back up power systems

Bean, I'm not trying to be a pest either. Just curious. The price of the batteries was not really my main concern. The rest of the post was what I was really interested in hearing your opinion. That is...

This APC unit is puts out a sine wave waveform (according to the APC website tech specs), so would you still deem it "unsuitable"? Is there another reason not to use it, other than the waveform, such as the trim specs as mentioned by Mac?

Thanks, Greg
 
Some APC units put out a true sine wave (standard AC power like what comes out of the 120 VAC receptacles in your house). They are much more expensive than the basic models. Be sure it says "True Sine Wave" on the data plate or the box. Other basic UPS units put out a "square" wave that approximates this wave. While this is okay for computers -- which convert the energy over to 12VDC and 5VDC before they use it -- it will put your inductive loads like motors through pure hell. The RMS voltage (the apparent voltage amplitude seen by the motor) will be significantly higher than a mere 120 V. This alone will cause extra wear and tear on the motor winding insulation. The "squareness" of the UPC waves, though, do the most damage by causing excessive heating.

For a mechanical analogy, think of it as driving over a series of square speed bumps instead of nicely rounded ones. The vibrations in your car would be much greater. Same thing in the rotation of a motor. Instead of a smooth rotation, you'll have 120 "jerks" (2 times 60 Hz frequency) per second as the motor tries to accomodate the poor waveform.
 
Thanks Runner, that makes more sense to me. So that's only an issue when running off battery, right? During normal operation, most units should run off line voltage, right?
If the APC unit I happen to have, says:

Waveform type: - Sinewave
Click to expand...

then that should mean I have one of the higher quality units you mention, and not suffer from this type of problem?
Thanks for clarifying things, the mechanical explanation helps me get my mind around it.

- Mac
 
Runner said:
For a mechanical analogy, think of it as driving over a series of square speed bumps instead of nicely rounded ones. The vibrations in your car would be much greater. Same thing in the rotation of a motor. Instead of a smooth rotation, you'll have 120 "jerks" (2 times 60 Hz frequency) per second as the motor tries to accomodate the poor waveform. [/B]
Click to expand...

Hey Runner, that's a nice analogy... i've had a hard time explaining this myself... besides just a "because they're meant to run on a pure sine wave"... which doesn't help someone very much:-) There's no easy way to explain the difference between an inductive load (motor) and other electronics.

When using modified sine wave UPS'... in addition to not being good for the pump and running hotter/louder, how much does it reduce the amount of battery time you get vs. when there's an equivalent non-inductive load?

Also, I'm guessing the popular inverters that are now found at all walmarts, bestbuys, etc... are a similar situation... most produce a modified sine-wave... correct?
 
What you have at Walmart and the like would most likely be a square wave or close to it.

If it doesn't say "True Sinewave" somewhere, I wouldn't feel comfortable with using it for motor loads. If it just says "sinewave", it could be a modified square wave to approximate a sine wave. Better than a square wave, but not a smooth sinewave curve. A true sinewave UPS is much more costly and they usually make a big deal out of it on the cover of the box.

Then again, APC seems to use "sinewave" to mean a true sinewave in their specifications:

Go to this link and check out the APC UPS products:
http://www.apc.com/products/category.cfm?id=13

Open up one of the PDF user manuals and look at the Specifications box. One of them I looked at said the unit was a "stepped sine wave". Such an thing is what you should avoid for inductive loads. On one of the industrial models, it says "sinewave" one a model that would definitely be a true sinewave.
 
ReeferMac said:
Thanks Runner, that makes more sense to me. So that's only an issue when running off battery, right?
Click to expand...
Exactly. These little units are in bypass mode until the power fails. The 100% online UPS units generate a true sine wave, anyway.
 
My understanding of the APC line is that the "Smart UPS" line is all true sine wave. The "Backup UPS" line is not.

That being said, I have a Backup UPS (1000kva) o my system. The only thing is runs is one Tunze 6100. It needs to be the one that is in the first port of your multicontroller.

The beauty of the setup is that the 6100 uses a transformer and driver so the modififed sine wave isn't a problem. It's also very low power so I get a lot of circulation out of one device in failed mode.

Cheers
 
Thanks runner... I hate trying to explain that!


NOW FOR A HOLE HOST OF ANSWERS:

1) Yes most cheap inverters do not offer a true sine wave.

2) There are many types of UPS. Cheap UPS systems are "single conversion". They have an internal relay that connects the batteries to the circuit when there is a loss of power. So during normal operation, the inverter and bateries are not "in the loop"

A "dual conversion" unit converts ALL of the AC power into DC, then BACK to AC. The inverter is always part of the circuit. These are better units, as the switchover time is less and the power seen by the end device never changes regardless of the source.

There are other types the are hybrids of the two listed above.

3) "true sine wave" stickers and lables mean nothing. NO JOKE some of the cheap units use the sticker to indicate the INPUT, not the outpu!

4) Run time is dependant on load. The better UPS systems have smart voltage and current regulators. They manage output and the amount of energy that is being coverted to AC. This is why most manufactures have several lines of UPS. Better battery managment and better output waveform.

5) Not to muddy the waters further but even true sine wave units may suffer nasty output (square wave) when a complex load (read inductive motor) is hooked up. Most of these units are simply not designed to run an electric motor.

6) Larger pumps have HUGE INRUSH currents. In other words to start spinning they draw many times their rated current. This is enough to smoke many UPS inverters... IN OTHER WORDS... DO NOT TEST YOUR UPS ON A MOTOR THAT IS NOT SPINNING!!!!!

LET ME REPEAT THIS!!!!

DO NOT hook up your pump to the UPS and turn the pump on without FIRST letting the AC power spin up the pump. With a dual conversion unit... this can pose a problem, as the inverter is ALLWAYS online!

All in all... this is why we don't use COMPUTER UPS systems for aquarium backup.

This is why MOST FOLKS that have used them find that they eventualy fail.

Bean
 
I think the big issue here is people trying to run loads that really are unnecessarily, i.e. the return pump.

Why bother? You'll need a massively large UPC setup to get any more than a few minutes time out of UPC, you'll be running the motor very rough as well. Now, I understand if you have no other option for keeping the water moving in the display tank, but really, a simple tunze stream on a UPC drawing some 20 watts would be able to last days on the same size UPC you'd need to run an iwaki 55 for 2 or 3 hours.

Really, all we are trying to do is ensure that the water keeps moving. You don't need lights, don't need skimmers, don't need heaters, only need to keep water moving. Anything more and you've got to go with a generator.

For the price of a setup to run a big iwaki for a few hours, you could probably buy a small tunze stream and decent UPS. Not only do you get a new neat toy for your tank, but you get a reliable backup flow system that will last many many hours.

I'm sure tunze never intended their product to be used this way, but with 1600+ gph flow for some 17w.. How can you go wrong?

jb
 
grim said:
I think the big issue here is people trying to run loads that really are unnecessarily, i.e. the return pump.

Why bother? You'll need a massively large UPC setup to get any more than a few minutes time out of UPC, you'll be running the motor very rough as well. Now, I understand if you have no other option for keeping the water moving in the display tank, but really, a simple tunze stream on a UPC drawing some 20 watts would be able to last days on the same size UPC you'd need to run an iwaki 55 for 2 or 3 hours.
...
jb
Click to expand...

I thought the same thing and is why i asked the question about whether an inductive-load drains the battery faster than the same wattage resistive load. I tried running just two maxijet's (about 25watts) on a UPS and only got 5 hours of runtime. It was an APC 1500VA "backup UPS". Based on calculations, I expected many more hours. The only conclusion I can come to is that it is very inefficient at running inductive loads.

I still haven't seen any other comments regarding the Tripp Lite APS512, but I think this is the best "auto transfer" soultion for the bucks.
 
How old is your APC UPS? How many times has it been tripped? How many times has it gone to discharge?

jb
 
new from best buy... started with an APC 725VA (BE725BB) and only got 1hr 15mins, then tried APC 1500VA (BX1500). The later cost $200.

IMO, the $$$ per hours runtime doesn't justify the UPS solution for my needs. The Tripp Lite APS512 with a 12volt ~100Ah marine battery solution @ about $350 is the cheapest auto-transfer solution with an adequate runtime that I've found.

Since this is the DIY forum, I guess I'll acknowledge the Playfair's DIY solution is still probably the best bang-for-the-buck:-)
 
thanks for all of the information guys - great thread - very helpful -

as far as the sine wave and its true form or not, does the following description indicate a true wave or not?

LINE POWER (AC): Maintains 120V nominal sine wave output. INVERTER POWER (AC): Maintains PWM sine wave output voltage of 120 VAC (+/-5%). DC CHARGER OUTPUT (See battery recharge rate section)
 
PWM can wear down the windings of a motor faster than usual, but it does a decent job of approximating a sine wave. And it can turn motors. True on-line UPS units use PWM. Hopefully this device is approximiating a 60 Hz, 120 VAC sine wave with PWM, but a can't be 100% sure unless I can look at the technical data.
 
okay - i wanted to put together a good backup using the deep cycle batteries in parallel, if i use the following:

quality inverter to produce true sine wave or as close as i can get, the switching device to go to battery power, the charger to maintain the battery -

i can find the inverter (although, the best one i can find is the pwm wave), charger - where or what do i use to detect the loss in power and switch to go to battery power?

a 2nd question, is there any harm in using a setup that has more power than i want - instead of a 500 watt system, like a 2000 watt system?? thanks.
 
question: If what I'm really looking for is something to run a heater and one small pump (say a maxi-jet 1200) is there an easy off the shelf solution?

I live in the mountains in Colorado. If the power goes out during the winter, my tank could easily be SOL if the heaters arent powered. Obviously some minimal water movement is desirable too. What do you guys think?
 
LovetoReef, you're looking for an auto - transfer switch. Best to have an electrician install that for you.
No, over-powering isn't a problem, the system will just run longer.

emoutz, I'd go w/ an APCC unit. Will buy you a couple of hours, and you can completely forget about it for about 2-3 years after you get it hooked up.

- Mac
 
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