Post by Carl on Mar 1, 2010 10:06:21 GMT -5
I think the worst we ever had was about 10-12 hours when someone (or some utility company) accidentally cut through underground cables. The agitation idea is good too but for me I want to feel safe even when I'm away on a trip or vacation. If the main tank filter is able to run without interruption automatically even through an extended power outage the stress on the fish should be minimal. Most of my experience with power outages for me or my aquarium maintenance clients has also been around this time (although an earthquake in 1987 and 1994 had a few maintenance clients out for a couple days). The agitation method is a last ditch option, as the majority of my clients had at least some sort of a battery backup, back in the 80s & 90s mostly in the form of a 'D' cell battery pump that I added a switch (I purchased these at Radio Shack) to that when connected to AC power it held the switch "open" and it closed (completing the circuit) it automatically switches to the battery pump. These were not great and actually only ran when power went out, however they got the job done. I agree with the security of not worrying about power failures while away or at work; as well many of my clients were also in agreement. I found that most of my maintenance clients realized that the cost of these and a UV Sterilizer often paid for the initial investment when the cost of lost fish was factored in (many of which had more than monetary value to customers). Carl
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