BMS Battery Alloy Shell Charger Problems

Sounds like a bad cord. Beware, cuz you could get a fire that way:
http://www.endless-sphere.com/forums/viewtopic.php?p=693832#p693832

Note the slightly melted edge of the L hole on the right, and the darkness of the hole itself vs the other two (G and N) because of the carbonized surfaces from arcing in there.
file.php


A different cord fits it fine; it was just a badly made power cord.
 
I had a simlar issue a few times when I first started using these chargers with these IEC C13 C14 connectors (sometimes referred to by the overall standard IEC 60320. Some suppliers even reference the very first 1980 IEC 320 standard).
I've got to push quite hard to get the plug all the way in on these BMS chargers. The resistance seems to increase part way in as the pins properly engage into the socket, even then they seem to work loose over time. They must be poorly matched parts- the cheapest ones available.
The same type of connection is used elsewhere without the same problem- eg the PC power supply. Perhaps it might be worth getting the connectors from a reputable supplier if you need the connect/disconnect ability? You can even get gold plated and rhodium connectors which would make sense for the higher power of some of these supplies. Just fitting properly would be nice, but they are cheap.
 
Also, just cuz it "looks" thick or feels heavy, doesn't mean it's good wire. I've run across cords that used STEEL CABLE in them instead of copper, especialy for large-gauge stuff like jumper cables. :roll:

It could also just be dense rubbery plastic that's very thick on the outside, and still use really thin wires on the inside (regardless of what AWG is printed on the cable sheath!). That's pretty common with extension cords, "cheap" power cords and power strips. :(


But either way: If anyone ever has a connection problem especially on something high enough voltage to hear arcing like that (the popping when you wiggle the cord), fix the connection one way or another cuz otherwise you're askin' for a fire! :shock:
 
LSBW
you are absolutely right
If I knew about MASTECH I would have never bought crap from BMS.
MASTECH website shows Just $300 for 100V 10A power supply, that is is VERY decent price considering NAmerican quality just looking at this on pictures.

On my 900W BMS charger I resoldered several wires, got rid of flimsy V/I readout boards, installed my own V meter, removed blobs of solder here and there, replaced cheap LEDs bearly visable .
Somehow for Chinese international colour codes for power wires does not apply, so I replaced ground wire with green colour wire among other things.
I have a nasty feeling that it will not work for a long. Quality is not there.
But all those crying for BMS charger help posts have educational benefits if not humorious when some here tries to teach non techs basic electrical stuff.
 
dnmun said:
there is a white thermal switch on the opposite side attached to the heat sink next to the npn switching transistors. you should check to see if the AC goes from one of the red wires from the plug to the red wire going over to the white switch. that switch may be open so the AC circuit is not completed. or you can disconnect the power and check continuity from the input through the red wire back through the blue wire to the pcb.
Click to expand...


I'm trying to find this thermal switch but I don't see any white switch attached to the heat sync?

Is it in this pic??


2013-02-03_12-56-31_169.jpg
 
the red and black wire looping over the top of that capacitor go to a small thermal switch next to the big npn switching transistors is what i was guessing. if the switch is disconnected then you would not have power to the front end of the charger.

but first verify that you have AC voltage inside, measure on the back side of the plug where those silver bars are.

that switch is right above where they have the R6 label for the 2.2ohm base resistor.
 
Oh OK then, so the main power switch sends power through the thermal switch then? I have verified power through the connector then to the board. I have also verified the main power switch is working. So I need to check to see if power is making it past the plug the thin black and red wires are going into then? I'll see what I can find.. Thanks for the help!!
 
OK I checked continuity from here to here and I have no connection with the switch on or off here.. Is that a correct test?

photobucket-38217-1359936783048.jpg



Just to verify I tested from the back of the plug at the large red wire to the back of the small white plug on the thin red wire. I think this is what you wanted right?
 
Sorry that was not clear, I meant to circle the thin red wire, at the back of its white connector . Yes there is a rocker switch, I have tested it and it works...
 
ok that explains what the red and black wire are for. it switches the high voltage onto the oscillator in the front end. there should be 170V DC on them. it goes over to the collector of the npn switching transistor.
 
GCinDC said:
dnmun said:
you have a short from the high voltage that is on the output of the diode bridge. the current flows from that high voltage circuit into the case somewhere, and then it is returned to the ground terminal of your service panel through the ground wire.
Click to expand...
ok, this makes sense. and the short is an error, missed in QC, that i have to detect before testing again.... seems like a replacement is in order. i don't have time for this... maybe if i could slide the board out, but the fact that it's glued in turns this into a pia job... despite being completely uncalled for...

fwiw, here's a side by side, not the best res:
20121129_152657.jpg

the numbers on the big white thing in the middle are different... one side is EE55...
20121129_152616.jpg
Click to expand...


greg sent this charger to me and i found the short by measuring the resistance between the heat sink and high voltage on the input caps. i found that the high voltage that comes off the rectifier and sits on the input caps is shorted to the case. i measured from the traces to the heat sink.

on the heat sink under the lip that covers them so you cannot see them in his picture is the rectifier diode, two switching transistors and then the schottky diodes at the back of the heat sink, from one end of the heat sink to the back.

so first i loosened the rectifier diode from the heat sink, checked continuity between case and the high voltage, still shorted.

so then i went to the first of the transistors. it has a thermal switch of some sort mounted onto the bolt holding it onto the heat sink, so i removed that. it has a two pin connector which you can see as that little white thing next to the heat sink and set in the black potting compound. i had to bend the heat sink back to get it unplugged from the thermal switch to remove the switch.

after i removed the thermal breaker, i could see a big hole in the first switching transistor, where the wire going inside the plastic case was exposed because the plastic had blown off. so i loosened the nut and removed the screw and pulled that transistor away from the heat sink, and now i have an open circuit, no longer is the high voltage grounded to the case. so i removed that transistor and ordered some more. toshiba GT50J325, 600 V IGBT, something like 40A. TO-3PL package. biggest i have ever seen. i think the L stands for large!

i think this is the only problem.

his other charger that had burned up the choke, has been waiting for me to rewind the choke so i am gonna find a shop that rewinds motors and buy some insulated wire from them to rewind his choke that burned up. that also requires moving the trace from underneath the choke so that it doesn't short to the choke any more.

i am gonna cut out the trace where it runs underneath the choke and replace it with a wire from the end of the diode that the trace connects to over to the input to the voltage regulator and so along with replacing the capacitor with a 100V1000uF cap, it should work again too.
 
amberwolf said:
Also, just cuz it "looks" thick or feels heavy, doesn't mean it's good wire. I've run across cords that used STEEL CABLE in them instead of copper, especialy for large-gauge stuff like jumper cables. :roll:

It could also just be dense rubbery plastic that's very thick on the outside, and still use really thin wires on the inside (regardless of what AWG is printed on the cable sheath!). That's pretty common with extension cords, "cheap" power cords and power strips. :(


But either way: If anyone ever has a connection problem especially on something high enough voltage to hear arcing like that (the popping when you wiggle the cord), fix the connection one way or another cuz otherwise you're askin' for a fire! :shock:
Click to expand...

Holy F*%&!

Steel instead of copper? Where did you get this cable from? Who gave or sold it to you? That seriously sounds like sabotage or something.
 
Just about every set of jumper cables I have purchased from harbor freight have been copper colored aluminum. Ill toss up some pics tomorrow, its funny stuff.k
 
bowlofsalad said:
Steel instead of copper? Where to you get this cable from? Who gave or sold it to you? That seriously sounds like sabotage or something.
Click to expand...
I don't rmemeber which person it came from but the ones I have were ina box from someone on the freecycle.org mailing list. 2-3 years ago. Magnet will stick to the cable of the steel one! Was also an aluminum one colored pinkish to look like copper, too. :roll:

If I ever run across them again I'll post a pic.
 
working on greg's chargers and the problem pdf had with his now made me go look at my piles of chargers and see if i could figure out how to make them work.

after an afternoon, i got all but 2 working and then found another one with some controllers, last one in the junk pile. all the others are new.

so i plugged it in and it blew the fuse first time, so i looked and realized i had left the ground loose and it had fallen right into the high voltage on the front end. like yeah it will run with the high voltage shorted to ground.!

so removed that little short and put in a new fuse, my last 10A fuse, and it seemed like it blew the second fuse in the same length of time, and same poof. so get a bigger hammer. now to the bigger fuses.

opened my box of 100 15A fuses, gonna use them all. put that fuse in this charger and it makes a nice light, and the lights go out, blown circuit breaker.

so i get to looking, the npn transistors usually cause this, but they look alright and the base resistor still measures 2.2ohms. the capacitors do not look puffed up and there is no smoke marks anywhere, just the fuse.

so i think it has to be the rectifier diode. i used the diode tester on my voltmeter and checked the diode legs and some show a diode but really only one or two legs appear to be a diode, and most look shorted. so i figure the rectifier diode bridge is toasted.

GBU 408, 4A 800 volts. $1.62/1 at mouser $1.27 for 10.

looked on ebay, some guy is selling a batch of 4 bridge rectifiers like this, where the legs come out the bottom along one side, and another didoe that is like the square table type, 4 corners type.

anyway this guy has these 5 rectifiers diodes for 99 cents plus $1 shipping, like yeah! i can do that.

turns out the guy actually lives right here in portland. but i saw a buncha ebay specials too, so i am gonna get a rectifier bridge for this one and fix it too. gonna buy 4 or 5 so if someone blows their rectifier bridge, lemme know.
 
Hey all, my chargers acting up.

I was following the OP's posts in the beginning about the charger that would not start spinning its fan, like my charger currently, but that story didn't seem to have a conclusion. Sorry have only read the first couple pages of the thread.



The charger is a 60.5V 5A charger I got from ping. The battery I'm charging is 14s 4p battery with 18650 samsung Li-NCM cells and 40A BMS all put together by cell-man. I've lowered output voltage to 58.8V for the battery, as it needs 4.2V per cell. See pics at bottom, I dunno why its not showing the whole width of the pics.


Here are some symptoms and tests I've done:

- I plug the charger into the battery and voltage drops to the battery voltage(52V) and the charge current is only 0.25A. The charger fan does not turn on automatically.
- I have tested the charger on a resistor and the fan in the charger was turning on and it was putting out 44V and 3.5A.
- when battery voltage was at 46V the charge current was about 2.5A initially and the charger fan turned on. The charge current decreased quickly as battery voltage increased and at about 48.5V the charger fan turned off, I'm guessing charge current was about 0.4A based on the next test.
- with the charge voltage set at 59.5V and battery resting voltage 49.3V, it charges at 0.33A.
- Currently the output voltage will not adjust higher than 59.5V. Although the charger was originally 60.5V.
- The battery has reached 57.7V after 2-3 days charging and charge current is 0. When I connect the charger I measure the charger voltage 58.7V and 0A. There is no charge current even if I raise the charge voltage to 59.7V.
- After that I connected the charger to the discharge leads it charges at 58.1V and 0.05A. With the charger off, battery voltage was 57.7V.


Things I have done that could be suspect:

- I did adjust the output voltage with the charger on.
- there was a big spark when I first connected it to the battery with the charger off. It blinded me for a bit because it was dark...
- I transported the charger in checked luggage on a couple flights.


Ping and cell man have told me its dead... I hope it just needs some of dnmun's prayers
what do you you all think?

1
20130103_120812.jpg


2
20130114_143933.jpg


3
IMG_20130216_232323.jpg


4
IMG_20130216_232245.jpg


5
IMG_20130216_232418.jpg
 
i assume you have no BMS on the pack?

the charger output can not be more than the voltage on the battery. did you measure the cell voltages to see how close they are to being balanced?

the fan is controlled by the op amps that shift it from CC to CV charging so when it reaches a certain voltage the fan will cut out. i think.

you have that latching output daughter board used for lipo so you may wanna take it out if you are gonna bulk charge these cells and have it continue charging when it reaches final voltage. for lipo you would leave it in.

that thyristor daughterboard should be removed and you should solder the black wire to the red wire in the middle and remove the red wire on the right side. i do that without removing the pcb by cutting the two wires black and red, short enuff that they will lay over each other from spot to spot, then i solder them together. that allows the charger to work on 120V only without the thyristor board burning up.
 
dnmun said:
i assume you have no BMS on the pack?
...
.
Click to expand...
I do have cell mans 14s 40a BMS on the pack.

Yeah that reading where the charger voltage was different from the battery voltage seemed a bit fishy to me. But I was measuring battery voltage from the discharge wires and had the charger plugged into the charge wires.

Lipo... this was originaly a lifepo4 charger

Ok im going to assume this thyresistor removal description is refering to the picture of the tiny circuit board.
Actually it seems like we're looking at the picture of the big board that shows the wires going to the daughterboard. But then what do you mean by the right wire... I guess you mean the one on the right as the wires lead out the top of photo 3 towards the daughterboard. I numbered the photos:D
 
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