Does anyone know of a piece of software that can give me exact (well... I don't expect miracles - anithing even remotely acurate will work) power consumption data for my computer, preferably in real time. Alternatively, a hardware method of measuring this is also ok but bear in mind that I mean to measure my battery power consumption.
Something like this?:
Link talks about conserving power, But not how to display/monitor real power in real time.
Reasonably close - Most likely, but probably a little on the expensive side.
Newegg sells a Kilowatt meter Less than $20.
The value shown will be for the computer Plus PSU losses. If you know the effiency of the PSU it then is a simple calculation reading x eff = Computer consumption excluding PSU losses.
Now for the your question of software - I assume you want to display this and/or graph it, on the computer. To do this you would need a unit that will provide a serial port or usb output (Most units similar to this provide a serial port output - For dumping collected temperature/humidity data or Like I have, two digital DVM that will display thier reading on the computer - they were about $100 apiece but got them cheaper as bought on sale.
Think I found one ($131 for meter and &73 for software and probable about as cheap as you will find)
Reason software does not exist to display this is no Total current measurement is available. If you could "get to" the battery voltage and if total current was available - IN DIGITAL formate then software could be written.
Above would work great for a desktop, But as I just noticed you are talking Laptop and battery. Answer = NO.
But what you can do is remove battery and follow above. The power displayed would be very close to what the Battery would have to provide. Reason for removing battery is to exclude charging current.
Linux does have built in battery status monitor readers (provided your hardware supports it), which show you the voltage, current, and watts consumed, as well as the current capacity and total capacity (in Watt-hours--shows the actual capacity, including degradation of the battery). I don't know of a Windows utility that duplicates this functionality, but it is possible that one exists.
Depending on what you want the data for, it may be worth it to install a dual boot partition of Ubuntu or some other distro and collect whatever data you need.
A laptop should have circuitry to monitor current (may not provide a way to monitor it and at this point it is not battery output current). Reason is that the charging circuit needs to switch from full charge to a trickle charge once battery is charged.
The state of a Battery can be determined by monitoring the Batt voltage and the time that it takes to decrease (using the discharge characteritics of the batterry). Current is not always a good mix as current may go up as battery E boes down. This is do to the circuits adjust to provide a given power (the work that they do for example I test a system that normally uses 28 V, but I check currents at 24 V and 30 V. Compared to 28 Volts, current goes down when I apply 30 V and goes up when I change from 28 -> 24 V.
NOTE: Not saying that a Current measuring circuit does not exist that can provide current/power when under battery in some laptops as a means to protect incase of high current conditions.
Most modern laptops do have circuitry to measure different aspects of the state of a battery (including output rate, voltage, and actual capacity--batteries degrade over time and lose charge capacity). Here's a link to one of the programs I was talking about: http://live.gnome.org/BatteryStatus
You do need a unix compatible computer to run it, however (meaning no Windows). There may be Windows alternatives, but I haven't seen any.