This is interesting and some advice would be gratefully received - two cars, 1996 TDi300 Land Rover Defender and 2019MY Countryman PHEV. I leave my cars undriven for 3-4 months at a time as I work overseas but the trickle chargers I use (a Cetek Battery Conditioner on the Defender over the winter but a Maplins Solar panel trickle charger in the summer and just a solar charger on the Countryman) are connected differently....... on the Defender both the chargers get connected with positive to the battery and negative to the body but in the Countryman I was advised to connect the trickle charger to the jump start posts under the bonnet with no connection to the body.
Why would it be different for each car - the last 4 Range Rovers I owned Also connected to the jumpstart posts because I couldn’t plug into any of the sockets as they were disabled by the Battery Management System was the car was locked up, which I assume is why the Countryman is the same as the modern Range Rovers - the 1996 Defender has no hi-tech electronics at all.
I have never suffered a flat battery in any car since connecting them up like this whereas before I had to jump start the modern cars because their batteries died after a month of no use, the battery drain was significant even when the cars went into “sleep” mode, not so with the Defender that only had a clock to power once the ignition was turned off!
its more of a safety thing ie having someone having a charger still switched on charge while disconnecting the clips off a battery that has been gassing for a while in a confined area i have seen this a few times someone forgets and believe me when i say the battery will explode and cover you is warm acid, i've done myself a few times it hurts Avery time, battery fumes are like petrol fumes,, thats one level why they move the connect points, and modern cars the alternators are 150-300 amp as well and battery's get a right good kicking with start stop.
also on some cars where the live feeds connect to stuff like body control and bsm modules and a long piece of wire ir the longest route for electrons to travel cuts down the risk of spiking , but spiking only happens when you add a uncontrolled power feed and allow a spark, see sparks are lightening million micro volts bit like welding if you force rod to metal it sticks and electric flow through it,, but if you allow a gap you get heat lightening this is on controlled this when touching a jump lead to a car is massive,
some cars when locked and go to sleep only draw 200 miliamps others might be 5oo miliamps so run down faster over time
