power usage

[Unregistered]

Does anyone know how much current the fast Sandisk ultra cards use? Are there any fast cards that don't guzzle power?

[n2ifp]

Originally posted by Unregistered
Does anyone know how much current the fast Sandisk ultra cards use? Are there any fast cards that don't guzzle power?

60 milliamps I believe, the standard uses about 36 milliamps, and the Sony MS uses about 45 milliamps when writing to the card, and they all use less when reading.

[pruss]

OK, so now my really dumb question. If it uses 60mA, and if the battery is about 1000mAh (right?), then it really shouldn't matter too much whether one uses the high power or the low power CF cards. After all, if under the best conditions, the battery only lasts about five hours, the best scenario current draw of the Clie will be 200mA. With the 60mA cards, being used continually, we get a current of 260mA and hence 3.8 hours. With 36mA, we get 4.2 hours. So the difference should be only about 25 minutes. And that's assuming it's being read continuously. (I assume that when they're not read, they go into powersave mode, right???)

BUT someone claimed in this forum that using the lowpower Sandisk card with mp3 just about doubled the battery life.

Are my calculations right?

Alex

[n2ifp]

Originally posted by pruss
OK, so now my really dumb question. If it uses 60mA, and if the battery is about 1000mAh (right?), then it really shouldn't matter too much whether one uses the high power or the low power CF cards. After all, if under the best conditions, the battery only lasts about five hours, the best scenario current draw of the Clie will be 200mA. With the 60mA cards, being used continually, we get a current of 260mA and hence 3.8 hours. With 36mA, we get 4.2 hours. So the difference should be only about 25 minutes. And that's assuming it's being read continuously. (I assume that when they're not read, they go into powersave mode, right???)

BUT someone claimed in this forum that using the lowpower Sandisk card with mp3 just about doubled the battery life.

Are my calculations right?

Alex

They look good to me. Some may increased their battery life a tad, but not doubled :).

[pruss]

And there is a power-save mode when data is not actually being read/written, right?

[n2ifp]

Originally posted by pruss
And there is a power-save mode when data is not actually being read/written, right?

Right! When the card is idle, no matter what type it is (the microdrive is the exception), the flash memory cards go into the sleep mode, including the MS.

In the sleep mode, power consumption is in the microamp region (very small) :).

[pruss]

Sandisk Tech Support says that their Ultra card uses 200mA read/write, 2mA sleep. 200mA is a lot: it really would lower battery life.

[n2ifp]

Originally posted by pruss
Sandisk Tech Support says that their Ultra card uses 200mA read/write, 2mA sleep. 200mA is a lot: it really would lower battery life.

Something is wrong here as SanDisk's brochure says power consumption is less than 30 miiliamps read/write at 3.3 volts. I just checked it a minute ago.

What your describing sounds more like a Microdrive.

The standard SanDisk is 21 milliamps read/write at 3.3 volts, 200 microamperes when in the sleep mode.

http://www.sandisk.com/tech/lit.asp