The WellSee MPPT solar charge controller is much criticised for being a fake. I thought I'd put it through a few tests.
By Julian
Youtuber, shed dweller, solar charge controller aficionado
Good morning all…
Youtuber, shed dweller, solar charge controller aficionado
This site uses Akismet to reduce spam. Learn how your comment data is processed.
You have to also check the currents. If mttp is working power loss would be minimal. Not conclusive but my impression: fake mppt, just pwn. That’s why you got so low panel voltage.
Edit: I am here because I found this on my long time ago discarded electronics pile and well just to make sure it was on the right place 😂
Oh and they are still selling this… thing.
Edit: I remembered they said in the manual that you must put a coil of certain muH for mppt. I just did that (well with a wild guess about the inductance) and… some mppt seems it is there.
For me, this thing seemed to do everything correctly but MPPT lol. I remember being so bummed when I hooked this controller up like you did and took my measurments and found that the amount of energy I was getting into my battery with the controller being utilized was the exact same as when I was charging my battery without it! Talk about dissapointing lol. I learned a valuable lesson though: research your purchases before you buy them!!
To see if is MPPT get voltage and current of solar panel, and then voltage and current going into a drained battery. When you are above 13.2 volts you have a fully charged battery and if it gave the batteries full charge it would hurt them. The volts on your meter are 13.7 volts. The bulk charge could be 14.4V , the float about 13.3V
***** and by better you mean exactly the same number but without the negative sign? LOL. I think you shouldn't play with electricity.
Crude method of control? Not MPPT,Not PWM… a Shunt base regulator?
Just remembered….There's another guy on Youtube that replaced the inductor with a larger one although he didn't feel he got much more out ov it though.
The reason why I'm particularly interested is that there is a current school ov thought that since panel prices are substantially dropping, it is often cheaper to just get a few more panels and use PWM controllers. And in my situation I have been able to pick up quite a few polys for a very good price (around $1NZD/watt). However the weather here where I live is often overcast since we are semi coastal but close to the hills. So that's the situation I want to optimise.
I'm guessing it works best when the difference between panel voltage and battery voltage is greatest. So, as you say, low battery voltage and high panel voltage which occurs when the panel is cold. If you're right about mono and poly panels, then I guess mono would work best with MPPT. I'm hoping that my experiments will answer some of these questions.
That will be interesting to see how you go with that design. 🙂 One thing I am curious about is does MPPT really do a good job during low light conditions? I understand it works very well on a sunny winter morning when your batteries are low, but some say it's great under cloudy conditions, but others say its lousy. I wonder if it also depends on the panels you use? I have noticed that the voltage ov polycrystalline panels falls faster in low light than mono ones.
Nope. It doesn't track, it's very unlikely to get anywhere near maximum power point unless the solar panel is very tiny. It was seeing how poor this thing is that finally made me decide to have a go at designing an MPPT controller myself.
Yeah I bought one ov these & I tested it exactly like you did, comparing the battery volts with the panel. And initially I thought it was good until I realised that a PWM could allow the panel voltage to rise while it was "PWMing".. 😉 So the next test was to compare the current with the Wellsee in & with it out (bypassed). Guess what? More current flowed into the battery with it switched out than with it in! That's not really MPPT is it?
The Wellsee has no algorithm – the 555 oscillator runs at a fixed frequency and mark/space ratio so there's no control of any kind.
I want to build a manually controlled MPP controller where I get to operate inside the control loop. That way I will get a feel for how the tracking algorithm should best operate. Ultimately this may lead to an Arduino based MPPT controller – which will be open source.
Yes, you're right – MPPT is only used during the bulk charge phase. At float you don't want maximum power. I would like to see the controller switch to a low frequency PWM during float charge.
What do you get with a dead battery? Say at 10.5volts. I would have thought that is when MPPT would work best. The closer you get to charged, wouldn't it float the charge? Sort of just keeping an eye on the battery. MPPT not required. I know nutting. Just asking questions of interest to me.
I FOUND THE SWITCH. Bulb now on in sky.