[aprssig] Battery & Charger for APRS Station

[John Habbinga]

I am installing a digipeater in a location that I want to have
reliable battery backup power.  For the last month or so I've been
testing out a setup where the radio and TNC run off of a 12 volt, 35
Ah sealed lead acid battery.

The battery is connected to the radio/TNC and it is connected to the
battery charger.

The charger is a CTEK Multi US 7000.  It is a multiple stage charger.
When it finishes charging it STOPS charging completely.  Every ten
minutes or so the charger tests the battery and if it needs to be
charged, then it adds current.  So it is not a 'trickle' charger.

My observation is that about once an hour the charger kicks in and
tops off the battery.  I don't get any interference from the charger
at all, even on HF frequencies.  You can find out more on the charger
I'm using at http://www.ctek.com/EN-US/Default.aspx

At 20+ charging cycles per day, am I prolonging the battery life by
frequently recharging when the battery is at such a shallow state of
discharge, or shortening it?