Little solar powered battery and led.

[Lziga55]

Hello, I'm Žiga, a student of electrical engineering. i decided to make a small off grid solar power plant with a 10w solar panel and 4 to 5 3000mAh li-ion batteries. I would use this as a power supply for a led strip with a consumption of up to 10W or 15W. so far I've done mostly arduino projects, such as the egg incubator. since I do not have much experience and knowledge about solar power plants, I am asking for your help in the implementation and composition of the project. I would probably use modules as that would be the cheapest and easiest. I mainly buy components from aliexpress. If you have any other ideas please let me know. But first, I should start by assembling the circuit. so far I've researched quite a few things about the operation, the bms for the battery, but I can't find out how to charge the batteries via solar cells. what module would you need for that...?!
please help and thank you

 

[Externet]

Welcome.
'Little' means nothing; 10 to 15W may not be 'little' for many. 4 lithium cell if in series, can be around 12V to 16V depending on chemistry and the charge voltage should be not more than 14 / 16.8V for the group. BMS board should be used then, and the solar panel should be of a voltage that the BMS can manage. If li cells are in parallel for a parallel LED string, a solar panel should be of according voltage at full sun.

For charging a cell to 4.200V, a solar panel of 5V (10 cells) is fine connected with a silicon diode to drop the excess voltage. No charging management board added.
Solar panels are current sources, not voltage supplies. Their behavior is they present their voltage of around 0.5V per series cell as soon as some light hits them with no load. The open-circuit voltage is present with little change at varying light levels. When sunny, their voltage does not drop with a proper matched load, it is then capable to push current to a load with stable voltage.

(-)----------------(-)5V solar panel(+)-------------|>|---------------(+)Li cell(-)-----------------(-)

Feeding the LEDs is just taken from the cell above, not drawn.

 

[Alec_t]

Welcome to maker.pro!
A 10W solar panel is never going to power a 15W LED strip, nor even a 10W one on a cloudy day.
You need a dedicated charger module to suit the cell chemistry and the number of cells making up a battery.
Is this a school/college assignment?

 

[Lziga55]

Welcome to maker.pro!
A 10W solar panel is never going to power a 15W LED strip, nor even a 10W one on a cloudy day.
You need a dedicated charger module to suit the cell chemistry and the number of cells making up a battery.
Is this a school/college assignment?

Hi, so we have a small old house without electricity. It is on top of the hill and its always sunny there. I need light there like once a month so I tought that 10w solar panel and 50Wh battery would be enaugh. And 9W is 4 meters of my led strip so probably it will be enaugh.
Question. Dont i need some kind of over charging and discharrging protection.. I dont have any idea how to do it. I thought that i should bought 4s bms and connect batteries to it and than connect solar panel to it somehow but yes, I need constant voltage so I need something between that. Please correct me if I am wrong. And output probably is same as input voltage so i need regulator there too. Actualy this isnt school project, but maybe it will become school project we need to make something in pairs or alone in school until january so maybe this will become school project or maybe it wont

Thanks for help

 

[Lziga55]

And I meant little electrarn as small. Sorry for my bad english.

 

[Alec_t]

Dont i need some kind of over charging and discharrging protection.. I dont have any idea how to do it.

Buy a proper balanced charger. The BMS provides over-charging and over-discharging protection.

 

[Lziga55]

Ok, if i use bms lets say 4s it needs 14 to 16 volts input for charging. How do i get constant voltage from solar panel?

 

[Lziga55]

I have an idea but I dont know if it will work. Solar panel 12v -> dc to dc step up converter to 16v -> 4s bms

So if solar panel would produce more than 4v it would convert it to 16 v which would charge bms - bateries.

 

[Externet]

Your ideals :

---> https://www.aliexpress.us/item/3256...582824!sea!US!0!AB&curPageLogUid=eiVoy9hS9EK6

---> https://www.cricklewoodelectronics....x-3.7V-Lithium-batteries-with-protection.html

---> https://www.aliexpress.us/item/3256...96&pdp_npi=4@dis!USD!29.17!7.0!!!211.99!!@210

---> https://www.aliexpress.us/item/3256..._id=202310021252283423000618971180009959709_9
3010c16962754728418514ea231%2112000034449794141%21rec%21US%21%21AB

With light ---> https://www.aliexpress.us/item/3256..._id=202310021236186689656225676100004577991_4

These have a switch that you can turn on when you visit the place ---> https://www.aliexpress.us/item/3256...763079!sea!US!0!AB&curPageLogUid=TC9Sdn2tjfqa

 

[Martaine2005]

Hoora for Cricklewood electronics!. These great shops are dying by the dozen.

Martin

 

[Bluejets]

So if solar panel would produce more than 4v it would convert it to 16 v which would charge bms - bateries.

Don't start out as a "free energy" geek.
One good rule to remember, surprised you haven't learnt it yet, energy out is equal to energy in , minus losses.

 

[Lziga55]

Don't start out as a "free energy" geek.
One good rule to remember, surprised you haven't learnt it yet, energy out is equal to energy in , minus losses.

I know I just want to try and learn something. I just dont know if this what i said before would work. And I know that there are cheaper products available, but where is all the fun it buying stuff

 

[Alec_t]

but where is all the fun in buying stuff

It's more fun than the fire or explosion which could result from messing about with a home-brew design if not built properly. Lithium batteries are dangerous if not charged and discharged correctly.

 

[Lziga55]

It's more fun than the fire or explosion which could result from messing about with a home-brew design if not built properly. Lithium batteries are dangerous if not charged and discharged correctly.

That is why i will use bms

 

[bidrohini]

You can get some idea from here.

 

[Lziga55]

Thanks!
What do you think about this module:
Just found this amazing item on AliExpress. Check it out! €1.84 12%OFF | TZT 3.7V 4.2V Charger 5V 6V 9V 12V Discharger Board DC DC Converter Boost Module For Diy Solar Mobile Power Charger Module

https://a.aliexpress.com/_mO44xEe

I want to try and build something or connect together and i think that this would work!

 

[Delta Prime]

and i think that this would work!

Prove to yourself that it will work do not think! Know!
I'm being the devil's advocate here! It will not work.
For the sake of your little house on the hill. there's no way around it he must do the math.