Meanwell-Megawatt-Cheapowatt VENTILATION

MEXICOWANDERER wrote:
All of these units must be raised up so they do not sit flat against the floor. They need feet at least 1/4" tall. Now owning all three types I can vouch for the fact that laying flat decreases air flow and in the case of the Meanwell a tperatire rise in excess of +30F.

Are there vents on the bottom or are they using the case metal?

Do you think the simple stick rubber feet are sufficient, big ones will raise it up an easy .25"

I imagine they aren't so easy to come by in your world...

I robbed feet off of blown-up UPS boxes and regulators for computers. The only thing that's easy to find is a smile and a "No Tengo / No Hay".

I can hear a difference in tone of the fan when I lift up the power supply. I do not know why this exists. Nutso engineering failure to not stick feet on.1/4" should be just ducky.

Mex,

What I have been doing is just sitting them on their side. I know it is not the elegant solution but it seems to work. I think it gets better air flow. In a sense, they are still stack-able, just not as stable.

Might need a 15 or 20 amp PSU if I go ahead and get a 12V ham radio. Crazy that a 65W radio pulls 14 amps @ 14.4V while TXing.

Where temps are critical, say 40c or higher and the PSU is working at capacity I definitely recommend the units not be placed on their side. Inside a compartment the ambient temp may be significantly warmer than what a person may think.

The newer Megawatts the 36-amp model got a higher velocity fan installed. The Cheapo has by far the noisiest fan but it moves more air than the older Megas or Meanwells. The middle in the noise dept is the newer Megawatt and the quietest is the Meanwell.

The Megawatt is by far the heaviest of the three.

My current upgrade to the BORG is thick aluminum end plate fascia, a pair of 120-volt green indicator lights. New calibrated 15-turn pots, an original pot to adjust the float voltage. Need a much bigger heat sink on the 8305 7.5 amp regulator chip. The float has a capacity of 3.75 amperes. Max capacity seems to be 82.2 amperes. I used RustOleum bed liner on the case. A "guitar case" strap handle. Need stainless steel S straps to wind charger and power cords.

What a fun project!

PS: I ended up choosing a pair of Megawatts the newest 36-amp model. The 60-amp won't fit the case.

At least my crippled body can carry this thing. I also need to get some 1/16" stainless aircraft cable and have been thinking about a switched tilt alarm with a screamer piezo emitter for theft resistance.

65 watts transmit power..With a class A, transmitter means 130w input

Straight Carrier wave Morse code, no modulation, uses the least power
Anytime you use modulation, the more input power used to create the transmitted signal

I thought it was fairly obvious that the casing of these power supplies were used as heatsinks for the transistors.

Since my Meanwell rsp50015 is on my cabinet door, I wanted some stress relief on the input and output power cords so as to not repeatedly stress the circuit board wiring receptacles. I had some aluminum window screen sections left over, and used these to attach the input and output cables. They are just over 1/4" thick and add some small percentage to the heatsinking, and of course allow airflow underneath the unit.

Thanks to Westend, I have lots of large finned heatsinks, I just have not shaped and adhered them to the casing adjacent to the transistors to assist heat removal.

It has to be over 70F and maxed out at 41 amps before my Meanwell's loud and powerful 40MM fan powers up. Otherwise the two quiet Noctua fans work admirably, and the unit does not really get warm providing 20 amps anyway.

I love my MW power supply. So do my batteries.

No Automatic underchargers for me.

Less heat on one side of the skin, less heat on the other side. Junction to case to pad mount to case. Too many transitions for me. Stick your finger on the inductor sometime. Running a fan across the outside of the case is equal to a lot of static heatsink area increase
It does not take much of a fan. Direct from T&E labs (trial-and-error).

It's a gas playing with these things. BTW 4-watts is plenty for an exterior fan.