Cheap(est?) Lithium MPPT Solar Charge Controller CN3722 - 12v Solar Shed

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
Thanks for watching - please subscribe, comment and rate!

[@craigminca7446]

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

[@arrowstheorem1881]

This Channel offers great Value! Luving it!

[@cameraman1234567890]

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.

[@johnbrady8848]

Your clear and well illustrated explanation is very much appreciated; thank you!

[@voneschenbachmusic]

Thank you for posting this - I've been wondering about the details of how these little charge controllers do MPPT...

[@Leo-mr7rg]

That's a really useful video ! Thanks for all makers that you helped !

[@milvolts1]

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.

[@arijunal]

This is the answer I was looking for. Thanks

[@PeterMilanovski]

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!

[@milvolts1]

@@PeterMilanovski , not to mention their price. Shout out to Mr. Welch. Thanks to him we were able to fill our needs

[@ReDDevill46Man]

My hero! Am looking into making a 18650 power wall for my campervan and this comes in handy.

[@DavidWangai]

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

[@PeterMilanovski]

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!

[@andthesunsets]

If I want to achieve 6A, can I use two of them on the same panel?

[@sqttube]

Very helpful and informative review. Thank you for your time.

[@zwaal022]

Hi Adam. Thanks for making this video. With your very clear language and explanation. I know now that this certainly is NOT a real mppt controller. But it seems to do a lot better then a simple pwm chargecontroller with only a regulation of voltage and current to the battery. Thank you once again.

[@chrisw1462]

Yeah, it's the cheap and dirty way of doing MPPT. You do lose a couple percent efficiency vs. a true MPPT, but at least it's better than PWM.

[@ahaveland]

@@chrisw1462 It's an MPP controller without the T.

[@chrisw1462]

@@ahaveland Sorry, but if you search Google for MPPT, you get Maximum Power Point Tracking. If you search MPP you get a whole bunch of stuff that _isn't_ MPPT.

[@ahaveland]

@@chrisw1462 You're taking this too seriously. If it statically keeps the input voltage to the maximum power point and doesn't track, then it is not a tracker. It is an MPP device and not an MPPT device. I don't care what others might call it or what Google says.

[@chrisw1462]

@@ahaveland If it's not tracking, it's not Maximum anything.. :-)

[@neilfox4721]

Just arrived the MPPT controller for 12 lead acid battery. It has a few more components on the solar input side and clearly performs MPPT holding the solar panel at 17.34 V but varies to maintain current. I have replaced the small Cheap(ist) PWM controller with this one for my solar green house that uses a 25W panel and it has increase the output to the battery maintaining a trickle charge just above 13v.

[@nosafetyswitch9378]

the MPP changes according to the irradiance available at any time so the voltage and current also change. The nominal MPP is based on 1000w/m2 insolation so unless you have exactly that, the Vmpp and Impp will be different than the nominal mentioned in your panel.

[@Francois_Dupont]

Thank you for this video, i wasnt sure if that little board was alright for my application.

[@databeestje]

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.

[@AdamWelchUK]

Useful info - thanks very much.

[@joeboxter3635]

@@AdamWelchUK Yes, but you have a 12V panel at 10W. So not surprised they designed it to operate at 17V - 18V Vmp.

[@andredejager3637]

Such a great find 😊 thank you

[@keyurrakholiya1603]

very nice video sir. super, neat and clear explanation. keep spreading knowledge.

[@arneanderson3416]

Super in depth, thank you. I’m trying to create a, let’s call it solar controller power supply, so that when I’m charging my “solar generator” that connects to the PV side of the solar charge I can monitor the stats of my panels. The three controllers I’m working with will not turn on without being able to “see” the battery on the batt. Terminals. My hope is to use one of these controllers and a simple 3s 18650 pack and connect this little power supply when I’m charging my solar generator, would it just be a matter of feeding that voltage back to the controller, probably with diodes to power up the solar controller?

[@pgScorpio]

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 !

[@DavidKaden369]

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.

[@2cyclebikeraricstreet195]

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

[@VinceLoschiavo]

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.

[@PeterMilanovski]

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...

[@frozenfritz]

very nice explainations and clear voice! thx

[@nathan100tz]

I was giddy with excitement watching this because I've been looking for a decent cheap charge controller for an 18650 lighting project I want to make. My wife groaned when she saw what I was watching. I will grab one and a 4S BMS, a solar panel, an adjustable buck, and some chip LEDs. Home free!

[@AdamWelchUK]

+pepefpv Glad to be of service!

[@nathan100tz]

+Adam Welch Looking at panels now and I'm a little confused. Because I want to run 18650s in 4S, fully charged the pack will be 16.8v. I was thinking an 18v panel would be better, but all the ones I can see appear to have a built in regulator for 12v pb batteries. So will a 12v panel work OK in this situation, or can anyone recommend a suitable 18v panel that isn't $100?

[@AdamWelchUK]

+pepefpv 12 volt panels have their maximum power point at about 17-18 volts. They might work ok for you. A 24 volt panel would supply voltages too high for this little charge controller. 18 volts would be the natural choice, but as long as you've got a volt or so of head room you should be ok.

[@nathan100tz]

+Adam Welch Awesome, thanks!

[@daytrader152]

Thanks for the video, Adam. I have ordered the first unit from eBay to solar charge my 3S 18650. How would you tap the leads from the controller to the load? Directly from the +/- battery leads? I am using it to drive a 12V motor.

[@engineer9750]

Hello Adam, you should try with lap power supply and CV and CC settings for solar cell and an electronics load for the load to get really good testings.

[@richardnanis]

The bigger 5A version is very interesting. I wish they would offer also a 10A version with a better build and assembly - that would be justs what i am looking for :-)

[@fireofenergy]

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!

[@beniaeschbach2626]

Thank you for posting this nice comparison! I would like to use a BMS with one of these. Have you run tests with a BMS? The BMS has its own (pre-set) voltages that can not be adjusted, so how much does a BMS mess up your good values from a charger like this. And what is the efficiency of a BMS? How much do I lose there?

[@milvolts1]

Adam, at 14:43 of your video you mentioned something about a balance board possibly balancing each series as to avoid unbalanced cells. Which board would you recommend for a 4s7p battery pack. Thanks

[@Paul-gz5dp]

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.

[@pebre79]

I learned a lot. thanks for posting

[@mukeshkumarsharma3413]

Hello Adam, I have the same kit, what you showed in your video, please tell me the working of two given potentio meter. i could get .. please help me and i have one question more, when i trying to check the voltage drop across the terminals "bat+ and bat-" then it showing 0V, what does it means? (battery was not connected on that time)....... thanks

[@themegak]

Hi Adam, I purchased the second mppt controller in this video. I am wondering if I need to use a blocking diode on the battery side of this board. I basically would do solar panel - blocking diode (I'm not sure if my panel has one built in so I'm going to assume it doesn't) - watt meter - mppt board - watt meter - battery. do you think I need another blocking diode after mppt board or watt meter. any thoughts from you would he greatly appreciated. thanks

[@miketony2069]

Very nice review I've wondered about these solar chargers for 18 650 batteries . I have a need for a small project that involves a PIR sensor and a esp 8266 processor. I think something like this in a 10 watt solar panel. Would keep it charged up

[@Totogita]

nice video! what make power inverter in the 400 watt range would you recommend?

[@cameraman1234567890]

I Honestly Believe that as long as there is a External Voltage Reference Regulator for the Switch Mode Power Supply's Feedback pin so that it monitor's the solar panels voltage, you basically have a Somewhat Crude but very Effective MPPT Charge Controller because the Job of the External reference Voltage Circuit is to monitor the Panel's voltage so that it doesnt dive and you dont get maximum efficiency. Having a circuit with a Potientiometer that allows you to adjust that external reference voltage Is What allows you to tune your circuit so that you achieve the correct Powerpoint for that particular panel and your particular application.

[@gw3436]

I have just bought and tested the 3s mppt controller , used a variable wall charger at 16.5v to replicate solar input ,the controller did charge the battery pack but wow it got super warm I think it would need a huge heat sink lol

[@philporritt5963]

Noticed towards the end of your clip that the wattage into the batteries increased when you moved the pot away from the panel MPPT voltage. Wouldn't it make more sense to peak the wattage input to batteries, as opposed to the wattage fed into the module from the panel.Great info though, keep it up.

[@atahghighi]

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?

[@martyjackson4806]

Hi Could you do a video on converting a cheap PWM solar controller to MPPT? Maybe add some inductors and ??? I don't know if it can be done. Or how. Thanks Marty

[@iceberg789]

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.

[@PeterMilanovski]

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...

[@iceberg789]

@@PeterMilanovski ah, you reminded me some very old stuff. 😁

[@keyurrakholiya1603]

can we use 11.1 V, 13AH lithium ion battery which has 8 cell in the pack?

[@oooodanieloooo]

How come the battery output drops when you adjust the mppt of your solarpanel. It´s still over the battery. Seen in 12:40

[@sophocha]

great videos! Is there a way of solar charging a 48v ebike battery while you drive the bike?

[@jimawhitaker]

Thanks for the video. I saw this same board and they ask if you want it for LiFe LiOn or Lead acid but I have to assume they all use the same IC and since I need to charge LiFe I might need to look elsewhere...

[@milvolts1]

My waterfall was powering up great. Until I messed around with the potentiometer of the battery voltage. It powers off my devices. Then after disconnecting battery and reconnecting it works again. Its been doing it regularly. Is there a way to reset the mppt to its normal state?

[@fabiuh991]

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

[@schubi128]

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.

[@cameraman1234567890]

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!

[@fariba256]

About the non-adjustable lithium version, is the final charging voltage (i.e. 8.4, 12.6 ...) automatically detected by the module?

[@AdamWelchUK]

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.

[@Qualitaetspruefer]

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?

[@KuntalGhosh]

Thats a pretty neat board , i can pot it in a box and use it to trickle charge my car cus i rarely drive my car and it ends up with a dead battery after few years.

[@Martinko_Pcik]

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

[@PeterMilanovski]

I saw the input wattage climb to the full 10W when he gets the panel voltage to 18.2V...

[@PeterMilanovski]

These things are still on eBay, there's higher power versions also, might be about that time to look into this again to see if anything worthwhile has changed?

[@milvolts1]

what do you think I can use to charge a 4S 50ah battery pack with solar? Thanks

[@xanataph]

I thought this was quite an interesting approach. So ever since I watched your video I have been on occasion monitoring the solar input voltage going into my Voltronic MPPT charge controller. Interestingly, the voltage variance is not that great. It usually does stay around the MPP point of the panel, 17 volts. Occasionally it's 16 volts. It only goes lower under adverse conditions. i.e. *really* overcast sky, when there is shadow on part of the panel & at the end of the day when the light is low. This panel usually puts around 5-6 amps in decent Sun when the batteries require it, so the wattage difference between 16 & 17 volts is only about 5 watts. That's not terribly significant either way for a large panel. The point being is that I believe under good conditions purely keeping the voltage at MPP is likely to be well good enough. It's only when those adverse conditions come that keeping a panel putting out 17 volts (or whatever the MPP is supposed to be) is likely harvest less energy than letting it fall towards the battery voltage.

[@AdamWelchUK]

+xanataph That's really interesting Xan. Thank you. I've not had a chance in the last couple of weeks to run a test like that. I think it's a reasonable theory that the designers have used and your tests seem to confirm. I guess monitoring the current on one side of the Buck converter and knowing the efficiency of the conversion you could assume the MPP on the other side too. Been thinking a lot about that little board! Thanks again for your experiments.

[@webdev217]

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.

[@benmeadors6799]

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?

[@jamesleetrigg]

Can you put power from the battery whilst it’s charging?

[@raghubhaibharvad6715]

Hello, bhai , 12v solarpanel & 12v li acid battrey pe a cheap lithium kam karege .....

[@miteshdhanani]

As to u have shown this it’s nice but would like to know if any 6V3W circuit is there for

[@1kreature]

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!

[@2cyclebikeraricstreet195]

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

[@2cyclebikeraricstreet195]

I think it's like 13.1V

[@miketony2069]

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?

[@jimawhitaker]

I'm adjusting the one with the two pots. I only have one inline meter. Is it ok to place that between battery and charge controller and adjust to maximum charge rate? or should I do it differently?

[@jimthvac100]

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.

[@kami37781]

Great comparison

[@mjp0815]

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.

[@AdamWelchUK]

+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.

[@mjp0815]

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.

[@user-hj1sv7qi4r]

Thanks for the video, but is a buck converter enough to charge control a 12v battery from a 12v solar panel? I thought that you must have buck-boost, how can it just be buck?

[@t0nito]

I guess this won't work with nominal 20V panels (Voc 38.3V)?

[@tupai62]

the input can connect with 18-20v solar panel to charge battery?

[@fred8565]

hi adam how can i get a couple of these mppt charge controller ? the fixed 3s cn3722 if they are still available . the seller don't ship to the us.

[@jaaasgoed]

So despite the incorrect solar panel voltage, the first one is actually more efficient. It gets more solar watts into your battery. Replacing the resistor divider on the first one with a pot would seem the best option then.

[@tonyrow123456]

I was thinking about this I was thinking the one that adjusts I have a 270watt panel 4 629 commercial battery’s I have the perfect suitor one which is supposed to be mppt but isn’t could I just swop that for this thanks tony

[@Hemewl]

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.

[@AdamWelchUK]

I'll see what I can do, but I've got a few things on my list to compete first.

[@Hemewl]

Thanks! Perhaps I'll beat you to it :-D

[@schubi128]

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?

[@100roberthenry]

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....

[@rainbowsalads]

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?

[@AdamWelchUK]

Yeah they are not ideal. I tend to use some now which have an internal battery.

[@kallisti_gold]

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 ?

[@QUADBOYification]

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.

[@woeileongchan9552]

Can the battery be used to power anything while it is charging? Any extra circuit needed? Or just hook it up?

[@kevsthings8328]

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.

[@panagiotissavvidis8271]

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.

[@emmanueltavora8642]

Hi, Julian! can I use it to charge my two 12volts 70amps lead acid batteries there are hooked in series? Thank You?

[@AdamWelchUK]

+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.

[@Luke-san]

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.

[@nathan100tz]

heat shrink tube

[@jimawhitaker]

The second controller, is it ok to adjust the output voltage with just a meter attached in place of a battery?

[@PeterMilanovski]

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....

[@theK174]

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 !

[@AdamWelchUK]

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.

[@MrBrymstond]

Do you have any balancing boards other than a BMS?

[@pleasecho2]

Wouldn't the combination of the adjustable controller and a balance board constitute a BMS?

[@rob902110]

Can you recommend something similar for a 500w system?

[@ranganatennakoon]

CN3722 MPPT is very nice module !!!

[@comewithmetowork4239]

Hey Adam! I bought a newer version of this chip but its a little different as it has a potentiometer on it. The ebay listing barely has anything to help the functions, it can do 1s to 6s i believe. Please check it out!

[@adamskiharvey3684]

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.

[@davidnelson1711]

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?

[@Ferret488]

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.

[@AdamWelchUK]

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

[@johnwyman6331]

I believe the first controller is using that large low-value resistor that measures battery current to adjust panel voltage to the maximum battery wattage, because that's what we're after isn't it? The most battery wattage? If so, then I would guess that there's no reason to measure and monitor current coming from the panel which probably keeps self-consumption to a minimum.

[@jehugarcia]

very nice info

[@AdamWelchUK]

+jehugarcia Thanks Jehu.

[@caserio323]

Garcia papa tu me apareses hasta en las sopas lol

[@fit2fly]

Thanks for the video. Does the controller really stop charging at 12.6V or does it trickle charge?

[@PeterMilanovski]

It stops.

[@Altune45]

I am trying to put together a cheap charging system for lipo battery to run a security camera. the camera uses 6 watts 12 volts. What do I need to keep this battery charged over long periods of time ? It will be a wifi camera. Thanks in advance..

[@tupai62]

This can charge 6v sealed lead acid battery?. It has fully charged led?..how to know the Batry is fully charged?

[@andthesunsets]

Working on a solar inflatable boat, is there a true cheap MPPT charge controller that can do actual tracking?

[@jakemitchell7893]

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?

[@AdamWelchUK]

+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.

[@gmichaeld7963]

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.

[@bokimne6697]

I could not find 5A contoller like you share on the link. Now you can buy the same but it is written 3A output current. Can you pass another link or it is the same controller. Thanks!

[@evercharles1607]

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?