Cheap(est?) Lithium MPPT Solar Charge Controller CN3722 - 12v Solar Shed
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- Опубліковано 30 вер 2024
- I've been trying to find the cheapest solar charge controllers the internet can provide for a little while. In previous videos I've been able to recommend some really cheap PWM solar charge controllers but the cheap MPPT versions have been fake. This time however I think I may have come across something which could be classed as Maximum Power Point Tracking.
❗️These links are affiliated and I may earn a small commission if you purchase❗️
CN3722 Lithium MPPT Charge Controller: ebay.us/mTXQBE
CN3722 Datasheet: admw.uk/j5
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A nice video but I feel these two watt meters are effecting results. Because you are only using such low watts with them in this test they each are drawing a significant portion of the power away from the charging of the load. I feel you need a much larger load. These test should not be done on a battery that is almost fully charged because the watt meters will be consuming a significant portion of the total load of the panel output as compared to what the battery is consuming.
Thanks mate great video. I've been undecided on which charge controller to go for as I have many 18650 projects and all of your video's on this subject are a great help. Cheers
You need to check the Vmpp at NOCT for the solar panel, not 25C. Panels are normally pretty constant voltage, so the datasheet is pretty much correct in that sense.
In normal full sun a 72 cell panel has a Vmpp of 36 Volts at 25C, but that's about 33 Volts at 65C (the actuall cell temperature). Your panel should list it's temperature coefficient on the rear sticker.
Useful info - thanks very much.
@@AdamWelchUK Yes, but you have a 12V panel at 10W. So not surprised they designed it to operate at 17V - 18V Vmp.
very nice info
+jehugarcia Thanks Jehu.
Garcia papa tu me apareses hasta en las sopas lol
You didn't say anything about the heatsink on the back of the board. I just got one of the adjustable modules. The heatsink is held to the back of the board with a glob of silicone rubber. The heat sink is mounted precariously and can touch the solder joints on the board. I am heatsink gluing a smaller heatsink directly to the diodes and MOSFETs. I don't trust their design.
Maybe you could have cut some squares out of aluminium and use thermal adhesive to stick them directly to the PCB and then replaced the original heatsink onto them... Or even go for a larger heatsink.. they do get quite warm when delivering 5A..
I have been doing the same comparisons with a 2 Amp, 3 Amp and 5 Amp MPPT board. I am getting similar results.
What I found is that the cheapest board (the first one shown) is set for a 17 vdc Solar input, and the output is set to 12 vdc. What they say for specifications is wrong. Also, the maximum current is 1.5 Amps instead of 2 Amps. Again, misleading. You have to change the CV ratio and the MPPT ratio on the boards to get them correct. Then there is the cheap parts they use. I blew the 0.1 Ohm Current Sense Resistors after a few tries. Probably rated for 1 Watt. I replaced them with 7 Watt Resistors and they are working fine.
The 3 Amp boards I bought had one adjustment for output voltage. No adjust for input. Still set for 17 vdc. They ran pretty well until, again, blew the 0.07 Ohm Current Sense Resistors. The current limit was 2.5 Amps. Changing them now to 7 Watts.
I have yet to receive the 5 Amp versions that are the same design as you have. I will test those next.
Thanks for this - very useful to know. Shame that it seems they've under-rated some components. Best of luck with the 5 amp version
its more like a manual power point tracking (mppt) device, but as long as you can track maximum power transfer point at the battery side, you should be ok, i guess.
Manual is so much better! I have had the opportunity to use an automatic MPPT charge controller and half the time it spends looking for the best point while the battery is not charging, it Hunt's around every single time a cloud will pass overhead... Not this thing! I'm really impressed with it's performance! I don't think that the solar panel ratings printed on the back are exactly accurate! I have tried different wattage panels and these charge controller's can be adjusted to get more than 20W from a 20W panel.. I have tried other wattage panels and it's exactly the same situation there too! I have since purchased over 10 of them... They just work so much better than anything else that I have tried or seen...
@@PeterMilanovski ah, you reminded me some very old stuff. 😁
I Wouldn't be worried about the "tracking" as long as I can set a roughly correct Powerpoint. What worries me more is the loss of efficiency of the adjustable board compared to the fixed version. It seems this is much more significant then the missing mpp tracking.
The Increased Current limit to 5 Amps on the larger board is worth it though, in my testing with both boards, the smaller board with about 5 watts going through it had an efficiency of about 98%, the large board with that wattage was about 98 as well, but with 5 Amps being shoved through it, the efficiency was about 89-92% depending on the temperature outside, etc. But still, 5 Amps at 20 Volts Makes for about 7.5 Amps at 12.6 Volts which is an insane difference in charging speed!
unless I misunderstood you, you actually got more wattage into your battery from the first and cheaper version. Or did I miss something?
No not really, as he started to adjust the solar on the second one, if you pause the video right where it gets to 18.2 for the panel, you will see that it actually got the full rated 10W from his 10W panel... He said that his panel should be set at 17.5V for maximum power point tracking but I think that it's actually at 18.2V. I have these and they are excellent! Their outputs can be wired up in series or parallel for more voltage or current respectively... Or both parallel and series at the same time for higher voltage and current... The are very flexible...
@@PeterMilanovski wait you can wire these up parallel? Also I think he set the output voltage too low, the IC seems to be on CV mode instead of CC mode
@@kaikart123 yes you can wire them up in parallel if they are connected to the same battery or battery bank!
I had purchased around 10 of these things and had been testing them on a 36V solar panel which can peak up to 45V, they are not intended to be used with 36V solar panels, the datasheet recommend staying at 24V panels or below, I have found that it can work with 36V but will fail if the battery is disconnected from it while the solar panel is delivering! I have burnt out two of them so far and both times happened when I was touching the test circuit, otherwise the first one ran for 4 months straight, as a load, I used a computer fan which draws 0.5A and an led light which draws 1A and this ran day and night. The second one ran for less time but that was all down to me fiddling with the circuit sooner rather than later... I don't think that it would burn out if I had stayed within the recommended 24V or below... This burn out problem might seem irrelevant but I'm using Lifepo4 Batteries which have a built-in BMS and they will disconnect from the circuit if there voltage drops below it's threshold value and this would cause the MPPT charge controller to burn out should the battery decide to go into protection! The battery would also disconnect if to much current is drawn so that's another potential problem....
But they can definitely be paralleled... Overall, I'm really happy with their performance! And I think that it has something to do with the fact that I'm using the 36V solar panels, I found that it would fire up with the slightest bit of light in the morning and still trying to get every last drop of light at the end of the day, it's actually pretty dark by the time it actually shuts down, first thing in the morning and last thing at night isn't really outputting anything but you can see that it's still trying to give everything that it gets LoL...
It does operate in CV mode, it will deliver up to 100W no problems, figuring out the cut off voltage is a little bit fiddly, I found that starting with a battery that isn't fully charged is a good way to start, after it's first few charge cycles, you can turn up the cutoff voltage to get it to where you want it to be, but once it's set, you will probably keep checking it a few times a day to begin with and later to once a day to once every few days till you just forget about it because it just works! And it needs nothing!
If you have more battery capacity than you actually need to use, in other words, you have enough energy storage to keep whatever you are running off it to keep running for more than two or three days without sunshine, then you won't have to worry about the batteries going into protection due to under voltage...
The batteries that I'm using are those 8Ah types that are usually used in computer ups power backup thing's, they are expensive per Ah but cheaper as a 12V complete battery that I don't have to build myself and it's protected against everything and has a built-in balancer! At $66Au each, I can purchase one a week and wouldn't notice it out of my pay!
I hope that this helps...
@@PeterMilanovski I never knew you could wire them up in parallel, I need to handle 6A so I could just use 3 of these right?
@@kaikart123 that's correct! With 10 of these I get a 1Kw... They do get pretty warm but with a computer fan also connected to the solar panel, it fire's up when the panel wake's up and shuts down when the panel goes to sleep which means that it's only working when it's needed, a diode in series with the fan and some capacitors after the diode will delay the fan turn off time, more capacity, more running time! That's just an idea though, if you are going to be using them at their 100W maximum rating, it wouldn't hurt to have some active cooling, either way, it has electrolytic capacitors on it and it's always best practice to keep them as cool as possible for long service life, capacitors next to a heat source always fail first before others that are further away from the heat source...
Thank you for posting this, I noticed that with the second module that the MPPT potentiometer did a better 10w (at 18v) on your video than the recommended 17.5v at 9.5w as you were adjusting it up&down
The available manuals of the second module recommend that you find the best MPPT point (constant voltage) of the panel you are using by adjusting the MPPT potentiometer
I also agree, I saw the second one peak at 10W when it was at 18.2V for the solar panel... I have since purchased a few of these and I'm impressed with how good they work! They can also be used in parallel for more current and I also found out that they don't like to have a solar input with no battery connected, they die, don't ask me how I know LoL. It turns on as soon as the panels see a tiny bit of light in the morning and won't turn off until it's almost to dark to see! They really try to get as much energy as possible!
After playing around with a couple of them, I purchased more of them!
I'm using 12v Lifepo4 Batteries and I have one of those controller's on each battery which the batteries are wired up in series! Apart from the 12V batteries having their own built-in BMS to balance the cell's inside, I don't need any other BMS because the charge controller looks after it's own battery and if one is at full charge, the rest keep charging! It's brilliant!
If I want to achieve 6A, can I use two of them on the same panel?
That is what happens when you get salesmen writing data sheets. This is a MPPC chip and that temp sensing input is for a temp sensor on the panel, NOT the battery. Frankly I am a big believer in MPPC and all my controllers at camp are MPPC. Power point voltage really only needs to be set seasonably as typical panel temps don't vary much. The big advantage is multiple controllers can be set to slightly different voltages as little as 0.1V difference to give priority to loads. This allows me to charge battery as primary and secondary send any portion of power to a water heater. This all happens seamlessly. While this chip has LI charge control, any buck converter can be turned into a MPPC controller or Linear Current Booster for pumping water without a battery.
I agree 👍 I am using the second one in this video and after watching it and setting up the mppc plus the cutoff voltage, it just works! No hunting around for the best point when a cloud will pass overhead! Some days I think that the MPPT charge controller that I used to use spent more time hunting around than charging! Because they won't charge until it's found the point! These things work in parallel or series or both LoL.. super flexible... I love it 💖.
When you lowered the input voltage to 15 V, battery watt meter reported higher wattage going to battery, which is I guess better compared to 17.5 v on input
I saw the input wattage climb to the full 10W when he gets the panel voltage to 18.2V...
This circuit is is simple, but nuts. It's a very good circuit. I have actually ran this MPPT board with my 60 watt solar panel, Output maxed out at 36 watts, Charged my battery pack 3S 11.1V Lithium Ion 10AH Battery pack and it recharged the battery faster than my switch mode power supply board i bought from ebay. That current conversion and 10% higher efficiency make all the difference.
mentioned in the video that the panel has a mppt point of around 17v, is this a value you calculated or something that was provided with the panel??
Provided on the panel.
Suggestion: When testing the output voltage, you can remove the batteries, and use a large capacitor on the battery side of the MPPT to adjust the output voltage of the MPPT/Charger.
It's possible but not while the solar input is active, no load on the output will kill it. Don't ask how I know lol... This is it's only fault, otherwise it works extremely well...
About the non-adjustable lithium version, is the final charging voltage (i.e. 8.4, 12.6 ...) automatically detected by the module?
The final charging voltage is set by a voltage divider on pin 10 - the feedback pin. It actually goes into constant voltage mode when this feedback pin hits 2.416 volts. So the voltage divider is calculate to suit what ever pack size you are after.
Can you tell me what i have to do to let the 1st board charge a 4s-Lion battery (16,8V) ? Have i to change R7 and what value?
I recognized that turning the pot away from the MPP hightens the output watts to the battery while lowering the input watts from the solar panel. Assuming the important thing is what goes into the battery it seem to me that the whole mppt hype is a bit of a faustian deal, because whats the point to improve the output of the panel while decreasing the output to the battery?
Hi Adam,
First of all I would like to say I love your videos !
But I would also like to place some remarks:
1. You should realy get your watt meters externally powered, so their own power consumption isn't influencing the measurements. (use the portapows or hack-in an external supply)
2. The mppt function of the CN3722 is really more a power point 'targeting' and it does a really good job, especially if you actually use the temparature sensor and mount it on your solar panel.
This since the mpp voltage is fairly constant, but temperature dependent (that's why they note Vpm on the panel 'at 25deg')
3. Note that the power USED by the charger depends primarily on the battery state. And if the solar panel can deliver MORE power than required for charging it will never be in it's maximum power point (resulting in a higher panel voltage)
On the other hand, if lighting conditions are insufficient (clouds) the solar panel will NOT reach it's nominal maximum power voltage (resulting in a lower panel voltage). So the mppt will only be effective in a small range of conditions.
4. When just charging batteries
the battery voltage is 'fixed' so you get an optimal harvesting of energie when you maximize the charging current.
5. The mppt circuitry will lower the current drawn when the panel is below it's Vpm, so on low light conditions (when the panel never reaches Vpm) the output current will become zero !
So do we want mppt at all when just charging ?
As long as the panel voltage stays above the battery voltage (and the buck working voltage) a buck converter will still try to provide the maximum possible current into the battery....
Just give it some thoughts,
and keep up the good work !
yes, but its mandatory to use a temperature probe on the panel. MPP voltage gets quite lower when panel heats up and if you dont monitor the temp, then you might be getting no power at all when still on MPP voltage of 25 deg.
What do i use to charge my enjoybot 100ah battery? I think i want to use a flexible panel on the car rooftop if it will fit. Sw Michigan i think it's like 13.1v lifepo4
LOL! A "book" converter! You plog in a book and the movie comes out!
interesting, i have an 18v /25w solar panel, so the smaller mppt board would put out the required 12.6v to charge the 3s battery pack?, or would i still need a 3s bms board too? thanks . i just want to be sure as i have had a fire with a 3s before lol....
I've written a blog post to show how to set up the second one in this video - robotzero.one/5a-mppt-charger-instructions/ I'll make a video for UA-cam later if no-one finds any errors in the blog post.
Thanks to your insightful video I was able to build my waterfall. Using the second mppt you featured. I used:
18v 50watt panel
4s10p lithium ion pack
It charges amazingly.
I'm using a stepdown to 12.6 volts for 12.6 v 3amp water pump, fans, remote relays and on/off timer also some digital meters and lights.
This is the answer I was looking for. Thanks
I am using four of them with their outputs wired up in series across four Lifepo4 Batteries which are also in series! Each controller looks after it's own battery and when one battery is fully charged the rest keep charging! The batteries are always in balance! I love these little things 💟.. they really are that good!
@@PeterMilanovski , not to mention their price. Shout out to Mr. Welch. Thanks to him we were able to fill our needs
Having tested this at 17,6v Solar input only you are missing the point of this board. It switches the output to be most efficient at lower changing voltages when e.a. the sun is dim or clouds are in front of it. So it's the dynamics of changes that give it its MPPT characteristics. You could have used a power supply with variable output voltage to simulate this.
***** so now there is below 50 quid MPPT that isnt fake.. but it is for lithium. Any idea if similar thing exists for lead acid battery? Thanks for the vid. (or using the adjustable is safe? given the charge profile is kinda.. lithium kind i guess, i dont know how bad it is for lead acid)
+gelisob I guess you say things like that in public and you have to live by them! But technology moves fast and yesterday's newspapers are today's fish and chip wrappers! There is a question over whether this is really MPPT and it's not exactly a fully featured charge controller that one might expect, but it definitely breaks that price barrier!
If you used the adjustable version on a lead acid system it would charge to your predetermined level in the correct manner, after which it would allow the battery voltage to fall away. It wouldn't float charge the battery. I think the charging cycle kicks in again if the cells fall to 95% of the termination voltage. At this point for lead acid the charge controller will act more like a switching charge controller rather than an MPPT or even PWM. I can't see it doing too much damage to the battery though.
Hehe, no worries about the statement - it used to be very true until very recently I believe. I was also following Julian to see if he's arduino-nokia-thingy-madzi mppt gets going for cheaper solution but he didnt seem to finish or make use of it finally, yet. The need for expensive MPPT always made entry to solar a lot pricier.. hopefully these thingies can change it. ordered one adjustable one for testing myself too. And thanks again for the vid, wouldnt have known to look into it otherwise. (ps. hint, you can go put annotation on your 50 quid statement vid tho and make ppl look your other vid too, more views)
Thank you for posting this - I've been wondering about the details of how these little charge controllers do MPPT...
i wonder how much power does the watt meter consume? if you put the two watt meters in line do the displays read the same?
Yeah they are not ideal. I tend to use some now which have an internal battery.
First off, yes, with temperature on panel constant the peak power point will be at a certain solar cell voltage. It will not change based on solar influx.
Once you have set it up for your panel it is good to go. The slight adjustment needed by temp to keep it on track looses minimal power compared to not tracking at all.
As you pointed out it is very specific to input and output voltages so one can resolder to adjust if possible, or adjustable may be preferred.
The higher power designs are as you also point out not as efficient for lower powers. This goes for the expensive controllers as well.
Only way to really confirm it's close to the max power point would be to have repeatable solar influx and test it by load testing the panels and creating the curves for them and compare against what you get from the mppt board. One way may be to simply set a fixed resistor on the output to give a similar load instead of charging an actual cell which will be varying a lot.
You will be surprised at how close it is to peak. Hope you are still having fun with solar!
What do i use to charge my enjoybot 100ah battery? I think i want to use a flexible panel on the car rooftop if it will fit. Sw Michigan
I think it's like 13.1V
What do you think about the ...
"5A-MPPT-Solar-Panel-Controller-Step-down-Constant-Current-Voltage-Buck-Module"
ITEM on eb*y 401616625064 with double LED display
or the 173852402786 with better design.
Your test is great. Would you be willing to try this on a 100-Vin/-20Iout Victron MPPT and show your results. The manufacture claims that with a battery of 24V (6S), it can do a 580W panel and output 98%+ charge with a max of 15A. And if you give a think, these numbers don't add up. Also, they do not publish their MPPT tracking curve. Don't have all the equipment (or expertise) you have. It would nice to see what you get.
I ask this because you will note that the output current of the first and hence the output wattage of the first was far higher than that of the second. And the MPPT I have behaves like the second one, not the first. Roughly you were getting 87% on the first one and 80% on the second one. (In mine, I see numbers like 65 - 75% with manufacture claiming 98% -- and I'm using a panel that is 60% of the rated of 580W ).
When you adjusted the pot to change the MPPT point and you adjusted the volage down to around 15V you said that the input power had gone down. But you did not seem to notice that the charge power had gone up which is what you really want, i.e. more power into the batteries.
+FireballXL55 I've looked back and you are right. It seems the efficiency of the conversion isn't great. As the panel voltage was brought closer to the battery voltage (despite this resulting in lower power on the panel) the battery charge did increase. Perhaps one day I'll retest this. Cheers.
Yes please....a more in depth test would be nice
Adam Welch when the temperature in the solarpanel rises, the mpp drops.
If the temperature of the panel is 50-60°C it's very possible that the mpp is 1.5-2 V lower.
@@AdamWelchUK I would definitely watch that video, I have more than 10 of them and I just love how well they work... I'm powering mine with a 24V nominal panel and I have four 12V Lifepo4 Batteries in series with a controller connected to each battery! They are automatically balanced! And they can be paralleled for more current!
I love them... I have been looking all day through your videos and Julian ilet's also because I couldn't find this particular video, the second charge controller isn't in the thumbnail so I kept going past it LoL... I have been trying to send people to this video but now that I have found it.. hopefully you can get some new subscribers... But please, if you have the time and opportunity, make another video about the second one and put it through its paces... That is if you still have it...
I'm not an expert, but, as far as I know, the maximun power from the solar changes by several reasons, like sun quality, actual load, panel temp, etc...
The maxium power will not be always at a fixed voltage.
So, this controller does something but is not FULL MPPT.
can this use my power wall solar panel and charger to 18650 battery pag, 4C4P setup. need this BMS too whit battery ? i has build 4C 4P battery pack because 3 cell have too low and 4 cell have good can take out step down board regulate just perfect 12,1volt out-. but i not know how and what can charge pack my solarpanel i have 45-100W some panel. normal little battery pack need only 45W panel give out 16-18V nominal 5-7A or my 100W panel 18-24V out and 8-10A what charger need buy ??? battery pack have 18650 bats. 4 cell =max about 14,7V 4P= 4x2200mAH=about 8800mAH capasity. how charging this ?????
seems to only be 70% efficient. and that's good? we have AC/DC power supplies now that are SHOCKINGLY efficient. encroaching 98/99%
Thanks for posting all this info over so many aspects of the main topic. I am new to solar and lithium. Last year I couldn't spell 'lectricity and now I am one. Many thanks. I note you used a 20 watt panel with about i amp of current. My smallest panel is a 100 watt which puts out about 6 amps. Will this be too much for the second, adjustable charge controller. Or, does the SCC just take what it needs. Can anybody clear this up for me.
Yeah not sure about that, I'm using a 24V 5A panel with the second one and it works perfectly fine even though it's maximum input voltage isn't anywhere near what a 24V panel can put out... I have 12V 200W panels but I haven't tried them yet, it's been working so good since I got it four months ago that I have no need to even check it... It's super reliable and fast... If there's any light whatsoever, it will be trying to get every last bit of energy that the panel can see... That's why I have more than 10 of them now...
@@PeterMilanovski Thanks, very helpful to me since I have little working knowledge. I keep finding that the Chinese protocol is to drastically overstate all specifications. I am building small battery packs in plastic ammo boxes and I think this is going to safely work for my needs based on your report and the fact that almost all stated specs are pretty much "bragging versus factual data". Again, thanks
@@davidfloyd9962 no worries! Just be careful because batteries are just batteries and there are things about batteries that not everyone understands. While each cell in a bank looks identical, inside each cell is a different story! Each cell has it's own (what's known as) internal resistance, it's this battery property that determines how fast it will charge and discharge!
In an ideal world we would want all internal resistances to be the same but this is not the case and we can't really do anything about it so we need a solution!
Having multiple cell's in parallel is asking for trouble! Yeah I have seen plenty of people who have done it too! But this is the wrong way to go about it...
I have been working on a solution to this problem for awhile now, I have found that each cell in parallel needs to have a diode in series with it to separate it from the rest in the pack! Then you need to be able to charge each cell separately from each other, in other words, each cell needs it's own battery charger circuit! The circuit must also have an isolated output so that you can place batteries in series for higher voltage output and the charge circuit must also be able to do the same!
I know what you are thinking right now LoL, this sounds really complicated! LoL you should try designing a circuit for this!
You can't just go ahead and purchase one because it doesn't exist! There's plenty of ic's that are designed for charging all types of batteries and I'm struggling to find one that will work with a single cell and has an isolated output! But I'm sure that I will work it out but it's going to take some time...
So! You may ask? Why go to all that trouble when we already have BMS systems that can Ballance the cells!!
Well, with what I'm going to achieve is, much longer battery life! And since each series string is isolated, if one cell dropped to the cutoff voltage in one string, it won't affect the other strings wherein the usual setup with a BMS, the output is shut down when one cell drops to the cutoff voltage even though there's still plenty of energy left in the rest of the cells!, And also, when cell's are charged individually, if one cell gets to full capacity before the others, it stops charging while the rest keep charging!
It's going to be a journey but someone has to do it... It might as well be me since I have already started LoL...
@@PeterMilanovski Thanks for your thoughts! I became aware of those drawbacks shortly after I started tinkering with lithium/solar. I really like Adam's approach to inexpensive but practical utilizations. I follow a few rules since I realize i am fairly ignorant. One rule is "Safety first". I do not recycle used cells unless they have a good pedigree and are closely matched. I have been buying items from Battery Hookup and I am quite choosy as to what i select. Almost always cells that have never been cycled such as their modem packs or new K2s and A123s. I have also bought some new Navitas prismatic Lifepo cells. Of course this opens up a whole world of wiring, bus bars, BMS units, storage boxes, connectors, SCCs and panels. Something of a "tar baby'. again, thanks for the input. DCF
@@davidfloyd9962 no worries, you are welcome!
I am pretty new to this module. Can you tell me if it is possible to charge less than 12 volt batteries, for instance 5v batteries using this module? Or it has to be exactly 12 volts output?
MPPT? ROTFL!
The modules are operating a a FIXED power point 18V.
That might be good under the reference conditions for most 18V panels, but be bad for all other ranges, and an absolute no-go under diffuse light.
I know these modules, built around the CN3767 very well and even use them, but with a tweak around the R1/R2 voltage divisor to provide a real MPPT with software.
Thank you Adam, for checking this out ! ==> seems quite similar to www.ebay.de/itm/272795749639 - MPP Solar 5A Step Down CC/CV Charging Module providing extra manual MPP adjustment + much larger inductor for better efficiency (quite poor with the tiny device you tested here) ... see also ua-cam.com/video/GlnjyFnFiR0/v-deo.html for it's charge performance testing (or start from beginning for all details & variations offered)
Looks like a decent little board for the price. Have you managed to find anything similar but facilitating a single lithium cell or a simple 5v / USB out?
This Channel offers great Value! Luving it!
The MPPT input on the CN3722 is just a input. as datasheet says. That neans you need a external MPPT controller what is aware of tge characterisricks of the solar panel you are using. And thats not only a voltage comming its depends (very) heavy on the temp of the panel and the power received from the sun (think about clouds coming over).
For more info about MPPT: ua-cam.com/video/0ItjKs7aJFM/v-deo.html
One problem with the circuit that I see is that it can't measure the power going in. The way that MPPT works is by measuring the power coming in, and then adjust the input voltage so that maximum power going into the circuit is at maximum. Then use DC to DC converter to put the voltage at the desired charging voltage for the batteries.
Constant Voltage is the cheap and dirty way of doing psuedo-MPPT, a couple percent less efficient than true MPPT charging. If you live in a higher lattitude or constantly cloudy area, those couple percent can make a huge difference in how much power you get over one day. The CN3722 is designed only for Constant Voltage MPPT.
This can charge 6v sealed lead acid battery?.
It has fully charged led?..how to know the Batry is fully charged?
I'm making one of these. As it turns out, the only data you need is the current going into the battery - nothing else matters. You just diddle the PWM signal to get the maximum current into the battery. This is NOT the same as the defined MPPT of the solar panel. Think about it.
AliExpress sellers sell (the first device as) 2s 3s variants. As i have one in hand ,asking if automatically detects output load, hence the voltage. Question stems as i want to charge a 2s and the device might be for 3s.
Very interesting @ 12:40 min by decreasing the mpp Voltage of the panel the output power is rising.
How is it that they make a 5a $5 mppt charge controller then it jumps to like $100.
Because the $100 version automatically tracks the mppt power point and most can take higher voltage for series panels. The cheap one is manual.and limited to 18V
привет из России. город Хабаровск.greetings from Russia. the city of Khabarovsk.
At 28V max in, you can't use the large cheeper panels around 30-40Vmp.
Using a battery that is charging provides quite a variable load, and the test is thus inconsistent. UA-cam star Julian Ilett correctly applied a load on his battery to prevent it from changing voltage during such comparisons. If the output voltage is constant, then a load resistor might be used to provide a constant load.
Isn’t the efficiency of the second implementation abysmal?
can we use 11.1 V, 13AH lithium ion battery which has 8 cell in the pack?
Working on a solar inflatable boat, is there a true cheap MPPT charge controller that can do actual tracking?
thanks for the video, this is not doing mppt it just regulate the panel voltage which is not mppt. Question : did you figure out why the efficiency is too low?
Would there be any danger for my batteries. Would it be possible for you to explain to me how to set a target voltage. This works like mppt charge controller? I use a Juta mppt charge controller. Do you think this in the video would work more efficiently?
Thank You!
Emmanuel.
It's designed for lithium cells and has a sensible charging profile so it should treat lithium cells well. To set the voltage I'd connect the correct amount of fully charged cells top the battery connections and turn the pot until the led suggests the charge is complete. I'd double check a little later using a multimeter after the board has gone through a charge cycle.
I've not used the Juta so can't comment on the efficiency I'm afraid.
My batteries are lead acid. Is there any problem?
run four 18650s to protect them and langthen there life span
Very helpful and informative review. Thank you for your time.
the input can connect with 18-20v solar panel to charge battery?
Where does the load connect up? Can it be connected directly to the solar panel and will the charger feed the battery energy back to the load when the sun disappears or does the load have to be connected directly to the battery. The trouble with the latter is that if the charger considers the battery to be fully charged, it will cut off the solar panel and use the stored battery energy even when the solar power is available.
Is there any way to use the logic circuitry of these chinese mppt modules to control a much larger power stage i.e. 50-100amps?
+Jake Mitchell Possibly. You'd need to look at the diode, mosfet and inductor ratings first. Then you might need to think about the shunt - possibly a voltage divider or opamp on there - thinking out loud it might be possible yes.
Jake Mitchell
this circuit uses VERY special logic P-FETs in a high side driver configuration. No chance to have more than a few A. Shame.
The second controller, is it ok to adjust the output voltage with just a meter attached in place of a battery?
No, I don't think so, I disconnected the battery while the solar panel was still connected and it died! I don't think a meter would present enough load to stop it from dying... I haven't yet had a look at it's datasheet to see if there's any mention of placing a resistor across the battery output to provide protection against this sort of thing....
Tengo un PROBLEMA Mi Aeromodelo (Un 4-m Planeador) Utiliza un Motor Para Subir, Su Batería Li-ON, (Es Pequeña y Ligera)
Pero sus Alas, están FORRADAS con Panel de Células Solares, Foto Voltaicas, ¿SE PUEDE TENER la FUNCIÓN DE CARGADOR DE
LAS BATERÍAS, MIENTRAS HAY TAMBIÉN, UNA DESCARGA DE LAS MISMAS, EN el MOTOR, los SERVOS y el RECEPTOR de RC?
Puede Recuperar o ¿se puede PROGRAMAR, para Diferentes Voltajes de Recarga de 1 a 6S o según el voltaje/carga de la Batería?
Sobre BANCO El Invento LUCE muy Bien y muy ligero, pequeño y No mas Practico que, un Cargador de Baterías mas . Pero SOLO lo
VEO PRACTICO Y ÚTIL si lo Podemos UTILIZAR en Vuelo RC, para Recuperar Batería, Para Casa, Ya Tengo los de ROBBE y Turnigi.
Hi Adam,
I'd love to hear about the efficiency gained from using this MTTP compared to the small 3A PWM you like so much.
I'll see what I can do, but I've got a few things on my list to compete first.
Thanks! Perhaps I'll beat you to it :-D
great find, perfect analysis.Can you connect the output of the little red mppt board into to solar input port of a pwm charge controller (designed for 3s lithium) to get your super cheap mppt charge and load controller for a 12v rated panel with 3s lithium? what I love about the mppt chip is that it is powered by solar, so you could probably run a small pump off it without a battery and still get mppt.
+mjp0815 That's a really interesting idea using it on the input of a PWM solar charge controller which might just work. I'll have a think about that and perhaps give it a go. Thanks.
Adam, thanks so much for your response! Maybe on second thought just connect the output of the mppt module in parallel with the battery and the battery terminal of your pwm charge controller, I guess all that is needed is load management, I remember you did not like the way the cheap PWM controller was doing lithium charging anyway.
Hi. I understand that following question might sound silly but it's comming from a newbie so please bear with me. I'm interested into making a portable battery system for charging my phone and tablet on the go (so value-wise 5V output with max of around 1,5A ) , using 18650's and auto step up/down converter (mine rated to max of 2A for in&out). Would it be better to set it up with 2+2 18650 in parallel (and get double capacity) or 4 in series (not sure here how this translates to total capacity since I'm stepping down from 16,8V to 5V )? Last question, is it ok to charge like you show in this video, multiple Li-Ions in series, using only end total voltage for charge termination and without balance port ? Thanks in advance and love the videos. Subbed !
The issue around charging batteries in series is that they start to fall out of balance as you say. One cell might be low, another much higher and the charger will keep charging - potentially an issue. Adding balancing circuitry adds to the complication of your circuit.
As a result most (all?) power banks on the market use batteries in parallel. That way they keep themselves in balance all the time. It also means you can easily charge from 5 volt USB. It does mean you have to step up the voltage when the cells become the power source, and there will be some losses, but it's not too bad.
It might be best to consider your capacity in Watt Hours rather than Amp hours. Lets take three cells - Nominal 3.7 volts each - 11. in total. Lets say they are 2000mAh cells.
In series they total 11.1 volts, and have a capacity of 2Ah that's 22.2 watt hours.
In parrallel they total 3.7 volts and have a capacity of 6Ahs and that is 22.2 watt hours.
So as you can see the results are the same.
Unfortunately if you are looking to solar charge your lithium cells I've not found a solar charge controller that works on a single cell voltage.
Hope that helps.
Can i use it with 80w panel?
Hi, Julian!
can I use it to charge my two 12volts 70amps lead acid batteries there are hooked in series?
Thank You?
+Emmanuel Tavora You're on the wrong channel for a Julian! The adjustable version would be suitable. It's a little different to most lead acid change controllers though - you'll have to set a target voltage and the charge controller board will get to that voltage and keep the battery there. There wouldn't be a boost/absorb charge like lost lead acid chargers.
Such a great find 😊 thank you
For the CN3722 "MPPT" means Manual Power Point Trimmable, halfway usable...
A complete fail was the CN3767 (should be for 12v Lead-Acid)
It never charges more than 13,55V, that is even not enough for floating...
Not to mention the necessary absorption level to avoid sulfation.
Actually the manual versions are better! You only need to set it once to your panel and forget it, same goes for the charge stop voltage! I have been using the second model in this video for some time now, I have a 48V series string battery bank made up of 12V Lifepo4 Batteries, I'm using one of those charge controllers per battery, each controller looks after it's own battery, no other BMS is needed! When one battery is at full charge, the controller stops charging but the rest continue so the batteries are never out of balance!
I was using a more expensive MPPT charge controller which automatically tried to match my panels but I found that every time a cloud went over, it would waste time trying to figure out the best point to set the MPPT, most of the time, by the time it figured it out, another cloud came over and it's back to square one! But this thing! Once set! It's fast from the slightest bit of light in the morning to the last bit of light late in the afternoon, it tries to get the last bit of energy!
This is just my opinion of it but I love it! It just works! I used to watch it all all hours and conditions of the day but I have since just given up... Totally hassle free!
@@PeterMilanovski Ok, you are pleased with not knowing what really happens.
Indeed with longer periods of low-light winter time they have an overall efficiency that is FAR below simple PWM controllers, since they will not begin to charge until the panel has reached 18V.
Then the CN3767 just charges to 13,6V and that is NOT adjustable. The battery NEVER gets a full load.
do you recommend it in 2024?
Wish I could figure out how to use these and other small MPPT Controllers as a Reference to drive FET and Inductors of 20-50Amp . Quite sure there is a way I'm just not knowledgeable enough to hack it. Guessing one could simply use the FET drive to Drive parallel FETs and Inductors to obtain the goal ?
Or you can simply use two or more of these in parallel for more current or Go the other way and wire them in series for higher voltage...
@@PeterMilanovski Yes but there has to be a way to simply expand they're current levels. Everything is there but the dang Current. That is derived by the inductor. Can we use one to manage a larger inductor ? Multiple inductors ? My Ep ever has two rather sizable inductors employed.
@@pulesjet I was just looking at the datasheet for the control IC chip on the PCB board, the datasheet only shows two diodes and one transistor! But the actual PCB has two double diodes which is four diode's and two transistors instead of one! So I think that the person who designed this board was thinking about reliability at the full rated 5A current... The only way to get more current out of it would be to use higher current capable diode's and transistors but mount them off the PCB board and onto a larger heatsink and connect them with wires, I don't know what that inductor is rated for though? It might also need to be upgraded and remotely mounted like the other components... Everything else is low temperature 🌡️... It's not impossible to do, just get the datasheets for the components that need to be upgraded and find higher current versions of them... Because heat is the only problem that's stopping it from delivering more current, oh and also there's a resistor that set's the limit for the current which also needs to be replaced with another value or a potentiometer so that it can be adjusted... The datasheet isn't to hard to understand to make the necessary changes...
@@PeterMilanovski We should be able to slave another Fet and inductor some how. I'm in the process of dying here. I don't have the time. All it would take is to drive another mos fet and inductor in parallel I would think ? Just use the little board as a Basis and driver.
@@pulesjet yeah I don't think that its that simple, adding another transistor or inductor in parallel could possibly destroy the controller IC which has to provide the energy to drive the transistors, in the datasheet, it only shows just one transistor in the circuit diagram but this board already has two transistors... I can see options but none of them are as simple as you would want them to be! The easiest option is to get more of them and parallel them together...
Sorry I change your name Adam!
Hi, can you please help me? I am building a power box for fishing with 4s lifepo4 battery cells. I have an old and very small solar panel (for testing) wich i am trying to connect the second mppt solar charge controller from you video to. I have installed it exactly the same as you did (especially ordered the watt meters for this purpose) but i am not getting any watt reading on the meters? I can adjust the voltage coming from the panel and i get 18V, but it does not show any watts (so its not charging the battery)?
The battery side only gives 13.3V (wich is the charge in the battery pack) and also no watts.
I really do not know what to do now. Am i doing something wrong? Is the solar panel broke or not strong enough? (no specs on it) Does the BMS i obviously hook up to the battery pack prevent charging from the solar panel? I seems to me when the panel generates 18V it should be charging the battery?
If you can please help me it would be great. I want to buy a bigger solar panel, but first i need to get it to work. Thank you very very much in advance for your help.
Should you need additional info i will be glad to provide it to you.
Reagrds from Holland.
Can anyone help me please?
Awesome little handy modules. Would love to see how accurate they charge and what actually happens to the charging process when the sun goes away for a while (not that that ever happens LOL)
Now I'm electronic man myself but I am starting to struggle with a bunch of naked pcb's that end up in boxes. You make the same 'mistakes' as I do and that is to solder the wires to the board without any mechanical protection.
Wouldn't it be time if everyone starts using standard size pcb's and we can get cheap modular cases? Luckily some sellers are now offering these lego style see through cases but when you have to order them separately the price of the module doubles.
Anyway great video again and yes I had a question mark stuck in my head about the mppt treshold level and how they would do it with that seemingly not complicated module. And then you pulled out the other module.
heat shrink tube
Affiliate links are broken.
Everyone has what they call MPPT. If I can't wire my panels in series to get the most from them then I don't see where it is really doing MPPT! When the input volts are near the battery voltage MPPT doesn't give much, could do almost as good with a PWM! Can't find what the max input voltage!
Datasheet says 28v max... www.consonance-elec.com/pdf/datasheet/DSE-CN3722.pdf
Where did you get those watt meters?
can i charge it with lead acid battery?
MPPT means ability to 'track' the max yield point in the panel.. which varies from panel to panel and also shifts with temp and illumination... it dfntly dsnt mean 'setting' a voltage to a set value (as is being done in the second controller)... an actual MPPT controller has a range of voltage in which it 'hunts' for the point which yields the maximum power... there are a few diff algos whicb do this in few diff styles.. but none of them use any preset values to operate.. this circuit appears a waste of time and money.
I think I mentioned the fact it doesn’t track didn’t I? More of an MPP solar charge controller I think I said? This has its uses in my opinion - it’s great for a little remote project that needs a small and efficient solar charge controller.
You shouldn't focus on voltage. The charge pattern is fluid voltage and high amperage.
If you look the amp in is lower than amp out.
Usually the voltage floats until the battery is 80-90% charged then it becomes fixed voltage (battery voltage) and the current (amps) lower.
There is three stages...
1Current ( int charge) Max current (high amp)
2 fixed voltage (main charge)
3 float, (battery voltage) low current.
((Min current))
Off.
How come the battery output drops when you adjust the mppt of your solarpanel. It´s still over the battery. Seen in 12:40
I assume this would not work with lead/acid auto battery?
The second CN3722 module would - set the output voltage and it'll do a pretty good job of charging the lead acid battery. The only issue is you wouldn't get a float charge - so your battery wouldn't be quite as well charged as it might be of an evening.
Thanks for the info. Could these be used with a 12V power supply instead of solar panels? It should work, shouldn't it? I'm thinking of using the variable one to charge a 2S pack. Thanks :-)
+Paolo Panzarino Yes it should work reasonably well.
@@AdamWelchUK This chip doesn't seem to power on with 12v input. Even though the datasheet says as low as 7.5v.
Why we need to put d2 i didnt get that
The CN3722 does a very simple DC-DC power conversion. In a way, the it is not a true MPPT solar charger because it does not scan the input power to find the actual maximum power point. Rather, it is a fixed input voltage converter. What it means here is, there is a pair of resistors that sets the voltage level where the solar panel provides maximum power. For most solar panels, this voltage is around 16~18V. If you have a battery that is at 12V, the difference between the MPPT voltage and the battery voltage is loss in efficiency. By regulating the input voltage at 16~18V, there is efficiency gain. For a smart MPPT solar charger with build in micro controller, the MPPT charge controller scans the input voltage/current to find the actual MPPT. But for this particular "dumb" MPPT charge controller, the input voltage is fixed. Thus, yes it does work, but it is not the actual maximum power point, especially if the panel is partially shaded. One advantage of this MPPT charger is there is a back flow prevention diode build in. Thus, at night, the battery won't be powering the solar panels.
Hello, is it posible use a cheaper module as a TP4056 board to charge a lipo cell from a couple of 5.5v@170ma solar cells in parallel? I'm thinking on power a 100mA (Max) load and set the TP4056 for 200mA max current to charge a 2100mAh lipo. Would this be cheaper and still work?. Thanks!
is it possible to extend an mppt controller/hybrid inverter PV input voltage? Perhaps just upgrading the input stage capacitors? I noticed a voltage divider network near the 100v 1000uF im guessing it reports the input voltage to the mcu. My mppt/inverter is a Easun Power ISolar SMV 3k 24v
Guess it's not a real MPPT but it says 95% efficiency so good enough.
+Asaf Shahar 95-98% is typical of many DC to DC converters in my experience.
***** Yes, but it suppose to do some current/voltage load adjustment. But really I mean you could just connect a buck converter to a Lithium-ion battery not sure it will be much worse...
No, it's a lot worse with a basic buck converter, but it will prevent over charging you batteries. With changing irradiance it will at some points become a basic PWM. TheMPPT controller is doing pretty well and use simple step up-step down algorithm but uses the input voltage as a target and not the output voltage (what a simple buck does).
databeestje thanks that is enlightening
Hi Adam, sorry for all my noob questions, but I really hope you can answer this one. I purchased the last Mppt you featured and connected it to my 4s7p pack along with a 25watt solar panel. I get a reading coming from my panel @ 19.8 volts, but no Amps. Battery is @ 14.5v. Can you please advice. Thanks. Oh and I have a 4s BMS connected to the batteries
It looks like a nice solar-powered battery charger, but how is it going to handle if you're drawing power from the battery at the same time as you are trying to charge it? It's a constant-current charger - drawing power while charging is going to really mess that up.
+Vyl Bird Now this is a good point - the constant current is set by the resistor being used as a current sensor shunt according to the data sheet. I think you have spotted an issue which I hadn't thought about.
If a load was pulling less than the charge controller was supplying then there would be a net gain in the battery but this might cause an issue with the termination calculation as it's based on current draw. If the load was more than the input could sustain then it probably has less of an effect.
Perhaps I'll have to test this a bit further - thanks for your comments.
Perhaps you could bodge something up by moving the shunt to the battery, with the load connected on the same side as the panel, but it's not designed to work like that - and reading negative values for current could really confuse the logic. That's how I solved it on the arduino-based PWM controller I designed.
Walk in front of the panel, and then check it. If it's anything like the (two different) buck converters I bought, they trip up. Hours later, the battery (3.2v LiFePO4) was only slightly charged, with a 6v panel. That should have been almost twice the amps into the battery than coming from the panel - minus inefficiency (what, 15% or so).
I'll try these but if they trip up from a sudden shadow, then _your arse is mine..._ LOL. This time, though, I'll try the slightly higher voltage of a real li-ion (a few in parallel), with your presented boards. If it doesn't work, then I know to put them in series (but that requires separate PCB for battery balancing - wraa...). It's just for my LEDs light.
Bty, thanks for the professional approach!
I got this charge controller. However, it is showing a green light (meaning fully charged) when my three Li-ion 18650 batteries in series is at a voltage of 10.5V. Full charge voltage is 12.6V. What is the issue and how can I fix it?
Presumably, the only important thing about MPPT is that the power going into the battery is the maximum it can be, so using a perturb and observe MPPT method it should be possible to only measure the battery side current and voltage, multiply the two to find the power output and then adjust the PWM duty to the DC/DC and observe if if the power goes up or down and make the relevant PWM adjustments. I do not see an advantage, other than data gathering, for measuring on the panel side rather than the battery side.
I don't understand how a Li Ion cell could be Over Charged ( Above 4.2V) if you never provide the batteries with more then 4.2V. It can't happen if the charger is set to 4.2V max.
Hi Adam. I have been following your channel for sometime now and have possibly made a mistake with selecting an alleged MPPT solar controller. The charge controller I have does not have any identified model numbers.
Allegedly the controller is capable at 40 amps, max pv of 50v with a max pv input of 520w (12v).
The display went off, it through everything off and never came back on. So I opened it up then noticed some strange things. There was identified mppt controller ic. There seems to be 2 chips one identified as made by HOLTEK, then another ic with no chip id. So I have serious doubts about weather it is a true MPPT charge controller. The board has an id of XW-LVD01-V2.0. There is no resistance on the solar input.
Any advice would be much appreciated.
Hi Adam .. just a quick question.. does that output to the battery stay at 12.6v for a 3S pack? I have a small pack that I am only balancing but not using a BMS. Just wondering if this thing would blow up my pack as the balancer probably couldn't keep up with the input.
My conclusion of this measurement would be that these are bad chargers. On 11:05 of you video: If your panel can deliver .55A @17.45V it can certainly deliver that (and even slightly more) at the battery voltage of 11.9V so if you would connect your panel to the battery directly the battery would already get charged .55/.44 =1.25 times higher charge current. So any charger of which the charge current is lower than panel current is not taking advantage from the maximum power point. Whether it is a tracking device or not.
I guess this won't work with nominal 20V panels (Voc 38.3V)?
So I noticed you don't have a 3s 18650 BMS connected to the mppt charger. Is that not required? I always thought it was necessary to monitor the individual voltage of each battery to properly keep the individual batteries balanced. Does this MPPT controller take care of all of that?
New to solar starting out with 8Ah LiFePo4 batteries. I've been looking at similar budget charge controllers. In the 3-4 years since this video has been produced, do we have a similar product but in a weatherproof case that might be used outside, or on a boat? Any one tracking a list of CN3722 based controllers ?