[E92Carrera]

Does anyone leave their car in sport mode? Or just switch as needed and usually leave it in comfort mode?

[SamS]

Originally Posted by jdong

I'd say the practical "what to expect" fuel economy of this car is something like:

Worst case: 20mpg
Average case: 26-28mpg
Trying really hard: 32-34mpg

I've just hit 7000 miles, and I'm seeing a stabilizing average of 26.8mpg.

This is my experience as well. I'm closing in on 4000 miles.

My long term average is sliding a bit, because I have a new commute which is heavy stop and go, and no speeds >40mph.

Originally Posted by E92Carrera

Does anyone leave their car in sport mode? Or just switch as needed and usually leave it in comfort mode?

Comfort mode is fine for normal driving. I'm probably in Eco Pro more often than Sport. Although I did have a bit of fun in Sport mode today because I was doing some off-and-on the highway.

[zenmaster]

If upcoming advances in battery tech provide more energy density, do you think we can practically "upgrade" the battery module to take advantage? i.e. extended electric range

[jdong]

Originally Posted by zenmaster

If upcoming advances in battery tech provide more energy density, do you think we can practically "upgrade" the battery module to take advantage? i.e. extended electric range

I think I wrote up a post a while ago describing battery capacity choices in the AH3. Long story short, the larger battery capacity will not be very useful without a way to introduce energy into the car that doesn't involve the N55 (i.e. a plug-in hybrid).

Currently, when braking at maximum regen, the battery gains about 1% every 1-2 seconds, which means it takes about 2 minutes of braking to charge the battery from the 7% "minimum" charge to the 85% "nominal" charge. It's hard enough right now to hit the energy storage limits unless you're going down a really steep hill, or feel like annoying everyone behind you by slowly braking half a mile before every red light.

If you put in a bigger battery, it's not going to have much of an efficiency win, if any. Maybe after you accumulate enough charge, you can drive longer in electric mode, but I'm not sure what's the point of that. Maybe novelty, but definitely not efficiency.

Once you put a plug on the car, though, then big batteries have their benefits.

[jdong]

Originally Posted by E92Carrera

Does anyone leave their car in sport mode? Or just switch as needed and usually leave it in comfort mode?

I use sport mode once in a while for novelty, or if I know I'm going to be driving very aggressively. I find that it's a bit TOO responsive to be useful for an always-on mode. It really lights up the car for some excitement once in a while, but especially if you have passengers, the car is a bit too twitchy for my tastes.

Normally I use either Comfort mode or mix in a bit of Eco Pro. I've found that using Eco Pro in situations where you can't resist the temptation to have poor driving habits is the most beneficial. For example, if I only turn on Eco Pro when stuck in stop and go traffic, I can gain an extra 1-2mpg over the course of a tank, without sacrificing my driving pleasure much. Using Eco Pro all day long makes me feel like I should've just bought a Prius

[zenmaster]

Originally Posted by jdong

Once you put a plug on the car, though, then big batteries have their benefits.

Seems like a simple circuit to allow plug-in. But can't the engine also charge the battery, which would make sense if the electric motor was able to more efficiently use the fuel for a trip? Not sure what you mean by "big batteries" though, assuming the newer power-storage densities won't come at a cost of weight or volume and would even be lighter.

[jdong]

Originally Posted by zenmaster

Seems like a simple circuit to allow plug-in. But can't the engine also charge the battery, which would make sense if the electric motor was able to more efficiently use the fuel for a trip? Not sure what you mean by "big batteries" though, assuming the newer power-storage densities won't come at a cost of weight or volume and would even be lighter.

It's never more efficient to use the engine to charge the battery instead of driving the car. The N55's specific efficiency (aka fuel to kinetic energy conversion efficiency) is very good. Trying to generate electricity from the engine incurs generation losses. The only case this tends to be untrue is if you hit stop and go traffic, which requires a lot of varying engine speed. But 85% of the current battery is already quite a good buffer.

The net win of the ActiveHybrid is primarily when the battery charges via coasting and braking, recovering otherwise wasted energy.

Is it simple to add a plug? I think it might be, yes. A battery charging circuit is conceptually very straightforward. However, that adds additional cost to the car, and at that point everyone will expect a meaningful all electric range. For that to be true, IMO the electric motor needs to be sized similarly to the new Panamera E Hybrid -- about 100HP.

Oh yeah, Californians will also expect carpool lane access, which means the N55 must be modified to reach ATPZEV emissions standards.

[zenmaster]

Originally Posted by jdong

It's never more efficient to use the engine to charge the battery instead of driving the car. The N55's specific efficiency (aka fuel to kinetic energy conversion efficiency) is very good. Trying to generate electricity from the engine incurs generation losses. The only case this tends to be untrue is if you hit stop and go traffic, which requires a lot of varying engine speed. But 85% of the current battery is already quite a good buffer.

The net win of the ActiveHybrid is primarily when the battery charges via coasting and braking, recovering otherwise wasted energy.

Is it simple to add a plug? I think it might be, yes. A battery charging circuit is conceptually very straightforward. However, that adds additional cost to the car, and at that point everyone will expect a meaningful all electric range. For that to be true, IMO the electric motor needs to be sized similarly to the new Panamera E Hybrid -- about 100HP.

Oh yeah, Californians will also expect carpool lane access, which means the N55 must be modified to reach ATPZEV emissions standards.

I agree with all that. However, I plugged some numbers into this: http://ecomodder.com/forum/tool-aero...resistance.php

and it seems that merely 25HP is sufficient to maintain 75MPH and 50HP would maintain 100MPH down the highway for 4000lb. Whereas, right now the electric motor (EM) runs only occasionally to briefly assist at those speeds, even when not accelerating. If there wasn't something like a cooling problem running the electric motor more frequently or for longer durations, then the (hypothetical) battery upgrade should actually allow the EM to contribute x% more for any trip.

[jdong]

Coasting? Sure, but most people with a "plug in hybrid" don't like it when their gas engine comes alive with the slightest press of the gas pedal, which is probably close to what BMW will have to do with a mere 25-50HP on tap.

With that said, spy photos show that BMW does have a plugin hybrid 5er in the works -- it seems like they're way ahead of us in exploring down this path

The AH3/5's drivetrain is designed in a way that lends towards a really good PHEV implementation that can be achieved "just" by making the battery and motor bigger. And I'm sure when BMW thought of this car 5-ish years ago, they had that in mind as well.

[iM]

Not sure if this has mentioned here before..
i always wonder if the full charge cycle helps lithium based battery to have longer battery life? I've done couple times of the full charge cycle on my AH3; drain the battery down to 3-5% during rush hour, then driving in DS till i get 100% fully charged battery. i am just not going to do this cycle runs if it doesn't help..

[jdong]

Originally Posted by iM

Not sure if this has mentioned here before..
i always wonder if the full charge cycle helps lithium based battery to have longer battery life? I've done couple times of the full charge cycle on my AH3; drain the battery down to 3-5% during rush hour, then driving in DS till i get 100% fully charged battery. i am just not going to do this cycle runs if it doesn't help..

No, it doesn't. The car has a smart charging system that is aware of the battery chemistry and state. The car only drains the top 50% of the battery (when you see 0%, it's actually 50%), which greatly extends the pack's life compared your lithium ion powered electronics where you drain down to 5% or less.

You really can't do anything to help the pack, nor should you. The only thing is you should not store the car for a extended period of time with the pack discharged at a low charge. In my experience the pack drains at about 3-5% a week so if you're not going to use the car for months, you should get the charge close to 100% before storing it.

[iM]

Originally Posted by jdong

No, it doesn't. The car has a smart charging system that is aware of the battery chemistry and state. The car only drains the top 50% of the battery (when you see 0%, it's actually 50%), which greatly extends the pack's life compared your lithium ion powered electronics where you drain down to 5% or less.

You really can't do anything to help the pack, nor should you. The only thing is you should not store the car for a extended period of time with the pack discharged at a low charge. In my experience the pack drains at about 3-5% a week so if you're not going to use the car for months, you should get the charge close to 100% before storing it.

Much appreciated for the info. btw, has bmw offered you a job, yet?

[jdong]

Originally Posted by iM

Much appreciated for the info. btw, has bmw offered you a job, yet?

Haha, I'm very happy with my current job

[zenmaster]

Originally Posted by jdong

Coasting? Sure, but most people with a "plug in hybrid" don't like it when their gas engine comes alive with the slightest press of the gas pedal, which is probably close to what BMW will have to do with a mere 25-50HP on tap.

With that said, spy photos show that BMW does have a plugin hybrid 5er in the works -- it seems like they're way ahead of us in exploring down this path

Not really coasting, merely maintaining speed on level ground, particularly at highway speeds. At 75 MPH you can't really tell if the engine comes on. And if it's parallel load sharing, then the engine simply requires and uses less gas.

What you said sounds good, except battery technology is basically the same now as it has been for the past few years now. So they have to use lighter materials for the car and/or a battery with significantly larger volume and weight.

But the point was not about how to make the best use of technologies in a whole new platform, but rather how could the same old car take advantage of emerging battery tech. By the time the battery pack needs replacement, or sooner, there might be 2x-5x more storage density, longer life, etc.

[Forgiven]

Another AH owner here..got it yesterday

[hanizh]

Originally Posted by ckret

Another AH owner here..got it yesterday

Congrats! nice car

[zenmaster]

C-pillar bling or didn't happen!

[Forgiven]

Originally Posted by zenmaster

C-pillar bling or didn't happen!

No blingy on C-pillar It was quick and easy, didn't even have to use floss to remove letters

[1M4]

Did you remove the trunk badge?

[Arktctr]

Originally Posted by ckret

No blingy on C-pillar It was quick and easy, didn't even have to use floss to remove letters

That will be the first thing I do when mine gets home as well! I will likely leave the trunk badge on though but the C-Pillar ones remind me of the hideous hybrid badges GM puts on their trucks (Tahoe, escalade, etc...) Totally unnecessary and looks out of place...

[Forgiven]

Originally Posted by MsportAH3

Did you remove the trunk badge?

No sir. But I might do something about it.

[PaulBailey@ltbmw]

How many of you AH3 owners have started modding your cars?