Re: Help idinifying circuit from Battery Charger
Tks Redwire but I only have two of these vs-70hr's kicking around so I guess that's out? I just recently converted an old PC power supply that I had kicking around to a bench top power supply but I do have a couple of power supplies from a TV receiver not sure what I could get out of that? These board delivers a bunch of voltages but since I am not a tech person I am not sure of the value of what I have in my junk box?? I derive a lot of satisfaction from taking scrap and turning it into something useful but most of my knowledge come from the great people on forums like this. I am a knowledge seeker.
Help idinifying circuit from Battery Charger
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Re: Help idinifying circuit from Battery Charger
Yeah probably best not to use a bridge and use discrete diodes - the original design spread the diodes out away from each other for a reason.
and holy crap, seeing some china shops selling the button diodes for less than 10 cents a pop in 1000 quantities... wonder how bad they are?Leave a comment:
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Re: Help idinifying circuit from Battery Charger
Any diodes used need heat sinking for cooling. This is the hassle.
With a 15A load, each diode will dissipate about 7W of heat, roughly.
If you use a bridge rectifier module, then all the heat is concentrated in one square for 28W.
The VS-70HF is a large 70A 800V stud-mount diode, you would need four.
But the hassle is mounting them on the heatsink, the cathode is the bolt so two of the four diodes need insulators or the special version with reverse-polarity (anode to case). Insulators can't transfer the heat, so the diode cooks or the plastic melts and they aren't a great way to go.
Simplest fix I think is bolt a 25-50A bridge module on the heatsink, the modules are isolated case so no more hassles with shorts to the metal.
Rectifiers from a scrapped PC power supply could work. They are two Schottky's in a TO-220 case and a bit more voltage for the battery. What else you got in the junk box.Leave a comment:
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Re: Help idinifying circuit from Battery Charger
It looks like the charger manufacturer tried to copy a car alternator's construction with press-fit diodes. But the plastic washers are terrible for heat conduction and aluminum rivets on copper likes to corrode and the skinny wires have to go. Yuck.
I would change over to a bridge rectifier module like KBPC5010 50A 1000V $3.00
But the big problem really is heat sinking the diodes. Even if you put in huge expensive stud-mount diodes, that small plate just can't get rid of heat very well. I would beef up the heatsink.
How many amps is this charger rated? Does it have a fan?Leave a comment:
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Re: Help idinifying circuit from Battery Charger
It looks like the charger manufacturer tried to copy a car alternator's construction with press-fit diodes. But the plastic washers are terrible for heat conduction and aluminum rivets on copper likes to corrode and the skinny wires have to go. Yuck.
I would change over to a bridge rectifier module like KBPC5010 50A 1000V $3.00
But the big problem really is heat sinking the diodes. Even if you put in huge expensive stud-mount diodes, that small plate just can't get rid of heat very well. I would beef up the heatsink.
How many amps is this charger rated? Does it have a fan?Last edited by redwire; 08-31-2019, 01:29 PM.Leave a comment:
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Re: Help idinifying circuit from Battery Charger
People sometimes replace them with 50 amp/400v D0-5 style stud mount diodesLeave a comment:
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Re: Help idinifying circuit from Battery Charger
No numbers visible on either of the 4?Leave a comment:
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Re: Help idinifying circuit from Battery Charger
I don't believe they should be split like that, what is the number on them? it should be marked on the side. I t could be the diodes have a high forward resistance so they could show open with a meter.Last edited by R_J; 08-31-2019, 11:55 AM.Leave a comment:
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Re: Help idinifying circuit from Battery Charger
Each diode can be tested with a multimeter and diode test. What seems to be shorted? the diodes?
It looks like all four diodes have a common point, the aluminum plate, so they could have 2 diodes in parallelLast edited by R_J; 08-31-2019, 11:23 AM.Leave a comment:
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Re: Help idinifying circuit from Battery Charger
Tks again R_J yes there are?? first time a have seen a diode looking like that?? The circuit seem to be shorted is there a way to test these diodes?Leave a comment:
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Re: Help idinifying circuit from Battery Charger
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Help idinifying circuit from Battery Charger
The photo is of a circuit in an older car Battery Charger. I was wondering if someone on here could identify this circuit and explain it's function and how it works. It seems to be a very simple circuit to convert AC power to DC power. The two leads from the Transformer connects to the two terminalsTags: None
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