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285 Posts
Discussion Starter · #1 · (Edited)
I bought two lanterns to be used for Halloween.

I didn't like the single led light so I decided to remove the whole led light + solar controller.

So the upgrade go from 1.2V Ni-MH to 3.7V Li-ion stepping up to 9V.

  • TP4056 lithium Ion battery charging modules
  • 1N5408 Diodes
  • 14500 3.7V Lithium Ion Protected Batteries (AA size of 18650)
  • Step-Up Voltage Regulator (9V - U3V70x family)
  • Black Vellum Card Stocks 54lb Transparent (Samples)
  • Red/Black 24AWG? Stranded Wires
  • 2 Pin Waterproof Connectors
  • RF Wireless Remote LED Controllers
I got the idea from this guy

The one bad thing about the module is that it doesn't have a automatic switch controlling the OUTPUT.
1) A simple hack as shown in the video above.
2) Add a switch like BJT Transistor or MOSFET.

I have tried using BJT Transistor but unfortunately it suck down volts (voltage drops from 3.7V to @ 2.4V).


^ The original solar controller

^ A simple "hack" for automating switch.


285 Posts
Discussion Starter · #3 ·
Updates: Oct 22, 2020

#1 - Solar chargers I have put together (using the hack as shown in the video above) didn't work as I expected. They worked fine when I tested them in the garage but when left outside, they didn't switch ON at night. After investigating the switching problem, I have discovered that solar panels were still charging (anywhere 0.2V to 2V) even at night.

#2 -
So I had to start over again and decided to give the MOSFET a chance again. After searching on Google, I found someone tried to build a similar solar charger setup. Based on that person setup, I found out what is the MOSFET I should be using. I ordered 3x NDP6020P (P Channel) MOSFETs from digikey.

MOSFET - NDP6020P ON Semiconductor | Discrete Semiconductor Products | DigiKey

Today, they arrived. I took apart (removed the hack) one of the solar chargers and put in the MOSFET. Now the solar charger seem to be working as should. The only issue I have now is the switching is not instant (OFF/ON). Not 100% perfect but it works.

Since I currently have 3 MOSFETs, I have fixed 3 out of 7 solar chargers. Will have to order more to fix the rest.


Oct 28, 2020

Here's the final (hopefully!) modification:

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