[amsat-bb] Re: AO-07 healthy CW

Tom Clark, K3IO K3IO at verizon.net
Mon Nov 27 21:22:32 PST 2006

Sil -- you have very sharp eyes. AO-7 was designed with a ~13.5v (i.e.
10@ NiCd cells) bus. The RAE battery was already assembled for the NASA
mission with 12 cells. As a result, two cells were not used. The Orange
& Black wires  going to the DA-9 connector are indeed the battery's
"gozinta/gozouta" wires. a V/2 telemetry tap (white) is at the
right-hand end. The other wires are for thermistors.

The battery box was carefully sized to the cells. The cells expand when
they get hot (under charging) and you will see thin Teflon sheets
between the cells, and thicker Teflon sheets surrounding the pack, to
provide som cushion. In addition, the Teflon provided electrical
insulation between the battery cases (as I recall, the cases were
supposed to be insulated, but one of the failure modes for this type of
battery was for the case to develop a leakage resistance to the NiCd

73, Tom

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