JTIS quotes that with a battery voltage not below 12.5V, on a high rate discharge test (applying a load of 300 Amps) then battery voltage should not fall below 9.6 volts at a temperature of 21 degrees centigrade (seventy degrees fahrenheit).

JTIS says to charge the battery if it's not at least 12.5V.

On battery temperature increasing after a 10-min drive, I suspect it won't as it's in the boot (trunk) and won't change worth mentioning in that time.

No mention of ripple etc in JTIS. But I quite like the idea that this could be an extra way to condemn a battery since changing the battery is a fix so often.

Bearing in mind the regulators fitted in each module (they tend to be 5V or 3.3V logic) I don't see any way that a few hundred mV of a/c ripple could cause any problems.