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How to prevent solar pannel DISCHARDING phone/devices ? Answered

Hi everyone

I recently bought a 15W solar charger (without battery) to charge myphone on the go.
sadly i discovered that, if the sun is not bright enough, the pannel will actually DISCHARGE the phone battery

This is really a show stopper... I'm afraid it might damage the phone battery too.

So I was thinking, is there a way to prevent this? I guess a diode in line would be the best option, is it?
How about  this:

Pannel ==/==> [male USB connector] + [diode] + [female USB] ==/==> USB cable => phone

Any ideas? hints?



4 years ago

First of all thanks a lot to all of you for the support

You all confirmed my idea, but I also ocme to another possible conclusion:

Sometimes solars are not powerful enough to pump some juice in the battery, but they are sensed by the phone that lights up the screen. Now, if the panel is not constant in time it might provide just enough power to trigger this, so that is the phone that, actually, is wasting power faster than the pannel can provide.

I have to try with the phone switched off and see if something changes.


4 years ago

Diodes non-LED, recommend Schottky but any will work.

A diode is a one-way electric valve..

The direction of current flow is identified by the ring ( two are right bottom left going )

D3.jpgPhoneSolar .jPG
Josehf Murchisoniceng

Answer 4 years ago

Just an addition to your answer icing.

You can salvage a diode from old electronics.

Any 1N400x series from Radio Shack will do.

I like 1N5817 in solar circuits 0.5 voltage drop across the diode.

You can salvage one from an old solar garden light.

Here is a pic to show forwards bias.


4 years ago

Yes, adding a diode is the answer.

Split the USB cable, and splice one into one of the power leads.


Answer 4 years ago

Thank you!!

Now, as for the diod... any advice on what to get?
like a source where I can scavenge one from and recognize the right type?