diff options
Diffstat (limited to 'docs')
-rwxr-xr-x | docs/CHARGING_ALGORITHM | 82 |
1 files changed, 46 insertions, 36 deletions
diff --git a/docs/CHARGING_ALGORITHM b/docs/CHARGING_ALGORITHM index a1a6e2b56e..4a89cac149 100755 --- a/docs/CHARGING_ALGORITHM +++ b/docs/CHARGING_ALGORITHM | |||
@@ -8,12 +8,13 @@ miss some information here, write to mail@uwe-freese.de. | |||
8 | 8 | ||
9 | [INTRODUCTION] | 9 | [INTRODUCTION] |
10 | 10 | ||
11 | This doc describes how the charging works for the recorder. The algorithm can | 11 | This doc describes how the charging works for the recorder. The algorithm |
12 | be found in firmware/powermgmt.[c|h]. Debug output is done in | 12 | can be found in firmware/powermgmt.[c|h]. Debug output is done in |
13 | apps/debug_menu.c. | 13 | apps/debug_menu.c. |
14 | Charging for the player and the FM/V2 recorder is done by the hardware and | 14 | |
15 | therefore isn't implemented in rockbox. Only the functions that calculate the | 15 | Charging for the player and the FM/V2 recorder is done by the hardware and |
16 | battery level are also used for these models. | 16 | therefore isn't implemented in rockbox. Only the functions that |
17 | calculate the battery level are also used for these models. | ||
17 | 18 | ||
18 | All following information is related to the recorder. | 19 | All following information is related to the recorder. |
19 | 20 | ||
@@ -38,15 +39,13 @@ voltage. Both voltage curves (charging and decharging) are used here. | |||
38 | [CHARGE OVERVIEW] | 39 | [CHARGE OVERVIEW] |
39 | 40 | ||
40 | - If voltage drops under a certain value (with "deep discharge" option on the | 41 | - If voltage drops under a certain value (with "deep discharge" option on the |
41 | value is lower), charging is started. | 42 | value is a lot lower), charging is started. |
42 | - If end of charge is detected, go to top off charge. | 43 | - If end of charge is detected, go to top off charge. |
43 | - Make the batteries completely full. 90 minutes of top off charge (voltage | 44 | - Make the batteries completely full. 90 minutes of top off charge (voltage |
44 | regulation at a high value). | 45 | regulation at a higher value). |
45 | - After that, do trickle charge (max. 12 hours with voltage regulation at a | 46 | - After that, trickle charge (voltage regulation at a nominal battery value). |
46 | lower value). | 47 | The trickle charge will continue as long as the charger is plugged in (this |
47 | - When trickle charge is done and you did not disconnect or shut off your AJB | 48 | is a change from the original charge algorithm). |
48 | by now, the AJB decharges normally since it reaches a low voltage and | ||
49 | everything starts from the beginning. | ||
50 | 49 | ||
51 | 50 | ||
52 | [NORMAL CHARGE] | 51 | [NORMAL CHARGE] |
@@ -89,7 +88,7 @@ Two facts on batteries are the reason why this works: | |||
89 | goes down when the temperature goes up. | 88 | goes down when the temperature goes up. |
90 | 89 | ||
91 | NiMH batteries have a smaller delta peak than NiCd, but is is enough for | 90 | NiMH batteries have a smaller delta peak than NiCd, but is is enough for |
92 | Rockbox to detect that the batteries are full. | 91 | Rockbox to detect that the batteries are full (in theory :-). |
93 | 92 | ||
94 | Related documents on the web: | 93 | Related documents on the web: |
95 | 94 | ||
@@ -114,20 +113,33 @@ It goes on again and then the archos firmware charger code would charge again. | |||
114 | So we have trickle charge in rockbox. | 113 | So we have trickle charge in rockbox. |
115 | 114 | ||
116 | In simple words, rockbox charges about 15 seconds per minute in trickle mode. | 115 | In simple words, rockbox charges about 15 seconds per minute in trickle mode. |
117 | An AJB consumes 100 mA when it's on and the charging current is about 300mA. | 116 | An AJB consumes 100 mA when it's on and the charging current is about 350mA. |
118 | So charging 15 s and decharge 45 s will keep the batteries full. | 117 | So charging 15 s and decharge 45 s will keep the batteries full. |
119 | 118 | ||
120 | But the number of seconds the charger is on in trickle charge mode is also | 119 | But the number of seconds the charger is on in trickle charge mode is |
121 | adjusted dynamically (between 1 and 24 sec). Rockbox tries to hold the battery | 120 | also adjusted dynamically. Rockbox tries to hold the battery level at |
122 | level at 5,65 V (top off charge, that means "make the batteries completely | 121 | 5,65 V (top off charge, that means "make the batteries completely full") |
123 | full") for 90 minutes, then a level of 5,45 V. If the voltage drops below the | 122 | for 90 minutes, then a level of 5,45 V. If the voltage drops below the |
124 | wanted value, rockbox will charge one second more the next minute. If is is | 123 | desired value, rockbox will charge one second more the next minute. If |
125 | greater than this value, is will charge one second less. | 124 | is is greater than this value, is will charge one second less. |
126 | 125 | ||
127 | Trickle charging runs 12 hours after finishing the normal charging. That | 126 | The number of seconds the charger is on in top off and trickle charge |
128 | should be enough for charging the AJB over night and then unplug the charger | 127 | modes is also dependant on the charger's output voltage: if the charger |
129 | sometime in this 12 hour trickle charge time. It is not recommended to trickle | 128 | supplies less than about 10v, the current into the batteries is less and |
130 | charge over days, that's because it is stopped after 12 hours. | 129 | thus the percentage on is increased to maintain the proper current into |
130 | the batteries. | ||
131 | |||
132 | The original recharging algorithm stopped trickle charging after 12 hours, | ||
133 | at which time the battery would be discharged until the the batteries | ||
134 | fell below the "start charging" level. At that time the charge cycle | ||
135 | would be repeated. | ||
136 | |||
137 | The time limit was removed by Jerry Van Baren (along with other changes) | ||
138 | in the February, 2005 timeframe. The rationale for this is that the | ||
139 | trickle charge level is very low. In addition, it is disconcerting to | ||
140 | have a AJR plugged in and "recharged" only to find out that the battery | ||
141 | is only 86% full. This was giving the Rockbox recharging algorithm a | ||
142 | bad name and frustrating our users. | ||
131 | 143 | ||
132 | Many chargers do top off and trickle charge by feeding a constant (low) | 144 | Many chargers do top off and trickle charge by feeding a constant (low) |
133 | current to the batteries. Rockbox, as described, makes a voltage regulation. | 145 | current to the batteries. Rockbox, as described, makes a voltage regulation. |
@@ -177,25 +189,23 @@ because it uses the raw voltages): | |||
177 | always set the battery level to 100% | 189 | always set the battery level to 100% |
178 | - the battery level is only allowed to change 1% per minute (exception: when | 190 | - the battery level is only allowed to change 1% per minute (exception: when |
179 | usb is connected, it is allowed to go 3% down/min) | 191 | usb is connected, it is allowed to go 3% down/min) |
180 | - if charging just started (or stopped), ignore the battery voltage for the | ||
181 | first 25 minutes | ||
182 | - after turning on the device, add another 5% to the battery level, because | 192 | - after turning on the device, add another 5% to the battery level, because |
183 | the drive is used heavily when booting and the voltage usually gets a | 193 | the drive is used heavily when booting and the voltage usually gets a |
184 | little higher after that | 194 | little higher after that (rebounds) |
185 | 195 | ||
186 | 196 | ||
187 | [WHICH CHARGING MODE TO USE] | 197 | [WHICH CHARGING MODE TO USE] |
188 | 198 | ||
189 | If you use your AJB connected to the power supply the whole time, select "deep | 199 | Jerry Van Baren's revised recommendation: Select "deep discharge OFF" |
190 | discharge on" and "trickle charge off". | 200 | and "trickle charge ON". This will keep your batteries charged up and |
201 | IMHO will not damage them. | ||
191 | 202 | ||
192 | If you want to charge your AJB over night and take it with you the next day, | 203 | Original recommendation: |
193 | select "deep discharge off" (that it starts charging immediately) and "trickle | ||
194 | charge on" (that the batteries remain full). | ||
195 | 204 | ||
196 | A special case: If you fill up the batteries that are still nearly full every | 205 | A special case: If you use your AJR connected to the power supply all |
206 | the time or if you fill up the batteries that are still nearly full every | ||
197 | night, it is recommended that you make a complete charge cycle from time to | 207 | night, it is recommended that you make a complete charge cycle from time to |
198 | time. Select "deep discharge on" and "trickle charge on" and wait till the | 208 | time. Select "deep discharge ON" and "trickle charge OFF" and wait till the |
199 | whole cycle is over (you can speed up the discharging a little bit by turning | 209 | whole cycle is over (you can speed up the discharging a little bit by turning |
200 | on the LED backlight). Even if the battery sellers say NiMH cells don't show a | 210 | on the LED backlight). Even if the battery sellers say NiMH cells don't show a |
201 | memory effect, I recommend making this procedure from time to time (every 10th | 211 | memory effect, I recommend making this procedure from time to time (every 10th |