X-no-archive: yes
In article , Eric Greenwell
writes
GeorgeB wrote:
I hate top posting in general, but it seems to fit here. Bumper has
noted very important points, and to add fuel to the fire, it is
important that the battery is designed for the intended service. The
only 1280 I see on the Power-Sonic sebsite is the PSH1280 which is
designed for UPS applications, and for 15 minute discharges of roughly
20 amps. I would not be at all surprised (they don't say) that just 2
or 3 of those will significantly reduce capacity. Your far more
reasonable discharge would be less severe, but I'd still guess it is
low on the number of cycles vs their more "traditional" designs.

According to the Powersonic Technical Manual

(http://www.power-sonic.com/techman.pdf)

their batteries are designed for cyclical use. The diagram on page 6
indicates 200 complete discharge cycles can be obtained before the
battery capacity reduces to 60%, or 400 discharges of one-half the
amphour capacity. The battery choice appears to be OK for glider use, so
I suspect the problem is as some other posters suggested: current drain
is higher than expected, a defective battery, improper charging, or even
erroneous voltage readings from the SN 10.

The only way to find out what the capacity of a battery may be is to
either do a timed discharge at a fixed current (tedious) or use an
instrument that measures the capacity and compensates for temperature. I
use such a device but they are expensive. My meter is now priced at
332.07 USD (185.00 UKP), so borrow one if you can.

For more details go to http://www.actmeters.com/actmeters.htm
and look on 'quick product index' for 'New GOLD-IBT Intelligent Battery
Tester'

Tim Newport-Peace

"Indecision is the Key to Flexibility."