MeanWell Mods - S-240-48

MeanWell Mods
MeanWell Mods - S-150-5
MeanWell Mods - S-150-12
MeanWell Mods - S-150-24
MeanWell Mods - S-150-48
MeanWell Mods - S-240-48
MeanWell Mods - S-350-48

See- ES Wiki MeanWell Mods for more

View attachment 2
Specs:
Mean Well S-240-48
240w max continuous output
48V - adjustable from 41V - 56V
5A max continuous output@48V -
48V x 5A = 240W
Thermal regulated fan
Factory Specs

Rated at 5A, but will surge-sustain much higher, burning components

Solution:
Restrict the amp output -
The "R33" resister is the key to regulating amperage.

Just getting started.
Format is greatly different from the S-150 and S-350's.
Current is adjustable through the R33 resistor! ... ?

The R33 resistor is hidden under a transistor and its heatsink.
Worse!
R33 appears to be 1 watt ~10 ohms.
Which means a typical pot (1/4w) will be insufficient for testing.
Will have to "trim" by buying and adding 1w resistors in parallel.
10 ohm + 100 ohm should produce about 9 ohm, at least it should give a baseline for various trimming.

Unless ...
R33 serves a differing function on this model?

I have a 2w 200ohm resister to run an initial test with (10 to 9.5ohm) ... should show some minor variance, or at least cause no damage.

Update: Just found and ordered up a "470 Ohm 1W 5% Rotary Potentiometer".
Should provide a full range of amperages.

ES Wiki page under development - MeanWell S-240-48


MeanWell Mods
S-150-5
S-150-12
S-150-24
S-150-48
S-240-48
S-350-48

I had a meanwell clone (copy) 48v 350W , this also has a built in fan and there was a part of the pcb that was unpopulated and after a bit of research and adding 2 extra passive components and a pot it became a 4-10A adjustable constant current psu. just wondering how similar your meanwell is to the clone that I bought, do you have any pics of the component side of the board ? ,

Edit: just found your other thread on the 48v 350W http://endless-sphere.com/forums/viewtopic.php?f=2&t=55658&p=843963#p843963 , this looks identical to the psu I have and yes r33 is where it all takes place, so Im guessing the 240-48 must be a totally different layout.

Just received 470ohm 1w pot.
Gonna attach 2 wires to R33 and use 1w pot to confirm for current mod.

Will trace R25 or equivalent to shift voltage range.
I will adapt 48V, to 36.45V capable, as my 9s x 4.05V charger. Should not require current mod at this reduced voltage.

Will post up charts of required values and include in post #1 and Wiki page.

SVR1 mod (voltage pot) mod will not allow significant voltage drop.
Added 147ohm resister in series with 1500ohm R48 resister, (next to SVR1 - voltage pot), which shifted voltage down to 56 - 36.2V, Secondary regulation circuit prevents lowering below 36.1V.
R33 mod does not work! ... and ... No shunts!

Did find the thermistor controlling the fan, Blue "disc" at upper left. 3200ohm at room temperature. Ran 2k ¼w resister in parallel and demonstrated continuous fan. Fan speed varied with voltage adjustment.
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Good picture of components



Conclusion:
Not "moddable" like the S-150 and S-350 are , but still valuable as slave units "in series".

See ES Wiki Page for full details - MeanWell S-240-48