Management Card Braindead after 7 minutes

[NoMoreJuice_apc]

Greetings,
I have two SMT1500 here, with external batteries. They supply a remote transmitter through an automatic transfer switch. I have two for redundancy mostly.
We sometimes face power outages beyond 48 hours, rarely though. The first UPS holds up for ~ 24 hours. During that time, I would prefer to have the secondary UPS' inverter outlets off, and have it turned on when the first UPS nears depletion. The reason: When its time for UPS 2 to take over, its batteries are already 40% down - just for its self-consumption alone to keep the inverter running, while it actually does not feed any equipment.

The situation right now is: When I switch the outlets off on an UPS that has no AC input, it will go brain dead after Approx. 7 minutes. And I can't turn it on again remotely unless AC is restored. There is no personnel on location to push front panel buttons...

The same applies to "Put UPS to sleep" on a timer. It will never will come back from coma unless AC is restored, and I would consider that a BUG.

So what are my options to keep the management card alive while the output is shut down and no AC present?

Regards, // Luis