Is disconnecting the battery a bad idea?

[kitcat7]

I'm thinking of installing an isolator switch to stop parasitic drain on the battery, however I'm wondering if the ECU or other small computer needs power all the time to retain important information. I know when some cars have their battery changed there has to be a connection to another battery to stop any damage being done.

Does anyone have any info. on this?

Thanks, Paul.

[neil-g8km6]

Mine was disconnected for at least 6 hours whilst changing the battery, no I'll effects 😃