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Solar Cell Phone Charger

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DonNMass

New Member
I apoligize if this has been beat to death on other posts.

I have a solor panel that through testing in direct sunlight is putting out over 7V.

Plugging into an old phone by splicing the phone charger plug to the cell panel wires, the phone doesn't charge.

I tested the jack and it's testing at the same V as the cell panel, 6.5 V's.

I also used 5 and then 6 batteries putting out over 5V and gain the phone didn't respond.

The phone charges when I reattach the jack to the 110 AC charger.

What's missing that gets the "juice" from the cell into the phone?
 

MikeMl

Well-Known Member
Most Helpful Member
When you test the solar panel and measure 7V, what is the load on the solar panel?

I'm guessing that the load is a high-impedance voltmeter, which says nothing about what the solar panel will deliver into a LOAD. To be useful as a solar charger, the panel would have to deliver ~ 50mA at ~6V, which by Ohms Law is R = E/I = 6/0.05 = 120 Ohms. Connect a 120 Ohm resistor across the panel, and go measure the output voltage in sunlight. I'm guessing you will see less than 2V, which means the panel is not suitable for this task. Rule of thumb: the open circuit voltage of the panel must be about 50% higher than the voltage you want it to deliver under load!
 

DonNMass

New Member
Does the charging jack on the phone look like a USB connector?

I was using an old phone with it's own unique male end. The phone would charge depending on intensity of the sunlight; however that overly simplistic configuration didn't allow me regulate voltage and prevent a surge over 5V.

I purchased a 5V regulator from Radio Shack, but learning from the experts on this forum, I think a more complete circuit board with resistors is required.
 
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