Timeline for Use transistor to auto swap power source
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 20, 2012 at 21:37 | comment | added | BackyardSamurai | From the looks of the charger it's rather "smart" it has multiple ICs and components. it also sports a nifty LED to indicate the battery's charge level when connected. I would look up the data sheets for the ICs but they've been obscured with some other markings stamped over top. It looks like it is based on a MAX1555 chip at its heart which should be able to do the job with minimal additional components right? | |
| Oct 20, 2012 at 20:51 | comment | added | D.A.S. | If the battery is loaded, the dumb charger can't tell if it is undercharged or not. A smart charger may use the interrogate and response pulse method. | |
| Oct 20, 2012 at 17:27 | comment | added | BackyardSamurai | Perhaps something like this? i5.photobucket.com/albums/y177/Midiot/DIY/oring.jpg (not my image but looks similar to what I'm thinking) where supply one would be the battery and supply two would be the external charge voltage and a transistor between the three leads at the load side of this schematic? | |
| Oct 20, 2012 at 17:13 | comment | added | BackyardSamurai | This may sound stupid but after rethinking your answer... If the charger can determine when to float the batt couldn't it be connected to the batter through an NPN acting as switch to ground so that when power is applied the charger either supplies the batt or power goes through to load? | |
| Oct 20, 2012 at 17:09 | comment | added | D.A.S. | there may be a smart reason why the battery must be removed to charge it. Your load current may affect the power source regulation a lot and diode drop may rise significantly. More details are needed for best solution, but Diode OR bridge seems like a cheap test to see if it works and if not report the PN and voltage drop. | |
| Oct 20, 2012 at 16:59 | comment | added | BackyardSamurai | The charger is actually meant to charge the battery out of system so I would imagine that once the battery reaches charge it floats and waits. I'm looking for a way to connect the battery permanently in the target device and retain use of the charger without physically removing the battery to do so. So, yeah. Like a cell phone. | |
| Oct 20, 2012 at 16:51 | history | answered | D.A.S. | CC BY-SA 3.0 |
