February 11, 2016

Juice

https://www.youtube.com/watch?v=HBu9LZa8Yrk

When the grid goes down, you'll have to generate the electricity to power your communications equipment and keep batteries charged in your portable gear such as handhelds.  Eventually, when it all goes away for good, you'll may wind up being your own power company, and the power company for your like-minded neighbors.

If you have your ham license or otherwise have some basic electronics knowledge, you can figure out the electrical power requirements for your equipment, and how long your generating capacity can keep it going.

harbor-freight-pack

Many of us started out with something like this piece of gear.  It is a Harbor Freight 3in1 Portable Power Pack.  It has a 12V 17AH (twelve Colt, seventeen Amp-Hour) gel-cell battery in it.  The current model is $60, but you can find them on sale for as low as $40.

How long will your gear run on it?  Most websites recommend only discharging your batteries down to 50%-70% of their total capacity.  That means the 17AH battery in the Harbor Freight pack is good for 8.5-11.9AH.  You can drain them further, but it will shorten battery life.

IMG_20150801_151448011

The Yaesu FT-817, a common portable HF transceiver, has a max receive current draw of 450mA, or .450A.  Going with a 50% discharge, 8.5/.450=18 Hours of receive time. Full power current drain on transmit is 2A.  8.5/2=4.25 hours transmit time.  Best case scenario? The fully squelched current drain is .250A.  Going with a 70% discharge, 11.9/.25=47.6 hours.  So, depending on how much your transmit, the TX output power, and how much receive activity you pick up, the radio will run on this pack for anywhere from 4.25-47.6 hours.

In the picture, the FT-817 is hooked up to a GoalZero Sherpa50. The Sherpa50 has a 5.2AH battery in it.  Depending on how much your transmit, the TX output power, and how much receive activity you pick up, the radio will run on this pack for anywhere from  1.3-14.56 hours.

Then you have to recharge the packs, which will be the topic of another blog post.

Field power is among the topics discussed during the Workshops being held this year in Wyoming.

2 comments:

  1. Would there be much inefficiency in using an Antigravity battery (believe this is 18AH) to juice up the Goal Zero? Unsure of a way to connect the two directly. Thanks!

    ReplyDelete