EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

[sam_sam_sam]

Well I bought another battery testing machine but this one is the EBC-A20 but this one seems to act differently than the EBC-A10H in that when charging it seems to check the voltage every so often or it is not functioning correctly and I have not figured out which case it is but everything else seems to work ok

But I have understand why this one does that every so often and it does not seem to have a certain pattern to it from what I can see so far

In the discharge mode it works just like the other one so I guess I will have to see if it keeps working or not

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

Are you using the same battery chemistry?
Some chargers stop for a fracture of a second, take a measure then continue changing. That’s with NICD, NIMH.
Lithium Ions are different and the charger constantly monitors CC and CV.

This is weird thing about this charger it does have those options and I was charging a battery with out the BMS protection board hooked up and it did this that why I am a little confused about what was happening when I saw that it going 200 milliamperes to 1.0 amp which it did this quite a few times and went back to normal then a few minutes later it dose the same thing again I had it set to now if I set it for 500 milliamperes it so far has not done this so I do not know what going on with this

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

Well turns out that the capacitor on the board where the buck converter is the capacitor and it was a brand name capacitor company but the ESR value was 0.07
330uf@25 volts

I put a 470uf@35 volt because I did not have one that was a 330uf@25 or 35 volts wrong height but I have this one which seems work correctly now I have ran it for several hours and it has stayed steady so far

[redwire]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

The only way to get a more accurate battery voltage is to stop charging it.
Many smart chargers will back off or stop charging for a few seconds, then check the battery voltage, as part of a self-check.
I've seen some do it every say 5 seconds, others every minute. This might be what you are seeing?

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

No sense I change this capacitor it has not done again for the last several hours and before it did not matter what I set the above 500 milliamperes it would do this every couple of minutes my other battery testing machine did not do this and they are all made by the same company

I would agree with you if it was constant every so many seconds or every so many minutes but this was randomly showing up and that is why it did not make sense also before I change the capacitors because there is one for the 12 volt regulator for the controller circuit it would take a few seconds before the screen would turn on now it turns very quickly now that capacitor did not really check bad but it was not a name brand there was not much difference between a new one and the one that was in there but there was a difference in the way it turns on

[redwire]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

EBC-20A is rated <18V 0.1-5A charge, <30V 0.1-20A discharge is that right? It's powered by a brick 19-20VDC 3.5A

I don't see you got a bad ESR reading. That 330uF 25V cap looks OK, maybe a fake Rubycon but YXF is rated ESR 0.16 ohms and you got 0.07 ohms.
There might be a bad connection in the charger or the brick is crapping out. I am still suspicious lol.

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

I would agree with you about the switching power supply might be crap but the soldering joints looked very good on all of the boards inside the battery testing machine itself and as far as weather or not the capacitor is a fake brand ( if it is a fake it is going to be hard to tell by the wrapping ) or not I was wondering that might self but I have to look at the other battery testing machine boards but I think that that capacitor for the buck converter is suppose to be 470 UF not the 330 UF that was there if remember correctly

I have get through testing a bunch of batteries before I can open the switching power supply brick and recap it because I am running low on some of the most popular UF values so I want to wait to do this investigation

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

EBC-20A is rated <18V 0.1-5A charge, <30V 0.1-20A discharge is that right? It's powered by a brick 19-20VDC 3.5A

I don't see you got a bad ESR reading. That 330uF 25V cap looks OK, maybe a fake Rubycon but YXF is rated ESR 0.16 ohms and you got 0.07 ohms.
There might be a bad connection in the charger or the brick is crapping out. I am still suspicious lol.

The power brick is a 4.75 amp or at the least that what is says that it is supposedly is but it is very light so who knows if it is one note the power brick does not get very warm even after many hours of use so that is one reason I have not taken apart the switching power supply yet

I can test the power supply brick on one of the battery testing machine because it has a feature that you can step up the current on the load by 0.050 ( or more ) increments which what I might do if this shows up again do this odd stuff again

But I would have to make up a testing jig for this type of testing which I do not have at the moment

On a different note but related for using battery testing machines

The reason for having the current so low is that these batteries had very low voltage on these batteries and I do not know if they are damaged by this condition so I am charging them very slowly so I do not have continuously sit there and check there temperature which I would have to do if I used a higher current level

I also bought the 8 channel version of this battery testing machine but I have to get use to setting up the parameters on this machine because it only has cycling menu not for single charging or discharging cycle but I have used it before but it not as quick as the single use setup

This is the battery packs that I am testing

https://batteryhookup.com/products/m...650-cells-3s2p

This is a little bit misleading that is in the description for this item

“We check all the batteries so you will get batteries with no bad cells guaranteed”
I got one battery pack that had no voltage on it and one that was at 3.something so I do not know weather or not these two battery packs will be any good or not

The other battery packs had higher voltage than this and they should be okay but we will find out shortly if this is the case or not

Also the BMS protection board that is showing in this description is also different than what is in this battery pack it is a BMS balancing protection board which I have not determined weather or not it functions correctly or not because the battery voltage was so low

When I get the other two batteries in these battery packs tested I tested them on the other battery testing machine so I can test the battery pack it self and see what results I can get

The one thing that is also different is that when you want to see the test curves on the graph you have to click on the channel number that you are using for the battery in question the one thing that that they left out of the graph is the quick look on the voltage and current reading you have to go back to the main page to see this information

One more thing is that you can only test one cell ( in a battery pack ) at a time which is okay but you can test eight batteries at a time which is a lot quicker

The reason I bought this battery testing machine that has eight channels is this how I am going to charge signal battery cells instead of the other battery testing machine which can only do one battery cell or a battery pack with more battery cells in series up to 24 volts

Now if I have a battery cell that the battery graph looks funny then I put it on the other battery testing machine to have a closer look at the battery graph curves which other battery testing machine does a better job of showing issues with the battery in question

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

Now I have to have a way to charge batteries with out tabbing on them that the battery testing machine can use with out having connection issues which is what I have work on now

[redwire]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

I have seen, if the power brick's output capacitors are failing, the high ripple voltage (with charging load) will stress the input cap on the buck converter, and then cause it to fail. So it could be a side-effect that you are seeing.

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

Now this makes sense I will check into this sometime today thanks for your input

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

One note on the battery packs that I have been charging up that the cells very low on voltage they are charging up nicely on very low current so there might be some hope for them after all I will post the test results when I have them

[redwire]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

What is very low voltage? I hear 2.4V or lower is really bad for lithium-ion cells, the electrode starts to corrode and ruin the cells.

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

It depends on how long it has been in that state of charge to weather or not it has effect it or not

One way you can tell if it has been to long at voltage less than a volt is if the voltage does not rise quickly then this is sign that they are very damaged and probably will not be good for use in anything meaningful

You will know when you load test the batteries and your milliamperes hours rating is not what it should be then you will know how damage they are

The lowest voltage that you can take these cells are 2.0 anything lower than one volt is if-e to weather or not it going to be good

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

The primarily test results are that the batteries have lost about 30% there useful life but for $7.50 for each battery pack I guess that is not terrible it could be better maybe after cycling them a few times the results might be a little bit better

One test I to do is leave these battery packs on the battery testing machine in the monitor mode and see how fast the self discharge charge rate is on these battery packs have this is with out the BMS balancing protection board hooked up

Then do the same exact test with the balancing BMS protection board hooked up and see if there is a difference in the test results ( I am hoping that these BMS balancing protection board are good because I would like to use a couple of them for a 9 volt battery pack )

Now it is time to test the BMS balancing protection board and see if they function correctly or not because these batteries were very low on voltage

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

Well I have one tested already and the results 5290 so this battery pack is good cycled once then load tested it charging and discharging curves looked normal for 2 batteries in parallel

Now I have to wait until all of batteries on the eight channel battery tester finish charging all of the battery cells before I test the battery packs on the other battery testing machine that can multiple battery cells and will post there results as I get them

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

I have seen, if the power brick's output capacitors are failing, the high ripple voltage (with charging load) will stress the input cap on the buck converter, and then cause it to fail. So it could be a side-effect that you are seeing.

I going to have to look at the switching power supply brick because I saw an episode where it did this again 100 milliamperes to one amp several times in a row but this was after many hours stable one amp output

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

Update
Some of battery packs are having balancing issues I have been charging/discharging cycling without the BMS balancing protection board hook up because the battery voltage was so low the other reason I have not hooked up the BMS balancing board is I want to see how balance these batteries are to each other so far I have one balanced battery pack and get 5.2 amp hours out of the battery pack

The other two battery packs that I have been testing are way out of balance by at least 0.250 volts or better and the amp hours are only 3.something I going to cycle them a few more times and see if this makes a difference or not if not I am going to separate these battery packs and rematch them so they are closer together than what I am seeing now

I also have to modify the BMS balancing protection board because I do have the type of connector that is on this board so I am going to remove them and just use wires to the board and test the BMS balancing protection boards and see if they work correctly or not

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

Well I solved this problem with this model and the external power supply remember the couple of EBC-A10H that the controller went bad well I ripped out that controller and the 24 volt switching power supply and I installed the EBC-A20 controller board the heat sink is the same exact foot print just done different and put a 12 volt @ 8 amps switching power supply with the same exact foot print the front face plate has the same exact foot print and it works very well now I do not have the wall wart and that nonsense to deal with

I going to reuse the case for the EBC-A10H that I want to use a buck converter that has voltage/current control pots and use the wall wart for this setup because only when I am testing BMS protection board for functionality am I going to use this type of setup

now I might use the 12 volt switching power supply output for this setup because the rated output is 8 amps and all that is needed is the power for the controller board and the buck converter way more than either devices need but what concerns me is the shared common negative power supply rail to run them at the same exact time

I would not be able to use both of them together but this would be fine

But I also had to change the ribbon cable plug on one end because on the EBC-A20 dose not have the charging function and the ribbon cable was also not long enough ( it has one less pin on the connector ) on it boy that was really fun to do it was not horrible only because I have done this before on another device

[sam_sam_sam]

Re: EBC-A20 Battery Testing machine capacitor failure on buck converter part of board

Now to do this on the second one to remove it from one enclosure to the other enclosure and redo the the ribbon cable connector and the switching power supply board from 24 volts to 12 volts and make the power supply wires from the battery to the mosfet board longer and then this one will be completely done

Then it will be time to work on the switching power supply board and the buck converter board with external pots for the voltage and current so I easily control them from outside of the enclosure on the enclosure that I had removed the controller board from because of getting rid of the having to use a wall wart to power the battery testing machine