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For those of you who have the knowledge/experience with this, a simple DIY or FAQ on battery changes and some of the resulting complications would be helpful. I suggest this after reading on the various forums about some of the problems that can occur with electrical power loss (dead battery/battery change), such as the electronics going into "transport mode", reset of the radio code...... With the electronics in our cars, it's not as simple as it was in the "old days". TIA

Only ever had to reset the clock on mine after disconnecting the battery. Done this 5 or 6 times I owuld say.

srhutch wrote:Only ever had to reset the clock on mine after disconnecting the battery. Done this 5 or 6 times I owuld say.

x2

Yup, disconnected mine a few times and it is just the clock that goes (or rather has gone) for me

This months BMW magazine is having some story about 2k worth of damage after battery change / jump start etc. Was on a 530.

Not aware of that to be hones, but when the time comes to change the battery on the X5 I will have to research first, that is for sure (think the X5 electronics are a bit more complex then on the Z).

I find when I disconnect the battery and then reconnect it, that my electric windows go mental. They don’t go down or up on one touch and they then sometimes play up when putting the roof down or up. I end up having to put them up and down a few times before they go back to normal. Weird

jamiecarpenter wrote:I find when I disconnect the battery and then reconnect it, that my electric windows go mental. They don’t go down or up on one touch and they then sometimes play up when putting the roof down or up. I end up having to put them up and down a few times before they go back to normal. Weird

This is the type of thing I'm concerned with along with the things I mentioned in my original post. I'm not in need of a battery change yet, but I'm sure the time is coming. Maybe if there's enough of a response, a pattern will develop on what/what not to do. Thanks

Had the battery off at least 20 times and there is nothing to go wrong. You just need to reset the clock and of course fuel/mileage use to date is zeroed on the computer. If you're really worried you can just connect another small 12v battery to the terminals or jump points while you do the change over.

pvr - had the X5 battery out a few times and no issues either.

Problems from jump starting when done wrong can be horrendous with blown diode packs on alternators, but that's a different story.

cj10jeeper wrote:Had the battery off at least 20 times and there is nothing to go wrong. You just need to reset the clock and of course fuel/mileage use to date is zeroed on the computer. If you're really worried you can just connect another small 12v battery to the terminals or jump points while you do the change over.

pvr - had the X5 battery out a few times and no issues either.

Problems from jump starting when done wrong can be horrendous with blown diode packs on alternators, but that's a different story.

All of the above

Thought that this might be of interest and possibly to the discussion. From a response to the same question on another forum:

"This gets discussed all the time over on the 5 series forums. The overall consensus is that this ISN'T total BS (with the 5er at least). Any battery with comparable specs to the OEM version will work just fine, but unless the dealer programs the car to accept the battery then the car will overcharge the battery resulting in shorter life expectancy as a result.

Is it the truth? Who knows, but that seems to be commonly believed at this point. With that being said, I changed the battery out on my 5er with a DieHard European battery from Sears and DID NOT take it to the dealer for coding. No problems so far.

This is what BMW Wiring Diagram Says about the issue:
http://forums.5series.net/topic/9831...st__p__1169846

Registering the battery replacement

Why register the battery replacement?

After fitting a new battery, the service function 'Register battery replacement' should be run. Registration of the battery replacement is necessary to notify the power management (software in the engine electronics and intelligent battery sensor) that a new battery has been fitted in the vehicle.
Without registration of the battery replacement, the power management does not run properly and this can lead to function limitations, for example reduction or deactivation of individual consumer units.

Register battery replacement

This function informs the power management in the DME/DDE of a battery replacement. The following operations are performed:

* The current kilometre reading is stored for the battery replacement.
* The stored measured values (battery charge statuses, current, voltage, temperature, etc.) are deleted.
* The power management is initialised.

Replacing the battery: other battery capacity or AGM battery

As the battery depends on the engine ands options fitted, the following information is coded in the CAS:

* Battery capacity (for example 90 Ah)
* Battery type: AGM battery or lead-acid battery.

In the case of battery replacement, in general the battery capacity used as series standard may be used.
On installation of a battery with higher or lower capacity or installation of an AGM battery, Progman must be used to recode the CAS:

* With Progman, run the retrofit ”Battery” (select battery capacity of the fitted battery).
* Register additional battery replacements with this service function."

jamiecarpenter wrote:I find when I disconnect the battery and then reconnect it, that my electric windows go mental. They don’t go down or up on one touch and they then sometimes play up when putting the roof down or up. I end up having to put them up and down a few times before they go back to normal. Weird

no radio codes are needed unless you have an aftermarket radio fitted that uses one
you will have to reset the clock (thats common sense really)

as for the windows going haywire thats because the control unit has lost the saved values for the windows end stop positions you simply have to re-initialise them (it's in your manual)

simply get in with all doors and roof closed
start car or simply till the ignition lights are on
hold down both window switches and keep held down for 10 seconds after window has reached the bottom
pull both switches up and hold them for 10 seconds after the window has reached the top.

now test and et voila windows initialised and they will now work in harmony with the roof

for changing the battery make sure you have a battery of the same CCA (cold cranking amps) and Ah (ampere-hours) rating as the original,

disconnect negative lead... secure out of the way
disconnect positive lead again secure this away from the battery terminals
dismount battery from it's holder being careful to remove the overflow pipe

fit new battery in holder and insert overflow pipe
positive first and secure it properly
negative last and secure it properly being sure not to bridge the two terminals (spanners are not a good idea stick to a 10mm socket on a 1/4 drive ratchet with an extension) make sure to put the plastic cover over the positive terminal before replacing the carpet

set clock
initialise windows if they need it

hope this helps

as for registering the battery replacement this is not necesary on the Z4's as they do not have IBS (intelligent battery monitoring system iirc) the new z4's will have it but E85 and E86's will not

E6x E7x E9X and some E81,82,87,88 will need the battery replacement registered

all cars equipped with auto start stop will need the battery replacement registered.

Incompatible wrote:Thought that this might be of interest and possibly to the discussion. From a response to the same question on another forum:

"This gets discussed all the time over on the 5 series forums. The overall consensus is that this ISN'T total BS (with the 5er at least). Any battery with comparable specs to the OEM version will work just fine, but unless the dealer programs the car to accept the battery then the car will overcharge the battery resulting in shorter life expectancy as a result.

Is it the truth? Who knows, but that seems to be commonly believed at this point. With that being said, I changed the battery out on my 5er with a DieHard European battery from Sears and DID NOT take it to the dealer for coding. No problems so far.

For the cars that run AGM batteries there is truth in that the car will damage a normal cell battery over time, agm batteries are designed to charge quicker with higher current, and also to cope with larger current drains as a result of so much electrical load being generated by the cars

here is a quick summary of it's advantages over the standard batteries
http://www.bmwtradeparts.co.uk/PDF/Why/ ... nology.pdf

Good post! I recently disconnected the battery for s cruise control mod. Usual suspects turned up. Clock, windows, bit, my xenons seemed to have adjusted to fully down! Could this be related? I was on a slope when I tool of the terminals? Any ideas? Cheers

so in saying that, i have a 06 Z4M - can i get an AGM battery thats not from BMW ? or is that just a bmw thing>? because from what i read here, as long as i replace with the correct CCA and AH i should bne fine?