Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Power Supplies and Power Supply Design
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 11-05-2021, 09:07 AM   #21
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

before repairing the battery 49v after 5 minutes of charging 54v means that the battery is charging, now 54v
Attached Images
File Type: jpg 2021_10_30_13_33_IMG_6775.jpg (902.0 KB, 9 views)
Alexbp is offline   Reply With Quote
Old 11-05-2021, 09:12 AM   #22
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

Before that, everything was fine for a year and a half.
Alexbp is offline   Reply With Quote
Old 11-05-2021, 09:19 AM   #23
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

after 2 months a 49v battery connected to a 2.3v motorcycle
Alexbp is offline   Reply With Quote
Old 11-05-2021, 09:38 AM   #24
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

battery
Attached Images
File Type: jpg 2021_11_05_16_36_IMG_6795.jpg (875.7 KB, 6 views)
Alexbp is offline   Reply With Quote
Old 11-05-2021, 10:33 AM   #25
eccerr0r
Solder Sloth
 
eccerr0r's Avatar
 
Join Date: Nov 2012
City & State: CO
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist Tech
Posts: 7,080
Default Re: I need a charger schematic YLT6722000

16S7P Li-ion... at 54V it's almost dead, so it'd suck up a lot of current.

Don't know, would have to reverse engineer that circuit in depth to figure out what's wrong and why the fr207 is heating up.
eccerr0r is offline   Reply With Quote
Old 11-05-2021, 10:47 AM   #26
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

This is understandable, but the current consumption is 2.10A
Alexbp is offline   Reply With Quote
Old 11-05-2021, 10:52 AM   #27
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

it turns out if the battery is completely dead this charger is very weak
Alexbp is offline   Reply With Quote
Old 11-05-2021, 10:56 AM   #28
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

how it is possible, the developers should know about it
Alexbp is offline   Reply With Quote
Old 11-05-2021, 11:12 AM   #29
eccerr0r
Solder Sloth
 
eccerr0r's Avatar
 
Join Date: Nov 2012
City & State: CO
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist Tech
Posts: 7,080
Default Re: I need a charger schematic YLT6722000

Again the MUR1060FCT is the diode dealing with the 2A/130+ watts to the battery pack. The FR207 is only powering the electronics to control the charge and theoretically should be far less than 1A.
eccerr0r is offline   Reply With Quote
Old 11-05-2021, 11:45 AM   #30
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

I understand that, but why does the FR207 burn out?
Alexbp is offline   Reply With Quote
Old 11-05-2021, 11:56 AM   #31
eccerr0r
Solder Sloth
 
eccerr0r's Avatar
 
Join Date: Nov 2012
City & State: CO
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist Tech
Posts: 7,080
Default Re: I need a charger schematic YLT6722000

That would require a more careful reverse engineer of your circuit...Don't know. Has it always been like this?
eccerr0r is offline   Reply With Quote
Old 11-05-2021, 12:02 PM   #32
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

ordered mur1060fct and fr307 order will arrive within the next week
Alexbp is offline   Reply With Quote
Old 11-05-2021, 12:06 PM   #33
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

I will try to replace it, I see no other way, although it is unlikely to do any good
Alexbp is offline   Reply With Quote
Old 11-05-2021, 12:17 PM   #34
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

If I understand correctly, it is necessary to change the scheme, but it would entail a lot of costs
Alexbp is offline   Reply With Quote
Old 11-05-2021, 12:28 PM   #35
Alexbp
Member
 
Join Date: Aug 2021
City & State: Siegburg
My Country: Germany
I'm a: Knowledge Seeker
Posts: 41
Default Re: I need a charger schematic YLT6722000

perhaps there is a better solution to this problem
Alexbp is offline   Reply With Quote
Old 11-05-2021, 03:27 PM   #36
CapLeaker
Leaking Member
 
CapLeaker's Avatar
 
Join Date: Dec 2014
City & State: Atlantic Canada
My Country: Canada
Line Voltage: Ground, 0Hz
I'm a: Hobbyist Tech
Posts: 5,044
Default Re: I need a charger schematic YLT6722000

Quote:
Originally Posted by Alexbp View Post
without load all cold voltage at the output 67.4v, when you connect the battery is strongly heated FR207, the output is 54v
Sounds about right if the battery is totally flat
CapLeaker is online now   Reply With Quote
Old 11-05-2021, 03:30 PM   #37
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 2,460
Default Re: I need a charger schematic YLT6722000

FR207 diode datasheet calls them (FR107,207,307) "fast recovery" but not really. It's a bit slow, rated 500nsec recovery. Higher voltage diodes are also slower. FR207 is 1,000V which is not needed at all. 1A should be enought for the charger control and LM358.
We don't know the charger's frequency, but I find a slow rectifier with no snubber will run hot and even fail, despite the load being small.

I would upgrade to a faster recovery diode with lower voltage, under 400V. Like UF4004 (50nsec) or BYV38-200 (30nsec) etc.
A mistake I have made is thinking the diode failure is due to current, so I upsize the diode but it's worse because bigger diodes are typically slower. FR307 is still 500nsec. slow.

The charger might have a design problem with spikes/ringing coming out of the transformer, if there is no snubber network across the secondary-side rectifier diodes. Or the primary snubber is inadequate.

Last edited by redwire; 11-05-2021 at 03:51 PM..
redwire is offline   Reply With Quote
Old 11-05-2021, 03:36 PM   #38
CapLeaker
Leaking Member
 
CapLeaker's Avatar
 
Join Date: Dec 2014
City & State: Atlantic Canada
My Country: Canada
Line Voltage: Ground, 0Hz
I'm a: Hobbyist Tech
Posts: 5,044
Default Re: I need a charger schematic YLT6722000

Quote:
Originally Posted by Alexbp View Post
I understand that, but why does the FR207 burn out?
Put a higher power rated and faster diode in place of the fr207. Theoretically you could put an ultra fast recovery diode there and heat sink it. These fr whatever diodes are not the best diodes to start with and I usually replace these with something higher rated. Then I never had anymore troubles with it.
CapLeaker is online now   Reply With Quote
Old 11-05-2021, 06:08 PM   #39
eccerr0r
Solder Sloth
 
eccerr0r's Avatar
 
Join Date: Nov 2012
City & State: CO
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist Tech
Posts: 7,080
Default Re: I need a charger schematic YLT6722000

Worth trying a faster diode, but still does not explain why the FR207 though always under load, only heats up when the main diode is loaded? Control logic should be about the same load regardless of main output load.

These chinese mains PSUs tend to be lower frequency due to size of the switching FET needed...
eccerr0r is offline   Reply With Quote
Old 11-05-2021, 08:39 PM   #40
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 2,460
Default Re: I need a charger schematic YLT6722000

The charger is pretty much at the max. for low cost architecture using a flyback converter for 135W. At this power level, the design has to be well done but this one is basic and low cost.

Under heavy load charging a battery, the transformer gets max duty cycle so both secondary windings will see the ringing and spikes at their worst.

The low voltage rail with D3 FR207 would get hot if the diode is slow and trying to switch off when the waveform is ringing, the diode will turn on and off many times during one pulse. When the diode is stuck on, slowwwwly turning off it will allow a -ve spike to flow through the 100uF 35V cap. LM358 can run to 36V but not handle -ve spikes. There's no other reason I think for it to heat up, how could it see a few A otherwise.

Main rectifier MUR1060 has R31//R32 4R7's with C7, as a snubber but R31 looks like dark splotch. If R31 is burnt, then this confirms the PSU has some design issues causing extra stress to the rectifiers. You would have to poke around with a scope to see if my guess is good.

R21 (27?) and R23 by U3 LM358 also look cooked, but maybe it's flux?

It could also be an the primary RCD snubber, as I see the usual 100V film cap there and they usually undersize the big resistor or use a crappy FR107 there.
redwire is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2022
Powered by vBulletin ®
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 03:10 PM.
Did you find this forum helpful?