Average modem power consumption in watts?

[Timothy Southwa]

I'm off grid and I need to know the average modem power consumption in watts when not doing much uploading or any gaming at all.

[Liz]

Good morning Timothy,

Welcome and thanks for posting. I'm getting that info for you since I don't know it off hand; it's a good question, no one's ever asked!  

After a quick search online, I found that routers and modems may consume 2 to 20 watts, with 6 watts being average, according to this site: http://energyusecalculator.com/electricity_wifirouter.htm

Once I hear back from the engineer I asked, I'll let you know, but for now, those numbers above could give you a ballpark figure.

Thanks,
Liz

[FIA Ranch]

Timothy,

Power consumption is not relative to what you are doing from a usage standpoint.  It only relates to providing the necessary power to run the components of the modem.

It is stated in the specs for your modem.  (e.g. - the HN9000 power supply is rated at 46 watts.)  So I would suggest using that number (depending on your modem) for your calculations.

[curtis-m]

Timothy,

My inverter shows a draw of about 9watts most of the time. I have the HN 9000

[Timothy Southwa]

Thank you for your help. But if the signal from the satellite is amplified in the modem and the signal sent to the satellite is powered by the modem, then I would guess that when a signal is neither being sent or received there may be only a few watts being used by the modem. Is this true? If not, how is the extra power being used during idle times. Curtis-m below says he uses 9 watts most of the time on his HN 9000.

[Timothy Southwa]

Thank you for telling me about your actual usage. Such information is useful to me.

[C0RR0SIVE]

Honestly, it will depend...  With you being off-grid you shouldn't depend on the "average" power usage, but the possible highest usage as well so that you don't overload your personal grid, unless you can predict when the signal will drop out and the modem ramps up transmission power and processing to try and keep a signal lock.

The label on the power brick states (at least on mine) Input at 100-130V @ 2.0A (which at maximum theoretical value is 260w), and the output is listed as 46w.

The only time these modems will use a TON of power is during heavy cloud cover, rain, and when it's acquiring a signal after being powered on, so you may want to plan for possible high wattage surges during those scenarios.

Power usage also depends upon how well your satellite is aimed, as well as general location in your beam assignment.

[C0RR0SIVE]

I think FIA Ranch looked at the wrong part of the label... Only the output is listed as 46w...  They should have focused on the input side since there is a loss of power going from AC to DC...

[FIA Ranch]

Catching up.....

Information source..... from the written spec.... as I said.... for planning purposes... the only number I believe you can use is Hughes.  I didn't look at my brick, but, obviously Corrosives is newer (or older) than this spec sheet since his states a different input current rating.


The difference between the input calculated wattage and rated power consumption is a function of voltage at the input vs the various voltages supplied on the output of the brick.  Thus the lower power consumption rating.  Since we are not given the output voltages or currents drawn by each of them, we can not calculate backwards into that 46 watt number.

I, obviously can't disagree with what curtis-m says his is drawing.  To use a simple analogy, the only precaution I would offer is that inverters, like cars, come in many sizes, shapes, and colors.  And as car advertisements all say "your mileage may vary".

Where I will respectfully disagree is that the power usage changes based on external influences such as weather, dish pointing, etc.

A one-watt radio is a one watt radio.  When the modem is powered up, the RF carrier (radio) powers up, and uses what it uses and doesn't change.

What does vary, depending on those external influences, is what modulation technique is used to modulate that RF carrier (send and receive data).  That is solely a function of the firmware in the modem talking to the NOC to optimize the transmission path.  And changing modulation technique, does not have any significant impact on power consumption.

Caveat: There may be some small power consumption change depending on how the firmware uses the chips in the modem for various modulation techniques, but I would expect that to be a very small number in the overall power usage.

It is only a question of how much data can be transported over the link under the current conditions using that one watt radio.  When the modem reads the incoming signal, if it is degrading or improving, it will tell the NOC, we need to change the modulation to slow things down or speed things up to optimize usage of the link.

So, Timothy, at the end of the day, it all depends on what approach you want to take to calculate your power needs.

[Liz · Accepted solution]

Good morning,

The engineer pointed me to this page in the Jupiter install guide on pg 15, http://customer.kb.hughesnet.com/Documents/1039649-0001_c.pdf the rated power consumption of the HT1100 is 46W. That's all the info we have as far as power usage.

-Liz

[foxbrook]

The power ratings on the label of a power brick are the ratings that were used when the power supply was tested by UL for safety. They may or may not have anything to do with the actual power draw of the modem. The reason for the higher input power rating, other than the efficiency loss of the circuit, is that UL requires the unit remain safe during fault conditions, such as a shorted output or a component failure within the power supply. Under these conditions the current draw can be higher, than under normal operating conditions.

Anyway, as I sit here typing this my Killawatt meter on my HT1100 modem shows it is drawing 23W at 120V input.

[FIA Ranch]

Excellent point foxbrook.... totally spaced UL involvement in this whole picture...

[Timothy Southwa]

Thank you for your help. You've given me a better understanding of things. I do still have some questions. One, do I understand you correctly? I think you're saying that the modem on the modem side of the adapter uses a fairly steady 46 watts no matter what.
There is the possibility that the modem uses power to amplify the incoming signal. But, if so, such must be little since an Iridium 9555 satellite phone uses only about 0.5 watts.
Is it possible that the modem uses much more power to compute and determine and straighten out the data contained in an incoming signal that's been seriously degraded by weather conditions, solar conditions, whatever?
In between transmitting and receiving times is the modem idle, using only a few watts at most? If so, then given the high uploading and downloading speeds of the whole system, the modem would be idle most of the time when someone is surfing the web, since he will spend much of his time looking at each website, printing it, whatever. If the modem uses little power idling, such could more or less provide a reconciliation between what you've said and what Curtis-m said.
Does HughesNet use the world's most inefficient power adapter, converting about 150 watts ac to 46 watts dc. I use only dc. Is there a way to connect the modem directly to a dc source of power?

[FIA Ranch]

Good morning.... let me work through your questions....

"I think you're saying that the modem on the modem side of the adapter uses a fairly steady 46 watts no matter what."

Not quite..... It is "rated" at 46 watts consumption of AC power.  That is the AC line side of the adapter.  As foxbrook pointed out (and I spaced out), the discrepancy between the numbers listed on the brick are what the brick is expected to produce to supply the modem and radio, and what it actually produces, and what its UL limits are.

Depending on the condition of the modem and radio components, the "brick" will produce the appropriate DC voltages on the modem side of the brick up to that 46 watt of AC consumption.

As curtis-m said, it appears that his is using somewhere around 9 watts of power.  And my caution with that is, as I said, there are different types of inverters (three to be exact), their quality, stability, etc. will vary, and so on.

That is why I said your decision is a personal choice.  For planning purposes, do you plan for "max" (46 watts), do you plan for "probable" (10 watts or so), or do you take a stand somewhere in the middle. (20-25 watts?)  That is just a "comfort" decision.


"Is it possible that the modem uses much more power to compute and determine and straighten out the data contained in an incoming signal that's been seriously degraded by weather conditions, solar conditions, whatever?"

In a word, no. It does use more computing power in the processor when it is dealing with exterior conditions (good or bad), but that does not translate to any significant difference in AC power usage.  Some minuscule changes?  Most likely.  But nothing in the grand scheme of things.


"In between transmitting and receiving times is the modem idle, using only a few watts at most? "

Again, no.  When the modem is powered on, the radio is powered on.  And the two devices are the sum total of AC power consumption, regardless of any user activity.  Other than the minuscule changes I mentioned above based on how hard the CPU may be working at any given point in time.

"such could more or less provide a reconciliation between what you've said and what Curtis-m said."

Think I answered that.  A simple analogy.  A car tire may be built to run 120mph (the UL rating), but will it ever?  Possibly, but not likely.

"Does HughesNet use the world's most inefficient power adapter, converting about 150 watts ac to 46 watts dc.

A couple of parts to that.

First, again, as foxbrook said, the 150 watt number is the UL maximum current draw that can be expected under the most extreme component failure.  As with most UL things, they have little relation to reality.

Second, the 46 watts is not DC, that is still on the AC side of the brick.

"I use only dc. Is there a way to connect the modem directly to a dc source of power?"

No.  the power brick produces several DC voltages from the AC source.  I have not taken a volt meter to determine what they are in this particular instance, but the common power brick usually produces anywhere from 3 to 6 various DC voltages that range from -/+5vdc to -/+48vdc. and are used for isolated purposes within the equipment.  It might even pass 120VAC through to the modem in addition to the DC.  As I said, I just haven't checked to see what it is providing.


Hope that helps.  If I missed something, or you have more questions, fire away......

[Timothy Southwa]

You have been quite helpful. Thank you very much. I may yet ask you more questions.

[Timothy Southwa]

Thank you for your explanation foxbrook. Also, I appreciate you reporting your actual power usage