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how can i make about 4 phone chargers directly from the solar panel which rates 24v and 20 WATS. Answered

suppose I have got 4 cellphone of which each charges at 5.0V. and 500Am how can i design a 4x(+& -) branches where I can connect my charging pins? the solar panel produces 24V and 20 watts. Now I know 5.0vx4 is equals 20V means i have sufficient voltage. also voltage out = {(R2x volt(in)} / {R1+R2}. 

are there some other formulas that I can use to solve the problem? please help!

5 Replies

frollardBest Answer (author)2013-05-13

Because phone chargers need to regulate their voltages, you don't just want to put 4 of them in series to use up the available voltage; It seems counter intuitive, but you want to:

Solar panel -- Charge controller -- Small-ish 24V battery for some short term storage -- 12-36V DC-DC converter that outputs 5V @ 2+ amps capability. That way, the battery can charge or discharge and always absorb some energy if the panel has it available, and the chargers can always take power when needed, not just when the sun is available.

Then hook up a squid of usb charging wires to that 5V output. That way you run ONE efficient converter between the 24 and 5V, and the chargers are not dependent on each other to get the job done.

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Sheen Amon (author)frollard2013-05-13

I wanted to make my own converter which can have at most 4 outputs. is it no possible to use specific electrical components to divide the voltage according to different devises which uses different electrical energy assuming the power they use did not go beyond the power supplied? if not then how is it possible with AC? and again one think I don't understand concerning solar panel is that a torch bulb that lights by two 2.5 batteries can not lighted by a solar panel which is 12V.

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frollard (author)Sheen Amon2013-05-13

addendum: I've edited the keywords of your question to be
"solar, electricity, battery, phone, charger, inverter"

...if you search those words, or even easier, look over >>> there at related ibles, you can find lots of solar chargers.

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frollard (author)Sheen Amon2013-05-13

Lots of questions there:

You repeated what you wanted, and I already told you it doesn't work that way very well. If you put 4 '5 volt input' cel phones in series, it might work but because they charge at different rates, when one finished charging, the voltage would no longer flow into the other phones.
How is it possible with AC? You have a 110 or 220 volt AC source that goes to a bunch of chargers, each charger in parallel over the 2 wires that they share. You can hook up an inverter to your solar panel (plus battery) and have it create 110VAC that you can plug multiple chargers into. Every conversion in the process loses efficiency.
Sun nuclear to light is a loss
Light to solar panel is a loss
panel to battery via wires is a loss
battery internally is a loss
battery to inverter is a loss
inverter to charger is a loss
charger to output is a loss
output to phone is a loss, where it again charges another battery.

That isn't to say it's not a usable amount of energy, but every time you convert it loses power, hence why I suggest you get the 24v and directly convert it to 5v with a DC-DC converter (yes, better to buy one), then you can plug as many 5v things in as you want.

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liquidhandwash (author)2013-05-14

If it were me i would buy a couple of these, but i suspect your solar panel is not big enough to charge 4 devices at once without a battery.

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