Help fix a 36v lifepo4 charger 5 amps.

[wineboyrider]

dnmun sold me a thermistor that I resoldered back in then hooked it up and this thing popped and made a bunch of smoke.
Not electronically oriented, but I can solder if someone can help me identify what went kablewey... and where to find a replacement part etc.....

 

[wineboyrider]

BUmp

 

[Racer_X]

Hej wineboyrider, that picture is a bit small and out of focus, can you please upload another more hi resolution picture.

 

[wineboyrider]

Updated pics

WHere the blue wire comes in from the AC line this thing popped it reads 50v 100uf.


The upper left corner is the thermistor that dnmun sent me and I thought was wrong.

 

[dnmun]

yep, sent you a pm, it is the output cap, i doubt if something like radio shack even has them, but if there is a good electronics store there, then they may have one. but it is cheaper and usually faster to buy one off the electronics sellers on ebay. you can buy one a little bigger too, or higher voltage, but you have to make sure the legs will fit since they have different spacings for different size caps, you can look them up in mouser, radial lead electrolytic capacitor. 50-63V and 100-200uF should work.

edit, if you can get it away from that heat sink that holds the output schottky diode, it will last longer too. but that is where the larger cap would be too big for the space.

 

[wineboyrider]

What about positive or negative on the capacitor? I mean does it matter which way it goes in?

 

[dnmun]

yep, you can see the negative and positive marks on the can, and on the pcb you can see which is negative and which is positive.

a good education of what the parts of that charger are can be obtained by you at this time. examine where the negative charger wire leaves the board, then follow that trace back throughout the pcb and you will see where the ground side of most of the little parts are connected, such as the little daughterboard that sets the limits.

the positive also is connected to the ground in parallel with that capacitor by a kinda bigger than others resistor, connecting the plus and minus traces, it is about 5k usually, and that is there to discharge the output lines when the charger is off and disconnected, so no voltage hides on the output cap. kinda a tradition of electronic design, and you can see kinda how the current goes into the positive side through the schottky diode after it is pushed out of the back side of the transformer from the oscillations created in the supply of current into the front end of the transformer by the switching of the power mosfet which is what you see on those heat sink on the front end of what is called a Switch Mode Power Supply SMPS

 

[dnmun]

ok, i just looked on ebay, and this is the best deal i could see. sounds like he will have it to you by thursday using regular mail, which is all it is worth. 105C helps where it is located, you are gonna end up with extras, so maybe others will follow this thread and get one from you.

problem for me with sending caps through the mail is that since they are so thick, the post office wants me to use a bigger envelope and expense where i always just try to send stuff through taped onto some cardboard to keep it running through their mail sorting machinery.

http://cgi.ebay.com/20-x-100uF-50V-105C-Radial-Electrolytic-Capacitor-8x11-/220749642048?pt=LH_DefaultDomain_0&hash=item3365b43940#ht_1446wt_698

 

[wineboyrider]

Sorry they are actually 50v 1000uF
My bad.
I'll look later when I get a chance.
My 12v dc fan went out on king charger too.
Everything seems to break in threes for me wonder what's next??????

 

[dnmun]

same place for the caps:

http://cgi.ebay.com/4-x-1000uF-50V-105C-Radial-Electrolytic-Capacitor-13x26-/230609926361?pt=LH_DefaultDomain_0&hash=item35b16c38d9#ht_1446wt_698

the fan will start working again after you oil it. peel the decal off then take out the rubber plug and put some lightweight oil in the recess then put the rubber plug back, decal back over that.

 

[wineboyrider]

same place for the caps:

http://cgi.ebay.com/4-x-1000uF-50V-105C-Radial-Electrolytic-Capacitor-13x26-/230609926361?pt=LH_DefaultDomain_0&hash=item35b16c38d9#ht_1446wt_698

the fan will start working again after you oil it. peel the decal off then take out the rubber plug and put some lightweight oil in the recess then put the rubber plug back, decal back over that.

Dogman was telling me to do that, but I wasn't sure where or how?? I'll try that and get back to you...
8)