Review of 18650 4 channel Lithium Battery Capacity Tester, Charger and Discharge | WattHour

[@chrisnegociosia]

I already bought my device, and I am already testing it, it works excellent, thanks to this video I learned how to use it, greetings from Guadalajara Mexico!

[@WattHour]

Great to hear!

[@AndehX]

4:16 The loop function is for charging and discharging a cell multiple times. This is useful if you have a cell that has discharged very low, and doesn't appear to hold a good capacity. Charging it and discharging it multiple times, can revive a seemingly dead cell.

[@1112223333111]

will it tell me if a new battery is fake? I just got one of these and hit auto its discharging now. I hope to see close to 3000mah or I got burned

[@johncoops6897]

44:17 - there is a mistake here! If a battery is under 3V, you should NOT "boost charge" it with 1 Amp. The TP4056 specifically limits the "Trickle Charge" to 1/10th C (ie: 100mA) until the battery voltage reaches a safe threshold (2.9V). This is to ensure that the battery is not harmed by relatively large charge current while it is in an under-voltage status. If you have cells that have been over-discharged, you should charge them at VERY low current until they reach about 3V. The TP4056 in this device manages everything automatically, so just let it do it's work for you. Also, at 45:35 - when charging completely stops it will immediately fall back to 4.15V to 4.17V and will not start again until it falls below 4.1V or so. When charging, once the cell reaches 4.2V the TP4056 will enter Constant Voltage mode ("Top-Up Charge") and continue to charge at reducing current until it reaches 4.2V 100mA. The cell is not actually full when it first reaches 4.2V, and needs the extra CV float charge to completely fill. This is shown operating correctly at about 51:20 onwards, when you see the current falling. It's a pity that the AUTO mode wasn't demonstrated. I assume it charges to full termination, then switches to Discharge and records the capacity?

[@ericklein5097]

AUTO likely also recharges the cell retaining the discharge capacity on screen. Would be great if someone would have an AUTO STORE mode that makes the last charge cycle stop at 3.6 or 3.7

[@johncoops6897]

@@ericklein5097 - I've tested now. AUTO first Charges to 100% then discharges to Cutoff Voltage. There is no recharge afterwards... It leaves the cell "dead flat". My Opus BT-C3100 etc seem to recharge after a capacity test, but most other devices don't. There is no real point doing multiple Charge/Discharge Loops at full discharge then stopping the last one at Storage Voltage. Each Loop just takes a cycle off the battery life. This unit only stores the last discharge only, not an average like more advanced devices. It also loses all memory after power is disconnected, which is annoying. Never the less, it's not a bad design for the price. I am going to modify mine to add charge current switches for smaller cells in remote battery holders.

[@jayfenwick4214]

it looks like it was above 3.0 volts @@johncoops6897

[@theo2378]

​@@johncoops6897my 1channel tester recharges the cell after a discharge test on Auto mode, I'm yet to purchase this 4 channel tester.

[@goyetus]

@johncoops6897 THANKS for the explanation!!! Im surprised as this module charges to 4.20 , falls a little, and charges again to 4.20 to assure the correct 4.20 voltage. I think my litokala 600 dont to that and leave my cells with less current. TP4056 is awesome.

[@TheRevKing2]

If you put the cell in reverse it will not blow up. No error message on screen or anything. It just won't let you do anything. I have put 100's of cells through this charger with no issues. Capacity readings are very accurate comparing it to my TEC-06 (in discharge mode. Not Auto mode). For now it's my best charger-discharger (and cheapest 17€) for 18650's, and i have many other good branded chargers

[@WattHour]

Thank you for the information. I did not find it in the description of the device so to be safe I did not try it.

[@christopherf7423]

Thanks for that. I have blown up a few tp4056 boards by plugging the battery in wrong. Kinad wakes you up.

[@mr.makeit4037]

Great job! I have the older charge/discharge board. But this newer board seems easier to conduct capacity tests and has a much better display.

[@guywhoknows]

I got one of these we've done over 400cells together over the part two weeks. No issues. So the below 3v is a trickle charge to 3v and it will switch to 1amp charge. Lower voltage it will touch charge, where you saw the voltage going on and off. In effect jump starting the charge. Take a while to do it.. If you have one charger it will split the battery current, between cells. You missed the 100ma cut off charge. When you're down to .10a it will stop the charge cycle. Loop is for doing charge and discharge cycles, where used batteries are used they can go up or down in capacity, so it common to run more than one cycle to get a "true" reading of capacity. You cannot get a factory capacity reading as the discharge current cannot be changed (500ma) which is fairly standard testing current. For adjustments it's about +30% Some of my older batteries have voltage drop due to the higher current and thus read a low capacity. This would be where the cell has a max discharge around 1.2a. Would be nice if you could get a case for it. And the battery holder is a touch small for HC cells as it's a tight fit. There is some board flex I put rubber spacer under mine to support the top when loading batteries. Charge voltage seems to be out a little, but discharge is accurate.

[@johncoops6897]

I've just written a comment above, regarding under-voltage cells. The TP4056 (clone) in this device applies the battery manufacturer's recommendations to use a very low Trickle Current until cells reach a "safe" threshold (nominally 2.9V). In this case it's set for 1A charge, so the trickle charge is 90-100mA. As you say, it will switch to 1A once cells reach 2-9V or so. The discharge current here is not 500mA, and it peaks at over 1A with a full 4.2V cell. See 35:43 - where a 4.04V cell is drawing 1.02 Amps (=3.94 Ohm resistor) so that will be about 0.73A at 3.0V. Since it's using resistors (rather than proper Constant Current) for discharge, the current will drop as the battery discharges. I assume it's allowing for that by sampling both the Voltage and Current, then accumulating a Wattage vs Time calculation.

[@guywhoknows]

@@johncoops6897 you assume correctly. The current drop with voltage seems to go in stages 104, 85, 75 usually as the voltage drops. I've ran through the same sell in different slots some time apart and had the same results. I'd had a feeling that they may be off from slot to slot due to some variables. But seemed to be spot on. It refused to go near low cells 0.25v was about the min or it won't let you charge the cell.

[@johncoops6897]

@@guywhoknows - the discharge current is a straight linear relationship with the cell voltage, according to Ohms Law. So if you see "steps" in the current display, that will be down to very slow update and/or averaging in the processor. For super-low voltage (

[@francescacosentino6975]

Congratulations for the review: well done and detailed. For this reason I add this clarification which I hope will be very useful. The manufacturer has made an important change; my release, which you see when you turn it on, is 4.4. In my case if you power with a single power supply the following happens: It is possible to discharge all four batteries but it is only possible to charge the two batteries that are on the same side of the power supply. I would like to point out that the "Charge" command is also accepted on the non-powered side but the current remains at "0" and for me this is a real defect of the software as it confuses the user's ideas. As soon as a second power supply is placed on the The other side also starts charging the other two batteries. However, if you leave it with just one power supply, the charging, I repeat, does not start, the current remains at zero and after a short time the charging cycle ends with the word end. It seems useful to me to include this new operating feature in one of the most complete descriptions available given that this object has no operating instructions

[@CriticoolHit]

Thank you. This actually cleared up a rather confusing statement they made at the 20 minute mark about charging one at a time.

[@christopherf7423]

What a detailed review. Wow. Really well done. Looking at Amazon, there were a couple of reviews, and both had that had some negative comments. As to the "it scratched my table", the dollar store or walmart or ace hardware has some plastic/rubber/felt stick on feet. As to the comment about it not charging to 100%: These units use the TP4056 chip. And the way the power is shared, you better make sure you have a very good power supply. Because if the voltage drops under load to about 4.5 volts, then the TP4056 will terminate charging around 3.9V, because that is when the current drops below its cutoff. I am not sure exactly what the voltage drop of the TP4056 is, but from memory, it think it is about 5-6V. I remember having this exact same problem with individual TP4056 boards with some cell phone chargers. If you are going to use individual usb C chargers, use good ones that don't drop the voltage under load, and use good, short cables made for power. To both comments that say there are no instructions, there is a download link to a pdf on the amazon product page just a few inches above the review that says there are no instructions. This video certainly provides more details. One of the reviews correctly points out that this type of battery holder will not fit the 18650s that have the button on the top, because those cells are too long. That is not really the fault of this device that the 18650s he is using is not really 65mm tall. But, it is a fair warning if you have those longer cells. His solution to attach the cells to an external battery holder is perfect. Perhaps messy, but definately works. And if your cells have nickel strips, your can easily attach them with good alligator clips with thicker wires, just as WattHour did in this video.

[@TheRevKing2]

I use the 5V output of an old PC power supply. Cheap and lots of power

[@tdomingues89]

​@@TheRevKing2can you use all 4 ch to Charge batts at 1A each ? Can the Charge BE reduce to 500ma each cell ?

[@TheRevKing2]

@@tdomingues89 All 4 slots charge at max 1A each. There is no option to reduce the amps. If you only use 1 USB C cable it will charge 3 slots close to 500ma each. I still haven't tried a 2A power supply and see what it does

[@tdomingues89]

@@TheRevKing2 the reason i am asking this, is because i wanted for all 4 slot to charge my cells at 1A each, i question my self if i connect a power suply of 5V 7.5A, if it will charge all at the same time at 1 A, and possible a resistor mod to lower the charge value to 500ma.

[@TheRevKing2]

@@tdomingues89 Yes. With that power supply and 2 USB C cables each slot will charge at 1A max. This charger needs a minimum 4A power supply to work properly. Not sure about the resister mod

[@JohnSmith-gs4lw]

According to the manual, those blue terminals above each channel holder are for connecting batteries outside of the black 18650 holders. That is, they are not “load connectors” but rather just external screw terminals connected to the same place as the spring tabs in the black holders. This should allow you to test LiPo packs.

[@WattHour]

it depends what you need and how you see it. if you need to charge someting, then it is a charge prot. if you need to connect to the battery, then it is for that purpose like load connector. thanks

[@albertograssi1991]

most underrated video ever great job mate!

[@chrisnegociosia]

I need to buy one and I didn't know how to use it, but now I do, thanks for the video!

[@johnclarke6647]

Good morning. I got one of these capacity testers from Amazon. Power supply is a problem. It will not accept my standard USB C power cables. I had to use my DeWalt light with a big 8 ah battery connected to it. It has both a USB A and C connectors on it. My tester has sporadic problems - the screen stops working from time to time, the dimensions of the battery boxes suck and the measurement between 1&2 differs from those on 3&4. Amazon is replacing it.

[@ebaystars]

very helpful comprehensive explanation of this charger/tester Im in thailand I can get these cheap but needed this data to make a sesnible buying decision Thank You kindly totally appreciated amount of hard work!!!

[@WattHour]

Glad it helped

[@DonnyKurnia]

I had one and yesterday I ruined the display when taking the cell out from the 2nd channel. Is it possible to replace only the display? What is the display specification that I should be looking?

[@alasdair4161]

I have tested mine with a data logging digital load and find it seems to under report capacity on all cells. I suspect it is the crappy cell holders that have high resistance steel contacts, they are wasting part of the discharge energy preventing it from being logged. You can measure the voltage drop from cell to PCB and it is too high. I only use mine for bringing up cells from zero V when cell harvesting, for that it is ok, but the numbers are too vague to be of much use when compiling high P count packs to get accurate capacity balance. Not bad value for a general purpose device, but not without some limitations.

[@TheRevKing2]

I found it to under report by 50 - 100 mAh. Not bad compared to other well known chargers

[@CameraRay]

Could I test a 21700 battery in a holder by connecting it to the blue +/- connecter at the top? Thanks.

[@WattHour]

yes. you can.

[@CameraRay]

@@WattHour Thanks.

[@spinaxchin]

Can you test other types of li-ion batteries using the external connectors (like 14500 and 21700)?

[@JohnSmith-gs4lw]

According to the manual, that’s what the blue screw terminals are for. Should be able to use LiPo packs.

[@ddavid2]

Quite exhaustive review! Thanks for sharing it with us!

[@hermanbril2682]

Yeah! I bought through your link the 4 channel version! Great video.

[@WattHour]

Thanks. I am glad y ou liked the video.

[@ericklein5097]

Either those cables have quite a bit of resistance or the USB C charger you're using doesn't hold voltage very well past an amp. I'm more inclined to think its the cables. That might be important for someone charging all 4 slots at 1A. If you're drawing 4A (which is pretty much the max you'll see any charger provide at 5V, most will max out around 3A) you probably want to make sure your charger has the ability to output enough current and hold its voltage. I think some chargers are going to have serious trouble trying to charge 4 cells since this module doesn't take any other voltage by taking advantage of QC or PD

[@cumulusvapes7]

you need great cables and thats why it has 2 INS, it splits the power and you have the higher amps, versus the one in only source. as far as i have seen/heard. mines in the mail so..

[@mareks2724]

Hello, he has three Liitokala Lii-500 LCD chargers at home. For testing bateries 18650. Is it worth buying this one? Liitokala will measure my internal resistance and capacitance. What else does this tester measure? Those mWh?

[@WattHour]

Hi, this is exactly I made this video for. I have explained all features. Please watch.

[@mapuche1971]

litokala is best

[@mareks2724]

Thank you @@mapuche1971

[@yakine13]

Can i solder 5v+1 to 5v+2 so that I use only one cable to charge all 4 cells? Also, the fan is annoying, it would be better if they disabled it during no discharge. I have to unplug it when charging only.

[@francescacosentino6975]

In reality, the fan is also useful during charging as this occurs with a fairly high current and the integrated circuit that takes care of charging (4056) heats up quite a lot. The fan helps the air flow to flow faster also to cool the integrated charging unit

[@kmaltman]

Great Video, BUT, it skipped over the internal resistance testing, which was what I was thinking of buying this board for. I will watch it again, in case I zoned out and missed it, but from memory , it only said at one point "its not very accurate at the moment" I have literally a couple of hundred cells to test, I have tested them for everything else, but till now don't have a gadget to measure IR, any comment on the resistance testing part. But apart from that very thorough and loved the subtitles (I'm a bit deaf), so great addition. Also I have some Li-po pouch cells to test, would this work on them, with some patch leads? Keith

[@mohammadhoutary1338]

I see that the batteries are almost the same type, but there is a difference in the internal resistance, according to what I saw. Is the resistance measurement inaccurate?

[@WattHour]

Yes the internal resistance as I mentioned (I hope you watched it) is very approximate.

Perfect review/TUTORIAL. Thank you very much. I'm buying one of these tomorrow, but one thing wasn't clear for a layman like me: how to power it? I have 2 celular phone battery chargers: one Samsung 5V 1A, and one Miei 5V 2A. Could I power this unit with both of them despite the ampere difference? Thanks again.

[@WattHour]

You are welcome. yes you can use them.

@@WattHour Great!

[@beakytwitch7905]

I replaced the charge/discharge 3R9 6Watt resistors with 39R 1Watt resistors. (The fan is then not needed) Changing the resistors of course upsets the measurements, only a 10th of the 1Amp current flows but the tester still reads 1 Amp. I need the lower current because I re-use old Li-Ion batteries and flowing an amp through them wrecks them. The old batteries come out of old laptops or discarded e-cigarettes, and get repurposed for small electronic projects where only small currents are drawn anyway. With the changed resistors the tester becomes usable to measure battery capacity -just divide the readings by ten, or divide the resistance by 100. Also usable to charge cells, or connect a cell to an external circuit. ❤😊

[@francescacosentino6975]

are you sure? the 6 watt 3R9 resistor is the discharge resistor and and by replacing it by putting a 39 ohm resistor happens exactly what you write. But the resistor that determines the charging current is a tiny "SMD" in the photo, you can see it at 12:28 and it has the writing "122" at 1,2 Kohm and you have to change that to change the charging current (be careful that the integrated charging is not always the same, in the video it was the TC4056A and therefore the resistance to have 1 A was 1.2 Kohm but in mine the integrated circuit is a slightly different model PW4056HK and the resistance is 1 Kohm so the writing on the tiny smd it is no longer 122 but "1001"), a current that I doubt passes through the discharge resistor because otherwise with 5V volts from a cell phone power supply you would never be able to give 1 A to a lithium battery through a 3.9 resistor Ohm. (Ohm's law prevents you from doing this). I believe there are switches that are responsible for making this switching between the discharge and charging paths, even if I don't have direct proof, I believe that the current indicated is the right one in this case. If you want lower charge values, refer to the datasheet of the integrated circuit that mounts your device: mine requires a resistance of 2 Kohm for 500mA and a 10 Kohm resistor for 10 mA.

[@camlinhall1363]

Great review thanks. I just wonder about the internal resistance measurement mR: Is it not useable on this test board? Or is a special procedire required to get a reliable parameter of internal resistance? The description given on Aliexpress seems to suggest something like that.

[@imranmusa6267]

It's a good one i learnt how to fully use the device after watching this video. But how can i know or see the actual amp's (amperes) of the battery. Thanks 👍

[@WattHour]

my friend you have either missed it or have not watched the video. please wach to get the naswer.

[@paulandersonnz]

Thansk for great video. Is it possible to use one 4amp power supply to supply both USB-C inputs?

[@francescacosentino6975]

No, with the latest firmware releases, it is always possible to discharge each of the 4 batteries even if you connect only one USB-C power socket. Charging, however, is only possible on batteries that are on the same side where the charger was inserted into the USB-C socket

[@lovebi8974]

I had replaced pw4056 by tp4046 but pin 5 alway hight voltage (not connect battery cell) ? It’s 4.12v

[@osenmosen]

Nice and exhaustive review. Only thing missing seems to be adjustable cut-off voltage for charging, then it would be a complete solution.

[@markusr1308]

Hello, can you recommend a more accurate capacity tester?

[@1112223333111]

so if I buy a 3000mah battery and hit auto, this should say close to 3000mah after the test, correct? did you verify that?

[@WattHour]

I did discharge for 9 or 10 hours. that should be enough. Please watch.

[@nookcyan]

Thanks bro for this video, very helpful.

[@WattHour]

Glad it helped

[@tcirit]

Could I use this instead of my Opus BT-C3100? Thanks for the review. Happy New Year!

[@IonNight]

Probably, I have the BC3100, an older model of yours and thinking of getting 4 of this one instead as the price is a lot nicer

[@victorjralarcio2514]

So the internal resistance is not accurate or somewhat not near the actual resistance?

[@novis2124]

Can it test lifepo4 ?

[@WattHour]

I mentioned how it works and I mentioned the chip. it has a hardware chip with the preset voltage for Li-ion batteries. so NO.

[@IonNight]

You need to get something similar to the BC3100 charger to test lifepo4

[@lmwlmw4468]

Nice work.

[@bekahmed5048]

Great job... what microscope is used please ?

[@WattHour]

Thanks. Here is the video for microscop kzbin.info/www/bejne/lau1eKiKor2Cnbc

[@stevemiddleton948]

Nice video, thanks for sharing your info. is this more accurate discharging then charging or charging then discharging or will they give the same answer?

[@WattHour]

the result will be the same because it uses the same 5% or 10% tolerance resistor to measure the current.

[@stevemiddleton948]

@@WattHour thank you, I did think that would be the case, do you know why my unit only goes so far during the charge of discharge cycle before stopping, I keep having to start the cycle up a few times, it’s a big annoying, I’ve ordered another unit incase this one is glitchy but I was wondering if you might have any ideas? I’m not able to get a mAh reading as it resets each time

[@ricardomontante3852]

Excelent video. I wanted to know about this product and your video is perfect

[@jacoblichtenstein3332]

Is it - like the tp4056 possible to charge this without the usb-c, but using a soldered + and - wires?

[@francescacosentino6975]

welded where? without an electrical diagram your modification proposal is impossible

[@MaruyaSAg]

Can this be used for button-top batteries or just for flat top batteries? I mean in terms of length, have you tried to see if a button top 18650 better fits in those cell holders?

[@WattHour]

any lithium Polymer. it is th chemistry. all LiPo batteries have the same voltages.

[@MaruyaSAg]

@@WattHour it’s not the type but rather the length I’m talking about. When I checked listings on AliExpress for products that look like yours, the descriptions said they’re only for flat top batteries. Have you ever placed button top 18650 batteries into those battery holders?

[@WattHour]

Oh, I assumed by looking at it you know the size and will connect it to the terminals using clips. this clearly is made to hold 18650 size. but you can charge or disharge any size if you conenct them somehow.

[@victorcollazo2442]

Great review thanks.Un abrazo desde Puerto Rico

[@backtoearth1983]

IS there a way I can limit the charge current. I want to attach leads to the channels to charge old vape batteries but only want/need half an amp max charge rate

[@WattHour]

in this video kzbin.info/www/bejne/gpzCkKuKrbGfj5I I have explined the chip used in the capacity tester. just watch it is a resistor you can change to manage the current.

[@beakytwitch7905]

You can best use a different device:HW-107 they are small boards that protect the cell from over charge, over discharge, and over temperature, and you can change the charging current by swapping the resistor. They are cheap to buy and a datasheet is available.

[@francescacosentino6975]

There is a way but it's not very easy. The current is set via an SMD resistor near the charging chip (4056). If you replace this resistor and follow the datasheet of the integrated charging circuit you can obtain different values. The resistor that the manufacturer mounts is 1 Kohm and causes a charging current of 1 Ampere, with a 2 Kohm resistor you will have a current of 500 mA and with a 10 Kohm one you will only have 30 mA

[@pulgarcitohernandez]

I just got a tester like yours, but when I put charge a baterry, it just charge to 3.5v max You thing the pruduct is detective ?

[@mihaiciornei5648]

LOVE U MAN! TNK U!

[@Avos7ka]

It is not clear the charge current and discharge current cannot be selected, is it automatic? And how to make the discharge current stable as the battery discharges? Thank you.

[@francescacosentino6975]

The charging current is regulated by an "SMD" resistor on the TP4056 charging circuit, one is installed for each channel. By changing this resistance you can obtain a different value (for this purpose I recommend you look at the TP 4056 datasheet). However, changing the very small "SMD" resistor is a difficult job. The discharge current is regulated only by the value of the discharge resistance, visible in the lower part of the printed circuit. The resistance is 3.9 ohms and therefore will flow a little more than 1A when the battery is freshly charged and is at 4.2V and about 1A when it is in the central phase. It will scroll less and less as the battery runs out. I would like to point out that the value of the discharge current is not detected in any way but is calculated by dividing the value of the battery voltage by that of the resistance. This is unpleasant but you can confirm it by cutting a resistor and seeing that the discharge phase continues, indicating a current that is evidently no longer there having cut the resistor. So by replacing the resistor you can change the actual discharge current but the calculation on the display will remain unchanged as if there were a 3.9 ohm resistor. In short, the device is rather "rigid" on the currents and the modifications are difficult for charging phase and give an incorrect value in the discharge phase

[@tallmanneal]

Quick question, I just received my 2nd board and cannot get either one to turn on. Nothing on the display or leds. I assume that the display should power on as soon as you insert the USB C cable, is this correct? I find it hard to believe that I have 2 boards with identical issues.

[@MartynDerg]

you really should have just cut out the faff entirely, where you didn't realise the cell in channel 2 was fully charged, instead of the text followed by minutes of you being confused. But otherwise, fantastic video, very informative, I'll be looking at getting one of these

[@squayssan5352]

Hi, Why for charging mode I reach 4.16 v (and 4.13 v for another cell) for one cell? Whereas with a classic charger I reach 4.20 volts. THANKS

[@francescacosentino6975]

The charge is regulated by a TC4056 integrated circuit. If you look at the datasheet, the constant voltage of the final phase should be 4.2, but in the specifications of the integrated circuit it can go from 4.13 V to 4.26: this largely explains the differences from you found. They are not "precision" components

[@bertgoat]

what size are the connector cables as none were provided when i bought the device?

[@WattHour]

which connectors? there is USB and there is the dupont wire.

[@bertgoat]

@@WattHour to connect the device to power in order to charge or test.

[@haluktosun4064]

Hocam merhaba, şarj ve deşarj 1 amper ile dolup boşalıyor, örneğin sony pil için 590 mA deşarj akımı önerilmiş ama bu cihazda bir seçenek olmadığı için 1 amper gibi dolup boşaltıyor ? akımı ayarlamak mümkün mü ?

[@WattHour]

Merhaba, Tüm özellikleri gösterdim. Şarj akımını değiştirme seçeneği olup olmadığını unuttum, ancak böyle bir seçenek varsa videoda olması gerekir. Türkçe altyazı ekledim. Umarım faydalı bulursunuz. Çok geç yanıtladığım için özür dilerim. Selam. Ahmad

[@goyetus]

Summary: TEMPERATURE TEST = 91º (With and Withouth Heatshink) What do you think, boss? I have good news or bad news...... I have done temperature test to the 6W3R9J resistors. With 4 cells discharging at 1 amp, ambient at 20º, they go to 91º . (using a Thermal Camera) I have tried to put heatsinks on each resistor, but the benefit has been null. I got 91º again. I have looked for these ceramic resistors all over the internet, to see if I could find a “datasheet” or similar, but I have had no luck. I don't know if the temperature range of 91º can be considered “safe” to use this device. I am considering putting a fan with more CFM to see if it improves the temperature of the resistors.

[@WattHour]

The resistor's job is decipate the heat. if it is for example 10W, then it will consume 10W regardless how much cooler you make it. When you cool it down, you cooling the ressitor and as a result, the resistor value general should be reduced and it would affec the voltage and curent and consumes enough power to be the same 10W. So do not cool it down. it won't burn. it has to heat up to drain the battery.

[@goyetus]

@@WattHour thanks for the detailed answer!!! Didnt know that!!!

[@widuralatest]

Great video. Thanks a lot.

[@Mad-Coo]

2550 Mah per cell?? Is that correct?

[@IonNight]

On an older cell, yes. If these brown cells are LG HG2 that are stored fully charged too long the capacity will go down

[@ovimiha77]

Is there a way to modify the discharge current? I would like to discharge at lower rate, like 0,5 or 0,35amps. Thanks

[@WattHour]

yes. change the discharge resistor.

[@ovimiha77]

​@@WattHouronly changing the resistor will not work ok. I need a slower discharge rate because I use them like that. But, original resistors are 3.9 ohns, starting discharge rate at about 1.02 Amps when battery is at 4.2v. I've changed the resistors with 10 ohms, the current on the display was the same, about 1 Amp at 4.2v but the current red with multimeter was about 400mAmps, and that seams the right value by ohm law. The total value red from battery is wrong like this, I'm getting almous three times the capacity value I measure with other device using same resistor value. Can you make a video using 10 ohms resistors, and view the readings?

[@ovimiha77]

​@@WattHouran update, with 10 Ohms resistor, which is 2.5 x 3.9 Ohm (aprox) the result is x2.5 from the result obtain with other type of tester. So the result I get with this tester, I divide with 2.5 and it's pretty close.

[@francescacosentino6975]

During the discharge phase, the device does not read the actual current but calculates it by reading the voltage across the discharge resistor. So if you put a higher resistance the current will decrease in accordance with Ohm's law but the value measured and displayed on the display will be unchanged; you can get the correct value by making the appropriate proportion

[@freakinccdevilleiv380]

Awesome

[@walterfreeman5893]

where can I get this charger

[@WattHour]

link in description. below the video where it says "more"

[@CelsoAraujo1980]

Hi. I have one of this, v3. But the cell voltage reading is not accurate. I've measured with a good multimeter and there is a huge difference. If I put the same cell in different channel, it shows different voltage reading. Did I get a broken one??

[@WattHour]

Hi, yours must have some issue. This module show very good if not excellent reading of voltage.

[@CelsoAraujo1980]

@@WattHour Thank you for you response. For sure, mine should have a big problem. Because with voltage reading completely wrong, charge and discharge doesn't work. So my device is completely useless. I already have ordered other one. From different supplier.

[@carlosjimz]

Just bought this device after watching this video, wonder how accurate is the mR reading if anybody knows

[@WattHour]

Don't expect such important value from such cheap proeuct. you need to buy something at lease $100 or higher to get a proper reading of resistrance. The reistors used are 1% tolerance. so it is 1% accurate.

[@sandipmajumder9344]

Please make a 500w battery capacity tester...

[@WattHour]

500W is huge. It wold have to be solidstate with huge fun. Interesting project. but I not if I will make. I am not sure if there is deman for it.

[@affchenaa5725]

Does charging 21700 li-ion batteries also work via the external ports?

[@WattHour]

and yes. that is what I exactly said.

[@affchenaa5725]

great, thank you very much for your quick answer. Unfortunately, my English isn't the best, otherwise I probably would have understood it straight away. and if I connect 4 cells in parallel, can I also charge them via the external port?

[@deleteduser3749]

Can someone recommend the best way to power this up on both ports?

[@WattHour]

I have already shown how much current ised. then just connected 2A chargers on each port.

[@Kris0725PL]

It is possible to dump firmware from this 4 channel device? I have 1st version with simple ui...second version is improved...3rd version is 4 channel. I need test for mod v1 to put v2 firmware ..but i dont have dump from v2 :(

[@WattHour]

Not possible. it is secured on the MCU.

[@Kris0725PL]

@@WattHour ok...i got name this mcu :) today i try dump flash and eprom

[@tdomingues89]

​@@Kris0725PLdid the Charger survive the dump?

[@berzeked]

@@Kris0725PLdid you find which IC is being used here, i will like to log data out from the 4ch capacity tester to a PC , looks like a header is available close to the IC but with no IC number I cannot figure out if that is I2C or UART , did you have any luck ?

[@Kris0725PL]

@@berzeked yes...this is holychip ic....but i cant do it any more :(

[@michaellaun]

Can you change the max charge voltage and use this for LiFePo4?

[@WattHour]

no we can't. there is a microcontroller and it has been programmed and we have the TP4056 chip which has fixed values.

[@NoNegotiations]

Ok, can someone help me please. I have this same battery tested. I have 18650 3.6v 3600 mAh battery, HOWEVER when I discharge it to find out the mAh (discharge to 2.5v), it only showing 3181 mAh. Is there something wrong with it, or are the calculations wrong? Please help.

[@WattHour]

that is correct. as the battery is used, the capacity is decreased. the reason for that is that it looses charge quickly and capacy is reduced.

[@NoNegotiations]

@@WattHour Thanks. How do I find the original mAh of the battery if there's no writing on the battery?

[@solarguy6043]

...or the people who sold you the battery exaggerated the capacity a bit. Not uncommon.

[@francescacosentino6975]

@@NoNegotiations no possible

[@jeffdowner2378]

I have bought two of these from different sellers ebay & Aliexpress BOTH arrived dead with no function at all Any common faults? Lost faith in this product

[@WattHour]

I have provieded link to the store I purchased from. I belive you have protection and get your money back.

[@Pet_pal]

Please use low amps charger if ur using fast chargers it doesn’t work

[@ericklein5097]

So dumb that they do not allow you to set the end voltage higher for discharge. You can storage charge/discharge to 3.5V but most people would prefer 3.6 or 3.7 for 18650's

[@WattHour]

for discharge you can go lower up to 2.5V

[@xuantranly5802]

@@WattHour What if I want to set the discharge application at 3.7v? Is there any way to do it?

[@lezbriddon]

batteries being +down is a complete deal breaker. I want to find the board designer, trap him in a lift with me for at least an hour, on the morning after a very spicy curry omelette and a gallon of extra gassy beer called 'old flatulent leg warmer'