WARNING!!!! Only charge the battery from...

Only charge the battery from the terminals under the hood.

Here's why.
The charge circuit in the car limits the amperage to the battery to prevent damage to it based on age and condition. Bypassing this and charging directly to the battery will make the circuit think it's weaker than it is and then limits the alternator charge amperage to the battery while driving. Over time the battery will create a memory at 70, 80 or 90%. Who knows what the value will be, but it will be less than full capacity.

Here's how I know:
Before changing my battery, I tested charging the old one from the under hood terminals. It took .10 amps. At the battery it took 4amps.
After swapping the battery: it charged at 1 amp at the battery (before install) and
1 amp under the hood(after installing). After registration it took 2 amps from under the hood.

So the car circuit upped the voltage to the battery after registering it. I would expect after some time the charge circuit will determine the actual values and bring the voltage down. This will be the charge voltage from the terminals as well as the alternator.

This car is not your average bear....
It has a dedicated charge circuit that is separate from the rest of the car. In most cars the battery goes to everything all the same. Meaning all circuits get the same supply voltage. If a circuit needs say +5v, then that circuit has a voltage divider as a part of it, old school is a resistor, new school if a transistor or MOSFET.

The 6 series, and others I suspect, sends power directly to the battery with it's charge circuit. AND I suspect there is a car buss that is supplied by the alternator and the battery. And maybe even smart with switching to maintain constant voltage to other circuits.

I could dig into this further but why. I'm done and know what I need to. Besides I have another project to work on.

All software BWM pertaining to the 6. Stay tuned.

Trying to understand what you are recommending, is it not so, that connecting the charger to the positive terminal of the battery and using the earthing point of the battery is the same as doing it from the jump start points in the engine bay. The +ve cable runs from the front through the car to the battery. The battery condition sensor monitors the battery at the battery inside of the boot and then sends the signals to the control centre.
BMW recommend and instruct the use of hard wiring to the battery +ve terminal and the -VE point in the boot with the C-TEK charger, rather than just using jumper leads to the same points. All as a matter of convenience.

Originally Posted by 645/333

Trying to understand what you are recommending, is it not so, that connecting the charger to the positive terminal of the battery and using the earthing point of the battery is the same as doing it from the jump start points in the engine bay. The +ve cable runs from the front through the car to the battery. The battery condition sensor monitors the battery at the battery inside of the boot and then sends the signals to the control centre.

The difference between charging amps on the new battery from terminals under the hood before and after registering the new battery (increased by 1 amp) shows that there is current limiting between the positive terminal under the hood and the battery. So it's not a "direct" wire.

+ve and -ve??? Is that a British thing?

Also of note (symantecs here) there is no "earthen ground" for cars. There is only difference of potential between + and a ground plane. And some countries have cars with a positive ground plane. Weird, I know.

Take a voltmeter and measure between the + terminal of the battery and the ground of an outlet...MAKE SURE YOU KNOW WHAT GROUND IS!!!! You can blow a meter if you plug into a hot blade. BTW, aren't you guys 220v?

I appreciate that there is no direct to earth on a car (ground/earth one and the same), it is the terminology we use for what the negative -ve / black cable in a car and positive +ve red cable or charging terminal. Perhaps a British thing!!!! I don't think so !!!
As for the cable not going directly to the battery, as I said I believe it would or if not then there must be another connecting point within the loom. The reason the battery is in the boot is that certain types of battery cannot operate properly with the varying temperatures that exist in the engine bay, secondly it is also a matter of space, given more room in the boot and a more stable environment. Unless you fully disconnect the battery then they do not recommend that you charge directly to the battery terminals, as this will damage some of the the cars electronics
finally I don't understand why you seem to make attack comments when a person is offering information in good faith, it smacks of arrogance !!! Yes I do understand what ground means !!!
Having checked the wiring diagram and the parts manual, the cable from the +ve terminal (red) in the engine compartment runs directly to the battery point, where it connects to the battery cable(plus pole). Which I think somewhat negates your comment/ warning !!!!!!!

Originally Posted by 645/333

finally I don't understand why you seem to make attack comments when a person is offering information in good faith, it smacks of arrogance !!! Yes I do understand what ground means !!!

I apologize. I did not intend to offend you or anyone. I only meant for the reader (any reader) of my post to understand that it can be dangerous if they do not know what they are doing.

I can imagine it now...
"Honey, the meter blew up in my face. I read how to do it on a web site".

Sincerely, I meant nothing towards you.

Here is some of what I found from BMW WDS
"The IBS is a mechatronic component for monitoring the battery condition. The IBS is secured and connected to the negative terminal of the battery. The power supply for the IBS is fed across a separate cable. For data transmission, the IBS is connected to the DME (Digital Engine Electronics) or DDE (Digital Diesel Electronics) via the BSD (bit-serial data interface)."

Also the BSD is tied into the alternator and does several things.

And from TIS

"On vehicles with IBS, recharging the battery directly at the battery terminals could lead to a misinterpretation of the battery condition and even unwanted Check-Control messages or fault memory entries.

If the battery is recharged while installed, it must be recharged using the jump-starting points...in the engine compartment.
Only then can you be sure that the recharging is correctly recognized by the vehicle electronics on vehicles with intelligent battery sensor (IBS)"

I was only making this thread to show actual proof that there really is a reason for charging from the installed jump-starting points and not the battery.

I needed to know since I will be installing a Ctek 7002 and thought I would share what I found out.

AS I pointed out previously I have a C-tek 7000 series connected to my car, it also has a battery condition monitor within the wiring, in fact it is a traffic light system, red/ amber/ green lights.
The extra wiring that comes with the C-Tek 7000,( is a higher spec model than that sold by BMW which is C-tek re-badged). Also has extra wiring which allows you to permanently wire the car. In fact BMW will sell you a connector which is installed into the back plastic strip which forms the lip inside of the boot, which is then hard wired to the battery, so when you connect you charger you just plug it in..... perhaps they don't market these in the US but I bet if you visit the parts department they will supply you with one somehow..... it is all about convenience.
The bottom line being as Yorgi often states that one of the key weaknesses of this model is the electronics and the power supplied. I learned my lessons from having flat battery on numerous occasions until I worked out an effective regime of trickle charging my car once per week and my battery is now 6 years old and still going strong. This C-tek model allows you to do a battery recondition charge, but it is recommended not to do this too often.
Ps if anyone cocks up after the effort we have put in to assist in this area, then they well justify your comment 'I read it on the web' !!!!!
I will post a pic of my installation !!!

I agree completely about the power supply and electronics which is why I am doing this. I also plan on doing a weekly maintenance charge.
Maybe I'm hyper sensitive but I swear the throttle was smoother after installing the new battery. Before I had to feather the throttle from a standing start because it stuttered a bit. And in the short trip I took yesterday it was smooth. I'll just have to go test drive it some more today, you know in the interest of knowledge.

Is this the connector you are talking about that the Ctek comfort indicator panel plugs into?

Lookie, you can see green. WoooHooo, The old one was black.

I also got one of the comfort panels.



It would be nice and clean to have it installed in the trunk.

Please post pics.

Thanks

Here are the pictures of my battery charger connections, hopefully uploaded correctly. The lights do flash on the connector subject to the battery condition. This then connects to the wiring connector of the C-Tek charger.

I have only had my 645 CiC a few weeks and had no indications of battery issues, but I don't drive it a lot so I bought a CTEK 3300 and Comfort Indicator. I installed the Comfort Indicator eyelets permanently under the terminals in the engine bay to provide a convenient connection for the charger.

I left the trunk open and removed the trunk floor while charging to ventilate the battery and was happy to see I did not have to disconnect the trunk light as it turned itself off after some minutes.

After some hours the first charge reached maintenance mode, I noticed the Comfort Indicator was still flashing orange. I started the charging cycle again - same result.

So I disconnected the charger and went off to think about it. When I came back 15 minutes later, the Indicator showed green.

I have since discovered that if I unlock the car and hence initiate some of the electronics, the Comfort Indicator will show orange or even red if I open a door. If I lock the door again, red will change to orange and after about 10 minutes when all the electronics have gone to sleep, orange turns to green.

So, I think I am okay. I thought others might be interested in my experience.

I have a parts dept. receipt that shows the previous owner replaced the battery with a BMW original (Exide) 6 months ago, but I don't think he had it registered (or drove much since it was done). So I guess I will make a trip to the dealer and see if they can find out the status. I wonder if they put in a date for the battery replacement and can back-date it, or is it just a matter of them checking that the battery specs are correctly set?

Originally Posted by colink

I have a parts dept. receipt that shows the previous owner replaced the battery with a BMW original (Exide) 6 months ago, but I don't think he had it registered (or drove much since it was done). So I guess I will make a trip to the dealer and see if they can find out the status. I wonder if they put in a date for the battery replacement and can back-date it, or is it just a matter of them checking that the battery specs are correctly set?

You cannot get the battery registration "back dated" unfortunately. All that registration does is tell the power module what type of charging cycle is needed. If the new battery is charged using a profile designed for an older battery then it could potentially be over charging it. I think it is worth getting it registered now anyway, everything may be OK given the time/distance driven was minimal. It is also worth asking them to check that the Ah rating & battery type (AGM or lead acid) registered corresponds to the battery currently fitted to the car.