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AO-40 update

Hej! Hr r en rtt fin frklaring p Oscar 40 lget,Vi hller tummarna!! 73 Hkan

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The problem is, that the Main Battery clamps the bus voltage down toabout 14V or even less, from its nominal 24V.

As Stacey described, this is obviously due to several battery cells in the main battery, which failed shortened in some sort of domino effect.

It happened so fast, that we were not able to completely isolate the main battery and use only the aux battery. At the moment both batteries are in parallel.. this will not damage the AUX battery, but it prevents it from charging.

The extremely low battery (and bus) voltage is a problem, because the transmitters and other electronics were not designed or may not work at these low voltages..

The IHU and receivers should still work, but without telemetry it is hard to predict what the current situation really is..

Since the solar panels pump all their energy into the remaining cells of the main battery, they will indeed get very hot.. Our hope now is (and that s what is to be expected) that these cells will ventall their electrolyte and dry out. When that happens, the cells should fail high resistance and our bus voltage should come up..

Thus, the improving sun angle should help in speeding up this process.But again, we yet do not know how long this will take.. but chances not bad for this to happen..

73s Peter, DB2OS
Pres. AMSAT-DL

Klla: amsat

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