Looking at S5/RS5 Sportback
11-08-2018, 09:56 AM
#21
AudiWorld Super User
As for the ***, it really is too bad that it was executed with an impact on the steering wheel. I hated it in my 328 because the wheel locked and the whole car shook when it turned on but didn't mind it at all in my Mercedes because you didn't even notice it was on, other than the AC would reduce in intensity a bit. Unfortunately the way they executed on the S5 means it won't be used as much as it would have otherwise, which undermines the environmental value of having the technology in the first place.
11-08-2018, 10:00 AM
#22
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I am not sure which Mercedes you have, but when my 2015 Mercedes CLS550's engine shuts off due to ***, the steering wheel is has no power assist and the AC compressor is off. Mercedes does have a small aux. battery to keep the main battery from draining while *** is activates, but in no way does that small battery will run the AC compressor and the power steering system.
Other thing I'm going to miss is the hold function on the brake when let's you take your foot off the brake by depressing it all the way first. Not a huge feature but I've used it a bit and don't see why everyone doesn't do it.
Still these are obviously not deal breakers and I'm super excited to get into the S5...
11-08-2018, 12:32 PM
#23
AudiWorld Senior Member
Other random stuff is also disabled when the engine shuts off:
- The auto open for the sunroof and windows stops working, so you have to hold the button down
- The windshield wipers stop wherever they are. This is a particularly weird one.
- As mentioned, power steering & power brakes go away
- AC stops
11-08-2018, 12:45 PM
#24
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Other random stuff is also disabled when the engine shuts off:
- The auto open for the sunroof and windows stops working, so you have to hold the button down
- The windshield wipers stop wherever they are. This is a particularly weird one.
- As mentioned, power steering & power brakes go away
- AC stops
11-09-2018, 04:20 AM
#25
AudiWorld Super User
11-09-2018, 08:46 AM
#26
AudiWorld Super User
11-09-2018, 09:19 AM
#27
AudiWorld Super User
The marketing behind 48v seems focused on better efficiency and more engine power with or without a smaller engine, but I think the key is this (from here:
Basically, it offloads belt-driven systems to the 48v electrical system, reducing load on the engine and allowing the car to shut off the engine without affecting those components. It sounds like an evolution of the existing "recuperative" technology in current cars (including at least Audi & BMW) that can disengage the alternator when the driver mashes the accelerator, and explicitly engages it during coasting (signified by the green battery icon in the "consumption" display).
Basically, it offloads belt-driven systems to the 48v electrical system, reducing load on the engine and allowing the car to shut off the engine without affecting those components. It sounds like an evolution of the existing "recuperative" technology in current cars (including at least Audi & BMW) that can disengage the alternator when the driver mashes the accelerator, and explicitly engages it during coasting (signified by the green battery icon in the "consumption" display).
Last edited by superswiss; 11-09-2018 at 09:28 AM.
11-09-2018, 10:25 AM
#28
Club AutoUnion
Some of that is already happening with 12V systems. Things like electric steering, electric oil pumps and other auxiliaries and then increase the alternator voltage to recoup energy and decouple the alternator when engine power is needed to reduce load on the engine. That's how the current power recuperation system works that Audi uses. The benefit of 48V is that you can transfer 4 times as much power using the same wire harnesses w/o increasing losses and having to beef up electronics and wires to deal with higher currents. Power = Current * Voltage, so 48V increases power four times without increasing current. This is also why EVs are now going to 800V batteries from the current 400V batteries. Double the power, half the charging time with largely the same wiring. More shielding is required, but you don't have to deal with higher thermal losses etc. So with 48V they can now electrify components that need more power, such as electric turbo chargers, AC and other systems.
11-09-2018, 10:42 AM
#29
AudiWorld Super User
The 48-volt system can also power the water pump and air-conditioning compressor, eliminating the need for belt-driven accessories, reducing drag losses and freeing space.
11-09-2018, 11:08 AM
#30
Club AutoUnion
@ superswiss — Thank You for your kind reply! This is my first German Car so I’m not following Mercedes or BMW.