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Video iPod : Do you want to test a current measuring patch?

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dreamlayers:
I found what seems to be a way to measure battery current on Video iPods, and I submitted the code in FS#9728.  I think this could be very helpful for decreasing power consumption.  However, the patch needs to be tested.  I think the values behave as expected, but one patch which appears to decrease current doesn't improve battery life.

The type of testing needed is simple:  at several levels of power consumption, measure battery current with an accurate ammeter/multimeter and compare with what the patch says.  However, I don't feel like doing this because opening up the iPod and making the electrical connections is difficult and I feel it would place my only iPod at some risk.  Does anyone already have a setup for measuring current? 

saratoga:
You could disable battery charging in rockbox, and then splice in an ammeter into a USB cable I suppose.  Unfortunately, I don't have an ipod video, so I can only take measurements on the Sansa.

dreamlayers:

--- Quote from: saratoga on January 18, 2009, 10:18:56 PM ---You could disable battery charging in rockbox, and then splice in an ammeter into a USB cable I suppose.  Unfortunately, I don't have an ipod video, so I can only take measurements on the Sansa.

--- End quote ---

The patch measures current flowing in or out of the battery.  It does not measure input current from external power sources.  When the battery is "charged" (not "charging" or "discharging"), the value is 0.   External current could be compared with battery current, though then it would be necessary to take into account the voltage difference and power used by other circuitry (eg. USB input or the Firewire DC-DC step-down converter)

My iPod cannot charge via USB, probably because the USB charging section of the LTC4066 chip is damaged.  That chip is also involved in measuring battery current, which would cast some doubt on whatever results I get.

If nobody else wants to test current measurements, I'll check it out myself eventually, maybe when I'm putting in a new battery.  The ribbon cable of the old battery would be convenient for measuring current.

Update:  I finally did the measurements using FireWire input.  See: http://www.rockbox.org/tracker/task/9728#comment27942

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