I've fitted a new potentiometer with a nice visible numbered dial which makes it much easier to see the relationship between PWM percentage and resultant power. Also, time now to check the buck converter components can handle 80 Watts of power throughput. As for sprinkling, you'll have to watch the video!
By Julian
Youtuber, shed dweller, solar charge controller aficionado
Great vids Julian, picking up lots of tips. Had a thought about cooling the panels, what about combining systems so that the panels could heat the house water storage tank, therefore more efficient panel output and excess heat stored in the tank = more efficiency, what do you think?
Hi, thanks for the video.
Can you put an ebay link for the automatic volt swicth.
Hey Julian, mind sharing where you got the potentiometer from? I've searched "large potentiometer" on google, but results are mixed in with "pots" etc for cooking.
I tried that in my video about the 20W panel and 21W bulb – not too successfully. The buck converter in a solar charge controller needs to regulate the input voltage (the panel voltage), not the output voltage (battery voltage).
That makes sense. How well would a basic DC-DC buck converter with the output set to 14 volts work? I know that it wouldn't track the maximum power point for varying conditions but would it work to take advantage of the power wasted under the standard sunny conditions of a solar panel producing 18 volts and a battery only needing around 14 volts to charge?
I don't have a schematic drawn up yet, but I'm thinking about starting a blog to support my YouTube channel which would have schematics and software listings.
There is always an advantage over PWM, but if small, that could easily be lost overnight if the MPPT unit has a higher standby current than the PWM unit. When MPPT units claim a 30% increase in power over PWM units, conditions have to be ideal for that to happen. You have to read between the lines of the marketing hype. It may well be cheaper to invest in larger solar panels and PWM controllers
Does this mean that there is no advantage to having an MPPT over a PWM controller on an 18 volt solar panel unless the panel is cold?
is it possible you could send the schematic to my email it looks real good my adddress is ayoung_585@yahoo.com thank you
this project looks coolkeep up the good work
The charge pump works fine, but there's another big design challenge coming up – watch this space!
Yeah, the hot panel had max power at a much lower voltage than the cold panel.
I think a sprinkler system (or even a closed-loop water cooling plant) would be hard to justify on cost grounds – probably cheaper to buy more panels.
I'm not sure it's time to "close the loop" yet. The voltage and current sensors need filtering – the Watts bargraph is just too jittery, jumpy, noisy to track properly. Then I need to play the part of "controller" to get a sense of how the tracking algorithms will work