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Old Aug 11, 2011, 08:03 AM
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Quote:
Originally Posted by Tom Frank View Post
Your #2 functions differently from mine. I just did a test starting with a fully charged camera battery and filled a 4GB flash card recording with my #2 connected to its dedicated car charger. I then plugged the camera into my PC USB port just long enough to erase the card, then immediately started a video with ONLY the internal battery powering the camera. I got a 35 min. recording... close to normal for my battery fully-charged condition.
Well, in this case my V2 camera behaves differently. After recording in the car with the dedicated car "charger", the battery is nearly completely depleted. After a 1 hour of driving, I am able to record only about 3 minutes of video with the internal battery.

Quote:
Originally Posted by Tom Frank View Post
Then starting with the internal battery depleted, I again wiped the card, plugged into my car charger, and began another recording sequence, filling the 4GB card again. After which I wiped the file from the card, and immediately started another recording without charging the battery from my PC USB port. That recording lasted just under 39 minutes, indicating the battery was fully charged while it was recording!

So it is clear to me that not ALL #2 cameras have the same charging issue that yours does.
Yes, it looks so. Can you measure your car charger voltage? My dedicated "charger" provides 4.20V on pin 4, and my camera has a Schottky diode on pin 4 as the only part. By principle, the voltage on battery module can not raise above 4.02V. I measured there about 3.95V - i. e. far from fully charge.

Quote:
Originally Posted by Tom Frank View Post
One thing I noticed from your voltage measurements is the voltage levels you measured appear to be higher than normal (I assume they are accurate measurements).
These voltages were provided by variable power supply connected to the pin 4 to test the camera behavior, not the dedicated charger. I wanted to test, how it can be charged better.

Sorry, they are not accurate. My old lab power supply was not stable enough and the camera significantly changes its power consumption depending on voltage. If you are interested, I can measure my camera again. Now I have a new equipment and I can measure accurately now.

Quote:
Originally Posted by Tom Frank View Post
I may be mis-understanding your readings, but a properly functioning protection circuit board should clamp the upper voltage limit available to the battery at nominally 4.2V +/- going into the battery. Anything higher can damage the battery, or worse, cause it to over-heat, swell, and possibly ignite if the voltage gets too high. There are some representative tests to show this on the chucklohr.com web site for the similar #3 SD version of the camera.
There are two circuits in my camera - CC/CV charger IC that limits voltage to 4.2V and limits current. But it is used only if I power the camera from pin 1.

If I power the camera from pin 4, the only protection represents the breaker inside the battery. I can measure exact voltage when it breaks, but is is probably a bit more than 4.2V (4.3V?). Keep in mind, that the circuit inside the battery module is not intended as charging controller. It is a last resort damage protection.

I seen 5.5V and more on battery module terminals when powering via pin 4! So there is no other protection in my camera than the circuit inside the battery module.

Quote:
Originally Posted by Tom Frank View Post
Assuming the external power source has sufficient current available at the proper voltage, the parallel connection with the battery should work in unison, with external source doing most all of the work if the battery is fully charged, and taking up the slack as the internal battery starts to be depleted, keeping the battery charged in the process. A special charging circuit is not needed if the voltage levelat the battery terminals is clamped at a nominal 4.2V. A lipo cell will stay charged to the voltage level on it's terminals. I routinely charge up to 4 cells in parallel with my flight battery packs, with the charger maintaining a steady 4.2V on the charging connection for the latter half of the charge cycle.
No, connecting any power supply in parallel with LiPol battery is always a bad design. Even with only 4.2V power supply, there is a risk of over-current when the battery is depleted.
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