Solar powered rock light.
It was dim and running out quickly. I prized out the LED reflector assembley with a screwdriver as it's only held in by silicon goo.
and levered off the small PCB carrying the four LEDs.
This picture also shows the uprated solar cell.
Testing at low current on a 5v power supply ( using a series resistor ) showed one LED was drawing current but not lighting up. Probably static damaged during manufacture. A second LED had a dry solder joint. Rummaged about and found a spare in the bitsa box. I've also ordered up a job lot from Amazon for future repaires.
At the same time I fitted an uprated solar cell that has about double the output of the old one.
Note the much larger amount of active cell in the array on the right. Deliveres about 140ma in bright sun.
Re-assembled the rock using clear silicon sealer. Works a treat now.
Here's how to identify the LED polarity:
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The LEDs on the PCB were all the same way round and connected in parallel. The Anode needs to be made positive vs the cathode to emit light and a current limiting method is needed. White LEDs are also static sensitive. The rock lights use a special chip that converts the 1.2v of the battery to the 3-4v tht the LED needs. It also controls the charging and discharging of the battery and the turn on at night
If the solar cell gets misty it can be restored using Brasso. If the misting is really bad then some 1200 wet & Dry ( used wet) can be used and then polish with the Brasso. I don't know how thick the resin overlay is so be careful.
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