Wednesday, November 29, 2006

WMR PowerGate 40 Backup Power System

A major reason I got my ham ticket was because I wanted emergency communications. I have a pretty good home setup for VHF/UHF in the form of a Yaesu FT-7800R hooked up to a Comet GP-3 antenna on my roof. What I haven't had, up until now, is some form of powering the radio if the power goes out.

Early last week I placed an order with West Mountain Radio for a few items:

  • A PWRGate PG40 backup power system.
  • An MK brand 73 amp hour gel cell.
  • Cables to connect the PowerGate to my Yaesu power supply and to the gel cel, along with my FT-7800R and VX-5RS HT.

The PG40 and cables came the next day but the gel cel didn't arrive today; it's dropped shipped from the manufacturer's warehouse.

The PWRGate has three power connectors:

  • Power in from a DC power supply, which in turn is plugged into mains power.
  • Power out to the radio.
  • Power to the battery for a trickle charge. This port also accepts power in from the battery.

The connectors are Anderson Power Poles.

During normal operation with mains power, the PWRGate provides a trickle charge to the gel cel and DC to the radio. If the battery drains down it could take a few days to recharge once mains power returns, so at some point I'll get a separate battery charger.

If the mains power goes out then the PWRGate's internal switch reconfigures the unit to take power from the battery and provide it to the radio. The power source transfer is seamless, requiring no user intervention, and when I tried it out I didn't notice any difference in the audio I was listening.

The reasons for using a gel cel are that (a) they're safer than lead acid batteries that you need to worry about keeping equalized since they are maintenance free, and (b) they are rated as spill-proof and don't give off fumes. Being a deep cycle battery, it can safely be discharged down to a low level without harm.

Here's a pic of my setup:

The PWRGate is the finned black thing sitting on top of another black box, which is my DC power supply. The leftmost cord plugged into the top is the power input, the middle is power to the radio, and the right hand one goes to the gel cel. The black square on the red cable to the cel's positive lead is a fuse holder. (I have a temporary cover over the gel cel as a protective measure so nobody accidentally shocks himself.)

Future refinements to this system will include a battery box to protect the gel cel and anybody who get a bit careless, a battery charger, and a cable with Anderson Power Poles on one end and a cigarette lighter receptacle on the other so I can power 12V devices including charging cell phones.

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