Will this new circuit work for a solar light?

Thread Starter

dameo182

Joined Nov 12, 2022
35
So I found a video on youtube from from bigclive.com, he made a dusk sensor to run a string of LED lights from a solar panel and a protected lithium cell, I want to use a non protected cell and I'm trying to use the tp4056 charge module as the protection in the circuit. Is this ok to do?
One of the pics is his original circuit, and I've drawn another with the module in the circuit, now I'm a complete newbie to circuit work so I didn't want to mess with this until I could be advised on it, I left out the resister before the LED strip as the strip has it's own resistors, which I learned from my previous 'picture frame thread'. So will this work or would I need to place the module somewhere else?
 

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Thread Starter

dameo182

Joined Nov 12, 2022
35
After looking at that for a minute I realised I won't be able to connect the plus side of the module, so yeah, I've no idea what I'm doing with it
 

DickCappels

Joined Aug 21, 2008
9,512
If the battery is to be charged with energy from the solar panel, you can probably figure out when current is being supplied by the panel and use that as a signal to keep the light off in the daytime. Do that and you're about done.
 

Thread Starter

dameo182

Joined Nov 12, 2022
35
If the battery is to be charged with energy from the solar panel, you can probably figure out when current is being supplied by the panel and use that as a signal to keep the light off in the daytime. Do that and you're about done.
Yeah I think that is what the original circuit does, something about an uneven voltage either side of the diode, when the solar panel is working it turns off the transistor. The only issue I have with doing it exactly as the circuit shows is that my battery isn't protected, and the charging module has that protection built in so I am looking for a way to add that in somewhere so that I can use any battery rather than only an old phone battery.
 

Audioguru again

Joined Oct 21, 2019
5,418
A very cheap solar garden light costs $1.00US. It uses an AA or AAA Mi-MH battery sell and a 2V solar panel.
The cheap ones use a battery that is junk because it has a low capacity and rusts away in a couple of months outdoors.
The cheap solar panel is too small has a plastic cover that gets sunburned like Big Clive has.
The cheap old ones used an LDR to detect sunlight but it also got sunburned.

I paid a little more ($1.50US) for higher quality solar garden lights and replaced their junk batteries with Name Brand batteries.
They have a 4-pins IC that detects no light on the high quality glass-covered solar panel to turn off the battery charger. When there is light, the IC steps-up the 1.2V battery to 4V with current limiting.

The IC produces a fairly high frequency of pulses but I use colors-changing LEDs that need smoothed DC so I add a Schottky diode in series with the LED and a 0.1uF (marked 104) ceramic capacitor parallel with the LED. The inductor in the circuit is small like a 1/4W resistor and its inductance is selected for the LED current (brightness).
 

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Audioguru again

Joined Oct 21, 2019
5,418
Many Lithium batteries with protection circuits and protection circuit module sold DO NOT properly charge the battery.
Phones have a proper charging circuit inside them and the protection circuit in the battery simply limits the current and voltage to prevent an explosion but allows a battery to be ruined when not charged properly.
 

Thread Starter

dameo182

Joined Nov 12, 2022
35
Yeah, this is turning out to be more complicated than I originally hoped. I'll stick to welding and fabrication and leave electronics to people who know better lol thanks for the help anyway guys
 

DickCappels

Joined Aug 21, 2008
9,512
1669578808575.png
This is one arrangement that one fellow found to work. Q1 shuts down the driver for the LED while there is sunlight on the solar panel.'
 

Thread Starter

dameo182

Joined Nov 12, 2022
35
View attachment 281619
This is one arrangement that one fellow found to work. Q1 shuts down the driver for the LED while there is sunlight on the solar pane.'
Thank you, but I was really hoping to just add the charge board to the circuit that clive made in his video, having watched how he did that I could follow it easily, but knowing where to add the charge module has me stumped. Thought maybe it could just go before the battery to provide the protection, but I don't know if the lights would work correctly then when I want them to turn on and off.
 

DickCappels

Joined Aug 21, 2008
9,512
No, it won't work. If you supply a little more information we can come up with something that will work.

Is the "LED Strip" the lights you want to power when in the dark? Would it be correct to assume that you want to power that from the battery?

What can you tell me about the LED(s) you want to light? - How many, what color are they (white? -this affects the voltage needed) how much current, etc.

1669614977070.png

Is this (above) the charging/protection module you have? If so you should connect the battery to BAT+ and BAT -, and take power for the LED from OUT + and OUT -. The solar panel should connect to the INPUT and GND connection points near the USB connector. The output voltage will be a little less than 3.7 volts. That may not be enough for your LEDs, so you may have to adjust your expectations. You also should think about how many hours you expect the LEDs to stay on each night and and whether your solar panel can supply enough energy to recharge the battery.
 

Thread Starter

dameo182

Joined Nov 12, 2022
35
@DickCappels sorry, I should have provided more info, I recently posted about help with a picture frame I wanted to make, I posted all all of the components in that thread that I would like to reuse in this solar lamp.
But the battery is a 4000ma lipo cell, unprotected, and I want to run a 5v LED strip that will be running from the battery when the solar panel doesn't produce power, and yes I want it to charge the battery during the day. Each of the LEDS on the strip draws around 10ma (if my memory is correct) and I'll use around 17 of them. This light I'm trying to make is as a christmas present for my dad in memory of my mum who died a month ago. She put a lot of time into her garden so it seems fitting to help light it up.

I made this brass bluetooth speaker/bedside organiser for her a few years ago, using a 12v LED strip, wrapped around a small tube inside the diffusers, I want tge light to look similar to this one, but obviously for outside use. Thanks for everyone's help btw.
 

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DickCappels

Joined Aug 21, 2008
9,512
Here is something for you to try.
1669654874409.png
EDIT: THE 4.7K RESISTOR SHOULD CONNECT TO THE CATHODE OF THE 1N5819 (NOT THE ANODE). See the schematic in post #23. \EDIT

The battery on the left side is the solar panel. You need to measure the charging current and if necessary, insert a resistor between the panel and the N15819. I highly recommend that you use a charger/protection module for the battery - these batteries can catch fire if mistreated and those modules usually cost US $1.00 or less (that is about a pound). Cheap insurance. If you want to go for the safe alternative let me know and I will modify the schematic accordingly.

The reason there are three transistors instead of the one that Big Clive had is that to drive a 170 ma load without spending a lot of current when the sun is out the gain of more transistors is needed. The transistors are 2N2222 rather than BC547 because the BC547, as good as it is, would probably eventually die from the 170 ma load.
 
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Thread Starter

dameo182

Joined Nov 12, 2022
35
@DickCappels thank you, that circuit seems very complicated to my newbie eyes though lol, but wouldn't the tp4056 board work as the protection board? I have a few of those already. Or are you meaning a different board all together? I'll be honest, I didn't realise making a simple solar light was this complicated, I thought I could just add the board into Clive's circuit somewhere to protect the battery and that would be it, I see now that I underestimated how much I would need to know about making circuits to get that done. For the picture frame I was originally making (it worked fine, I just didn't like the look of it when lit up) I have the tp4056 boards, some boost converter boards to make the output 5v and a box of different resistors, but given the solar part seems so complicated I may just give up on the idea, people have better things to do than spend their time teaching me basic electronics, but thank you for the help you and others have offered to me, it is appreciated
 

Thread Starter

dameo182

Joined Nov 12, 2022
35
You can add a little board like this one and turn your unprotected cell into a protected one.
Thank you, I actually hadn't thought of that, but going off of the other comments about this project I'd still have to increase the strength of the circuit to handle the 170ma and I genuinely don't know how to do that, I like simple, and this really isn't lol
 

DickCappels

Joined Aug 21, 2008
9,512
The circuit in post #16 will handle the 170 ma.

Is your charger/protection board the same as that shown in post #14? I can add that to the circuit if you like.

Your comment about how complex the circuit looks reminds me of when a senior engineer gave the schematic of a groundplane video board he wanted wired up. I looked at it and complained "Why does it have so many parts?!" His answer "Because it takes that many parts to make it work!" We were friends for years after that.
 
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