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johansen Newbie Joined: 01/08/2014 Location: United StatesPosts: 3
Posted: 09:31pm 30 May 2025
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Has anyone here thought to build a solar mppt from off the shelf adjustable power supplies?
Take a cheap power supply like this for example https://www.ebay.com/itm/156427262392
and replace the voltage adjustment potentiometer with either a digital potentiometer controlled by something. Or a linear method using analog electronics.
you will need a resistor to divide down the solar voltage going in, and monitor it so that it feeds forward into the output regulator to avoid oscillations and shutdowns.
Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1156
Posted: 09:59pm 30 May 2025
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Guess the idea is possible; if one has the skills to modify an existing PSU and design the ancillary electronics to make it work; there are a number of practical problems in doing this.
The donor PSU would have to work off the PV supplied voltage and more so have its electronics run off the battery with no PV input. Extra external control circuitry to monitor Input voltage, Output voltage and current, be it in the form of a CPU or some other decision making logic. By the time you do this extra work, it would be easier to just design and build the whole thing from scratch.
Cheers Mike
JackS Newbie Joined: 04/03/2009 Location: New ZealandPosts: 8
Posted: 03:54am 31 May 2025
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You might get some ideas from Warpspeed's https://diysolarforum.com/threads/simple-home-made-analog-mppt-contoller.47057/