voltage spike on solar lipo charger

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adafruit_support_mike
 
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Re: voltage spike on solar lipo charger

Post by adafruit_support_mike »

Looking good!

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bwh13
 
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Joined: Thu May 23, 2013 6:15 pm

Re: voltage spike on solar lipo charger

Post by bwh13 »

Hey hey Everyone,
I've got an update on the LDO I've been working on.
I ended up using a Texas Instruments LP3964 voltage regulator as the heart of the circuit primarily because of its ultra low dropout voltage (24 mV @ 80mA). It has 5 pins (bent & staggered) that offer a shutdown capability that I didn't take advantage of. Simple components: 3 caps, a 10K resistor, a 25K trim. pot. & a couple of terminals.
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I soldered it up to an Adafruit perma-proto board (which I trimmed down in size because I have limited space in my time lapse enclosure.) I used the adjustable breadboard power supply to feed it 6.0v - which I can get in full sun from the solar panel and which shut my rig down a couple of months ago. I set the trimmer up so that it will shave these higher voltages down to 4.1 V which I get from a new and fully charged LiPo. Best of all: it works. I'll be testing it in the field early next week and post after its had a week out in the sun.
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The caps might not be sized appropriately, but it was all Radio Shack had in stock when I was there.
Comments appreciated!

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