Uninterruptable Power Systems (UPS)

[DrJoe]

All Thanks for your input to my question.

I’ve taken your input and decided to contact APC. Through their website I was able to upload my Eheim Pro # 2080 user manual to them. I asked them for a solution and the following was their respone was: “ An aquarium pump requires a pure sine wave at all times. For this reason, you would need a Smart-UPS which outputs a pure sine wave while on battery. The smallest Smart-UPS we have is the SUA750. I will place a link to it here:
http://www.apc.com/resource/include/techspec_index.cfm?base_sku=SUA750

Because the pump only uses around 30W, you should see around 1 hour and 45 minutes of runtime when the UPS is on battery. “

Also they informed me of their Trade-UPS program where you can take advantage of APC's Trade-UPS program, (Customers may trade in old UPS(s) regardless of brand, for new APC UPS(s), with a full 2 year warranty at up to a 25% discount!. As a benefit to our customers, now you can also buy additional APC accessories including Netbotz, at a significant discount, if purchased along with your Trade-UPS.), You can also view weekly specials, purchase replacement batteries for both UPS units and laptop computers, and also purchase from APC's Factory Outlet Store.

I’m going to look into acquiring a pure sine wave UPS and may rig it if possible with a larger battery like user 10000p did.

Take care in hooking up a higher capacity battery and draining the cell as the recharging circuit is designed for lesser current and will burn it out. The other is heat dissipation. The original unit was only meant to run for "x" amount of time and by extending this period you add to the heat buildup. Installing small fans and possibly extra heatsinking will help with this. (I've done several of these over the years with good success).


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yeah, sad isn't it? It's VERY hard to make a sine wave with any electronics, so, a smart UPS will work fine. Mains AC is a modified sinewave, it is basically smoothed out with the massive capacitance billions of miles of wires has to offer. You may be able to do the same thing with a large(not that large) poly. capacitor or a talatium maybe even a large ceramic. The problem with that is that it will slightly turn it back into DC or have some capacitive resistance therefore lowering the voltage of the electricity or the max. current. I am still fairly new to this and I prefer DC because it is much easier to work with and doesn't hurt as much, just burns. The reason why an aquarium pump requires a sine wave is the same reason a bell requires a sine wave, because it is built for a sine wave. If it was a square wave, then that may be a problem because it may cause the impeller to spin the other way. This is because the impeller in most if not all pumps and AC motors will follow the wave. The electromagnet will go from north to neutral to south and the impeller will follow. If it was a square wave, the impeller may not be able to "catch up" and when the polarity changes again, then the impeller may go backwards, therefore possibly doing an erratic dance. It really depends on your equiptment, the mass of the impeller, the resistance of the water, the form of the wave... really hard sometimes...

oh yes, and by the way.... I just found that on the web, I did not actually do that...

mg:I looked up convoluted and that's exactly what it said :rofl::rofl:

I'm an Electro-Mechanical Engineer and I only understood the words

Dr Joe

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[robbob2112]

I’m going to look into acquiring a pure sine wave UPS and may rig it if possible with a larger battery like user 10000p did.

While I like the idea of cheaply adding bigger batteries for longer life (like the car battery) I would think for safety you would have to have some sort of isolation and current limiting circuit to prevent burning out the charging circuit itself.

Just a note, there are several models of UPS by APC (and others) that are made for a second external battery to be hooked in. From having replaced batteries on the external packs like this at work I can say they do have an electronic circuit board in them and are not just wires and a battery.