BMS Battery Alloy Shell Charger Problems

The unmarked pot on my 900w really seemed to have an effect on the fan, and how the charger acted vs it's settings too.

My fan seems to be following the normal temp protocol properly now, but when I was messing with that pot I could get the fan on or off independant of temperature.
I had to back it off to get the fan off when charge was done and charger was cool.
Now it chargers properly and the fan only comes on when the heatsink is warm.

I have
two voltage
two current
one indicator light adjustment
one unmarked mystery pot noted above.
 
Maybe the mystery pot is in some way connected to the NTC sensor. Maybe it does have an adjustable temp threshold, and the change you see in charger operation is just due to the fan load screwing with the CC/CV regulation
 
What do you reckon to this issue.

I have voltage and current set..or so I thought.

top voltge 83 volts
current at 20 amps

plug in a battery at about 78 volts..it charges at 20 amps for a period..say 2 minutes..not more.

Then the a red LED on the board..not one of the two on the front panel, turns on. and a buzzing. almost like , (and it could be though i cant feel it) a relay buzzing. When this happens, output current drops to 10 amps.


At this point I unplug it. it does not sound healthy.

The pots appear to be 30 turn units...at least the two voltage ones on the 2kw unit.

Any idea how to set it up?
 
Well they are certainly 30 turn, ..I have heard of bourns 25 turn, though there is some leeway in the 25 turn.
But definitely 30 turn,I checked them both twice. there was voltage increase all the way up the 30 turns, and that is 30 full turns not 30 half turns. Definitely 30 turn from clicks at one end to clicks at the other end.
 
I just learned the hard way to be more careful with the charger leads when it's on. The meanwells self protect, but I guess these emc-1000 do not. I carelessly bumped and grounded the positive lead I guess. There was a SNAP, and a wisp of smoke.

So now I guess I know not to do that. Not sure why there isn't protection like the Mw's though.

Examination of the 'blast radius' on the board led me to pcb location 0201, a small capacitor I think. 400v 4.7 micro farad.

Upon cutting the white silicone away, it basically fell off. the pcb traces look fine, and pcb is fine on the bottom, just a dirty on the top.

Is that normal to happen?
Is it likely this is the only thing needing replaced?
100_1480__1435694859_73_187_98_129.jpg
100_1483__1435694883_73_187_98_129.jpg
It went @ the light black circle below the diode marked '7' and to the right of the small shunt in the picture.
Fixability probability?
Thanks!
 
recently my travel charger, an EMC-400 turned the plug (chinch) into plasma. i have used it many times without any problems, but this time, when the disaster happened, i forgot to turn on the switch on the charger before i have connect it to the battery. on the EMC-400 the switch has a strange function or better say its confusing because if its pluged into the socket, the red LED already lights up, but it has no voltage on the output. only after switching it on its there.
Ok, now what would you guys expect in this case? I would have expected a little spark because the cap on the output is not charged, but this happened:

06OigV.jpg


the switch i forgot to turn on (i wonder whats the use of it?):

rtNnYr.jpg


edWPgO.jpg


p1JRMK.jpg


3oeIw8.jpg


finger burned:

DbQiNs.jpg


the sidewall of my kitchen where the bike was leaned to messed up (it is has melted into the surface and cannot be removed):

ueBZeo.jpg
 
here comes the really strange thing:

the small 5A fuse on the output did NOT blow, while the Adaptto controller went into protection.
charging "through the controller" is nothing special. electrically speaking there is only a shunt in the negative line and the controller watches current.

I only can explain this myself that the current sensing of adaptto controller is extremly fast and it recognised the over current that must be at least above 150A, while the 5A fuse was to slow to blow.

JW5Mb7.jpg


no short inside the chinch connector or the charging lead:

Zte8NJ.jpg
 
yes, fuse is slower than the electronics that shut off the mosfets.

but what shorted? that is too much spark for the output caps inrush current imo. maybe take a nick off the contacts but that looks like a dead short.
 
dnmun said:
yes, fuse is slower than the electronics that shut off the mosfets.

but what shorted? that is too much spark for the output caps inrush current imo. maybe take a nick off the contacts but that looks like a dead short.

it only can be because of inrush current or short somwhere else inside the charger, because there was definitely no short at the connectors solder joints (have add pics) or in the charging lead, but its like you said hard to believe..

about adaptto: the controller did not shut off any mosfet as there is no in this line. there only is the shunt and it monitors current.

maybe there is a problem with the charger that causes a short if the switch is off and battery voltage will be applied to the output. what do you say?
i think i will try it again on the work bench to see if its reproducible or not.
 
i would suspect that the charger side connector had a bent ground shield that was jammed into the central + lead on your charger connector (which was the RCA type) at that point the battery was shorted across the output and the fuse in the charger itself saw no current except for the inrush current to the output caps. the BMS output mosfets turned off on the BMS for overcurrent.
 
A lot of those and other connectors used for charging connector for battery packs are junk. I have seen those and rca plugs short out to a spark or melt. Can't we have a better style plug on factory made packs.
KFF did you smell you fingers ??? Still lucky.
 
dnmun said:
i would suspect that the charger side connector had a bent ground shield that was jammed into the central + lead on your charger connector (which was the RCA type) at that point the battery was shorted across the output and the fuse in the charger itself saw no current except for the inrush current to the output caps.

thats what i also thought and i disassembled the connector on charger side, but there was definitely no short. the DMM also did not show a short (only momentary because of the cap what is normal).
the charger works normal and also no damage on the bike aside from the mess.

another thing:

the charger is 60V / 5A model that was set by factory to 66V. I turned up the volts to 82,5V for my 20s battery. Nothing else touched. Maybe it has something to do with this in combination when the switch is not ON? But on the other side as already mentioned i have used it many times without any problems - only the switch was on.

I have another EMC-400 charger that is 72V / 4A model and before i turned up the volts on the 60V model i have compared most biggest electronic parts inside between those two, and the only difference i could spot was the big coil. There is a sticker on it with same ratings as the charger so i believe only a small difference in inductance or current handling - all other parts did look equal (as ex. 100V cap on the output, etc).

maybe its already known: http://www.avdweb.nl/solar-bike/ele...eight-lifepo4-ebike-battery-charger-800g.html
check the vid he made showing the sparking. his charger is only 40V or so, mine is 82V!!
 
Thats some nice carnage Maddin!

I'm working this morning on the issue I had above.
I mistakenly thought the relay would protect the bare leads when the charger is on, but not connected to the battery. The meanwell does this- you can make a dead short, but it's protected.

Anyway, accidentally bumping the leads and probably grounding the positive resulted in the blown capacitor above. It's still the only thing I see that had any apparent damage.

I replaced it today, reenergized to figure out there was a blown fuse where the ac plug is, and upon replacing that, the new fuse immediately blew again.

So I'm at a loss. Unless the capacitor was to be considered polar for install, which I doubt, I'm not really sure what to even check next.

I'd be very surprised if I'm not the first one that did this!
 
the charger cannot fail this way. the relay isolates the output so it had no causation.

if the fuse on the input is blown then there is something shorted in the front end.

we have no idea which capacitor you are talking about because there is no picture.
 
the charger cannot fail this way. the relay isolates the output so it had no causation.

Exactly what I thought too. But it went 'POP' in the charger when it was turned on with disconnected leads. I'm sure I bumped the leads on a metal table leg, but that is all. Could be coincident, but it happened exactly the same time I pulled the leads up to connect to battery, and the definitely bumped the metal.

The capacitor is pictured and noted as well as pcb location. I posted this like a week ago above.
It's the only apparent failure I saw, besides the fuse on the 110 input. Both replaced, and the fuse still pops immediately.
 
no, there is no picture and no analysis of the failure and the charger output is isolated if there is a relay on the output. no way to know if there is a relay on the output either since there is no picture of it. don't even know what charger it is.
 
Hi all
I'm helping a friend of a friend- you know how it goes!
His charger died and he asked me to look at it. It's an EMC 180w 8s lifepo charger. A high voltage power transistor is blown (cracked and smoked see pics). I'm going to order in a new part and tryfor the repair.
A few q's.
There is no other obvious damage ( I can't test it until I replace the part cause it blows the input fuse) is it likely to have destroyed more with its demise? Anything else I need to know other than trial and error.

I'm wondering if it has something to do with his charging habits. When he charges, he puts it on a 6hr timer and leaves the premises for a few days ( golf club) to come back to a full battery. Plays golf, charges, leaves etc
Is leaving this type of charger connected to the battery, but off ( remember timer) OK?
There is no relay on the output and the output fuse is fine. I thought this practice would cause DC side damage if any.
Hopefully some more experienced souls can share their wisdom :)
Kdog
 

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you need to clean off the black soot so we can see the damage to the surface. if the switching transistor has been removed it should not have a short anymore so it should not blow the input fuse. that usually is a shorted rectifier bridge or capacitor.

what is the part number and those two transistors should be replaced together since they have to be a matched pair if it is a push/pull oscillator circuit.

you need to give up better picture for diagnosis. closer and if you can follow the traces by holing the board up to a light so you can see through the pcb then it will help you follow the track of the input current for us.

your friend should not charge it and leave it charged. he should charge the battery when he is about to use it and leave it uncharged until the next time he uses the battery and charge it up then.
 
cheers dnmun
cant get a better picture right away (at work,lunch break) but ill get one soon.
the part number is j13009 (Fairchild) the data sheet tells me its a power switching transistor- is this for switching the DC to a higher freq for the transformer?
ill test a few more things tonight and report back. is this likely to be a random failure or is there something that specifically does this?
I realise that his practice is not best for battery life, but I was wondering if this would be bad for the charger at all (leaving it plugged into the battery whilst off). I might try and change his habit/mind but he likes it that way !
kdog
 
i have some of those if you want. there should be two of them so you have to use two new ones. it is FJP13009, there is a large TO-3P sized part too, capable of much more current.

the one remaining may be shorted so that would account for the fuse blowing but i recommend that you test the transistor to see if it is shorted.

you should also test the rectifier diode bridge too. use the diode tester on your DVM and find all four diodes in the bridge with your DVM and be certain that they are not shorted. you should see the forward bias in one direction and open circuit in the other direction when probing the rectifier diode bridge legs. you can do it while the bridge is still soldered into the circuit.

you can use the diode tester to examine the remaining npn transistor too. i will let you go google the part number and find the data sheet from fairchild. it will give you an idea of what you are looking at. why they are used here. if you cannot find it lemme know. i lost my files when i lost my disk the last time i restored my windowsXP and it locked up my disk so i had to reformat.

i can help you examine the rectifier and the transistor with the diode tester but let you do it at your own pace so you become familiar with the collector, emitter, and base first.

for an npn transistor there is a pn junction between the base and the emitter. just like in the the diode bridge except a little different. so you will see the forward bias of the junction when probed with the diode tester. you will also see it when probing the base collector junction, but different value because of different doping profile of the silicon.

you should not see conduction from the collector to the emitter with the diode tester. that is normal for a transistor because if the transistor conducted while there was positive voltage on the collector then it would be always on instead of turning on only when the base current is injected. hope that makes sense.
 
Thanks for your help dnmun
I did some testing this morn. the rectifier and caps are fine. Both the power transistors were blown one was cracked and the other looked ok but was shorted across all pins. I took it out and double checked.
I probed a few of the SM resistors and I can't get a reading on R6 ( open circiut) and it looks damaged (see pic). It's between the base on Q1 and R2 (which joins the big cap and r3) the last three digits are ..R20. Any way of finding out what value this is?
Cheers
Kdog
 
R20 means .20 ohms. usually they are 2.2ohms. so it will appear shorted unless you have an accurate meter. but they always do burn up. as usual i did not look until now so i edited this and need you to read the number on R20. is it 2R20?

it is called the base resistor and it limits the amount of current that flows into the base when the transistor is turning on in that cycle of the oscillation. so low resistance means easier to turn on faster is the way to think about it. but limited.

maybe someone has some surface mounts, anyone? or you can find a 1/2 watt leaded resistor and solder it there. but buying one of the surface mounts may be a little task. so double check to be sure it burned. there is an identical one on the base of that hiside transistor too, it may still be ok but both should be replaced. it doesn't have to be exactly 200 milliohms either. you can make the leaded resistor into a big loop and solder the ends of the legs onto the surface mount solder spots with the resistor up in the air. if you follow me. like a big U with feet turned inward like pigeon toed.

if you have cut both of the transistors out then heat up the remaining solder around the parts of the leg remaining so it melts and whack the board on the bench to knock out the remaining solder and leg bits. or use a solder sucker or better yet one of the fancy soldersucker heated iron.

when clear, power it up again and see it blows the fuse again. i can send you some fuses too. but i have those transistors, somewhere.

EDIT > was thinking about this and since you have to replace that base resistor, you can add a switch to the outside of the case and connect it in that base drive circuit. run a wire from that spot where the surface mount is soldered down and connect the resistor in that wire and then connect the wire on the other side of the switch to the base leg of the transistor, right there on the leg when you solder it in place. that is the factory way to put in the power switch. then you never have to unplug. i have a little rocker switch too you can have.
 
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