I am new to electronics, so please bear with nonsense questions, if any.

I want to make a Solar Mobile phone charger. I found various ways in internet to do that. I am confused between using TP4056 module and LM2596 module.

I have two solar panels - a 6V 100mA panel and a 9V 200mA panel

I have to make a 5V 1A DC output to charge my mobile phone through USB.

Allow me to describe the advantages (what I understand) of using either module.

TP4056 - This module is basically used to charge Li-ion batteries with 3.7V DC. But it has also a 5V DC output tertminal. From the datasheet of TP4056, I found that typical input supply current is 150 microA. But the output of my solar panels are much larger.

LM2596 - This is a switching mode regulator. It efficiency is higher. I can set the output voltage to 5V (from a wide range of 4-40V) DC by adjusting a screw. Here is the datasheet of LM2596.

Now, I want to know the following things.

  1. Which solar panel should I use?
  2. Which module is better to make the charger - TP4056 or LM2596?

Thanks in advance.


2 Answers 2


First of all, you will not be able to generate a 5V 1A output with any of these modules, simply because your solar panels aren't strong enough. Even if we assume you use the (stronger) 9V 200mA one and step the voltage down to 5V with 100% efficiency (which isn't possible), you would only get 9/5*200mA = 360mA at 5V. The real vlaue will be even lower.

But in general, what you want is a simple step-down converter, either with fixed 5V output or adjustable output set to 5V. The TP4056 is not the right module, because it's designed to charge the LiIon battery by itself, but the phone has the charging circuit already built-in. The LM2596 would therefore be the better choice.

But if you continue with the project, I strongly suggest that you use a better solar panel, because at less than 360mA, your phone will charge either very slowly or not at all.

  • \$\begingroup\$ you are right. I have to use 5W panel. Just for a clarification, every such project I found, they are using 6V panels, So basically their chargers are slow, am I right? or there is something I missed. \$\endgroup\$
    – ddas
    Commented May 23, 2017 at 8:54
  • \$\begingroup\$ @ddas Yes, a 5W panel would be the minimum for 1A output. The voltage is not so important, as long as it's within the input range of your step-down converter. But 6V is probably too low, as the step-down converter needs some voltage "to work with", which can be determined by the datasheet. Your LM2596 for example needs 7-40V input to generate 5V output. Also keep in mind that the voltage of a solar panel drops considerably under load. \$\endgroup\$ Commented May 23, 2017 at 9:11

First of all, since your phone is charged with 5V, it already has a battery charger IC inside. So TP4056 is out of the question.

However, that IC (and the rest of your phone) needs a stable voltage, so you'll need a voltage regulator, and that's just what LM2596 is.

Since you will be using a regulator, your solar panel doesn't have to provide voltage which is close to 5V (you're still limited by what your regulator is capable of, typically 25-40V depending on the parts which were used), so go for a panel with higher voltage and more importantly, higher power output. If your mobile phone is a modern one, it may refuse to charge if you give it anything below 0.5A.


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