Author Topic: Fake IMAX B6AC charger teardown -- advice sought  (Read 19600 times)

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Offline Whales

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Fake IMAX B6AC charger teardown -- advice sought
« on: February 14, 2015, 10:54:30 am »


My student group was unable to get our lipo chargers to pass tag and testing (PAL).  This particular model has a built in AC adaptor and it's worth noting the makers claim CE certification.

Yes .  Fakes are not always bad -- many people are fine with fake B6 chargers.  This does however explain why this charger never took my Li-ions above 4V whilst claiming they were fully charged to 4.2.

The reason I'm told they failed the tag and test was that they had a metal case and a three-prong plug, but the case was not earthed.  I initially presumed the manufacturers had cost-cut by avoiding to add an earthing wire and mount-point internally, but having a look inside quickly explained the real reason:


To me this makes sense: laptop-style power bricks are "double insulated" and likely cheaper in some situations than spinning your own primary side board.  This design seems perfectly fine but I'm not sure if there is a convenient spot in Australian regulations for devices like this.  At the moment I'm researching what the regulations are because my only knowledge comes from these forums, Dave's videos and Wikipedia.  If anyone knows some great material to read, please link me to it.

Downhill
Anyway, from "OK" things turn to 'not so okay' in a couple of areas of this product. You may notice a large capacitor on the left side of the board flying on long leads -- it can't sit flat because of a MELF diode obstructing its footprint.  Then there's the wonderful soldering of the arrayed SMD resistors on the right (output side) of the board:


Both of these problems can easily be lived with.  Underneath the charging board however is a more subtle problem: a couple of TO-220 packages are poorly heatsunk against the bottom of the case:


The nearest package in this shot has a definite air gap between itself and the pad when assembled.  I wasn't able to get the right angle for the camera to show this, but the two surfaces are no-where near touching and you can see daylight between them the whole way.


I've since fixed this with some thicker SIL pads I had lying about but I don't want this as a permanent solution if I can avoid it..  This problem may have come up because of me disassembling the item so I will compare it with our other charger.  Not happy -- I would have preferred it if the three screw-mounting points were re-arranged so that a couple of them sit right next to the packages on the underside, ensuring they are kept well clamped against the case.

Power Supply
This is the fun part and why I decided to make this topic: a 100% authentic super awesome gigglepower PSU.


Before I go any further I need to point out how easy this was to open.  If they used any glue it was barely functional: the top split off easily.  I had issues stopping it from falling off after I assembled it so I glued it shut myself.

Apart from the massive cap on rectified mains there is no mains filtering.  A Y cap, an X cap and an inductor are all AWOL, but hey, at least they didn't skip on the tiny glass fuse!

Again I'm not happy.  This does not inspire confidence in its ability to handle nasty messes of mains-slapping.  Would this meet Australian standards?  I doubt so (and don't want it to), but I'm not sure.

Conclusion
I'm going to suggest my group use external laptop adaptors to power our chargers for the time being.  The designers were polite enough to leave the DC jack inputs on the charger board from the IMAX B6 designs without the internal AC adaptor.  We have lots of laptops and are going to get them tagged anyway, so this is easy.

EDIT: It looks like the DC jack is disconnected until I solder a link across CN0.  I suspect this is to avoid someone using the internal adaptor and an external one at the same time.   This socket works as is, I don't know what CN0 is for.  Silicon bridges the gap instead.

EDIT2: It appears the insulation atop the main input cap in the PSU has melted slightly where it would touch to the black plastic case.  This is odd -- surely the whole cap would have melting symptoms?
« Last Edit: April 28, 2015, 06:02:04 am by Whales »
 

Offline SeanB

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Re: Fake IMAX B6AC charger teardown -- advice sought
« Reply #1 on: February 14, 2015, 01:20:00 pm »
Laptop psu fuse is there for the final QC tester, they also do not loke having a brick blow up on the bench on first and last QC test, so leave the fuse in. Probably also a 5A fuse in the clips as well, you don't want "premature" fuse failure before all the tracks are blown off. Capacitor deformation is likely from reaction with the plasticiser in the plastic case, probably Bisophenol A used in the PVC mix to make it more pliable and easier to mould. Transistor mounted like that is par for the course, it might last the warranty, though it will work better if on some flying leads and mounted properly.
 

Offline rollatorwieltje

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Re: Fake IMAX B6AC charger teardown -- advice sought
« Reply #2 on: February 14, 2015, 08:17:59 pm »
Try pulling 5A from that power supply, I bet it will melt.

Also charge a multi-cell battery and check how well matched the balancing system is. Wouldn't be surprised if it is off by several percent, this kills the cells over time as they won't discharge equally.
 

Offline mrledman

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Re: Fake IMAX B6AC charger teardown -- advice sought
« Reply #3 on: April 26, 2015, 04:23:50 pm »
Hi

I have one of these fake chargers over in the UK

Was working fine charging my Lead Acid batts (motorbike and car) and was fine with my 2S LIPO batts for my Tamiya trucks, had it for about a year and it was charging my car battery overnight (4 amps) and you guess it in the morning still had a flat battery and charger display was dead.

Cut a long story short I ripped the unit open and found the internal PSU had blown up big time, its a little more advanced than yours, it has the X, Y rated and PIE network noise filter bits fitted and generally filled the plastic box component wise but the capacitors on the secondary side had blown the cans clean off the rubber bungs / legs this had shorted out the output and bang the switching transistor and PWM IC went taking some SMD resistors out with it, funny thing is the fuse never blew !

I am looking at finding a replacement to shove back in the blue box and have come to a stop on 1 thing, voltage

Do you know what the output voltage is from your PSU ?

I have found sites saying its either 12, 15 or 25V @ 5 - 6 amps but no 100% conclusive answers, my gut feeling is its 12v @ 5a, I plan on using 6S packs so don't want to buy a 12V only to find its not good enough to charge the 6S lipo packs (think the charger board uses PWM - DC/DC conversion but not looked at the circuitry in detail)

I have found some good quality 12V @ 5A that will fit in the box ok but would like to verify that voltage before spending out.

Also over in the UK this charger as new would pass a PAT test (portable appliance test / safety test) as its marked as double insulated so therefore does not need to pass an earth bond test or even have an earth even though its got a metal case, it should not have any earth leakage unless the ac / dc PSU is that bad / defective so its UK legal, would question its CE approval thou !

Your main smoother cap brown plastic sheath has not melted its more likely that the white glue stuff its stuck down to and the orientation / position of the cap the edge is touching the black case and its worn / pressed though it, see this quite often on poorly made electronics.

I ended up drilling and screwing the T0-220 devices to the back plate as I too noticed the air gap.

The 3rd thing I found was the plug in banana type connector post breaks off inside the red or black plastic so I ended up changing the plugs on the leads to better quality ones.

The rest of the unit does not look too bad and it is pretty accurate with my calibrated Fluke series 29 multimeter when run from external PSU (old 15v 6A Toshiba laptop supply)

The one last annoying thing is the volume of the buzzer, ended up taping over the top of it to quiet it down as it was way too loud.

Thanks for your post as with your help maybe I can get mine sorted.

mrLEDman






 

Offline mikerj

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Re: Fake IMAX B6AC charger teardown -- advice sought
« Reply #4 on: April 27, 2015, 12:00:56 pm »
I am looking at finding a replacement to shove back in the blue box and have come to a stop on 1 thing, voltage

Do you know what the output voltage is from your PSU ?

I have found sites saying its either 12, 15 or 25V @ 5 - 6 amps but no 100% conclusive answers, my gut feeling is its 12v @ 5a, I plan on using 6S packs so don't want to buy a 12V only to find its not good enough to charge the 6S lipo packs (think the charger board uses PWM - DC/DC conversion but not looked at the circuitry in detail)

The stand-alone (i.e. no integrated PSU) B6 chargers have an input range of 11-18v and run quite happily from 12v.  The switch mode regulator is quite a clever circuit that can step the input voltage up or down, which is why they can charge something like 15 series connected Ni-Cd cells or 6 series connected LiPos.
 

Offline bianchifan

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Offline Mechatrommer

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Re: Fake IMAX B6AC charger teardown -- advice sought
« Reply #6 on: April 27, 2015, 08:33:29 pm »
Informations on fakes 'n clones
http://www.rcgroups.com/forums/showthread.php?t=1951734
so which one is the fake? which one is the clone? and which one is the original? how long we should expect the original to last?
edit: i have the older version imax b6. i did order this b6ac version but the seller screwed up he sent the b6 version. he then had to send the ac adapter for it later. after looking at the teardown, it not much different from b6 version, only it got built in compartment for the ac adapter.
« Last Edit: April 27, 2015, 08:37:28 pm by Mechatrommer »
if something can select, how cant it be intelligent? if something is intelligent, how cant it exist?
 

Offline Whales

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Re: Fake IMAX B6AC charger teardown -- advice sought
« Reply #7 on: April 28, 2015, 06:00:46 am »
I had forgotten about the buzzers in these things.  I believe NASA uses them as a form of electronic propulsion.
« Last Edit: April 28, 2015, 06:04:32 am by Whales »
 

Offline JBaughb

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Re: Fake IMAX B6AC charger teardown -- advice sought
« Reply #8 on: April 28, 2015, 06:40:19 am »
 I picked up one a while back without the integrated PSU (fake) for a robotics project I was working on. It works fine using my bench supply as a power source (after a quick calibration). I always hook up a multimeter while its charging to monitor supplied voltage.

I think if someone doesn't use it often enough to justify a legit model, this model should be recommended.

At least on your PSU there is a fuse and the input diode bridge.

Also, these integrated PSUs have actually improved. I've seen older models where the "laptop brick" was only 2/3 the size of the one included in yours. Maybe its a case of "shenzhen market daily special". People should open their fake units and we should make a list of the different integrated chargers. Should be entertaining and enlightening.
« Last Edit: April 28, 2015, 06:45:28 am by JBaughb »
 

Offline Mango Mussolini

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Re: Fake IMAX B6AC charger teardown -- advice sought
« Reply #9 on: January 22, 2018, 05:24:00 am »
I need help to identify this part in my IMAX B6 10 AC Pro (picture)  :-//

(This thread is old - but good - and is related to my question, so I'll give it a try here...)

The diode got fried during discharging. It seems like (hopefully) it's the only part damaged. Charging still works just fine. I'd hate to throw it away as it's capable of much more than dealing with RC LiPo batteries. I've googled for hours about this and can't find answer to this specific issue...

I'd really appreciate any help!  :)
 

Offline stj

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Re: Fake IMAX B6AC charger teardown -- advice sought
« Reply #10 on: January 22, 2018, 12:41:08 pm »
part number should be on the other side.
 
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Offline Mango Mussolini

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Re: Fake IMAX B6AC charger teardown -- advice sought
« Reply #11 on: January 22, 2018, 10:31:37 pm »
You're right! Excellent!  :-+

Googling "eyeglasses" gives 88.5M hits. (from what I can see) It's time!  ::)

IRF 2807...

Thank you, sir!
 

Offline stj

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Re: Fake IMAX B6AC charger teardown -- advice sought
« Reply #12 on: January 23, 2018, 04:22:45 pm »
btw, this is the latest clone.
https://www.banggood.com/IMAX-B6-Mini-80W-Digital-DC-Battery-Balance-Charger-XT60-Plug-p-1202402.html

looks real good with the new output socket and the extra software mode of "programmable psu"  8)
i'm going to have to get one!!!
 


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