Battery Ah

[VikingPower 513]

This morning the work van battery was  dead. The BMW and the T5 share exactly the same battery.. So naturally im going to replace VW T5 battery with the one from the BMW, and now wants to install a Lithium one in the BMW. 

A few questions to that, 
How low on Ah can i go with the new lithium battery? In a normal BMW m135i they use 80ah AGM battery
. 
As most of you already know, i dont have aircondition, heated seats, Idrive + soundsystem, heater matrix or anything niceness in the car. 
What i do have is Electric windows, 4 amp blower fan for interior cooling, 3 amp raspberry pi.. 

The BMW also have IBS (intelligent Battery Sensor).
As I understand, its not possible to remove this system so i would have to replace with a lithium battery that is made for IBS? 

[racy_estate 160]

vor 3 Stunden schrieb VikingPower:

As I understand, its not possible to remove this system so i would have to replace with a lithium battery that is made for IBS? 

You need to modify the cars software with ISTA or a different system, that allows you to switch the battery size to the smallest one. With this procedure the new battery is recognized correctly. 
Can't tell you if the electronics makes a difference in terms of cell chemistry. There are different statements. But i need to ask: Whats the reason that you dont go with a small size AGM battery? Mostly this is a very cost effective method. And i can tell you, that the cranking amps of most 20-30Ah batterys are sufficient for nearly every motor. 

[VikingPower 513]

58 minutes ago racy_estate wrote:

You need to modify the cars software with ISTA or a different system that allows you to switch the battery size to the smallest one. With this procedure the new battery is recognized correctly. 
Can't tell you if the electronics makes a difference in terms of cell chemistry. There are different statements. But I need to ask: What's the reason that you don't go with a small size AGM battery? Mostly this is a very cost effective method. And I can tell you, that the cranking amps of most 20-30Ah batteries are sufficient for nearly every motor. 

I also have done this, when registered the battery i mounted 1 year ago though not changing the size, since it was the same. 
AGM even at 20amps are just too heavy to make sense for a weight upgrade. Im at the point, where the car could be very close to a sub 1300kg half tank. (1365kg) with just a bit more than half a tank. So the more waight saving the better. Lithiumnext RACE40 weighs 2.6kgs.. But is not IBS optimized. Their Track60 are IBS compatible and weighs 4kg dead. So that is a 18kg weight saving. Allthough in the wrong end of the car, but then i must just remove more in the front 

[Phil130i 730]

vor 8 Stunden schrieb VikingPower:

As most of you already know, i dont have aircondition, heated seats, Idrive + soundsystem, heater matrix or anything niceness in the car. 
What i do have is Electric windows, 4 amp blower fan for interior cooling, 3 amp raspberry pi..

All this doesn't really matter as long as you don't want run all your electrical consumers while the engine is off.

Ah just states the capacity of the battery. Eg. 80A x 1 hour = 80Ah or 40Amps x 2 hours = 80Ah and so on..  When the engine is running the alternator powers all the electrical consumers.

I run a 12,5Ah battery and for me thats enough capacity. I don't have any unnecessary electrical consumers that I use when the engine is off so no worry about the small capacity.

bearbeitet 17. April von Phil130i

[VikingPower 513]

vor 36 Minuten schrieb Phil130i:

All this doesn't really matter as ling as you don't want run all your electrical consumers while the engine is off.

Ah just states the capacity of the battery. Eg. 80A x 1 hour = 80Ah or 40Amps x 2 hours = 80Ah and so on..  When the engine is running the alternator powers all the electrical consumers.

I run a 12,5Ah battery and for me thats enough capacity. I don't have any unnecessary electrical consumers that I use when the engine is off so no worry about he small capacity.

Interesting! I will try to see if i can find out if there are any way to see/calculate how much Amp/Watts starter motor + what diverse electronic modules consumes when you go into the car and wants to start it. I can probably not find anything, but running a 20ah battery is possible would probably be more than i really need. 

[dawenth 168]

I have the Noco NLP30 in my M135 with all the comfort-shit working - i just switched to the smallest possible Battery-size via bimmerlink.

[VikingPower 513]

vor 18 Minuten schrieb dawenth:

I have the Noco NLP30 in my M135 with all the comfort-shit working - i just switched to the smallest possible Battery-size via bimmerlink.

That is interesting.. 8ah battery lol :P 
Can you share a pic of how it fits in the space? Definately an interesting option, especially with the low weight.. 

bearbeitet 17. April von VikingPower