Your opinions on my solar charge controller design, Improvements???

Thread Starter


Joined Oct 11, 2019
Hi I am currently wanting to make some solar powered lights. I could buy a charge controller for a sla battery, Cheap enough but id like something I can fix. Doesn't have to be top spec just has to charge a battery.

Edit :Just realised a silly mistake. Using a 12.1v zener in the voltage regulator makes more sense then a 12v relay. Also would be more efficient. Durrr me

Iv come up with this design. Before ordering the bits. Does anyone see any issues with the design. I am only using a 25w panel.
The bottom bit is me switching from 13.4v to 13.5v. The slope is about 10ms.

Kind regards Rick
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Joined Nov 6, 2012
There is no need to turn anything "On" or "Off".
Just replace the Laptop Power Brick in this Circuit with your Solar-Panel.

If You want to add more Panels,
just put this same Circuit on the Output of each Panel,
then You can parallel as many as you'd like, and they will all play nice together.
2-Amp Battery Charger FLAT .png
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