I'm constantly adjusting this Mppt pot. see where I get maximum power? So 16.8 on the input no 17 and a half. it's dropped off uh, 16.5 down to 15 at 69 Watts So it's definitely around the 16 and a half volt mark and I think the reason that voltage now is maxing out at a slightly lower voltage is because the panel has been in full sun for many minutes and so it's probably pretty baking hot and solar panels have a lower output voltage when they're hot. so this works fine and it will maximize the power output from a 100 watt panel.

But what if I put a 300 watt panel in here like the two panels that are next to the shed. In fact, the left hand panel here the all black one there is 325 Watts and the blue one there is 240 Watts So maybe we'd be all right on the blue, but not on the black. This unit does have a 300 watt limit and in fact it's a software limit. So um, if you go to ah, now you see now the sun's coming out I might better get a bit more power by raising the voltage, possibly a little bit more because the panel cooled down a bit, which is why Mpbt charge controllers actually hunt for the maximum PowerPoint They're constantly moving either side of the current PowerPoint to try and find where that maximum PowerPoint is.

The solar panel will be hot again now, so you probably Max the wattage at a slightly lower voltage. Yeah, this is a software 300 watt limit if it sees 300 watts on this watt meter, it'll shut off the output and say over power I think but you can buy this mod this module without the display and in fact I can take this display off and it will continue to work. So you could potentially defeat that 300 watt limit simply by not having the microcontroller and display on here so that it has no means by which to switch off the output. So there it is.

There's the ZK Sj20 power supply charging the power. Queen Life Pro 4 Battery We've just got a cloud at the moment I'll wait for the sun to come back out. You can by using the Mppt function, allow the solar panel to rise up to its maximum power voltage. even if the battery is a much lower voltage which it is about 13 and a half on the battery, 16 and a half on the solar panel.

If I allow the solar panel to come right up to a much higher voltage like 20 volts, you can see the power output collapses away to nothing. It's simply unable to develop any power when it effectively open circuit. General Is a high voltage, but no power. Bring the MP voltage back down to about 16 and a half and we're developing 75.

Watts Bring the maximum power voltage right down to 12 volts and it's not so bad. I Mean it's still 60 watts? And then of course, if we go down to ridiculously low voltages like eight Nine volts, we do get significantly less power. Turn this pot quite a lot. It doesn't seem to be entirely linear, so yes, it definitely prefers well definitely develop more power at a voltage which suits the solar panel, and hooking a solar panel directly to the battery will of course pull that amount of power down because it can't develop the voltage it wants in order to maximize that power.

Now I don't know quite where that battery is in terms of its state of charge. We can estimate it with 70 watts of power, it's being pushed up to 13.6 volts. So I don't think it's anywhere near being close to being charged because we'd be looking at voltages closer to 14 if it was near the top. So that's about all I can do with this thing until I Get the fans once I get the fans and I can get this thing properly cooled I Can try driving it at higher power levels.

Um, higher current levels on both the input and the output. but I think that's it for this video I am battling with the clouds a little bit. But yes, I'm able to charge that battery using this module from that solar panel. Now at 70.

Watts this is hot the heatsink is I mean it's not at the point where I have to take my hand off it, but it's very close to that. My hand is hot under this heatsink and any hotter and I probably I'm pressing my hand up against it now, but any hotter than that and I probably wouldn't be able to hold my hand on it I don't know what temperature that is about 50 degrees, maybe something like that. Now you might want to set a lower voltage limit on the output because you might be thinking okay I don't want to charge the battery Beyond say 14.2 volts. We can set that because if I set this to output and now I just disconnect the battery which I'll do with this banana plug.

We can see that currently the pot is limiting at 14.5 volts. if I bring that down to 14.2 volts which is about there and reconnect the battery. we're getting less power and I don't know whether you can see this but the Mppt light the blue one is not actually on and I can get it to come up by slightly raising that limit on that um, control voltage part. But now if I disconnect the battery, the output voltage maximum is 15.2 which is a bit too high.

So certainly if you want to impose a voltage limit to prevent the battery going over voltage, it does slightly impact on the control. Loop For um, the maximum power point, let's just bring this back down to 14.2 again, so limit the voltage to its it's quite Twitchy Oh yes, it's all over the place. Okay, 14.2 reconnect the battery. We're now a little bit down on power.

Let's look at the input CV which is the Mppt point and can I increase that power? Yes, I can by taking the solar panel voltage down I've actually raised it a couple of Watts So it does impact on how this thing operates if you want a voltage limit on the output. And now because it was just getting a tiny bit warm I've stuck it on top of my Ryobi fan. Tickle it down a bit. Cheerio!.