BMS Battery Alloy Shell Charger Problems

dnmun said:
the fuse is under the plastic cap where they have the emblem of a fuse. you could put a rocker switch underneath for on/off too.

yes it must be under this cap, but something is broken off there :(

izeman said:
maddin you should not compare it to the one i gave to you. ;) normally the board is not screwed to the case. this was something i did to make it stronger and fail proof.

i know, but i want to mention how cheap these chargers are built. nothing compared to european or us standards.
As i told you the charger you lent me is off his "electronic head". It very often sporadic turns to fully charged (green led) and stops charging. Sometimes it doesn't cut off which is very dangerous without bms (it simply charges further and further if it exceeds the set voltage without reducing current). Glad i was in the room and took a look every few minutes. It was already at 93V the first time i noticed this strage behaviour :shock:
 
i disagree. i have three elcon chargers. each retail for about $800 so they are not cheap but i think the EMC-1000 is a better charger and can handle a lot more current. sorry you can't find the fuse. it seems clear where it is and if you can find one of hose rocker switches then you can insert it under the fuse by cutting out that rectangular spot outline on the plug base.
 
dnmun, what type of elcon charger do you have?

The smallest one i could find is the PFC1500:

http://www.elconchargers.com/catalog/item/7344653/7638003.htm

imho i would say this one has better, more durable electronics than the EMC-1000 (it also has better protection features and a pfc :p ), but i hadn't seen pics from the inside yet. I have had think of it, but it is way to heavy and to big for my usage. Its listed for about 350$ :wink:
 
i have three of the 912-7200. 12A @72V. they are huge in size but have programmed charging profiles which i cannot change but the one in my ZENN car is set up for the specific DEKA gel VRLA packs i have in the car. but another one is programmed for CC/CV for a lifepo4 pack which i have not used yet and i bot another one that is the older model of the 912-7200. i bot it for parts off ebay thinking it had only a fuse blown that i could fix. turns out the fuse was blown as i expected but the ignorant dufous who worked on it could not figure that out and cut out the schottky diode for no reason and then when he put the case back together he left out the heat sink clamps. never mentioned that in the ebay ad. whatta jerk. damn.

so now i have to figure out a way to replace the heat sink clamps which i think i can handle with some self made bars and holes drilled through the external heat sink to clamp them. but on this older one i decided to hack it up in current to see if i can push the current up and use it for charging my hybrid 44Ah 21S lipo/ 87Ah 24S lifepo4 pack at 18A up to 88.4V by adding a second schottky diode on the output instead of the one it is wired up for and then i am gonna add some solder to the current feedback shunt to spoof the charger into pushing more current.

it will work on 120 or 240V so i can then hard wire this hacked charger onto my charging plug on the car, and i am gonna use the relay they have on the output as a way to shut off the charger by the cellog alarm or by using a remote control to turn it on and off so i can leave the main charger float charging the lead acid pack and then switch on the lipo charger with the remote when i wanna charge the lithium pack up in advance of using the car. another project, another time.
 
sorry for your not so lucky ebay purchase..
this must be some very very old elcon chargers, and as for the comparison with the EMC-1000, i would say things now are a bit different.
 
look at this EMC-900:

v2ki.jpg


The charger i have set to 8A and 91V (22s LiMn), but sometimes it doesn't reduce current or cut off. If i would not always pay attention to the display, it would had burn down my battery and probably itself too.
I also noticed it sometimes does stop sporadically during a charge (LED turns to green) while the battery is not full. I guess it is not an overheat issue because it was not very warm, but sometimes when it stops, the fan was not running. Than, after disconnect and reconnect the plug, the fan suddenly starts instant to run and it continues charging :?:

izeman, its a pity. the charger is so much nicer with the display, but it seems like it has lost his brain and become insane.
I only have seen it about 5 times out of 20 charging cycles so far working properly.
 
did you try to adjust the final voltage again after it drifted above the set point? how did you measure the voltage when adjusting it? was there a battery connected to the output when you adjusted the terminal voltage?

when the charger turned green, did the charging current stop at the same time? if it did then that means the BMS had turned off the charging mosfet for HVC. it restarted charging after a period of time long enuff to drain the voltage off the high cell.
 
wow this is a NICE charger. who did install the amp-meter? ;) oh yes. that was me ...
i can't tell you why you have those problems, as i NEVER had any. i charged at least 30 times and it was always w/o any issues. the meter FOR SURE has nothing to do with it, as it's only inline of the output line and not incluencing anything.
 
dnmun said:
did you try to adjust the final voltage again after it drifted above the set point? how did you measure the voltage when adjusting it? was there a battery connected to the output when you adjusted the terminal voltage?
why should i measure the volts when i have this nice display on the charger? And as i said, it sometimes does reduce current at exact 91V and cut off when current has dropped to about 5% CC. I did not try to adjust volts again, because what should this change?

when the charger turned green, did the charging current stop at the same time? if it did then that means the BMS had turned off the charging mosfet for HVC. it restarted charging after a period of time long enuff to drain the voltage off the high cell.
the current also stop if it turns into green. I have NO BMS and it can happen at any s.o.c., so its a problem with the charger.

izeman, i know the display cannot have something to do with it and you did a neat work. And i only just took the lid off, twisted the two pots for the volt adjustment and closed it again. It must be something other wrong with it. Very strange. Maybe you can use parts from it to repair my charger? :lol:
 
dnmun said:
sounds like a bad connection then. you can open it up and see if you can find a loose wire or the relay contacts may be flakey.
maybe, but whats with the problem with the fan?
sporadically cut off (fan not running) -> disconnect and reconnect to the socket -> continues charge and fan is running instant
 
the fan is turned on when the IGBTs get hot. there is a three terminal device attached to the nut on the heat sink clamp and when it gets warm it is on a balanced input to an op amp so the op amp is switched on and that turns on the transistor for the fan.
 
yesterday i started examining maddin's charger. what a mess. the little mosfet completely exploded leaving a lot of grey debris all around. one resistor also desintegrated and the little 8pin ic also burned one of his legs. there must have been a massive current flow to cause that. i removed all obviously broken parts and cleaned the board.
interestingly there is no 78xx chip for the 12v voltage regulation. and the broken one is a mosfet. hitachi 2SK1808. and there is no voltage regulator visible. i can't really read what the 8pin IC's printing is. maybe someone could take a picture of his emc100 charger and show me the parts installed. mainly: R209, R210, U1, C210, Q201. i will then try to replace those parts and see what happens.

IMG_0201.JPG

IMG_0202.JPG
 
i don't have mine open, but the 8 pin IC is a dual opamp 324 i would guess.

but all of those parts are on the output of the secondary winding of the transformer and not on the 12V output of the regulator.

so i am thinking that what has happened to put so much voltage there is that the output of the charger, that goes through the schottky diodes and the choke there, is somehow shorted to the 20+V that is on the output of the diodes behind the transformer.

so before replacing the parts, look for a short between the output positive and the power to those parts. it may be be a short from the choke to the traces running across the pcb underneath the choke. that is what i found on a similar failed charger. except smaller sized.

you could try verifying that the four diodes there on the output of that secondary winding are all functional since if one of them failed it might cause a problem, but i doubt if it could blow these parts up. but maybe.
 
look from the end, maybe the relay is in the way, but you may see where the choke is touching the pcb. see if there is a trace running under the choke. it doesn't look like the choke overheated and would have burned through the shellac to contact the trace though.
 
@ izeman

when the charger was blowing i did some measuring at the back side of the PCB exactly at those legs from this Mosfet or whatever it was. Don't ask why i thought this was the regulator.. imo there should be no problem with the choke or the diodes.

Currently im working on a travel charger built of two Meanwell HLG-240W with display and relay cut off. With the KPC 1200 charger im not very happy, because almost everytime when i switch it on or plug it into the socket, the automatic circuit braker cuts off :( i guess this is because of weak inrush current limitation and no PFC circuit.
Aside from this it works as it should and with the temperature controlled fan i installed it is almost inaudible.
Recently i saw a charger with PFC on BMS battery site. It is only a small one but hopefully they become more and more.
 
dnmun said:
it is not a mosfet. it is an npn transistor that turns the fan on and off.

ok, seems like i was on the right place for a 12V source :)
 
ok, finally went out and opened my charger. it is hardwired to the battery so i have to look outside with the sun reflecting off the lens of magnifying glass. danm. almost blind now.

everything i thought about those parts is totally wrong. i thought it was the switch for fan but i am totally totally wrong.

the U1 is UC3842BN which is the IC pwm controller used to switch that mosfet 2SQ1808.

look for a resistor on the source leg and that is how the power delivered by the mosfet is controlled. i don't have the document in this computer but there is a white paper on how they work somewhere i read at one time. pin 2 is where the feedback goes onto the 3842 and if you look at the traces you will see where the output of the optotransistor IC202 is attached to pin 2 on the 3842.

https://www.google.com/search?q=uc3842bn&espv=2&biw=1024&bih=653&tbm=isch&tbo=u&source=univ&sa=X&ei=dO8lVND1NYS5ogTy2oDAAQ&ved=0CD8QsAQ

i see that the R210 is attached to the gate leg of the mosfet, and R209 and the diode D205 which i assume is a zener to protect the gate. so gate drive is from R210 and the R209 may be there to do the initial startup for the oscillator by taking a signal off the trace that seems to come off the choke there in the upper left. that would make sense if the choke has an initial voltage impulse on power up. not sure how it works though.

C210 is 103J100
R210 is 100R
R209 is 10kR i think, could not read it but measured about 9.9kR on one scale and 8.63kR on another scale while in the circuit. i think the last ring is red so that means 2% i think.

do you need C207, the electrolytic?

so sorry i mislead you and i looked for the voltage regulator under the lip of the heat sink and it is not there either. all of that may be on the daughter board. so there is no 4 diodes on a secondary winding that deliver power to the back end.

this design is fundamentally different from the kingpan design used in the low power chargers. it uses the 3842 for the oscillator instead of using a TL494 like the other chargers. i guess that is because it does not require much current to switch the IGBTs in the front end as it takes to switch the big big npn transistors used in the kingpan type charger.

so sorry.
 
thanks a lot for your support and taking your charger apart to achieve that. very much appreciated. yes. this charger works quite different from the posted design here in the thread. i have several kingpan style one and they DO look different. and to be more confusing on the very first sight they have the voltag regulator (7812) almost at the very same place as those emc1000 ones have the mosfet. i guess with the values you posted i can make some progress as soon as i have the parts sourced. i guess i now have all values for all the parts.
 
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