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author | Björn Stenberg <bjorn@haxx.se> | 2003-04-23 11:52:01 +0000 |
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committer | Björn Stenberg <bjorn@haxx.se> | 2003-04-23 11:52:01 +0000 |
commit | 313c825d857b90f23f3e87738c6c87fdc24b4a15 (patch) | |
tree | 8385271635b06682da4aa9378d2dd6b8c390d78a | |
parent | 942bc9449ea587fc3d50a468da56df32baf0748f (diff) | |
download | rockbox-313c825d857b90f23f3e87738c6c87fdc24b4a15.tar.gz rockbox-313c825d857b90f23f3e87738c6c87fdc24b4a15.zip |
Better power calculations
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@3589 a1c6a512-1295-4272-9138-f99709370657
-rw-r--r-- | docs/BATTERY-FAQ | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/docs/BATTERY-FAQ b/docs/BATTERY-FAQ index 201e30c660..35829a2dae 100644 --- a/docs/BATTERY-FAQ +++ b/docs/BATTERY-FAQ | |||
@@ -188,8 +188,26 @@ A12: In our testing we found the following results: | |||
188 | HD on, reading, backlight off ~ 600 mA | 188 | HD on, reading, backlight off ~ 600 mA |
189 | HD spin up before read max 800 mA | 189 | HD spin up before read max 800 mA |
190 | 190 | ||
191 | So leaving the unit on and paused consumes ~100mA, and thus much less | 191 | Using the power draw measurements shown above, lets look at the numbers: |
192 | than needing to reboot the unit. Your mileage may vary. | 192 | Power-down and restart vs. paused for 15 minutes.: |
193 | |||
194 | Pause for 15 minutes will draw: 94 mA / 60 minutes * 15 minutes = | ||
195 | 23.5 mAh. | ||
196 | |||
197 | Power-down and restart will draw about (800mA / 3600 seconds * 3 | ||
198 | seconds = 0.6666 mAh) + (600 mA / 3600 seconds * 6 seconds = 1.0 mAh) + | ||
199 | (230 mA / 3600 seconds * 8 seconds = 0.5111 mAh) = 2.18 mAh total used. | ||
200 | |||
201 | Thus, leaving it paused for 15 minutes draws more power (23.5 mAh) than | ||
202 | turning off and then on again (2.18 mAh). | ||
203 | |||
204 | So where is the break-even point? | ||
205 | |||
206 | Each second of pause will draw about 94 mAh / 3600 seconds = 26 µAh. | ||
207 | |||
208 | 2.18 mAh / 26 µAh = 2180 µAh / 26 µAh = 83.5 seconds | ||
209 | |||
210 | Thus a shutdown and restart uses as much power as 83.5 seconds of pause. | ||
193 | 211 | ||
194 | Q13: When I plug in the charger when the Recorder is turned off, it turns | 212 | Q13: When I plug in the charger when the Recorder is turned off, it turns |
195 | itself on and starts charging in the Archos software? What's up? | 213 | itself on and starts charging in the Archos software? What's up? |