"I park my car at the end of the parking lot so I have to walk farther. I'm improving my health."

Well, yes you are. Are you less likely to be at risk for CVD because of that reason alone? Probably not.

A better analogy would be that some people are so obsessed finding a spot near their location that they forget to check a location a bit further (a different parking lot, the places more further away). And, given the state of our health and our lack of body movement in this age of comfort a little walking doesn't hurt. Especially if you walk in a good posture. Again, lazyness isn't a good argument. Usefulness is.

That message on 1 AM? Or custom messages, or different messages taken from a database. I like how in Navicore the messages of reaching destination differ (at least in the languages I tried). Gets less boring, sometimes its actually funny.

Do you think you can stick your findings in a comment on the bug? Testing equipment, methods, etc.

Be nice to have a little more ammo behind than pure FUD.

Sure, but Nokia (at some level) is well aware that their chargers draw well below 1/10th of one watt at idle. They know that it costs pennies to keep the thing plugged in all year. The issue is a political one in that some misguided tree huggers (the green movement) is being catered to, or one of the "Green" maemo programmers thought it worthwhile to add that message without fully understanding the reality of how the hardware performs. Unfortunately no one in Nokia management veto'd that aspect of the O/S. As MARA has pointed out, the AC-4U adapters have an EnergyStar certification. My measurements confirm that the AC-4U adapters draw a small fraction of what EnergyStar allows.

I'll add my findings to the bug. Hopefully some intelligent people within Nokia will understand and take action to remove this nagging, pop-up text message.

I didn't want to get all anal here so I did not explain how I intentionally ignored power factor in my measurements. The truth is the voltage and current are "out of phase" when making the measurements. I knew this at the time, but was too lazy to bother measuring it (in case any other electrical engineers want to accuse me of not being aware of it...I was fully aware of it). Because the voltage and current are out of phase (the voltage lags the current when driving a predominantly capacitive reactive load, i.e. charging the input capacitor in the AC-4U) my measurements lack a little in completeness. Simply quoting AC current, as I had done, was intentional, and those microampere readings were accurate, but to precisely know how much "power" is being drawn by the AC adapter at idle we would want to know the difference between the voltage and current (the phase angle). Basically, my numbers are valid because I gave readings in microamps, not milliwatts. I mention this here in the interest of full disclosure. Even with the missing information we still have our answer of:

The amount of energy these adapters use at idle is so minuscule it isn't necessary to unplug them...ever.



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Nah, it's an EU regulation issue, largely out of Nokia's hands.

I'm less concerned with informing Nokia (as you say, they certainly know how their hardware performs) than with educating people who happen to read the bug and don't have access to the official figures, or stopping those that want to come along and spread their FUD.

:P

BTW- While my test setup was still on the workbench I measured several SAMSUNG cellphone chargers, a Motorola and a different Nokia (cellphone) charger at idle.

Results are that each charger drew the same current as the two previously tested AC-4U chargers at idle....approximately 450 microamps at idle (on average). This is not surprising as they are probably very similar internally.

There is a much higher idle current on AC adapters which have LED lamps on them. One of my Kodak digital camera charger/adapters have such an LED lamp. Several milliamps are needed to light that LED lamp. You will notice that the Nokia AC-4U has no such LED lamp.

The Nokia N800 has a setting in Control Panel (settings>control panel>display>LED) for the blue LED under the gamepad. If you have any of these boxes checked the blue LED could flash or it could light constantly when the device is on (i.e. uppermost check box). This can waste a tiny amount of electricity if you don't care about seeing the LED. If you don't care about the LED then uncheck the boxes.

Having the LED checkbox "device on" checked while the AC-4U is plugged in effectively does the same thing as adding a constant LED load when the N800 is in standby (screen blanked)...similar to my Kodak digicam adapter's internal LED. (When the AC-4U is unplugged the blue LED flashes in standby/"device on" which isn't as energy consuming as constant on, but it isn't zero).

Be aware (most people here already are aware) that having Bluetooth radio active (on) in standby and/or Wifi radio on in standby wastes more than the blue LED if you are not using either BT or WiFi. I leave my WiFi enabled because I get VOIP calls randomly (Skype or Gizmo...or several others), but I turn my N800 Bluetooth off unless I am using BT. I leave the Blue LED disabled most of the time too.

I have several "plug strips". Every one of them has a Neon indicator lamp which glows (orange) when the strip is plugged in and switched on. The most common neon lamp is known as a NE-2. These lamps draw similar currents to the Nokia AC-4U adapters when the Nokia adapter is at idle. The current is roughly between 300 and 600 microamps. For what it's worth.

M5

Also the LED is controlled by CPU so any LED change also wakes up CPU from power saving mode so the glowing effect may be costly. N810 has custom chip for this so it no longer applies (=CPU can sleep).

I would be interested in actual difference (current drawn from battery) when changing BT/Wi-fi settings. Both BT and Wi-fi have good power management so it shouldn't be much when enabled and sitting idle but definitely there is some difference (both chips have its own ARM CPU and when enabled, they are loaded with firmware and sleeping in power save mode, when disabled they are completely off).

Can you measure current from battery while the device is on? That would be useful for all kinds of testing (display on/off, brightness min/max, reading from SD/MMC vs network streaming, DSP on/off, ...)

I can measure battery drain with various Nokia N800 WiFi and BT settings but I would be entering into an area with potential unknowns.

Measuring idle current on the AC-4U charger/adapter was a no brainer. Properly measuring what the WiFi radio in the N800 draws would involve some reverse engineering to be sure I was really measuring what we want. I'd hate to come out and say authoritatively the WiFi radio simply consumed 18 milliamps only to learn later that it is much more complicated because of how the clever designers at Nokia implemented it. Ditto for the Bluetooth. Throw into the mix that I believe the 400mhz CPU throttles up and down too, I'd not know how much of the power during a Gizmo call was related to the WiFi and how much was the CPU processing the voice data. Same goes for WiFi web browsing. I can adjust the transmit power on my Linksys WRT54GS with DD-WRT. I don't know what effect that may have on the N800 802.11 radio's power consumption. If my DD-WRT setting is at it's lowest, would the N800 boost it's 802.11 thinking my router was very distant?

Cellular phone radios increase and decrease transmitter power as needed to reach a cellular tower. For example, if you have a 20 minute conversation on a cell phone when you are at the outer ring of a cell tower's range your handset battery will be drained more than if you were right next to the tower. The handset had to use maximum xmit power to stay linked to the remote tower. Nokia may have similar technology in the N800 for the 802.11 WiFi. I just don't know.

I endeavor to be accurate. There is just too many possible things going on for me to feel comfortable in making accurate measurements isolated to the N800 WiFi and BT consumption.

I could measure battery drain with display dim and bright, display off. I could also determine how much current is involved in lighting the blue LED under the gamepad.

Reading SD/MMC would NOT be as precise because different brands (and size) of memory cards will draw different amounts of current.