MeanWell S-350-48

Specs:

Mean Well S-350-48

350w max continuous output

48V - adjustable from 41V - 56V

7.3A max continuous output@48V -

48V x 7.3A = 350W

Thermal regulated fan

http://www.meanwell.com/search/S-350/default.htm]Factory Specs

Problem:

Rated at 7.3A, but will surge-sustain much higher, burning components

Solution:

Restrict the amp output -

The "R33" resister is the key to regulating amperage.

For testing purposes, I soldered 2 wires of a 2s balance plug to the ends of the R33 resister.

Then plugged a multi-turn 2K Pot (potentiometer) into the balance connector.

Then I lowered the voltage to minimum and applied "load".

Removing and measuring the pot's ohms at each 1/2 amp mark.

(Pot must be removed to measure! "In circuit" it is laid parallel with R33.)

Restricting Current (Amps):

9.1A = (OEM resister only) .350K = 350ohm

7.9A = 2.000K = 2000 ohm

7.5A = 1.432K = 1432 ohm

7.3A = 1.200K = 1200 ohm

7.0A = 1.000K = 1000 ohm

6.5A = .775K = 775 ohm

6.0A = .580K = 580 ohm

5.5A = .458K = 458 ohm

5.0A = .368K = 368 ohm

4.5A = .288K = 288 ohm

4.0A = .225K = 225 ohm

3.5A = .180K = 180 ohm

3.0A = .132K = 132 ohm

2.5A = .098K = 98 ohm

2.0A = .065K = 65 ohm

1.5A = .038K = 38 ohm

1.0A = .013K = 13 ohm

Wider Amp adjustment:

Disconnect, or remove R33.

Replace with adjustable "pot"

Amps ........ Ohms

1A ... from ... ? ohms

2A ... from ... ? ohms

3A ... from ... ? ohms

4A ... from ... ? ohms

5A ... from ... ? ohms

6A ... from ... ? ohms

7A ... from ... ? ohms

8A ... from ... ? ohms

9.1A ... from ... 350 ohms

10A .. from .. ? ohms

11A .. from .. ? ohms

12A .. from .. ? ohms

13A .. from .. ? ohms

14A .. from .. ? ohms

15A .. from .. ? ohms

16A .. from .. ? ohms

17A .. from .. ? ohms

18A .. from .. ? ohms

19A .. from .. ? ohms

20A .. from .. ? ohms

etc.

Need lower voltage high drain rig to determine higher amps.

Not precise ... used analog amp meter.

Widening the voltage range:

By changing the value of the Voltage pot, I was able to lower the output range substantially.

1K = 38.3 - 56.7V (oem)

2K = 29.8 - 56.7V

5K = ? - 56.7V (<20V - 56.7V estimated)

10K = ? - 56.7V

20K = ? - 56.7V

100K = ? - 56.7V

As I will demonstrate later, there can be great advantages to lower voltages.

Note! The higher value pots (100K etc) only allow a very "coarse" adjustment at the high voltage end. Harder to fine adjust.

Lowering Voltage

Lowering voltage could take advantage of higher amperage.

Without removing components, amperage is regulated below 9.1Amps.

R33 has a measured resistance of ~350ohms.

Component View

Raising Voltage?

Not tested ... or recommended!

This model has 63V caps ... a fairly strict limitation!

350 Watt!

To be safe and effective, amperage should be adjusted as voltage is altered.

Volts x Amps = Watts

Watts should equal, or be slightly below, 350 watts.

56V x 6.25A = 350w

55V x 6.36A = 350w

54V x 6.48A = 350w

53V x 6.60A = 350w

52V x 6.73A = 350w

51V x 6.86A = 350w

50V x 7.00A = 350w

49V x 7.14A = 350w

48V x 7.30A = 350W

47V x 7.44A = 350w

46V x 7.60A = 350w

45V x 7.77A = 350w

44V x 7.95A = 350w

43V x 8.13A = 350w

42V x 8.33A = 350w

41V x 8.53A = 350w

40V x 8.75A = 350w

39V x 8.97A = 350w

38V x 9.21A = 350w

37V x 9.45A = 350w

36V x 9.72A = 350w

35V x 10.00A = 350w

34V x 10.29A = 350w

33V x 10.60A = 350w

32V x 10.93A = 350w

31V x 11.29A = 350w

30V x 11.66A = 350w

29V x 12.06A = 350w

28V x 12.5A = 350w

27V x 12.96A = 350w

26V x 13.46A = 350w

25V x 14.00A = 350w

24V x 14.58A = 350w

23V x 15.21A = 350w

20V x 17.50A = 350w

15V x 23.33A = 350w

10V x 35.00A = 350w

5V x 70.00A = 350w

Yeah ... I'm gonna try pushing everything to the limits ... and then a little further!

(Will test to confirm)

In Series

"In series" is when the negative of one power supply is run through the positive of another - combining their voltages.

Important!

When run in "series" the DC "negative" must be isolated from the 110AC negative ... on all but the primary unit!. Otherwise, the DC positive from the primary unit will "short" through the AC negative on the secondary unit.

The negatives are usually connected through the "ground".

Not confirmed yet!!!

It appears the S-350 series is ready for "in series" with no mods!

Not confirmed yet!!!

Submitted to Endless Sphere WIKI

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