Ha ha, nice one. The user twiddlable max power point is perfectly adequate. This is a nice little board for use with small panels (given its 300W limit) where you want to charge a variety of small batteries. Find me a solar controller near this price point which offers some form of max power point configuration, and does both buck and boost on the CC/CV output for battery voltages both higher or lower than the solar array input.
The idea of MPPT (t stands for tracking) is that if a cloud passes by (not a huge one of course), it still manages to find the sweat spot (max Power). Your device does not track. And I see many comments saying exactly that. You can get better MPPT devices, and they are (or should be) worth their money if they do their job well. If there is a good working ESP32 version anywhere, I would build it.
If the voltage setpoint is allowed to vary a little with current and temperature, it's possible to get pretty close. That can make sense for smaller panels where a full MPPT isn't worth the complexity.
But as the video shows, the maximum power point voltage doesn't vary much with different amounts of light (because solar panels vary their maximum current in response to light, not so much the voltage), and even if you're off the maximum point by a couple of volts, it doesn't hurt the watts very much. So these fixed-voltage "MPPT" devices do work well in practice, even though the "MPPT" marketing is technically wrong.
@@cmyanmar13 That's true for a single small panel. An array or larger panel that gets partially shaded WILL change voltage, and it's MPPT will vary quite a bit.
@@chrisw1462 one could connects the panels in parallel if max current permits lol... or get a bunch of those converter and put one per panel at that price haha
These are not really MPPT chargers because they don't do tracking. They operate according to a setpoint. However it should be quite easy to modify something like this into a true MPPT by adding a microcontroller to monitor the voltage/current and "twiddle the pot". A simple Arduino circuit should do it.
Really interesting idea! Sweeping the entire IV curve at regular intervals seems the easiest to me. Maybe also maintain logs of how fast conditions are changing, so the sweeps can be done at longer or shorter intervals according to the prevailing rate of change. What would you replace the pot with, a transistor with it's base driven by the arduino or something?
@@nginmumbetse7894 you could use a digital potentiometer. There isn't even a need to sweep the whole curve. Just the area around MPP is enough eg around 70 to 90% of open circuit voltage. But better yet would be directly modulating the PWM from the micro.
@@cccmmm1234 I get confused looking at charts where there are several different MPPs, local and global, and other strange (to me) behaviour. This added to talk of oscillation in hill climbing methods just led me to think a full sweep might be the best bet, but I'm the first to admit the guts of MPPT are a little beyond me
@@nginmumbetse7894 Yes, MPPT can oscillate, but small oscillations don't really matter so long as they are close to the MPP. The problem is when there are large steps and there are multiple peaks. These are probably best addressed with a sweep. So maybe the best is to do hill climbing (even if it oscillates slightly), then try a coarse sweep every minute or so to make sure you're not stuck on a local minimum.
everybody is complaining this device is not real MPPT and other complaints. But this board is super cool for me because I want to build a power supply out of parallel buck converters, this is just perfect device, you have fluctuating input voltage, and you put lots of these in parallel to get a single output (relatively smoothed) voltage, and you get power supply redundancy. Power supply like these (which can be connected in parallel) for 2,000 Watts cost like 500 bucks. Here for 30 dollars you can buy a 700W buck bust converter (aka MPPT ZK-SJ30) , 3 pieces would be enough to make a redundant power supply of about 2000W
That's interesting! I wonder why there isn't more cheap charger pcbs from china with real MPPT tracking! In my uneducated head it seams relatively easy ic/device to make/develop. Simple maximizing of output power by limiting output current until V on input reaches V MPP!
There are many constant charging variables influencing the MPP . Maybe this can be the case for controllers with a small AI implementation to track the maximum power of solar cells. Potentially, later loading the discovered data into a multi dimensional mapping array; similar to what we have on car ECU(s).
I'm finding my panels (old secondhand 230W panels ex solar farm, roughly 40V Voc, listed Vmp 29V) are giving me the best output at 26V on the MPPT twiddle pot, today. Really cloudy October day late afternoon, panels in shade, getting a whole 2 Watts! I noticed that as I creep up on 26V on the MPPT pot, the output rises very steadily until just above 26V, there's a very sudden collapse of the output. I guess this makes sense when you look at the shape of the power curve. I got to thinking - is it better when setting the MPP 'target', to choose a level a little lower than the one you think the panel's going to operate at, most of the time - so that although you'd be harvesting a little less power overall, you might avoid 'falling over the cliff' on sunnier days, and stay on the more gently sloped side of the power curve? I don't know how much the MPP shifts around but I might try say 24,25V instead of my 26V and see if it gives more 'consistent' operation
from what I read it can be powered from both sides (either input or output) , but I guess the best thing would be buying a 12 volt AC adapter for something like 200 milli-amps, and connected it through a diode to the input. this way it will be powered 24/7 and if the battery goes out of power it will still be able to operate.
I would call this a MPP in that it is able to be adjusted to its maxiumum power point. But no T as it does not track, ie automatically adjust itself (to try obtain the maximum wattage from the panels available amps X volts)
hello, I have an SJ20 without the LCD display. I don't know how to adjust the MPPT potentiometer... I connected it to my small hydroelectric turbine but when I turn the MPPT potentiometer, nothing happens... what do you think?
I connected bulbs as load. in fact I can adjust the output voltage, and now the input voltage if the input voltage is approximately 10 volts higher than the output voltage. (input voltage: approximately 36/38 volts, output voltage set at 29 volts) impossible to lower the input voltage via the MPPT below a certain threshold, which is related to the output voltage...
Mine no longer charges after I accidentally reversed polarity then I saw a bit of smoke appear from under the display. No burn marks nothing. They should have put a 20a fuse on this board. Gutted really. I used it to charge all my stuff.
Not REAL MPPT as the T means tracking. This one is kinda MMPP Manual Max Power Point But I think it may be better than the "PWM" ones. "PWM" because it is not even a real PWM, but that is another history...
0:39 - those flexible panels usually do not deliver at all. They are far too expensive and quite often crap based on the specs and what they deliver compared to the real ones. We have similiar 79 W figures in north germany facing south with a 30° pitch. They are more or less a mess considering the price you have to pay. We have only 1 company that is able to deliver 100W as promised but those are far too expensive. We have checked those with a Wp Meter for solar panels and there we got the 79 and 80 W max output, depending on which panel used. But the mppt tracker looks quite fast to me. When you turned it on it had instantly the value which is quite unusual.
I think in this case MPPT stands for "Manual Power Pot Twiddling" :P
😂 I like it 😂
Ha ha, nice one. The user twiddlable max power point is perfectly adequate. This is a nice little board for use with small panels (given its 300W limit) where you want to charge a variety of small batteries. Find me a solar controller near this price point which offers some form of max power point configuration, and does both buck and boost on the CC/CV output for battery voltages both higher or lower than the solar array input.
The idea of MPPT (t stands for tracking) is that if a cloud passes by (not a huge one of course), it still manages to find the sweat spot (max Power). Your device does not track. And I see many comments saying exactly that. You can get better MPPT devices, and they are (or should be) worth their money if they do their job well. If there is a good working ESP32 version anywhere, I would build it.
If the voltage setpoint is allowed to vary a little with current and temperature, it's possible to get pretty close. That can make sense for smaller panels where a full MPPT isn't worth the complexity.
But as the video shows, the maximum power point voltage doesn't vary much with different amounts of light (because solar panels vary their maximum current in response to light, not so much the voltage), and even if you're off the maximum point by a couple of volts, it doesn't hurt the watts very much. So these fixed-voltage "MPPT" devices do work well in practice, even though the "MPPT" marketing is technically wrong.
@@cmyanmar13 That's true for a single small panel. An array or larger panel that gets partially shaded WILL change voltage, and it's MPPT will vary quite a bit.
@@chrisw1462 one could connects the panels in parallel if max current permits lol... or get a bunch of those converter and put one per panel at that price haha
if a cloud passes you will get less power no matter what, no algorithm is capable of getting energy from nothing
it is just a fixed input voltage, not much tracking on that device :P Julian is the T part :D
These are not really MPPT chargers because they don't do tracking. They operate according to a setpoint.
However it should be quite easy to modify something like this into a true MPPT by adding a microcontroller to monitor the voltage/current and "twiddle the pot". A simple Arduino circuit should do it.
Really interesting idea! Sweeping the entire IV curve at regular intervals seems the easiest to me. Maybe also maintain logs of how fast conditions are changing, so the sweeps can be done at longer or shorter intervals according to the prevailing rate of change. What would you replace the pot with, a transistor with it's base driven by the arduino or something?
@@nginmumbetse7894 you could use a digital potentiometer.
There isn't even a need to sweep the whole curve. Just the area around MPP is enough eg around 70 to 90% of open circuit voltage.
But better yet would be directly modulating the PWM from the micro.
@@cccmmm1234 I get confused looking at charts where there are several different MPPs, local and global, and other strange (to me) behaviour. This added to talk of oscillation in hill climbing methods just led me to think a full sweep might be the best bet, but I'm the first to admit the guts of MPPT are a little beyond me
@@nginmumbetse7894 Yes, MPPT can oscillate, but small oscillations don't really matter so long as they are close to the MPP.
The problem is when there are large steps and there are multiple peaks. These are probably best addressed with a sweep.
So maybe the best is to do hill climbing (even if it oscillates slightly), then try a coarse sweep every minute or so to make sure you're not stuck on a local minimum.
everybody is complaining this device is not real MPPT and other complaints. But this board is super cool for me because I want to build a power supply out of parallel buck converters, this is just perfect device, you have fluctuating input voltage, and you put lots of these in parallel to get a single output (relatively smoothed) voltage, and you get power supply redundancy. Power supply like these (which can be connected in parallel) for 2,000 Watts cost like 500 bucks. Here for 30 dollars you can buy a 700W buck bust converter (aka MPPT ZK-SJ30) , 3 pieces would be enough to make a redundant power supply of about 2000W
That's interesting! I wonder why there isn't more cheap charger pcbs from china with real MPPT tracking! In my uneducated head it seams relatively easy ic/device to make/develop. Simple maximizing of output power by limiting output current until V on input reaches V MPP!
There are many constant charging variables influencing the MPP . Maybe this can be the case for controllers with a small AI implementation to track the maximum power of solar cells. Potentially, later loading the discovered data into a multi dimensional mapping array; similar to what we have on car ECU(s).
I'm finding my panels (old secondhand 230W panels ex solar farm, roughly 40V Voc, listed Vmp 29V) are giving me the best output at 26V on the MPPT twiddle pot, today. Really cloudy October day late afternoon, panels in shade, getting a whole 2 Watts! I noticed that as I creep up on 26V on the MPPT pot, the output rises very steadily until just above 26V, there's a very sudden collapse of the output. I guess this makes sense when you look at the shape of the power curve. I got to thinking - is it better when setting the MPP 'target', to choose a level a little lower than the one you think the panel's going to operate at, most of the time - so that although you'd be harvesting a little less power overall, you might avoid 'falling over the cliff' on sunnier days, and stay on the more gently sloped side of the power curve? I don't know how much the MPP shifts around but I might try say 24,25V instead of my 26V and see if it gives more 'consistent' operation
Does this stay powered on using battery voltage, or do we need to turn it on manually the next day when the sun goes down and comes back up?
from what I read it can be powered from both sides (either input or output) , but I guess the best thing would be buying a 12 volt AC adapter for something like 200 milli-amps, and connected it through a diode to the input. this way it will be powered 24/7 and if the battery goes out of power it will still be able to operate.
Nice test.
Good demo but would be interested it's efficiency (not watched part 2 yet).
If we cant limit current output then how can this be used for CC/CV charge cycle?
I would call this a MPP in that it is able to be adjusted to its maxiumum power point. But no T as it does not track, ie automatically adjust itself (to try obtain the maximum wattage from the panels available amps X volts)
hello, I have an SJ20 without the LCD display. I don't know how to adjust the MPPT potentiometer... I connected it to my small hydroelectric turbine but when I turn the MPPT potentiometer, nothing happens... what do you think?
I connected bulbs as load. in fact I can adjust the output voltage, and now the input voltage if the input voltage is approximately 10 volts higher than the output voltage. (input voltage: approximately 36/38 volts, output voltage set at 29 volts) impossible to lower the input voltage via the MPPT below a certain threshold, which is related to the output voltage...
Do you get much power boost if you attach garden hose to the back of the panel to keep it water cooled?
No power boost at all!
Disappointingly, the SJ20 only yielded 13A max current in a recent test.
Mine no longer charges after I accidentally reversed polarity then I saw a bit of smoke appear from under the display. No burn marks nothing. They should have put a 20a fuse on this board. Gutted really. I used it to charge all my stuff.
resurrect the muppet!
🎼🎵🎶"Here Comes the Sun, Doo-N-Doo-Doot..."🎶🎵🌞😁⭐⭐⭐⭐⭐
Not for long - it's raining again tomorrow :(
Not REAL MPPT as the T means tracking.
This one is kinda MMPP
Manual Max Power Point
But I think it may be better than the "PWM" ones.
"PWM" because it is not even a real PWM, but that is another history...
How many fish 🐟
Not much a MPPT controller when you have to turn pots for maximin smoke!!!
0:39 - those flexible panels usually do not deliver at all. They are far too expensive and quite often crap based on the specs and what they deliver compared to the real ones. We have similiar 79 W figures in north germany facing south with a 30° pitch.
They are more or less a mess considering the price you have to pay. We have only 1 company that is able to deliver 100W as promised but those are far too expensive.
We have checked those with a Wp Meter for solar panels and there we got the 79 and 80 W max output, depending on which panel used.
But the mppt tracker looks quite fast to me. When you turned it on it had instantly the value which is quite unusual.