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A 'dead' battery problem stresses the entire electrical system by slowly lowering the voltage over a long period of time. That systemic lower voltage is super bad for any active electrical/electronic systems throughout the car. Yes, the security system is active during shutdown/locking after the initial shutting down of everything that shuts down. Removing the neg cable first (for the first and most important reason) is because the car is negative ground. IF you touch anything with a wrench while removing a neg cable in a neg ground vehicle, NOTHING happens. BUT if you remove a pos cable with a wrench and touch ANYTHING grounded or electrically connected to an isolated system, ZAP!, SPARKS!, & possible burning skin or other! The second reason (specific to at least our Crossfires), is the alarm system siren needs to be shut down correctly when battery is removed. If you remove the pos cable first (and your alarm module is functioning), you'll get screeching siren right next to you since your hanging over the battery post right about where it is mounted.

So at least two reasons for removing the neg cable first AND not allowing the battery to slowly die bringing any electronic systems with it. I say personal preferences abound about removing the battery or tending said battery before storage. A battery is a pretty good 'filter' for most reliable 'tenders' BUT there could be an issue with a tender over-voltage that the battery might not be able to 'filter' it.


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