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Old Nov 24, 2009, 06:19 PM
First to go over 106K feet
Crist Rigotti's Avatar
USA, IA, North Liberty
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Key chain camera battery

I have a key chain camera and brought out 2 wires from the battery so I can use my Li-po charger. This circuit board was on the battery (1S 3.7 270mah). What's it for? The camera is supposed to be charged through the 5v usb port which causes the camera and battery to get very warm when doing so, hence bringing out the 2 wires.
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Old Nov 24, 2009, 08:45 PM
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SteveM732's Avatar
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The chip on the left is an 8205A dual n-channel mosfet and the chip on the right is a DW01 single LiXX cell protection circuit. See page 5 of the DW01 datasheet so see how the two chips are connected and work together.
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Old Nov 24, 2009, 09:28 PM
First to go over 106K feet
Crist Rigotti's Avatar
USA, IA, North Liberty
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Great! Thanks. Do I really need this in my camera?
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Old Nov 24, 2009, 09:32 PM
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Quote:
Originally Posted by Crist Rigotti View Post
Do I really need this in my camera?
If you are going to charge from USB you must as it is a ~5 volt supply. If you charge using your own charger then you won't have any issues with over charging, but you won't have the circuit to protect you from over discharges.
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Old Nov 25, 2009, 07:43 AM
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rich smith's Avatar
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Originally Posted by SteveM732 View Post
If you are going to charge from USB you must as it is a ~5 volt supply. If you charge using your own charger then you won't have any issues with over charging, but you won't have the circuit to protect you from over discharges.
Steve summed it up and as usual he's Johnny-on-the spot with a link. As I mentioned in the other thread the main purpose in these spy cams is to prevent discharge. Without it the Key Cam would be a "one use" camera.

Overcurrent and overvoltage functions never used because the cameras do not draw very much even when taking pics (50ma in the ones I measured) and the charging circuit never went above (4.19v worst case in mine).

PS However note that, like the Silverlit ones, it does not function as a charger and will not work simply connecting to a 5v supply.
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Last edited by rich smith; Nov 25, 2009 at 07:54 AM. Reason: 5v supply
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Old Nov 25, 2009, 09:57 AM
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Originally Posted by rich smith View Post
As I mentioned in the other thread...
Oh great, there is nothing like spending time helping someone only to find out they had received the correct answer hours earlier in another thread.
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Old Nov 25, 2009, 10:50 AM
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I dunno Steve. How come you don't read EVERY SINGLE WORD of EVERY SINGLE LINE in EVERY SINGE POST in EVERY SINGE THREAD of EVERY SINGLE WEBSITE like me?
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