DIY UPS setup for Aquarium

So I have been toying with the idea of running my aquarium's critical systems (filter and heater) off a UPS, since the last 11 hour power outage we have had in our area. The UPS I am using is a Meissner and it is a 1400 VA with a maximum output of 840 watt. I reconditioned it and replaced the batteries and cleaned it up since it was a second hand unit with dead batteries:

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I had had a spare male to female kettle cord lying around (the old monitors usually came along with these) I removed the female side and connected a multi plug too it:

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I wanted to somehow bolt it to the side of the UPS so that if there leaks water on the floor the plug wont be lying in it so I took some multi purpose glue and stuck it too the side of the ups so that it stays out of the water, just waiting for it to dry.

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So when I set this up only the mission critical systems will be plugged into it my heater: 200 watts and my HOB filter: 6 watts. If push comes to it I would only run my filter off it. So the drain on the UPS would only be my minimal. The lights I will run off the mains as per usual.

 

Very interesting project. Id like to run one myself for my air pumps and maybe my small wattage flow pumps in my fish room. Could you please add where one would acquire the required components and how much it costs.

 

@Michael11: Will do, my project ran into a small hiccup. In the process of refurbishing the old UPS I must have somehow wired the batteries incorrectly screwing it up. So now I have a smaller unit running a 600 VA with an output of 350 watt. I currently have an small 15 watt fan connected too it. So it is almost triple the consumption of my pump, but it will be a good indication of how long it will last. It has been running since 14:45 and all is good so far:

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Id love to set one up but dont know how much it will set me back.

 

@Michael11: Well let me see how the test goes with this smaller UPS then I can let you know, you can buy a UPS from almost any computer store these days. The only question is how long will a 600 VA last on just running the filter instead of the 1200 VA I wanted to use originally.

 

@Michael11:A 600VA can handle 300W for about 30 minutes, so it should theoretically be able to carry 15W on its own for 10 hours or so. And considering my pump is only 6 watt it could be double the amount. So if I am correct I should get almost a single day out of it.

 

Following ths one.

 

The crucial part which determines the duration your pump/filter/heater will run is the amount of batteries and their capacity you are using.@Swagasaurus -you should give us the battery data for your first and second UPS.What happened to the first UPS?Assuming your 600VA is 600VAh your 6W pump will run 3-4 days.

 

@JCL: I doubt the 600VA's batteries is running @ 600Vah, I reconditioned the first UPS but somewhere I screwed up with the wiring. So I shorted it out, I ran that fan on the 600VA for about 3 hours before it started running low on power considering it is a fan (bad power consumption) and that it is 18 watt. So I should technically get around 12 hours out of it.

Not much but the filter would at least be running for 12 hours longer than it would have if there was a power outage. I will run a proper test over the weekend and see the type of mileage I get out of it once it is hooked up to the filter.

 

UPSs are strange beasts, and difficult to predict how long they will last. If I may, I would like to point out a few things that may assist in sizing/getting the right UPS.

Firstly we need to differentiate between the VA rating of the UPS and the Ah (ampere-hour) rating of the batteries. The VA rating determines the maximum instantaneous power that the UPS can deliver. So in choosing a UPS you need to calculate the total power that you will need from ypur heater, pumps and other items. My guess would be that the heater wpuld be the major contributor, mine is 300W. Lets say it all adds up to 400W. Multiply this by 1.2 to get your VA rating required. In this case it would be 400*1.2=480VA. Choose a UPS bigger than this.

Next you need to determine the size of the batteries in the UPS. Typical office UPSs have between 1-4 batteries that are typically about 7Ah each. Normally the UPS will not completely drain the batteries to zero, so you can work on about 50% capacity, meaning that you have only 3.5Ah available. Lets assume we have a 600VA UPS with two 7Ah batteries. That means we have available a total of 7Ah from the two (half the total of 14Ah).

Since the heater is not on all the time, switching on only if the temp drops below a certain value, lets assume it has a 33.3% duty cycle, meaning that it is on for only a third of the time. The pump and other stuff is on full time, so the total average usage is 200W (100 for the heater and 100W for everything else). The batteries are runing on 12V, so we calculate the total amps being sucked from the batteries by dividing the 200W by 12V, giving us 16.6A. Since the batteries can deliver a total of 7Ah, we expect the UPS to last for about 7Ah/16.6A=0.42h, or 25min.

Be careful with this though, because there are other factors to be considered as well. In the winter this will be less whenyour heater is on for longer. You also have issues like the fact that most office UPSs are square wave types, also reducing your efficiency. I typically add another 20% margin on my calculations just to be safe.

Hopefully this helps a bit?

 

@JJFury: Totally agree with you. UPS is a strange beast, I am only planning on running the most important device on the UPS which would be my filtration. The way I see it the least important would be my lights followed by the heater and then my filtration. Keeping the tank warm wont be an issue, the big issue is the filtration once that crashes it puts all the fish in the tank at risk.

I am field testing it now I got it directly hooked up to my filter since 15:40. Will see how long it lasts under full charge.

 

@JJFury -finally somebody who post a more technical/scientific comment.However, I don't agree in all aspects, UPS systems are not at all unpredictable beasts.They are based on technical design criterias.I can see why you made certain assumptions in your example, however I believe that many roads lead to Rome and would set up my system slightly differently.First of all, a heater is virtually a pure resistive load and it's power factor would be close to 1 so 400W wouldn't really translate into 480VA, however the assumption will be valid for other loads like air pumps, power heads and filter pumps etc.Having said that, it doesn't really matter, every user would have to work out what his requirements are which would obviously depend on a number of factors like tank size, covered or open tank, isolated sides (used by some people in winter) etc etc.There seems to be consensus between a number of people that lights, and to a certain extend heaters aren't that critical but the filtration should keep on running to make sure the good bacteria will stay alive.Regarding heating, I would install one heater connected to the mains power supply and a second heater to the UPS which would be set to a few degrees lower than heater 1 (depending on the type of fish involved).This would in essence ensure that during a power failure the tank would initially be left 'to itself' wrt heating and as such ensure that the UPS isn't run dry by the biggest consumer. So the UPS will at first only keep the filtration going and only after a while (which will be different in each case) and could well be 1-2 days only, the tank will have cooled down to the point where the 'UPS connected' heater comes in.This will substantially extend the duration the UPS will keep on running.As I already stated in my earlier response, the batteries will determine how long the UPS can 'keep going'.As @JJFury stated, most UPS are supplied with a number of batteries, however there are units which use external batteries (as opposed to built in ones). This setup will allow for greater flexibility. Also whether normal batteries or deep cycle batteries are used would be of relevance.The 7Ah batteries mentioned in above example seem fairly small, I have some motorbikes with 20Ah batteries and these aren't really that big.If I were to install a UPS I would certainly go for 2-3 car sized batteries.@Swagasaurus -Still waiting for the data on your batteries (quantity and Ah rating).There isn't really much point in telling us how long your fan ran, this will be a function of the quantity and capacity of your batteries, whether they were fully or only partially charged, in good condition or not and a few more factors (UPS efficiency, power factor of loads etc)Also would like to hear more on your wiring mishap which blew your 1200VA UPS. What the heck did you do?Finally I would like to mention something @JJFury touched on already, the fact that some UPS may not generate a 'pure' sinusoidal waveform but more of a square wave form. Some manufacturers specify that their UPS will supply 'pure' power which can be used to power any power consumer and their usually much cheaper models will generate a 'simpler' power supply not suited to running certain consumers like motors.Keep this in mind when choosing your UPS and wanting to run a power head or filter pump.

 

Glad to report I get about 12 hours of operating time out of it, which is pretty good considering the small size of the UPS.

 

Mounted the plug against the side of the UPS and installed it next to my tank neat and tidy, and when the power cuts I don't need to worry about my filtration when I am not home:

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Wow, that is quite impressive for the little UPS. Well done.

@JCL, you are quite correct, but I believe that the power requirements for most of the pumps we use in our hobby is small enough that it won't matter. Correct me if I am wrong, but I understand that the issue with motors on a square wave UPS is that they run warmer than usual? This migt be an issue if you run a pump long term, or if you drive a hard working motor like a compressor motor in a fridge, but I suspect that most return pumps run quite a bit under their full capacity and should be able to handle the 12 hours odd from time to time.

 

I would also like to add that magnetic drive pumps are some of the most power efficient pumps you can find anywhere. And when running there is less electricity wastage than normal pumps.

 

Really weird for me to see someone doing something like this. Awesome idea m8.

 

Well, you brought the issue up of the square wave output and I just emphasised this. There are differences between ups and ups (clean vs dirty power, cheap and nasty models vs expensive high tech) and that I came across a vendor's website where they specifically mentioned that some of their UPS were not suited for certain loads (like motors).Yes the motors would run hotter due to the square wave but you might well be correct that the relatively small return pumps (we are usually talking pumps of a few watts to perhaps up to 50-70watts max) would cope with the waveform, especially as they are imersed in water and driven by the UPS for a limited amount of time only.I wish I had a few UPS to play around and check their output with my osciloscope, but unfortunately I haven't.However there may well be another point to consider which would shoot down your assumption that the motors will only be run from the UPS for a short time.When connecting the filter motor to your UPS (like @Swagasaurus did), isn't it driven by the UPS all the time? I think so (I am sure there are again differences between various designs). When driving a PC you can't afford to have a 'warm switch over' otherwise the PC will reboot during it. So the PC is supplied by the UPS output whether the supply voltage is present or not. As such whatever output form the UPS generates (pure sinus or square wave or mixture) will be fed to your PC (or whatever you connect to it). In that case one would need to look into the long term effect and how it effects the life-span of the pump.I will look into this issue in a bit more detail in the near future, but perhaps the answer isn't a UPS at all but a battery bank topped up by a trickle charger and driving an inverter. Will report back.

 

Hehe, well, hence my initial comment that UPSs are strange beasts...

There are two types of UPS, online and offline. The online type basically feeds the output directly from UPS all the time as you described. The offline type swithces main power to the output until it fails and then switches to UPS power, if that makes sense. They actually switch over so quickly that the PC wont even notice it, no warm up required as is the case with generators. The most run-of-the-mill desktop UPS are offline types. The online UPS are more expensive and are more typically used in server environments or where they have 'dirty' power, ie low voltage, surges and spikes.

A battery bank with dedicated charger and inverter is by far the best, but this becomes pricey.

Personally I use an APC 1200 VA pure sine-wave UPS, also offline type, to which all my aquarium and TV stuff is connected. It can run my 32" tv with surround sound and all the aquarium stuff for about two hours. If the TV is off it will probably do quite a bit more.

 

@JCL: I think you are over thinking and over complicating things a bit I have multiple companies running sensitive equipment worth millions of rand's on UPS's of all shapes and sizes. And contrary to your statement all of the equipment still works perfectly fine when you consider the equipment is about as sensitive as it gets.and these devices are connected too the equipment 24/7.

The pump is not running off the UPS even though it is connected. When it is connected with the power up the UPS acts as a bridge between the AC power and the device. Smart-UPS uses "line-interactive" technology - it still means there is a relay in the circuit, so you still get a small break in power supply, but a Smart-UPS also incorporates a transformer that gives additional filtering for mains interference such as spikes & RFI, and it also can give boost/reduce by automatically tapping or removing another coil on the transformer to reduce the impact of brownouts or surges. They also give a sinewave output rather than squarewave.