18650 Battery Charging

Hello everyone;

I'm in need of some advice; as some of you already know I'm simply a hobbyist; therefore I'm sure I'm missing several points on my project.

I am building a Solar and USB 18650 Battery Charger; to power my Arduino for future projects.
The idea is to have some "mobility".

  • Info

As for the circuit; it exactly as this one (but with 4 Batteries):
Link: https://www.electronicshub.org/solar-battery-charger-for-18650

  • Modules

TP4056
Model: 18650 Lithium Battery Charging Board
Supply Voltage: 5v
Maximum Charging Current: 1000mA
Battery Discharge Voltage Protection: 2.5v
Battery Over-Current Protection (Current): 3A

USB DC-DC Booster
Model: 5v 600mA USB Output Charger
Supply Voltage: 0.9 ~5v
Dissipation Power: 1- 50w

  • Remarks
    I'm a little bit clueless if I'm doing this correctly; and really don't want to blow up these batteries (kinda scared to be honest).

In my project (Photo Bellow); I can see that I do receive power; either from USB or Solar Panel.
However the USB output is 0.33v. I can't really understand why.

Another thing that I'm afraid of is the total voltage output of the 4 batteries (15v).
According with several researches; I could find projects with one TP4056 per battery.
Thus I'm thinking that either it will charge slowly; or I'm putting too much effort into this charging module.

Can anyone provide me some hints?

Best regards;

datasheets of used modules and schematics of your setup?

Greetings; I couldn't find a suitable datasheet for both modules. As I got them on AliExpress.

As for the circuit; it exactly as this one (but with 4 Batteries):
Link: https://www.electronicshub.org/solar-battery-charger-for-18650

TP4056
Model: 18650 Lithium Battery Charging Board
Supply Voltage: 5v
Maximum Charging Current: 1000mA
Battery Discharge Voltage Protection: 2.5v
Battery Over-Current Protection (Current): 3A

USB DC-DC Booster
Model: 5v 600mA USB Output Charger
Supply Voltage: 0.9 ~5v
Dissipation Power: 1- 50w

Your boostconverter deliver 0.6A max, but your charging circuit draws 1A. Guess what will happen :slight_smile:

:o Ok... I really have no idea. :stuck_out_tongue:
No power? Should it blow (excessive current)?

How are your 4 x 18650 cells connected? If they are in series making a 14.8V battery then a TP4056, which only charges a single battery to 4.2V, is not going to be much use.

Series connected Lithium batteries really need a proper charger that can balance the individual cells. You can get away with a simpler constant current charger provided you don't mind getting a shorter battery life. But not a single cell charger.

Steve

Thank you Steve.
So I should use 4 TP4056 in series instead correct?

Your original circuit has two batteries connected in parallel. You cannot connect the batteries in series using this circuit design, and there is no need for the high voltage a series connection would produce. I would suggest you get the circuit working with just one battery as a test, and see if you even need more than that. Even though the original circuit uses two batteries, I don't know if multiple batteries in parallel is really safe.

rgxHost:
Thank you Steve.
So I should use 4 TP4056 in series instead correct?

You haven’t answered the question about how the batteries are connected. But you can’t connect TP4056s in series, it won’t work.

Steve

rgxHost:
:o Ok… I really have no idea. :stuck_out_tongue:
No power? Should it blow (excessive current)?

Exactly. “No power”. Also called overcurrent protection.

"I am building a Solar and USB 18650 Battery Charger; to power my Arduino for future projects.
The idea is to have some "mobility"."

I think you can buy solar charged USB battery packs/banks, which may save some money and time. Check ebay and the usual sources.