Car battery

Modern cars seem to need to be 'told' they have a new battery.

Do modern car radios still require a code? In my current car the radio shares the same display and controls as many of the other car functions. In my much older previous car the radio was somewhat more integrated into the fascia and not so easily removed as a standard universal brick type unit.

I'm not sure that there are any other major gotchas. The cars engine management may lose some of your personal driving habits but on cars I've owned it has been stated that the ECU re-learns them within a short time of driving. The car may perform slightly differently to what you are used to but only for a few miles.

How modern? I've always been wary recalling issues with less modern cars but have had no bother more recently, I've not changed a battery in anything younger than about 8 years though.

Modern car radios aren't even a discrete device, they are part of the computer that's embedded into the dashboard. Nothing to nick, so no code required.

Last century I made a long double ender cigarette lighter plug lead, and used that from a doner car to the 'patient' car. That was in the good old days when the cigarette lighter sockets were not switched via the ignition key. Those days have long gone.

Depends on the make and model.

Can still do it via the OBD-II

Nor me but I try to connect my slave battery to the starter motor feed and earth on the engine to preserve codes as the clip is too easy to dislodge if it is on the battery leads.

In message snipped-for-privacy@davenoise.co.uk>, "Dave Plowman (News)" snipped-for-privacy@davenoise.co.uk> writes

I wonder if that only relates to start/stop functionality as you can use a conventional battery and override the s/s function. Battery charging characteristics are different.

Good point. I was thinking of making something up rather than using jump leads.

When I changed the battery on my 59 plate astra petrol, it didn't care at all. No details were lost, radio still worked, etc.

Some cars are ok, some aren't. Google to see what other people do.

making up a battery pack of a few alkaline batteries to end up with 12V and connected to a cigarette lighter plug might be all that is needed.

In that case, can't you leave the ignition switched on while you swap the battery?

No cigarette lighter on this car. I think I'll go with AJH and find some safe connection points to couple in a spare battery. Modern car electronics have gone way beyond my level of understanding. Air bags, alarm, window position coding, auto door locks... long way on from my 1935 Morris tourer!

Nope. My previous (2010) and current (2018) car have unswitched cigarette lighter sockets as well as switched ones.

My car needs a new battery coding to the car. This is to reset the adaptive charging system which is designed to minimise the load on the alternator and enable regenerative braking (ordinary diesel not a hybrid). Also to know the true state of charge of the battery for the start/stop system.

not even an "accessory socket" hidden away somewhere (including in the boot)?

I know someone who killed an old Peugeot (not all *that* old) by changing the battery. It wouldn't start afterwards and needed a new ECU, which was not economic. This wasn't a con, either, it was not exactly a common occurrence, but not all that rare either.

I can't remember the model, just that it was a something-0-something. There was a lot of stuff on the Net (found *after* the event, of course) about how to disconnect the battery safely, which boiled down to removing the ignition key, waiting a while, then disconnecting the battery. But absolutely nothing electrical must happen after removing the key i.e. the driver's door must be closed and the window must be open to take the key out, and the bonnet already open. I can't remember what phase the moon had to be in.

In message snipped-for-privacy@outlook.com, Robin snipped-for-privacy@outlook.com writes

There are USB connectors in the glove compartment and in front of the passenger seats. More faff than croc clip leads in the engine bay. At least I understand how they work:-)

Hmm. This reads like techno speak for needing to pay money to your vehicle supplier. There are no electronics in car batteries. The battery I have ordered is an equivalent of the one fitted and I don't see any way the onboard computer will be able to tell it has been changed.