January 13, 2007
Henry Wyatt II, K4YCR
ARRL VA SEC

An excellent and relatively inexpensive “smart-charger” for higher capacity batteries which came from “Sam’s Club”. It works with gel cells too.

Let’s take a hypothetical weather event, one that the “Weather Channel” says is going to be the worst in years. You are planning ahead though … batteries have been charged and you head-out for the EOC (or the nearby shelter) with that fully charged pack and a spare. Twenty minutes after you arrive, the first pack goes belly-up and after a few choice words, you substitute the spare pack.

The CBA II with connection adapter made from old radio case. The analyzer connects to the computer with a USB cable and to the battery being tested with an “Anderson Power-Pole”.

Are you working on borrowed time? Can you work the rest of the eight-hour shift without a communications blackout? Knowing the condition of the batteries is an absolute necessity.

Do you have a way to check each cell in the pack to find the weakest link? I am not trying to sell a battery analyzer, but if you can borrow one, or maybe the local club can obtain one, it can be tried by everyone, probably to their amazement. It did me!

The 17 AHr gel cell that worked so well during Katrina, has one cell dead (shorted) and the spare that I have in the jump-starter tested at only 2 AHr. Time has come to buy some replacements and recycle the old ones.

I purchased the West Mountain Radio, CBA II at the Dayton Hamfest last May. (See review in QST, February 2005) As I am keyboarding this article, I am also testing a “2.5 AHr” 6-cell, rebuilt (by me) commercial battery for a GE MPA/MPD. We will see whether I finish before it does (or not). Starting at 8.1 volts fresh off the charger, it is down to 6.88 volts, having delivered 1.25+ Ampere-hours in the process at a discharge rate of 1.00 Ampere.

Simple, one-cell fixture for testing individual “AA” battery. The clip leads terminate in a “Power-Pole” and also function as a battery connector for gel cells. There is also a fuse in the clip leads. Remember, these batteries can produce a tremendous amount of heat if accidentally shorted.

This is a much higher rate than the radio would draw in normal use (exception would be the “motor-mouths” that forget they do have an interrupted power source).

Computer Battery Analyzer display

Oops, the curve is beginning to “knee” over, indicating the last gasps and the tell-tail beeps for the exhausted battery. I better finish and say “test-um” … Henry says so!

Actually, this can / may be done with a resistor bank, bulbs, or any other load that you might like to use. Just remember, don’t try to “get the last drop” … sending a cell into reversal could be dangerous, not to mention ruining the cell.

Even simpler, use the radio against the clock. This requires no additional equipment, only time and participation in the local ARES nets.

The test ended, with the battery pack producing 1.45 AHr at that high discharge rate. Now, to re-charge the pack and test another.