BMW Battery Registration/Programming with ICOM cable

Programming and Registering are 2 different things. They use totally different equipment.
So I needed a new battery because my old one was holding an 11.5v charge when the car was off. I ordered a Braille no weight, 21lb battery from HP Autowerks with their custom battery tray. I had a shipping timing issue and Harold made sure it got to me before I went away.

So I come back from vacation and look for a good indy to install my new battery. I found Pinnancle Motor Werks in Stirling, NJ so I went there to get my battery installed/registered.

They have an Autologic for those wondering.

Anyway so we go through the menus to register the battery and since the Braille is an AGM battery, I need to program my car so it charges the battery correctly.

SO if you’re replacing your battery with an AGM and you have a lead acid battery, you NEED to program the correct type! Registering and programming are 2 different procedures.

However, the Autologic device had only the following options: 90Ah AGM, 90Ah, 80Ah AGM, 80Ah, 70Ah AGM, 70Ah, 55Ah, and 46Ah. I think that was all of them.

The Braille I bought has a 31Ah rating….what to do?

Basically my indy didn’t want to be held liable for damages later incurred….understandable. So I told the shop to program my car as a 70Ah AGM, the lowest Ah AGM available on my car. I was concerned about my car being programmed to charge an AGM, not a lead acid.

So we’ll see if my battery holds up. I was mainly concerned that my car was programmed to charge an AGM. The Ah rating will be something I will monitor over the life of the battery.

So things I learned from this: (For those of you who just want to read about registration and programming)

Battery Registration does 3 things:

1) Logs Mileage.
2) Tells the car a new battery is installed.
3) Not sure about this one but I think the car records the condition of the battery at 80% of the capacity… a reference point.

Now there is programming with ICOM A2 or ICOM Next…..which requires reintializing modules, mainly the CAS and FRM module.

Our cars have many different Ah ratings (90Ah, 80Ah, 70Ah) and types (AGM vs non-AGM). There are other parameters that differ as well but these are the main ones in programming. The main difference the computer needs to know is AGM or non-AGM. AGMs will charge differently. I guess different Ah ratings tell the car how long to charge the battery and how often to maintain it. Ah ratings are basically a reserve rating. A 1 amp draw on my 21lb Braille will last 31 hours before a recharge is needed.

Anyway, so the reason why I have decided this was a bad decison is because:

1) The CCAs on the Braille are 550A. Stock = 750A. This battery is fine for warmer climates but since I’m on the East Coast…..I’ll be needing a battery heater and a tender.
2) The Ah rating on the Braille is 31Ah. Stock = 90Ah. This is why I need a tender.

Those with a BT tool:

Reset Battery Adaptation and Battery Registration are redundant entries and send the same command. You can only use this option if you are replacing the battery with the SAME spec. Same Ah (capacity) and type (AGM vs non-AGM).

If you decide to install a battery with a different type or capacity you need to have the car programmed so it knows its capacity and type.

Here, AGM batteries will be explained:

In September 2002, the first VRLA batteries, better known as AGM batteries came into use. 

VRLA means valve-regulated lead acid, or a lead battery with a pressure relief valve.

AGM stands for absorbent glass mat, or absorbent glass-fiber fleece.)

An AGM battery (90 Ah) is currently installed in the E46 with the M56 engine. Its use in other vehicle models will follow.

The continuously increasing energy requirements of modern vehicle electrical systems, demands ever more efficient battery solutions. A modern luxury vehicle has some (100) actuator motors that have to be provided with electrical current. In addition, there are safety, environmental and comfort features that are increasingly becoming part of the standard equipment such as ABS (anti-lock brake system), DSC (dynamic stability control), EPS (electric power steering), heated catalytic converter, electronically controlled suspension, air conditioning and navigation systems. Current consumption is considerable even when the vehicle is not in use.

AGM batteries are more expensive to produce, however this extra cost is offset by the following benefits:

Much longer service life

Improved starting reliability at low temperatures

Reliable starting of engines with high starting current requirements

100% maintenance-free

Low risk in the event of an accident (reduced environmental risk)


Service life of AGM batteries 

(1) Available capacity [%] 

(2) Distance [thousand km]

(3) AGM battery 

(4) Lead-calcium battery

(5) 50% capacity line

Brief description of components 

AGM batteries can be recognized by the black housing and the lack of the “magic eye”.



Positive grille with silver alloy
Set of positive plates

Positive plate
Set of negative plates

Negative grille
Block of plates

Negative plate
Block box with base strips

Separator made of glass-fiber fleece


AGM batteries differ from conventional lead-calcium batteries in the following points:

Larger plates:

Larger plates allow a power density some 25% greater.

Glass-fiber-fleece separators:

This enables a cycle consistency up to 3 times greater to be achieved.

This improves cold-starting ability, current consumption and service life.

Airtight housing with pressure relief valve:

The inspection plugs are sealed and cannot be opened.

Acid bound in grass-fiber fleece:

In contrast to conventional lead-calcium batteries, the sulfuric acid in a battery with fleece technology is not held as a liquid in the battery housing, but rather it is completely bound (100%) in the glass-fiber fleece (separators). This gives increased security against the acid escaping and thus reduces the environmental risk. For this reason, no acid can escape if the battery housing is damaged. In addition, the AGM battery is sealed to be airtight. This is possible because the gases are converted back into water by the permeability of the separators.

How it works 

AGM batteries differ from conventional lead-calcium batteries in their environmental compatibility and their retention of gases during charging.

When a vehicle battery is charged, the electrolysis process emits the gases oxygen and hydrogen.

In a conventional lead-calcium battery, these two gases are released into the atmosphere.

In an AGM battery, the two gases are converted back into water: The oxygen created at the positive electrode during charging moves through the permeable glass-fiber fleece to the negative electrode, where it reacts with the hydrogen ions that are brought in with the electrolyte, to create water (oxygen cycle). In this manner, the gases, and thus the electrolyte, is not lost.

Only when the gas production is excessive, that is when too much pressure is generated (20 to 200 mbar), does the pressure-relief valve open, thereby allowing gas to escape while also preventing entry of atmospheric oxygen. Because the pressure in the battery is regulated by a valve, the AGM battery is also known as the VRLA battery (valve-regulated lead acid).

Service Instructions for AGM Batteries 

When handling AGM batteries, certain special factors must be taken into consideration with regard to battery renewal and installation location.


Warning: Do not charge AGM batteries with 14.8 volts! Do not use rapid charging programs!

When charging batteries in the “stand alone” mode, the maximum charge voltage of 14.8 volts must not be exceeded. Even briefly charging an AGM battery with a charge voltage of more than 14.8 volts (voltages usually used in rapid charge programs) will damage the battery.

Installation Location

Warning: Do not install AGM batteries in the engine compartment!

Because of large temperature variations, AGM batteries must not be installed in the engine compartment. This would result in a significant reduction in the service life of the battery.

Do Not Open

Warning: Do not open AGM batteries

On no account should AGM batteries be opened, as oxygen from the atmosphere would cause the battery to lose its chemical balance and cause it to fail.

Battery Replacement

An AGM battery, when installed as original equipment, must always be replaced with an AGM battery. 

In special cases, where a customer’s driving profile (e.g. short distance driving), results in a discharged battery, the AGM battery is a recommended replacement. Note that replacement batteries resulting from a customer’s driving profile cannot be claimed under warranty.

So as long as you replace your battery with the same spec (CA, CCA, Ah ratings, and type (AGM, non-AGM)), then you just need to register your battery.

If you change any specs you may need to program, then register the battery….especially when retrofitting an AGM.

I don’t think small differences in ratings will require programming, just registration. As long as the Ah rating and type are the same/similar values, then you should be good.

EDIT: I also forgot to mention that the battery I received was a bit smaller than the ones in the DIY guides here and on M3post. My power distribution block sat directly over the negative terminal opposed to next to it, like the ones in the DIY.

I had to configure it in a weird way. I’ll post up a picture later.

I did not want to remove the distribution block because it holds the main fuses for our cars and also I would need to cut, fuse, and terminate 4 or 5 wires, some being a pretty thick guage. I’m lazy….