**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

I recently came into a large supply of new MeanWell, (Mean Well), switching power supplies.

Enough, and cheap enough, that I don't mind sacrificing a few on the alter of R&D.

**Specs:**

Mean Well S-150-24

150w max continuous output

24V - adjustable from 19.5V - 29.8V (As tested on 2 samples)

6.5A max continuous output@24V -

24V x 6.5A = 156W

No fan - Open grid shell - convection cooling

Factory Specs

**Problem:**

Rated at 6.5A, 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, (then as high as 10K), 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 2 other resisters.)

**With the following results:**

8.5A = OEM

8.2A = 10K

8A = 8.1K

7.5A = 4.6K

7A = 3.3K

6.5A = 2K

6.0A = 1.65K

5.5A = 1.3K

5.0A = 1K

4.5A = .81K

4.0A = .63K

**Wider Amp adjustment:**

Disconnect, or remove R33 & R38.

Replace with adjustable" pot"

Working with 12.6V LiPo pack through inverter

Amps ...... Ohms

1A ... from ... 70 ohms

2A ... from ... 175 ohms

3A ... from ... 287 ohms

4A ... from ... 392 ohms

5A ... from ... 500 ohms

6A ... from ... 610 ohms

7A ... from ... 715 ohms

8A ... from ... 855 ohms

9A ... from ... 920 ohms

10A .. from .. 1050 ohms = 1.05 k

11A .. from .. 1140 ohms

12A .. from .. 1293 ohms

13A .. from .. 1357 ohms

14A .. from .. ? ohms

15A .. from .. ? ohms

16A .. from .. ? ohms

17A .. from .. ? ohms

18A .. from .. ? ohms

19A .. from .. ? ohms

20A .. from .. ? ohms

etc.

A 2K pot should provide a, near to, 20 amp capability.

A 300% amp increase!

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 = 19.5 - 29.9V (oem)

2K = 15.1 - 29.9V

5K = 9.8 - 29.9V

10K = 6.6 - 29.9V

20K = 4.6 - 29.9V

100K = 2.9 - 29.9V

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.

**Raising Voltage?**

Not tested ... or recommended!

This model has 35V caps ... a fairly strict limitation!

**= 150 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, 150 watts.

29.4V x 5.1A =150W - 7S Li-ion - 2 in series

*****= 58.8V 14S Li-ion

28V x 5.35A = 150W

27.3V x 5.5A = 150W - 2 in series

*****= 54.6V 13S Li-ion

26V x 5.77A = 150W

25.2V x 5.95A = 150W - 2 in series

*****= 50.4V 12S Li-ion

24V x 6.25A = 150W

22V x 6.81A = 150W

21V x 7.14A = 150W - 2 in series

*****= 42V 10S Li-ion

20V x 7.5A = 150W

18V x 8.33A = 150W

16V x 9.4A = 150W

14V x 10.7A = 150W

12V x 12.5A = 150W

**Note**- modding below 11V demonstrated occasional ... "unreliabilities".

10V x 15A = 150W

9V x 16.67A = 150W

8V x 18.75A = 150W

7V x 21.42A = 150W

6V x 25A = 150W

5V x 30A = 150W

4V x 37.5A = 150W

3V x 50A = 150W

2V x 75A = 150W

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 neg 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".

3 points of "ground" to remove.

The external ground - terminal 3.

The green wire, at F1 near terminal 3.

The bottom of the circuit board, under screw hole next to fuse. (Cut circuit traces, or insulate with ... fiber, or nylon, washer and screw?)

The case can be "properly" grounded by connecting the AC ground wire to the removed green wire directly.

**Lowering Voltage**

Lowering voltage could take advantage of higher amperage.

Without removing components, amperage is regulated below ~8Amps.

*R33, combined with it's neighbor R38, have a measured resistance of ~865ohms.*

Removing both and replacing with a 2K pot allowed me to produce a 14V 10A supply.

Removing both and replacing with a 2K pot allowed me to produce a 14V 10A supply.

(1.1K setting. Will compile a chart for higher amperages.)

14V x 10A = 140W

14V 10A in series with with 2 paralleled 28V 5A = 42V 10A 10s charger.

**Fan Mod?**

With a listed 85% efficiency, the 150w power supply should produce a maximum of 22.5w of heat.

Considering the large heatsinks, I would think this to be adequate, so long as convection (air) is not restricted.

**Component View**

MeanWell Mods

MeanWell Mods

**S-150-5**

**S-150-12**

**S-150-24**

**S-150-48**

**S-240-48**

**S-350-48**