Invest in a UPS!!

CanadianReef · 08/21/2006, 12:05 PM

If you haven't yet I recommend adding a quality UPS to your power system. APC makes a number of units that give you an option of the sign wave shape you want. If you match the wave shape to the power consumption of your pumps you can increase their efficiency, reduce heat, and thereby reduce wear. Iam using a gen-x that is almost silent.

King-Kong · 08/21/2006, 12:41 PM

Can you help a mook like me out; what's this sine wave business in relation to choosing a battery backup?

CanadianReef · 08/21/2006, 12:50 PM

Power comes in a wave. The wave relates to the phase of the power, the reason power is called AC is because it is alternating current. 60 times a second it changes phase from one extreme to the other. But the way it does it could look like a nice smooth ocean wave or it could look like stair steps. Expensive electronics like home theatres, electric motors, anc computers all like a particular type of "wave." My main pumps perform coolest with a perfect sine wave, the power heads like a staircase(called a square wave).

You didn't need to know all that, just know that bad power comes into our home, your devices are slightly hurt by it, or at least perform crappier. A device that can give them gourmet power will make them work better.

CanadianReef · 08/21/2006, 12:52 PM

Recommendations are the APC Smart-UPS brand. They are reliable and there are lots of them on ebay cheap $100+. I have 1 on my tank that feeds all the pumps (lights don't need it) and I can withstand 24 hours of power loss with the only loss being that my lights are off. Came in very handy a few times.

King-Kong · 08/21/2006, 01:12 PM

Thanks for the info. I was just examining this the other day.

Reason is I just purchased a vortech pump, and a battery backup is sold by the company as a $150 accessory (30hr run time @ 50%->10% power). I figured that for $150 I could put together a small array of APC's and probably get more run time, but looking at the specs on the APCs made me question it.

My power also went out the other day and my main PC (350w PSU) was running on my APC 500 for about 10-15 minutes before I got up to shut if off. After it shut off I switched my vortech to it and ran it at about 50% for probably another 30-40 minutes before power was restored.

What kind of UPS/APC should I look for to run a 15w-40w powerhead for long durations?

plandy · 08/21/2006, 01:21 PM

Yep, I just put in an order for APC SmartUPS 1500VA

We get a lot of power outage around here

So I am not taking any chances with my new 90 gallon reef life with tons of expensive stuff at risk.

Thanks,

BeanAnimal · 08/21/2006, 01:37 PM

Guys.. this keep coming up and there is a lot of bad info out there.

First:

Computers and other equipment does not care what type of waveform is fed into it. They use switch mode power supplies that do not rely on the shape of the waveform to operate.

MOTORS on the other hand rely 100% on the smooth transisiton from postive 60 volts to negative 60 volts 60 times a second. The net voltage per swing is 120volts. The "sine wave" looks like a smooth set of peaks and valleys with gentle cuves and no sharp corners. Cheap INVERTERS aproximate this shape using a series of stair steps. The worst being a single step from peak to peak... the better ones have a large number of little steps.

The more malformed the "sine wave" from these cheap inverters, the harder a motor (and inverter) have to work to keep spinning.

The APC smartups units put out a modified sine wave (step wave as mentioned above). It has a lot of steps in it.. but it is still not a sine wave.

I am an APC channel partner (as well as LIEBERT and some others). The smart UPS units are at best suitable for a small power head. Running larger pumps on them is NOT a good idea and can lead to UPS or PUMP damage very quickly. Worst case, the UPS may catch on fire do to overloaded outputs. Please not that when this happens, the unit does not usually kick the breaker, as the overload is not really a result of over current.

We can get into a long discussion about what is inside a smart ups (or other similar unit) and why it is alomst 100% not suited to run a motor. The bottom line is (not matter what some of you might think) that these units are just not a good idea to use in this situation.

Do as you wish, but please take "I use an APC on my setup without problems" FWIW. It is an uniformed opinon and simply misuse of a product that may have very serious implications.

If you insist on running a return pump on a UPS please consider the LIEBERT GXT2 series (true sine wave and built like brick outhouses). TrippLite also makes some very good true sine wave products that are more industrial and suited to exactly what you are trying to do.

Not trying to beat anybodies idea up... but some "ideas" are not good ideas, no matter how well they sound and appear to work at first try.

CanadianReef · 08/21/2006, 01:46 PM

Hey, you are first to know anything better, so thank you. I will look into that. Just to put current equipment to use; in your opinion are the smartups useful for powerheads or will they cause damage to the ups? Also, if the draw from the pumps is less than 15% of the rated throughput is there any danger using an APC for power interupts which happen every 4-5 days for a couple minutes at a time(storm brownouts)? APCs are not constant on, they jump in when the power is cut correct? So running the power through it until I can get a more suitable supply would not be doing cumulative damage to the UPS? Lot of question, sorry, but you know more than I so I must ask.

To be clear, I am planning to change, just thinking about the short interim.

King-Kong · 08/21/2006, 02:23 PM

Quote:

Originally posted by BeanAnimal
Guys.. this keep coming up and there is a lot of bad info out there.

First:

Computers and other equipment does not care what type of waveform is fed into it. They use switch mode power supplies that do not rely on the shape of the waveform to operate.

MOTORS on the other hand rely 100% on the smooth transisiton from postive 60 volts to negative 60 volts 60 times a second. The net voltage per swing is 120volts. The "sine wave" looks like a smooth set of peaks and valleys with gentle cuves and no sharp corners. Cheap INVERTERS aproximate this shape using a series of stair steps. The worst being a single step from peak to peak... the better ones have a large number of little steps.

The more malformed the "sine wave" from these cheap inverters, the harder a motor (and inverter) have to work to keep spinning.

The APC smartups units put out a modified sine wave (step wave as mentioned above). It has a lot of steps in it.. but it is still not a sine wave.

I am an APC channel partner (as well as LIEBERT and some others). The smart UPS units are at best suitable for a small power head. Running larger pumps on them is NOT a good idea and can lead to UPS or PUMP damage very quickly. Worst case, the UPS may catch on fire do to overloaded outputs. Please not that when this happens, the unit does not usually kick the breaker, as the overload is not really a result of over current.

We can get into a long discussion about what is inside a smart ups (or other similar unit) and why it is alomst 100% not suited to run a motor. The bottom line is (not matter what some of you might think) that these units are just not a good idea to use in this situation.

Do as you wish, but please take "I use an APC on my setup without problems" FWIW. It is an uniformed opinon and simply misuse of a product that may have very serious implications.

If you insist on running a return pump on a UPS please consider the LIEBERT GXT2 series (true sine wave and built like brick outhouses). TrippLite also makes some very good true sine wave products that are more industrial and suited to exactly what you are trying to do.

Not trying to beat anybodies idea up... but some "ideas" are not good ideas, no matter how well they sound and appear to work at first try.

So what do you think they are running here, for such a "cheap" price, yet with such long performance:

http://www.aquariumspecialty.com/cat...f8cce43d50231d

BeanAnimal · 08/21/2006, 02:29 PM

They should be ok for powerheads. I am sure some people have small return pumps connected up to them as well.

Let me put it this way. I can get the SmartUps for a LOT less than you guys... and I would never dream of putting one on my tank. To prove the point to somebody last year, I hooked up a CyberPower 1500 (and a 900) to mag 9.5 both of them burned inside within 5 minutes. The SmartUPS would likely fair a little bit better... but it is still not designed to handle such loads PERIOD.

APC units are "Standby" and some are "Line Interactive" NONE are "online".

Let me explain.

STANDBY: The unit is stupid. When mains power fails, a relay switched the batteries into the inverter and the inverter powers the output. The units OUTPUT is driven by the batteries during an outage. At all other times, the UPS does NOTHING but charge the batteries.

LINE INTERACTIVE: The unit monitors the AC mains power and filters it. When it sags, it boosts the power by fiddling with the waveform (very bad for motors! PC PSUs could care less). When the voltage spikes, the unit uses a bucking circuit to (inductors) to modify the output voltage by lowering it to the correct level. Beyong a certain threshold or during a mains outage the DC buss powers the inverter. The inverter then powers the output. Any unit you see that has "AVR" (automatic voltage regulation) uses this BUCK/BOOST technology. Something you 100% do not want to use on a motor.

ONLINE (AKA double conversion): In these units, the mains power is emmediatly converted to DC through a rectifier, from there it powers the DC bus and also charges the batteries. The KEY point is that the DC BUS is ALWAYS powering the inverter and the inverter is ALWAYS what provides the power ot the OUTPUTS. The batteries and DC bus are always part of the circuit. Voltage swings on the input are taken care of by the smart DC bus and the sine wave never varies, no matter what the input voltage. When the mains dissapear, there is no switchover, as the DC BUS is already doing all the work.

Now... I don't know of ANY ONLINE ups systems that don't output a TRUE sinewave. They cost to much to do anything less! Some standby units offer true sine wave (tripp lite). You should stay away from the Line Interactive units because of the issues with voltage regulation and what it does to the output sineave during brownouts or spikes.

You may want to consider a GOOD inverter that does SINE WAVE and a few good batteries and a relay. There are plenty of DIY UPS systems you can find (I think PLAYFAIR here at RC did a decent one). The nice thing about car batteries is that they are cheap, can be charged in the CAR during a long outage and provice much better power than a dekstop UPS.

The VA rating of the UPS is not a measure of how long it will run... but the load that it will handle. Even though a motor is nowhere near the MAX rating of most small UPS systems, it can still damage them due to excess current draw as a result of the horrible output regulation on a UPS that is designed to run switchmode PSU, not big honkin AC motors.

Hope this helps.

BeanAnimal · 08/21/2006, 02:32 PM

Quote:

Originally posted by King-Kong
So what do you think they are running here, for such a "cheap" price, yet with such long performance:

http://www.aquariumspecialty.com/cat...f8cce43d50231d

Umm those appear to be 12V DC pumps... they battery units likely just have some smarts in them so they can interface between the controller and the pumps. When the mains fail, the controlller fails and the little battery packs take over.

King-Kong · 08/21/2006, 03:23 PM

The power connector for the pump itself has a converter (inverter?) on it -- would this make running my own UPS on it a different case than most other pumps, such as the concerns you listed up above?

wsurf4me · 08/21/2006, 04:17 PM

If the pumps and controller are DC shouldn't you be OK? I've always heard you could run Tunze streams off of a UPS because they're DC, not sure about the Vortec.

BeanAnimal · 08/21/2006, 04:47 PM

IF the pumps and controller are DC, you should be OK. The only problem may occur of the controller itself is designed to work off of the peak of the AC sine wave. The step wave can case such circuits to behave in an eratic way. In this case I doubt you would have a problem.

theatrus · 08/21/2006, 04:56 PM

If you're going to augment any battery backup system, invest in deep-cycle batteries. Normal car batteries just aren't made for being discharged and recharged over most of their storage energy, while deep cycle can be (just never ever totally deplete a lead acid battery)

Lutefisk · 08/21/2006, 04:59 PM

Quote:

Originally posted by wsurf4me
If the pumps and controller are DC shouldn't you be OK? I've always heard you could run Tunze streams off of a UPS because they're DC, not sure about the Vortec.

My Streams appear to work just fine on a "modified sine wave" inverter. Maxi-Jets, Mags, etc. may work but they sure make a racket and understanding the effects of a stepped sine wave in inductive situations I don't run them on the inverter.

Paul

breedingroom · 08/21/2006, 09:04 PM

following along..........

lastin1 · 08/21/2006, 11:05 PM

Quote:

Originally posted by BeanAnimal
MOTORS on the other hand rely 100% on the smooth transisiton from postive 60 volts to negative 60 volts 60 times a second. The net voltage per swing is 120volts.
[/B]

Where did you get that information from? 120 volts is derived from RMS of ~170 volts. The A.C. current peaks at ~170 volts and switches 60 times per second. If you place a diode in line with household power and connect a capacitor to it, the measured D.C. voltage should be close to 170 volts. The diode chops one side of the A.C. current and the capacitor charges up to the peak of the sinusoidal wave.

BeanAnimal · 08/22/2006, 07:28 AM

Lastin1 it was a simplified illustration of an AC signal... . and I guess I should have stated the clearly esp when talking about voltages. I guess people do read stuff and "take it to the bank" without understanding the context (which I should have noted).

I surely did not think there was a need for a discussion about RMS voltage and actual peak to peak values or the true peak value and RMS voltage to illustrate what the motor sees, which in the end is a 120V swing that needs to be smooth. I should have put more thought into my explanation... as it appears it was not very usefull.

I am very aware of the RMS voltage and the peak voltage (somewhere right around 169.7 for 120V) I am also very aware of how diodes work and how to derive DC from an AC signal.

Lutefisk · 08/22/2006, 09:03 AM

Quote:

Originally posted by BeanAnimal ...
MOTORS on the other hand rely 100% on the smooth transisiton from postive 60 volts to negative 60 volts 60 times a second. The net voltage per swing is 120volts. The "sine wave" looks like a smooth set of peaks and valleys with gentle cuves and no sharp corners. Cheap INVERTERS aproximate this shape using a series of stair steps. The worst being a single step from peak to peak... the better ones have a large number of little steps.
...

Quote:

Originally posted by lastin1
Where did you get that information from? 120 volts is derived from RMS of ~170 volts. The A.C. current peaks at ~170 volts and switches 60 times per second. If you place a diode in line with household power and connect a capacitor to it, the measured D.C. voltage should be close to 170 volts. The diode chops one side of the A.C. current and the capacitor charges up to the peak of the sinusoidal wave.

I think BeanAnimal was focusing on the wave form rather than the magnitude of the signal. Obviously both are important but while less expensive inverters and UPS's may be acceptable in the area of voltage they tend to fall short of producing an appropriate output for AC motors.

AC motors are designed for a constant rate of change in the voltage rather than the theoretically infinite rate of change of modified sine waves as they "step" from one voltage to the next and the esentially zero rate of change as the voltage remains the same before the next "step".

To use a faulty analogy, using a modified sine wave on the AC motors that most of our pumps use is like turning the pump by hitting it with a small hammer many times per minute while a true sine wave is like a steady constant push.

All that being said, in a pinch, like post hurricanes here in Florida, I run a minimal number of pumps on a modified sine wave inverter and deep cycle battery. You can hear them "growl" when powered off the inverter but I haven't had one fail on me (I do have some pumps that won't run on the inverter but some, such as Maxi-Jets do). My Tunze streams do just fine on the inverter output (I understand that they are actually DC motors which is how they are so easily able to change their speed).

Paul

rdmpe · 08/22/2006, 01:47 PM

Since true sine inverters are a lot more expensive than the mod form inverters, what would you guys recommend for "headroom" when running pumps? For instance, my Dart pumps supposedly pull 160 watts max and I have a mag 9.5 that does about 90 watts I think. If I just wanted to run a single dart I would probably be fine with a 300 watt true sine wave inverter right? Should I figure about twice the running motor wattage for an inverter?

Also, there are some nice inverter/chargers out there geared toward RV's, auto switchover, etc. but $$$.

08/21/2006, 12:05 PM	#1
CanadianReef Registered Member Join Date: Aug 2006 Location: Temple Terrace, FL Posts: 154	Invest in a UPS!! If you haven't yet I recommend adding a quality UPS to your power system. APC makes a number of units that give you an option of the sign wave shape you want. If you match the wave shape to the power consumption of your pumps you can increase their efficiency, reduce heat, and thereby reduce wear. Iam using a gen-x that is almost silent. __________________ -Ken Current Tank Info: 90Gal reef, Dolphin pump, PVC framed aquascape

08/21/2006, 12:50 PM	#3
CanadianReef Registered Member Join Date: Aug 2006 Location: Temple Terrace, FL Posts: 154	Power comes in a wave. The wave relates to the phase of the power, the reason power is called AC is because it is alternating current. 60 times a second it changes phase from one extreme to the other. But the way it does it could look like a nice smooth ocean wave or it could look like stair steps. Expensive electronics like home theatres, electric motors, anc computers all like a particular type of "wave." My main pumps perform coolest with a perfect sine wave, the power heads like a staircase(called a square wave). You didn't need to know all that, just know that bad power comes into our home, your devices are slightly hurt by it, or at least perform crappier. A device that can give them gourmet power will make them work better. __________________ -Ken Current Tank Info: 90Gal reef, Dolphin pump, PVC framed aquascape

08/21/2006, 12:52 PM	#4
CanadianReef Registered Member Join Date: Aug 2006 Location: Temple Terrace, FL Posts: 154	Recommendations are the APC Smart-UPS brand. They are reliable and there are lots of them on ebay cheap $100+. I have 1 on my tank that feeds all the pumps (lights don't need it) and I can withstand 24 hours of power loss with the only loss being that my lights are off. Came in very handy a few times. __________________ -Ken Current Tank Info: 90Gal reef, Dolphin pump, PVC framed aquascape

08/21/2006, 01:21 PM	#6
plandy Registered Member Join Date: Jul 2006 Location: Schenectady, NY Posts: 411	Yep, I just put in an order for APC SmartUPS 1500VA We get a lot of power outage around here So I am not taking any chances with my new 90 gallon reef life with tons of expensive stuff at risk. Thanks, __________________ Peter Landy Schenectady, NY Recent Returnee to the Marines! 12gl Aquapod New "custom euro" 90 gallon under construction!

08/21/2006, 01:46 PM	#8
CanadianReef Registered Member Join Date: Aug 2006 Location: Temple Terrace, FL Posts: 154	Hey, you are first to know anything better, so thank you. I will look into that. Just to put current equipment to use; in your opinion are the smartups useful for powerheads or will they cause damage to the ups? Also, if the draw from the pumps is less than 15% of the rated throughput is there any danger using an APC for power interupts which happen every 4-5 days for a couple minutes at a time(storm brownouts)? APCs are not constant on, they jump in when the power is cut correct? So running the power through it until I can get a more suitable supply would not be doing cumulative damage to the UPS? Lot of question, sorry, but you know more than I so I must ask. To be clear, I am planning to change, just thinking about the short interim. __________________ -Ken Current Tank Info: 90Gal reef, Dolphin pump, PVC framed aquascape Last edited by CanadianReef; 08/21/2006 at 02:05 PM.

08/21/2006, 12:41 PM	#2
King-Kong Registered Member Join Date: Oct 2004 Location: Gainesville, FL Posts: 2,346	Can you help a mook like me out; what's this sine wave business in relation to choosing a battery backup?

08/21/2006, 01:12 PM	#5
King-Kong Registered Member Join Date: Oct 2004 Location: Gainesville, FL Posts: 2,346	Thanks for the info. I was just examining this the other day. Reason is I just purchased a vortech pump, and a battery backup is sold by the company as a $150 accessory (30hr run time @ 50%->10% power). I figured that for $150 I could put together a small array of APC's and probably get more run time, but looking at the specs on the APCs made me question it. My power also went out the other day and my main PC (350w PSU) was running on my APC 500 for about 10-15 minutes before I got up to shut if off. After it shut off I switched my vortech to it and ran it at about 50% for probably another 30-40 minutes before power was restored. What kind of UPS/APC should I look for to run a 15w-40w powerhead for long durations?

08/21/2006, 01:37 PM	#7
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	Guys.. this keep coming up and there is a lot of bad info out there. First: Computers and other equipment does not care what type of waveform is fed into it. They use switch mode power supplies that do not rely on the shape of the waveform to operate. MOTORS on the other hand rely 100% on the smooth transisiton from postive 60 volts to negative 60 volts 60 times a second. The net voltage per swing is 120volts. The "sine wave" looks like a smooth set of peaks and valleys with gentle cuves and no sharp corners. Cheap INVERTERS aproximate this shape using a series of stair steps. The worst being a single step from peak to peak... the better ones have a large number of little steps. The more malformed the "sine wave" from these cheap inverters, the harder a motor (and inverter) have to work to keep spinning. The APC smartups units put out a modified sine wave (step wave as mentioned above). It has a lot of steps in it.. but it is still not a sine wave. I am an APC channel partner (as well as LIEBERT and some others). The smart UPS units are at best suitable for a small power head. Running larger pumps on them is NOT a good idea and can lead to UPS or PUMP damage very quickly. Worst case, the UPS may catch on fire do to overloaded outputs. Please not that when this happens, the unit does not usually kick the breaker, as the overload is not really a result of over current. We can get into a long discussion about what is inside a smart ups (or other similar unit) and why it is alomst 100% not suited to run a motor. The bottom line is (not matter what some of you might think) that these units are just not a good idea to use in this situation. Do as you wish, but please take "I use an APC on my setup without problems" FWIW. It is an uniformed opinon and simply misuse of a product that may have very serious implications. If you insist on running a return pump on a UPS please consider the LIEBERT GXT2 series (true sine wave and built like brick outhouses). TrippLite also makes some very good true sine wave products that are more industrial and suited to exactly what you are trying to do. Not trying to beat anybodies idea up... but some "ideas" are not good ideas, no matter how well they sound and appear to work at first try.

08/21/2006, 02:29 PM	#10
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	They should be ok for powerheads. I am sure some people have small return pumps connected up to them as well. Let me put it this way. I can get the SmartUps for a LOT less than you guys... and I would never dream of putting one on my tank. To prove the point to somebody last year, I hooked up a CyberPower 1500 (and a 900) to mag 9.5 both of them burned inside within 5 minutes. The SmartUPS would likely fair a little bit better... but it is still not designed to handle such loads PERIOD. APC units are "Standby" and some are "Line Interactive" NONE are "online". Let me explain. STANDBY: The unit is stupid. When mains power fails, a relay switched the batteries into the inverter and the inverter powers the output. The units OUTPUT is driven by the batteries during an outage. At all other times, the UPS does NOTHING but charge the batteries. LINE INTERACTIVE: The unit monitors the AC mains power and filters it. When it sags, it boosts the power by fiddling with the waveform (very bad for motors! PC PSUs could care less). When the voltage spikes, the unit uses a bucking circuit to (inductors) to modify the output voltage by lowering it to the correct level. Beyong a certain threshold or during a mains outage the DC buss powers the inverter. The inverter then powers the output. Any unit you see that has "AVR" (automatic voltage regulation) uses this BUCK/BOOST technology. Something you 100% do not want to use on a motor. ONLINE (AKA double conversion): In these units, the mains power is emmediatly converted to DC through a rectifier, from there it powers the DC bus and also charges the batteries. The KEY point is that the DC BUS is ALWAYS powering the inverter and the inverter is ALWAYS what provides the power ot the OUTPUTS. The batteries and DC bus are always part of the circuit. Voltage swings on the input are taken care of by the smart DC bus and the sine wave never varies, no matter what the input voltage. When the mains dissapear, there is no switchover, as the DC BUS is already doing all the work. Now... I don't know of ANY ONLINE ups systems that don't output a TRUE sinewave. They cost to much to do anything less! Some standby units offer true sine wave (tripp lite). You should stay away from the Line Interactive units because of the issues with voltage regulation and what it does to the output sineave during brownouts or spikes. You may want to consider a GOOD inverter that does SINE WAVE and a few good batteries and a relay. There are plenty of DIY UPS systems you can find (I think PLAYFAIR here at RC did a decent one). The nice thing about car batteries is that they are cheap, can be charged in the CAR during a long outage and provice much better power than a dekstop UPS. The VA rating of the UPS is not a measure of how long it will run... but the load that it will handle. Even though a motor is nowhere near the MAX rating of most small UPS systems, it can still damage them due to excess current draw as a result of the horrible output regulation on a UPS that is designed to run switchmode PSU, not big honkin AC motors. Hope this helps.

08/21/2006, 03:23 PM	#12
King-Kong Registered Member Join Date: Oct 2004 Location: Gainesville, FL Posts: 2,346	The power connector for the pump itself has a converter (inverter?) on it -- would this make running my own UPS on it a different case than most other pumps, such as the concerns you listed up above?

08/21/2006, 04:17 PM	#13
wsurf4me Registered Member Join Date: Oct 2000 Location: St. Pete Posts: 806	If the pumps and controller are DC shouldn't you be OK? I've always heard you could run Tunze streams off of a UPS because they're DC, not sure about the Vortec.

08/21/2006, 04:47 PM	#14
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	IF the pumps and controller are DC, you should be OK. The only problem may occur of the controller itself is designed to work off of the peak of the AC sine wave. The step wave can case such circuits to behave in an eratic way. In this case I doubt you would have a problem.

08/21/2006, 04:56 PM	#15
theatrus 100-mile-commuter Join Date: Dec 2004 Location: almost nevada Posts: 4,721	If you're going to augment any battery backup system, invest in deep-cycle batteries. Normal car batteries just aren't made for being discharged and recharged over most of their storage energy, while deep cycle can be (just never ever totally deplete a lead acid battery) __________________ Custom electronics purveyor. blueAcro.com Current Tank Info: 90g SPS+mixed reef (10 yrs): LEDBrick LEDs, 40g custom sump, Ca reactor, chiller, Vortech, lots of custom electronics

08/21/2006, 09:04 PM	#17
breedingroom Registered Member Join Date: Nov 2002 Location: Astoria, NY Posts: 292	following along..........

08/22/2006, 07:28 AM	#19
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	Lastin1 it was a simplified illustration of an AC signal... . and I guess I should have stated the clearly esp when talking about voltages. I guess people do read stuff and "take it to the bank" without understanding the context (which I should have noted). I surely did not think there was a need for a discussion about RMS voltage and actual peak to peak values or the true peak value and RMS voltage to illustrate what the motor sees, which in the end is a 120V swing that needs to be smooth. I should have put more thought into my explanation... as it appears it was not very usefull. I am very aware of the RMS voltage and the peak voltage (somewhere right around 169.7 for 120V) I am also very aware of how diodes work and how to derive DC from an AC signal.

08/22/2006, 01:47 PM	#21
rdmpe Registered Member Join Date: Apr 2003 Location: Central Florida Posts: 3,737	Since true sine inverters are a lot more expensive than the mod form inverters, what would you guys recommend for "headroom" when running pumps? For instance, my Dart pumps supposedly pull 160 watts max and I have a mag 9.5 that does about 90 watts I think. If I just wanted to run a single dart I would probably be fine with a 300 watt true sine wave inverter right? Should I figure about twice the running motor wattage for an inverter? Also, there are some nice inverter/chargers out there geared toward RV's, auto switchover, etc. but $$$.