ibs sensor
#11
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My Ride: 2005 545i Black Sapphire - Fully Loaded
Model Year: 545i 2005
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i had the high battery drain awhile back and what i did was simply remove the IBS. It has been several years so far no more high battery drain message since, it's a common problem for the e60 the IBS goes bad.
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The two key functions of the IBS are the DME wake-up function and the control of recharge voltage.
After the engine is shutdown the DME takes recent history of the battery SOC (state of charge) it holds and transfers it to the IBS memory and then goes to sleep. The IBS also sleeps, but wakes up every 40 seconds for a fraction of a second to take a snapshot of negative terminal voltage and exit current in order to update the SOC. If something is drawing power and the SOC is dropping the IBS can send a signal to the DME and wake it up. The DME can then force a shutdown of systems (radio, lighting, etc.) that are drawing power. The goal is to preserve enough charge in the battery to enable starting.
During engine and alternator operation the IBS measures the temperature of the negative battery terminal (with the objective of also measuring battery acid temperature). If the battery is charged with an excessive voltage during high acid temperatures the battery can experience excessive gassing, grid corrosion and removal of water in the electrolyte. The terminal temperature sent regularly by the IBS to the DME is used in an algorithm to determine the optimal output voltage that should be sent by the alternator to the system to minimize these side effects of charging and extend battery life.
Incidentally, this optimum voltage can vary significantly between FLA and AGM batteries. An AGM should never be charged with more than 14.6-14.7V, whereas the FLA can safely see up to 15.5V on recharge (again depending upon acid temperature). This is why if you replace your battery with exactly the same type it could be argued that reprogramming is optional, but if you change from FLA to AGM, not registering the battery could lead to very short battery life.
After the engine is shutdown the DME takes recent history of the battery SOC (state of charge) it holds and transfers it to the IBS memory and then goes to sleep. The IBS also sleeps, but wakes up every 40 seconds for a fraction of a second to take a snapshot of negative terminal voltage and exit current in order to update the SOC. If something is drawing power and the SOC is dropping the IBS can send a signal to the DME and wake it up. The DME can then force a shutdown of systems (radio, lighting, etc.) that are drawing power. The goal is to preserve enough charge in the battery to enable starting.
During engine and alternator operation the IBS measures the temperature of the negative battery terminal (with the objective of also measuring battery acid temperature). If the battery is charged with an excessive voltage during high acid temperatures the battery can experience excessive gassing, grid corrosion and removal of water in the electrolyte. The terminal temperature sent regularly by the IBS to the DME is used in an algorithm to determine the optimal output voltage that should be sent by the alternator to the system to minimize these side effects of charging and extend battery life.
Incidentally, this optimum voltage can vary significantly between FLA and AGM batteries. An AGM should never be charged with more than 14.6-14.7V, whereas the FLA can safely see up to 15.5V on recharge (again depending upon acid temperature). This is why if you replace your battery with exactly the same type it could be argued that reprogramming is optional, but if you change from FLA to AGM, not registering the battery could lead to very short battery life.
on a side note bmw also realized if their cars stay parked for more than 3 days the battery draw is large enough to pose a problem. car never really sleeps SO that's why it's good to replace this IBS if it's bad. just a small level of protection....for $200 lol
#13
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great explanation, I replaced battery with another excid. I went with the exact same spec one that the OEM one had and that excid suggest. The problem with the IBS is that when it goes bad it draws power and doesn't relay info properly so battery doesn't get a good charge. I also read they can get on the frits and work and then not work well so again will run for a while as I still right motorcycle in (prolly most of this week) and see how it is.
on a side note bmw also realized if their cars stay parked for more than 3 days the battery draw is large enough to pose a problem. car never really sleeps SO that's why it's good to replace this IBS if it's bad. just a small level of protection....for $200 lol
on a side note bmw also realized if their cars stay parked for more than 3 days the battery draw is large enough to pose a problem. car never really sleeps SO that's why it's good to replace this IBS if it's bad. just a small level of protection....for $200 lol
This problem is not isolated to BMW. All new cars have so many computers that stay alive when at rest (anti-theft, remote door opener) that it is difficult to keep them starting after a long idle period. My wife drives a Lexus SC430 and with a fresh fully charged battery they are only good for about 10 days parked before they commonly will not start.
And of course with any battery the length of time the battery will last, given a stable at sleep closed system current draw on the battery, is a function of the battery's designed capacity and the level of charge. Older batteries or defective batteries that are not fully charged will be the first to fall.
#15
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Hello all,
My 545 is inside a heated garage. I have noticed that after 7-10 days of not starting it, the car feels just a bit strained to turn over. The battery is 2 years old and I have already replaced dthe alternator and tested the voltage. All is fine with the charging system. I know these cars draw a lot of power , even not driven.
i am going on a trip for 3 weeks. If I disconnect the IBS for that period of time, do you guys think I will retain more of a charge when I come back?
My 545 is inside a heated garage. I have noticed that after 7-10 days of not starting it, the car feels just a bit strained to turn over. The battery is 2 years old and I have already replaced dthe alternator and tested the voltage. All is fine with the charging system. I know these cars draw a lot of power , even not driven.
i am going on a trip for 3 weeks. If I disconnect the IBS for that period of time, do you guys think I will retain more of a charge when I come back?
#18
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#19
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Hello all,
My 545 is inside a heated garage. I have noticed that after 7-10 days of not starting it, the car feels just a bit strained to turn over. The battery is 2 years old and I have already replaced dthe alternator and tested the voltage. All is fine with the charging system. I know these cars draw a lot of power , even not driven.
i am going on a trip for 3 weeks. If I disconnect the IBS for that period of time, do you guys think I will retain more of a charge when I come back?
My 545 is inside a heated garage. I have noticed that after 7-10 days of not starting it, the car feels just a bit strained to turn over. The battery is 2 years old and I have already replaced dthe alternator and tested the voltage. All is fine with the charging system. I know these cars draw a lot of power , even not driven.
i am going on a trip for 3 weeks. If I disconnect the IBS for that period of time, do you guys think I will retain more of a charge when I come back?
#20