Need change battery, will car disable itself?

[CBeau]

..... or anything fun like that? Been there done that with other cars.

[Bigglezworth]

The car will be just fine. Simply swap it out. If you do have a concern, simply start the car, leave it idling, remove the negative cable followed by the positive cable, and remove battery. Reattach replacement battery in the reverse manner.

[CBeau]

The car will be just fine. Simply swap it out. If you do have a concern, simply start the car, leave it idling, remove the negative cable followed by the positive cable, and remove battery. Reattach replacement battery in the reverse manner.

Thanks much!! I think i'll just connect a good but wrong size battery in there while taking existing (in another vehicle) for core charge.

But just curious, or maybe I misinterpreted what you wrote.... if you have car running and disconnect battery it won't continue to run will it? Even with alternator functioning properly I'm pretty sure with some other cars... German cars incl..... that I have, that circuit needs to be complete to still run??? I know some cars I have, fuel injected Porsches specifically, if the battery gets too dead-dead and even if alternator fully functioning the car will stop running.

[Bigglezworth]

You can start the car and entirely remove the battery with no affect on the operation of the car. The battery's sole purpose is to use DC current to start the car. The alternator provides AC current to operate all electronics and to ensure battery is fully charged.

[LaserSVT]

You can start the car and entirely remove the battery with no affect on the operation of the car. The battery's sole purpose is to use DC current to start the car. The alternator provides AC current to operate all electronics and to ensure battery is fully charged.

I uh... well.... but...., dude seriously? Look I realize I am a short timer here but I read your posts and I take you as one of the people who really knows what is going on and is someone I really listen to for advice on these cars but everything you just said is really really bad.

I own a performance and service shop. We are the only 5 star shop in Waco Texas. We have been slowly stealing the Euro cars from the specialty places and it has been a STEEP learning curve. Hell I still refuse to work on a Bosch fuel system from old Audis and Mercs. LOL My particular specialty is electronics though. Both repair and diagnostics. Please, I do not wish to offend you but I need to correct everything you just said.
Cars actually run on the battery and use the alternator to keep it charged. Think of the battery as your gas tank and the alternator as your gas station. Now granted the car can stay running off the alternator alone but the alternators on board regulator is monitoring the battery and if you remove it the alt will put out maximum voltage thinking it needs to fill a dead battery. This is bad for all the cars modules as they do not like to be above 14.4 volts and the alt can hit 15 volts with no battery. Also with a live positive cable floating around while swapping the battery and you are asking for all kinds of trouble including fire. If the car is running and you change the battery you can get power spikes and damage anything from the alternators regulator all the way to the main ECM. Please do not change a battery while the car is running.

What I have noticed with Euro and some American cars that have stereo codes or require relearn procedures for their throttle bodies and such is that the best way to change a battery is to put the car in the on position (not run) and then remove the battery. This way the car thinks it just lost power and not does think its being stolen. You put the new battery in and the stereo wont code and the learned curves are still in its memory. Been a great saver on Mercedes as far as getting stereo codes goes. Doing it that way I have never had to hunt down a Merc stereo code or have a Toyota try and figure out how to make its throttle body relearn how to work. Camrys are the worst when you change the battery. They can take up to a week to relearn how to idle.

The other thing I wanted to touch base on is the current comment. Being a power generator the alt does make AC power but it has a half wave rectifier that changes it to DC before it leaves the alternator. AC on cars electronics will fry them instantly. Its a Direct Current system and if Alternating Current was passing through your car you would get electrocuted any time you touched a metal part.

I hope this helps the OP and others understand a cars charging system a little better. This is the route I will be going soon in my Audi. The dealer put a new battery in the car before I bought it but its a cheap Walmart battery and while it is for an Audi its nowhere big enough to even lock down in the tray. I will be bringing in an AGM from Autozone for my car.

BTW, while I dont buy much from Autozone due to quality issues they do have a new series of batteries that is just spectacular. You can only get them through a mechanic shop that has an Autozone account (most do) and can not just go into an Autozone and buy it at the counter even though the battery is there. They are the same cost as the batteries you can buy at the store give or take five bucks but they are better quality and have a killer warranty. They are offered in many levels with AGM (Absorbant Glass Mat) being the top level. AGM batteries can take deep discharges without getting hurt and is why most Euro cars spec them. They also keep almost all their cranking current available even when near dead. A lead acid battery wont start an Audi if below 50% capacity. An AGM will do it at 20%. Yeah they are more money but they last twice as long and everything they do is better.
But the warranty with these batteries rocks. If you are at a lake in the middle of nowhere and using the cars stereo as your entertainment and kill the battery they will send a truck to jump you for free. If the battery is so dead that it can not take a jump then they will replace it for free. If its so late that no Autozone is open or around they will reimburse you up to $200 for hotel and food for the night.

Its the battery I am going to put in my car. Retail is $220 but I think normal counter price for Autozones top AGM is $175. Just point that out to the shop should you decide to buy the one with the killer warranty and they should be able to discount you down to $190 without issue and still make money. The one you buy at the counter is 900 cold cranking amps and has like a 92 amp capacity. The other version I mentioned is 1000 CCAs and I believe has a 105 amp capacity. Thats enough to run a stock Audi stereo for 8+ hours near max volume and still be able to start the car.

[Bigglezworth]

Significant diatribe above and not in dispute. The OP asked regarding swapping, and my 'intent' was to suggest that if you have concerns with items that have presets needing to be reset once you disconnect from a primary electric source, you can - FOR A PERIOD OF TIME - unhook the battery while the car is running and perform the swap. Only takes 5 minutes max to swap a battery. NO dispute whatsoever that the battery is integral to an automobiles electrical system as provides an electrical buffer to alternating current. Obviously you wouldn't want to drive any where without as a stall would leave you stranded - not to mention all the other things out lined in the post above. 40 years doing a quick swap and have never once had a single electronics problem.

[atikovi]

You can start the car and entirely remove the battery with no affect on the operation of the car.

And risk frying a bunch of electronic components should the positive cable accidentally touch ground if the no-load hasn't already.