Super PWRgate PG40S Auto-Switch

Ham In The Box - Super PWRgate PG40S by West Mountain RadioSometimes you just need that right piece of gear, that one need that is weird to fill, but you need it…you really, really need the right piece of equipment..

Well, the West Mountain Super PWRgate PG40S Auto-Switch is one of those pieces of equipment. And then some! Yeah, it’s that flipping good.

Let me share a little background first. For several years now I’ve been working on putting together radio and power equipment to keep communications going during emergencies, disasters, especially during a grid-down. Why? Other than the obvious answer, during my 30+ years of responding to emergencies and disasters I’ve learned that stable and reliable communications is a top priority. How much so? In every single incident where a firefighter was injured or killed, communications (poor or lack of) played a major role. Communication problems were the single common thread through all of these incidents.

Now, let me change to something completely different for a minute. I’ve been around long enough to remember the first personal computers. You know, the kind that didn’t even have a hard drive. I remember several times I would be working on these early computers and the power would flicker…everything lost! Yup, all the work that I had been doing was gone into some special “data zone” never to be seen again.

Finally after that happened a couple of times I learned about uninterruptible power supplies (UPS). Through pure magic it kept your computer going even when the power, not just flickered, but went out completely. It was as if the computer gods decided to smile down on us mere mortals. Yeah, I didn’t know at the time is was just a battery, auto-switch, and a battery charger built into that wonderful, magical UPS box.

Now, fast-forward to today…during times when communications are needed most I don’t want them to fail just because the power suddenly, unexpectedly flickers or goes out altogether. Because…DUH…during emergencies, disasters, and grid-down the power should be expected to go out! Yeah, no-brainer right?

Well, to meet the uninterruptible power supply needs that I foresaw, it would take a whole lot of money to buy the right UPS. And even then it wouldn’t have all the options and features that I wanted. So naturally I decided I was going to build my own solution. No, I am not a masochist, I just like to use my brain, to be challenged, and work with my hands. So, another great adventure was headed my way!

As I began to layout my first power box I had written down my “mission statement” for the box itself. Then I listed the “restrictions and requirements” that went into great detail. One of the biggest needs was the ability to automatically switch from the AC to DC power supply to the battery supplied DC power. The quest began!

Here is the mission statement for this piece of equipment –

“Provides clean DC power from an AC power source and automatically switches to battery back-up providing DC power when the AC power fails.”

I gotta tell you…it wasn’t hard to figure out. As usual I started doing some serious research into the options available out there on the market. And it became clear real quick that there was a pack leader, a unit that simply stood out among the others in terms of reliability and quality…West Mountain Radio’s Super PWRgate PG40s.

Here is the technical story from their website –

  • A Super PWRgate is a 12 volt backup power system rated at 40 amperes continuous from either a Power Supply or a Battery.
  • The Super PWRgate has a built-in four-stage battery charger with selectable current rates of 1, 4, 7 or 10 amperes.
  • Connected equipment will instantly switch to battery during a power blackout or power supply failure.
  • Uses two 80 ampere Schottky diodes as an OR-Gate to isolate the battery and power supply from each other.
  • Low loss PWRgate provides forward voltage drop of less than 0.3 volts at 20 A and 0.37 volts at 40 A.
  • Optimized for use with GELLED & AGM type batteries, but will keep flooded lead acid and marine type batteries near full charge as well.
  • Solid, durable construction in an aluminum case with heat sink. Includes mounting holes for convenient and secure use in mobile units.
  • Uses Anderson Powerpole®connectors
  • Dimensions: 1.65″ H x 5.25″ W x 3.9″ D

Specifications –

Maximum Voltage: ·                     18 Volts DC
Maximum Current: ·                     40 Amperes
Circuit: ·                     Diode OR-Gate
Diodes: ·                     Two Schottky 80 Ampere, 20 Volt
Voltage Drop: ·                     0.25 VDC at 1 Ampere

·                     0.37 VDC at 40 Ampere

Charging Circuit: ·                     Smart, linear charger

·                     Fuse switched for 1,4,7 or 10 Amperes (±5%) maximum

·                     Peak voltage limit: 13.8 (Gelled), 14.2 (AGM), (±2%)

·                     Peak voltage limit set via internal jumper to GELLED or AGM

·                     Peak voltage terminate point: 0.1 Maximum current

·                     Float Voltage: 13.5 volts (±2%)

LEDs: ·                     Green – Indicates charger is “ON”

·                     Red – Indicates peak “PK” charge voltage

·                     Yellow – Indicates Float “FL” voltage

Connectors: ·                     Anderson Powerpole, 40A
Dimensions: ·                     1.65″ H x 5.25″ W x 3.9″ D
Weight: ·                     0.9 lbs, 0.4 kg (aluminum enclosure with heat sink)
Mounting Holes: ·                     Two, 0.175 in. d, at a distance 4.875 in., for #8 hardware


Typical application –

Findings –

  1. I couldn’t get the unit to fail when switching from the power supply to the battery. No matter what I tried it performed the power switching perfectly. There wasn’t even a flicker in any of the equipment I tested it with.
  2. It really does a great job of keeping a battery charged. Technically that makes it a battery “maintainer” and not so much a charger. But, I ran my big 100Ah battery kind of low, then let the PWRgate go into charge mode. Yup, performed flawlessly; the unit didn’t even get hot.

 Summary –

This is a high-quality product that does exactly what they say it is supposed to do…and what it needs to do. For my radio set-up it is an essential piece of equipment and I am 110% satisfied with it. Awesome job West Mountain!





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