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Teardown pics of recalled Sunvilla LED-lit patio umbrella battery/solar charger

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jwet:
SOLVED!


The circuit as designed will overcharge the battery by about 200 mV in the solar mode.  Diode D2 is supplying the Vcc to the 312F controller chip but unfortunately is also the sense terminal for the battery voltage.  The RC is fine and is specified on the data sheet.  Diode D2 drops about 200 mV (schottky) and throws everything off allowing the battery to reach 4.4.  I removed (shorted) this diode and the circuit works as I would expect.  The battery can also be charged from a circuit in the stalk with an AC adapter, I haven't analyzed that.  It would have to repeat the battery protection circuit or have a real charger.  The protection circuit should have been placed downstream of the battery rather than between it and the solar cell.  This way it could protect the battery in both modes with a simple 5v adapter backfeeding charging voltage from the stalk.  I'm going to do a bit more study but will likely implement this change.

RJHayward:
jwet:
   You can research a 4-pin controller IC, used in many of the simpler garden lights:
   Try:. YX8018 4-Pin IC,
    and:. YX8050
   The yard lights can be placed in 'Totem Pole' relation, for having a later switch-on...the top light will hold off, the lower (Umbrella if you want), so it won't turn on until 10 pm, or whenever that first, top light goes dark, from discharge.
   For lower power strings, running on NIMHD type AAA batteries, you could always skip the power wart option and put a few of those singular lights out, nearby.  At least that gets you out of the risks of Lith ion batts.
RJ
P.s. photo shows flip flop assembly, triggered by flashlight.

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