Dodgy: Megacell Charger - 16 cell 18650 tester - Page 1
Forum section: electronics / general

author: fubgumfaw
author_rank: Regular Contributor
timestamp: February 24, 2021, 08:02:51 pm
content: I try to help where I can and I like to support promising projects. I like it when people innovate and create new products. I've supported probably 15 projects in the past 6 years related to battery technology, motor controllers and motors. I'm an avid EV builder with an EE degree. Some of these projects work out well and others are bomb shells. The Megacell Charger/Monitor looks promising and innovative so I got on board to see for myself. Unfortunately this project is a bombshell and needs serious improvements to make it worth having! The short answer is: Do NOT get one!https://www.indiegogo.com/projects/megacellcharger-mass-production/x/25194611#/This is the youtube channel (The Cell Doctor) for this project:https://www.youtube.com/channel/UCzPputw3dkkFjxaZU2nmamg/featuredI tried to buy one probably a year ago when I found a video about them on youtube. I have to honestly say that I'm glad that this didn't happen! A year ago, this project was so premature that it was mostly useless. I was able to pay for one in November 10, 2020 and it arrived January 20, 2021...almost 4 months wait!!! I used the cell tester for a little while and decided to buy another one. I have since requested a refund.I thought I'd post my results and experiences with this cell tester after near continuous use since I got it...1. This is an Indiegogo project. It is common that crowd funded projects are "works in progress" and what you get may be far from a complete product.2. The Megacell Charger is definitely a "work in progress" and far from reliable and trustable.3. The charger has 2 button on it. They are oddly placed and they are the entire input method for accessing the functions of the charger directly.4. The "Reset" button is highly problematic! It's location is such that it is easy to press and that stops all testing as the charger reboots. Any test results are lost! I pulled out the plastic riser and shortened it so it can't get pressed accidentally. I've reset the charger by accident far too many times! GRRR! What's more, you need this button to get to lots of functions in the charger.5. The other button is labeled "Function" this button scrolls through all the cells one at a time and it also is how you access the menu of options. Honestly, these things need at least 2 more buttons. The interface is simply too hard to navigate with it's current 2 buttons.6. The battery tester has fixed size cell holders that fit 18650 cells only. It can't be used as a universal charger/tester for other LION cell sizes.7. The charge control IC's can support LIFE cells and yet the charger does not have this capability. It could also support LIPO and HV LIPO and does not.8. The cell holders are very poor at holding cells. It is common that cells fail testing because of the cell holders NOT securely holding cells in place. The springs are too weak and the cell holder design is cheap.9. Good cells fail for no reason. I have 16 brand new Panasonic cells. I filled the charger with them and set it to do a 2 cycle capacity test on all 16 cells. It failed all of them with a status of "BAD"! This is simply preposterous and highly improbable! Failing 10-20% of cells tested is pretty common, but 100%...well that's a serious issue with the charger! To date, ALL cells that this charger has failed, test good every where else. Rerun the same test and those same new Panasonic cells all tested as good with varying capacities. WTF?!10. Initial set up is painful at best. It communicates with your phone or PC via WIFI instead of bluetooth. This means you need to get it authenticated with your WIFI router before you can access it with the software. The steps are not particularly obvious if you are not familiar with ad-hoc WIFI. I'd toss out the WIFI functionality and use bluetooth instead! Data rates are not high enough that bandwidth matters.11. The phone apps are garbage and mostly NOT usable. The latest Android app crashes more than it runs.12. The windows app is pretty clunky and NOT user friendly. Non-intuitive is the word I would use. I test complex software that configures and manages routers, firewalls, cable modems and other networking hardware for a cable company. Of the existing apps for this charger it is probably the "best" of them and it's not great.13. There is a browser interface, but it's buggy, incomplete and lacking functionality. Honestly, I'd dump all the other apps for the charger and develop the web interface exclusively! It has a tendency to run away with CPU and RAM. Leave it running for 30 minutes and these will start climbing like crazy! YEAH!!! A browser app sucking up all resources!!! WTF?!14. The windows and phone apps and what happens at the charger are seriously laggy. Select some function to perform, wait like 10-20 seconds and maybe the charger will start doing something. This means you'll probably press the button several times thinking the command never got to the charger. This lagginess has bit me every time I use the windows app. The web interface does not have this issue.15. Completeness and quality is lacking. The plastic shell is flimsy and thin and clunky. The screws are too short and strip out easily. The "humps" that cover the fans means you can't stack these things for storage. The screw terminals for power are so deep inside the shell that they are hard to get to for adding fork terminals under them. Unscrew one of the screws too far and you will have to take apart the charger to get it out...GRRR!16. Inside 12 of the 16 bays are 2 solder pads for a JST connector. Why just 12 and not all 16 bays? These through holes are dead center in the bays. If you put a connector here, you can no longer use the bays for testing cells. Why not have JST connectors already in place in the front face of the charger? Why not use universal cell holders so none of this is needed?!17. I soldered wires to each contact point for each bay and brought them out the front so I could add my own 21700 and 18650 battery holders. This improved reliability quite a lot and doesn't effect the existing 18650 cell bays at all.18. In each bay is a small temp sensor. It is dead center in each bay which means the cells rock back and forth on the sensor. Placement is poor and they will get broken off. I covered mine in conformal so this would be less likely and to blunt the sharp edges on the temp sensor.19. My charger is now 1 month old. Both fans are making groaning sounds since they are sooo cheap! I need to replace BOTH fans after 1 month of use!!!20. Communications and support from the people that make these chargers is seriously lacking. Ask a question via email or the Indiegogo Contact option and expect to be ignored. IF you get a response back after a week, you are lucky! I've had the vast majority of my communication attempts be 100% ignored! Most of them are to report bugs and issues with the charger and software.21. I have tested around 300 new and used cells in mine now. You would think the same cell in the same bay would test to close to the same capacity when tested twice. This is rare! I'd call 100mah variance reasonable. One test may result in 2600mah and the next one 2100mah. This sort of test result is simply NOT usable!22. Same cell in another bay has similar results. Capacity results are speculative at best and not really trust worthy. I've tested the same 16 cells 6 times in a row and each result can be wildy different.23. Cell Ir is an important detail. I cam measure this on the Megacell Charger, ISDT D2, iCharger 4010 Duo and the XTAR VP4+. However, the results on the Megacell Charger will vary for the same cell so much that this measurement is not reliable.24. I compare results with an ISDT D2, iCharger 4010 Duo and an XTAR VP4+. They all produce consistent results test after test on the same cell. The Megacell Charger does not. I do this to get consensus or "similarity of test results". I can't trust what the Megacell Charger tells me!My conclusions:This cell tester is a great idea, but is unreliable and poorly implemented. It fails good cells far too often. It fails to produce consistent test results for the same cell about 95% of the time. Build quality is poor. The various ways to interface with the charger are clunky and poorly implemented. In good faith, I have to warn people away from buying this thing!

author: thm_w
author_rank: Super Contributor
timestamp: February 25, 2021, 10:32:29 pm
content: Not really sure why you'd buy this when you can get 7x 4 cell nitecore style chargers for the same price, enough to charge 28 cells at once.I guess the allure is a PC interface?

author: fubgumfaw
author_rank: Regular Contributor
timestamp: February 25, 2021, 11:58:48 pm
content: Quote from: thm_w on February 25, 2021, 10:32:29 pmI think you are referring to a universal charger and they are dime a dozen! I wanted a cell tester. They do a bit more than apply a current to a cell until it gets to 4.1v.A cell tester...1. cycles the cell at least twice. That's 2 charge and discharge cycles so that both charge and discharge Ah can be measured.2. measures the Ir of the cellDepending on how good the cell is, charge capacity can be much higher than the discharge capacity.Ir varies widely. This is the Internal Resistance of the cell. You want the lowest Ir possible. Old cells tend to have higher Ir than new cells.If you know of a Nitecore device that does this for 16 cells, that would be great! I didn't care about having an app persay, it just an aspect of the Megacell Charger so I presented how well it worked.SkyRC makes a 4 cell universal tester.XTAR makes the 4 cell VP4+ tester.ISDT makes an 8, 16 and 24 cell tester, but they cant hold anything larger than an AA cell...almost pointless!I have 1400 18650's and 800 21700's to test. I need a lot more test capability than 4 cells at a time!

author: thm_w
author_rank: Super Contributor
timestamp: February 26, 2021, 12:29:49 am
content: Yes 4 cell battery testers. Seems simple enough to hook up 4+ units giving you 16cell capacity no?https://www.eevblog.com/forum/reviews/whats-the-current-good-li-ion-(18650-cell)-desktop-analyzer-charger/http://lygte-info.dk/review/Review%20Charger%20LiitoKala%20Lii-500%20UK.htmlI paid $20 for Varicore V40, same as above.

author: fubgumfaw
author_rank: Regular Contributor
timestamp: February 26, 2021, 04:48:23 am
content: Quote from: thm_w on February 26, 2021, 12:29:49 amI wish these other chargers were as good as the much more expensive SkyRC...and they aren't. It's the only other option besides the Megacell that does logging.I read through that thread and was already aware of all the chargers mentioned in it.I've never run across the Varicore v40 and didn't see anywhere to get it in the USA.By the time you get 4 of any of the better 4 cell chargers, you are well over the price of a single Megacell Charger and still lack all the other cool stuff the Megacell Charger can do. This is why I bought a Megacell Charger. It seemed like the right choice. You can also connect multiples of them together and log/track/control all of them from the same PC app. Its a great concept/idea, just a poor implementation.With literally thousands of cells to test, I need something that can test a lot of cells and do it rapidly.Unfortunately, the Megacell Charger is not exactly reliable or trust-able. I trust my XTAR VP4+ far more! This thing seemed like a good idea, but it's not ready for prime time.

author: thm_w
author_rank: Super Contributor
timestamp: March 09, 2021, 11:18:00 pm
content: Saw another Liitokala unit Lii-S8, 8 cells, although its almost the same price as 2x 4 cell chargers:https://www.aliexpress.com/item/1005001491062193.html

author: fubgumfaw
author_rank: Regular Contributor
timestamp: April 01, 2021, 06:46:12 pm
content: Quote from: thm_w on March 09, 2021, 11:18:00 pmThis looks like a charger and NOT a cell tester...there IS a difference! I looked and see "charger" and nothing about cell cycling.1. A charger takes whatever is there, applies a voltage to it at some current level until the cell reaches full charge.2. A cell tester charges AND discharges a cell multiple times and records both capacities to determine charge and discharge capacities. They often times record Ir as well.I'm not sure if people understand this...1. It is common that cells discharge to a LOWER capacity than they charge to. This is common for any chemistry.2. In case it got missed: Discharge capacity is commonly LESS THAN charge capacity.3. To know a cells real capacity takes AT LEAST 2 charge and 2 discharge cycles.A charger will never cycle cells.Many so called "cell testers" do a single cycle...which is insufficient.So far I have found the XTAR VP4+, SkyRC and the Megacell charger do all of this. Of course the Megacell charger is wonky as hell and highly unreliable...so it's not worth having ATM. The VP4+ does a pretty good job.

author: thm_w
author_rank: Super Contributor
timestamp: April 08, 2021, 10:50:15 pm
content: Quote from: fubgumfaw on April 01, 2021, 06:46:12 pmYou are right, its worse than the 4 cell models"Q: Does the Lii-S6 have the function of detecting the capacity of the battery?A: it has a charge level display, but it cannot be considered a battery capacity test. This screen records only the charge that the charger charged the battery, which is different from the battery capacity detection technology. This is very important."Have you actually seen a difference in capacity from 1 discharge/charge cycle compared to 2? I'm surprised unless the cell was overly discharged to begin.

author: fubgumfaw
author_rank: Regular Contributor
timestamp: April 09, 2021, 05:54:14 pm
content: Quote from: thm_w on April 08, 2021, 10:50:15 pmI agree...discharge capacity is what matters. Charging a cell starts at X charge level and stops when the cell is charged. This may be useful, but only IF the cell is 100% discharged. Even then it is still just half the picture.I have run across this many times since I am testing hundreds of 18650's and 21700's. The cell will charge to ABC capacity, discharge to DEF capacity and charge to yet another (GHI) capacity. It is common that cells will charge to a much higher capacity than they discharge at. This can be for several reasons and may be an indication of reduced cell life. IF a cell charges to 3000mah and discharges to 2900mah, that's close enough that I don't care. If the cell charges to 3000mah and discharges at 1500mah, then there is something really wrong with the cell and it is probably best for limited use applications or recycling. Probably Ir is also very high.

author: fubgumfaw
author_rank: Regular Contributor
timestamp: April 12, 2021, 04:54:35 am
content: I have these cell testers now...1. XTAR VP4+ is trustable to measure discharge capacities accurately. I've verified it against my iCharger 4010duo and my ISDT D2 and it has nearly identical capacity results as they have.2. OPUS BT-C3100 is the second most expensive and is testing capacities about 200mah higher than the other two cell testers.3. LiitoKala LII-500S, despite being the cheapest of the 3 cell testers has produced results very similar to the XTAR VP4+. It's cheaply made and has lots of poor design choices in it so its cost is not surprising. It does surprise me that it is reasonably accurate so far.

author: fubgumfaw
author_rank: Regular Contributor
timestamp: May 04, 2021, 10:30:04 pm
content: I bought a second XTAR VP4+ yesterday...Several things got me over the price hump of the VP4+1. It supports cells larger than 18650's in all 4 bays and the others either do not at all or only in the outer 2 bays.2. It's the best cell tester of the 3 in every way!3. It's faster than the other 2 cell testers. The Opus claims it will do 2 amps, but the same cell in it takes 2X longer to test than does the VP4+. I think it's the discharge cycle that is so much slower. Maybe it needs an added fan like others have told me they do them. I think the smallish discharge resistors are the real problem. They can't handle the wattage that the much larger precision resistors in the VP4+ can!4. The VP4+ does cell Ir and the others do not.5. Put the VP4+ in test mode, set the current and it stays exactly like that cell after cell after cell. It only changes mode because you changed it or it was unplugged. The other 2 cell testers, you need to set this and current every time you install new cells to test.6. My VP4+ has ran continuously since I bought it new in December 2020...yeah...5 months of continuous use or at least plugged in and powered up.

author: fubgumfaw
author_rank: Regular Contributor
timestamp: May 04, 2021, 10:34:33 pm
content: This thread is really about the MCM...I have found the development team for the software and joined their ranks! I have not done much of value yet. I'll be pulling out my MCM soon, adding 16 universal bays to it and then doing a lot of testing with pre-prod firmware and software. I plan to mount it to a piece of plywood which I will screw to my wall so it's out of the way and yet easy to access. The other cell testers will get mounted there too...

author: Super-ev
author_rank: Newbie
timestamp: June 05, 2021, 01:44:20 am
content: Yea yo, this charger is a scam.Straight-up dogshit build quality. I guarantee they make them for $15-30 tops.And it doesn't actually work.I've never been able to test my cells consistently with these chargers.I have 3 chargers that I modified to have better springs and contacts but still, every cycle only targets 0-6 cells max. I can never get more than 6 cells to charge or discharge at the same time.And I'm using a single Megacell charger per 40A psu.Yes, I've contacted Alex but for him, this isn't a problem. Because for most people the inaccuracy is fine))not like you're advertising a professional tool...He also told me that it's inaccurate on repurposed cells, and wants me to use brand-new cells.... BRO this charger is advertised for repurposed cells!!! This is actually a scam!I've also tried getting community support on the Facebook group chat but that just lead to more dead ends.Fair warning to anyone interested in buying..Ps. If you're located in North America and want a Megacell Charger. Hit me up!

author: fubgumfaw
author_rank: Regular Contributor
timestamp: June 05, 2021, 02:22:26 am
content: I tried it on 16 brand new Panasonic cells and the results were either all 16 failed or capacities were all over the place.Test the same 16 cells again and you will get new test capacities.These chargers are pretty bad...totally agree!