I bought an arduino uno 3 and was thinking about making a line follower robot or any other stuff but with solar panel as a power when I researched about it , I figured I should use lithium batteries but I don't know which of these charging module should I use https://makerselectronics.com/product/mppt-solar-controller-5a-dc-dc-step-down-cccv
or this https://makerselectronics.com/product/lithium-battery-charger-protection-module-bms-3s-25a-12v
or should I use this I want to power a big project like I use 8 batteries energizer usually
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or can I just attach solar panel directly to arduino and thanks in advance
Lithium batteries are very dangerous if overcharged, among other risk factors. to mitigate this risk, most commercially available batteries are sold with protection circuits built into the connection.
This battery has no protection.
This one is protected.
Solar cells produce a varying voltage at a constant current depending on the available light intensity.
I've used a TP4056 charging module and I've never had issues
As long your charging module has overvoltage and undervoltage protection you should be good.
In any case don't peer anything directly from your lipo and alsways test the over and undervoltage protection of every charging module before I lengthening it to your project so you know it's working properly.