Tips: Batteries at the Heart of Portable Comms

Back about 20 years ago, NiCd batteries were notorious for having a pronounced memory effect caused by a special type of crystal formation within the battery. This particular mechanism has been eliminated in current NiCd cells but our memory of it, so to speak, is long.

Today's batteries all have some kind of memory in which the capacity of the battery changes with patterns and depths of discharge. Each type of battery chemistry exhibits this effect for different reasons - some types stronger than others. Unfortunately, it's also referred to as a "memory effect" which is confusing to those of us who remember the old "memory effect." Nothing like calling two different things by the same name to generate a lot of confusion!

Because this effect varies with battery type, blanket statements about it are unwise. Isidor Buchmann's *excellent* and very readable book, Batteries In a Portable World, and its sibling website, www.batteryuniversity.com, tackle the full spectrum of battery types and how to apply them.

On the website, I highly recommend taking the opportunity to read the section "How to Prolong Battery Life."
The book is available from the ARRL Store and other book sellers. Both should put a charge into your understanding of this important energy source that is crucial to effective emcomm operation. Good luck and may your batteries live long and prosper!
-- Ward Silver, N0AX,
Contributing Editor, QST; ARRL Contest Update Editor; St. Charles, Missouri

www.arrl.org/ares-el?issue=2013-03-20

Letters: Batteries

Just read the article on batteries in the last issue. The article addresses rechargeable batteries and calls them an energy source. Rechargeable batteries are limited energy storage devices. So, why is this important? In a major event when recharging is not an option (read widespread power failures), rechargeable batteries become paperweights very quickly.

Emergency communicators should be looking at primary cells, like alkaline cells, which can be stored for years at a time at room temperature. They work reliably. They work independently of other energy sources. Many hand held radios have battery packs to accommodate AA's or other sizes.

Another option is to adapt to what's lying around. If hams set up their various radios (especially hand held radios) to work with, say, 12 VDC sources, all kinds of options pop up.

For example, the 12 VDC battery in a car or truck can be used, even if the vehicle itself has been wrecked. Granted, it's not convenient to haul a car battery along with hand held radios, but one can keep a station on the air for quite a long time at, say, a shelter. They can even be used to recharge lower voltage NiCd, NiMH, and Lithium ion batteries! We need to be flexible and adaptable. There are lots of other options also.

Something else to keep in mind: widespread power outages often last from just a few days to a few months (remember the aftermath of hurricane Hugo in South Carolina?)

We need to be prepared for long term outages to be useful over the long haul.

- Art Feller, W4ART, retired Communications Officer, Office of US Foreign Disaster Assistance, Agency for International Development, US Department of State, Arlington, Virginia

www.arrl.org/ares-el?issue=2013-04-17#toc05