This is from the old read-only forum. I don't know how to import the topic, so I'll just continue here. Hope I am on the right sub-forum. http://arduino.cc/forum/index.php/topic,22648.0.html
Basically, the problem is charging the LiPo battery without removing from the system.
The god members including sir AltairLabs contributed much on this topic, and the updated partial schematic follows.
To those who can answer the question, please bear with me, for I am a novice in application of electronics.
Questions: 1. Sir AltairLabs suggested I connect the LiPo directly to the D2 diode, bypassing the FET. If the outside source is to be connected, will the current from both sources merge on the node after the diodes? Will this affect the charging of the battery since the loads will "effectively" source from both the sources, wrong? Or shall we revert to the original circuit, connecting positive terminal of LiPo to FET? 2. Switching regulators will be replaced by common linear regulators, since the deadline of this project is in two weeks time; the planned switching regs cannot be delivered in 2weeks, so we dropped that plan. I have read a lot about the disadvantages of linear regs, but we have no choice. So we opted to continue this project using linear regs. The problem is, the power dissipation of the regs. We computed, and dissipation can reach up to 2.5Watts burst, 1Watt continuous. If we are to add heat sink, can this stabilize the regulators? 3. Application circuits from the datasheet suggested we use .33uF before and .1uF after the regs, is this really enough? I thought the higher the capacitance, the better?
Thanks in advance!
@AltairLabs, hopefully you will read this. ^^