What trim to adjust output voltage

[smurphy]

Hello,

What trim to i need to adjust to set the output voltage of this charger?

I want to set it to 56,70V for a 80% charge of my 14S6P pack.
Do i need to set it with or without load?

Thanks

Steven

 

[izeman]

you need to set it w/o load. and i would just try any of the three. no much of a deal
connect a voltmeter to the output, read the voltage, then turn one of them half a turn in any direction, if the value changes: BINGO. if not: turn it back to it's original position.
you could also install a 2 position switch with resistors installed. so each setting sets the output voltage to 80% or 100%.

 

[smurphy]

Thanks Izeman. Will try that.
That switch is also a good idea

 

[Samd]

No no if it's a Kingpan only adjust the one in the corner. The other two are a pita to fix.



Sent from my iPhone using Tapatalk

 

[999zip999]

I made a wooden screwdriver from a chop stick.

 

[heathyoung]

Impressive - looks like the designers have stepped up the quality of the transformers on these - Litz wire.

What brand is it? Looks better made than the usual junk. Really unusual not to use an output inductor - must be ZVS or resonant.

 

[Peter.bp]

Really unusual not to use an output inductor - must be ZVS or resonant.

Flyback converter doesn't need output inductor when you have proper output stage driver (dV/dt under control).

High current / low voltage winding is easily built using several single strand wires in parallel.
In addition, several single strand wires in parallel (when they're wound properly) gives much less parasitic inductance than Litz wire and takes less area.

 

[smurphy]

Got them from here:

https://bmsbattery.com/ebike-charger-ev-charger/797-c300-300watts-lifepo4li-ionlead-acid-battery-charger.html

It is the top trimmer that did it.

 

[heathyoung]

Really unusual not to use an output inductor - must be ZVS or resonant.

Flyback converter doesn't need output inductor when you have proper output stage driver (dV/dt under control).

High current / low voltage winding is easily built using several single strand wires in parallel.
In addition, several single strand wires in parallel (when they're wound properly) gives much less parasitic inductance than Litz wire and takes less area.

300w is pretty unusual for a fly back converter - especially when using two devices - looks like a half-bridge (especially with two caps) - for $30 I would buy one to tear down. My money is still on a bang-bang control ZVS

 

[heathyoung]

Actually - looking at the topology - and the feedback windings - I might suggest that this is an isolated buck converter with PFC - using the only buck PFC chip ever made (TI) - I would love to see the other side of that PCB in high resolution.

Appears to be maybe 2 power and 2 rectifier devices. Hmmm have to reverse engineer this one...

 

[Samd]

Its a well known kingpan.

Google kingpans on endlesssphere.com -> plenty of threads.

Touching the other two trimpots is the stuff of legend.