How do I know my hybrid is working correctly?

[sorcerer]

So, we've had our late 2013 (November, so a 63-plate) RX450h Advance for about four and a half months now and whilst I absolutely love the car, I'm getting rather deflated by reading of other's fuel figures and how their cars seem to operate compared to mine. This is the first hybrid I've ever owned or even driven so I'm acutely aware that I could be doing something wrong, but examples include:

• Even if the Battery icon is showing 7/8 bars, by the time the car has moved its own length on my driveway, the ICE fires up. I thought the ICE only fires up when needed to keep the Battery charge level from getting too low? At 7 out of 8 bars I would have thought that the car would have set off and driven on Battery alone, at least to the top of our cul-de-sac and not just about 15 or 16 feet - the rear wheels are still on the driveway and not even on the road before the ICE bursts into life. Same at traffic lights or junctions - I only have to breathe on the accelerator pedal and the ICE fires up.
• If I manually select EV mode I hardly have to get the wheels rolling before I get a message saying that EV mode has been deactivated due to excessive acceleration! Excessive acceleration?? I've hardly even touched the accelerator pedal!
• On the very rare occasions that I've actually managed to get it to run in EV mode, it just will not go any faster than about 23mph (it certainly does not reach 25mph) before I get the message that EV mode has been deactivated due to excessive speed - and yet, just this very night, I've seen a posting from @Mr Vlad who has a 62-plate RX450h, that said "I've read somewhere on here somebody struggling to get more than 23 mph in EV mode. I regularly get over 40 and how it pulls in EV mode compared to my previous IS300H is gobsmacking"
• Another quote from @Mr Vlad in the same posting was "Come up to Leeds but this time all the way in sport mode. Yes I broke all speed limits lol and still returned over 32mpg" No matter how I try, I can't even reach 32mpg and that's driving it like it's got Faberge eggs on the back seat!

So is there something wrong with my car or have I just not got the hang of driving it?

[ColinBarber]

Don't use manual EV mode, it is really just for moving your vehicle on/off your driveway etc.

The ICE will always fire up quickly, especially when cold.

The trick is getting better economy is to get up to speed, say 40 mph, lift off the throttle so the car switches to EV mode and then lightly press the throttle to maintain speed without needing the ICE to restart.

[sorcerer]

Thanks Colin, I'll give it a try.

[olliesgrandad]

In the 16 days I've owned my car I've averaged over 35mpg in 907 miles according to my phone app. This is measured tankful to tankful. This is my 3rd lexus since October 2016 so I'm used to driving hybrid. My 2015 gs300h averaged over 44mpg over 27000 miles. Driving a hybrid is totally different to a conventional car. Watch the Lexus YouTube video that will help. 

[Mr Vlad]

This RX being your very 1st hybrid is gonna do your head in for a short while. It did me when I got my 1st hybrid (the IS300h and all previous cars had manual gearbox ) I couldn't get to grips with it so after 5 weeks it went for an auto box sports mondeo. I'm not saying goes get rid but be patient and learn your car.

As Colin stated. Get upto the desired speed, so longs as it's below 40, then gently release pressure on the throttle. 

There are a few videos on YouTube made by lexus on how to drive the hybrid.

I found that after driving the mondeo I got used to an auto box. This was good for me as I found driving the 2nd 300h I bought was so much easier than previous. 

Your economy will get better with time and from the info given you.

Oh. On 1st start up of the car the engine will always start up no matter what. My car shows 3/4 full but within seconds it drops to about 1/4. 

Don't fall into the trap that you have an EV car. Our cars can go into EV mode but I've found that happens when the engine is at normal temp and the Battery at anything over 1/4.

So to answer your question. No. You just haven't got used to it yet. Just go out and drive it and enjoy it. They truly are a superb machine.

[sorcerer]

Thanks very much Mr V, will do  

[Glover]

John.  I suspect the ICE starts up because it's not warm and the system needs a warm engine so that it can respond quickly to throttle inputs, charge the batteries etc.  I understand your frustration; yesterday (and I don't know how I did it) I filled up and because the car was warm it started up in EV mode and recorded mpg of 99.9.  Usually that drops fairly quickly to high 30s but for some reason when I got home having travelled approx. 10 miles in stop, start city traffic and with a few hills thrown in my mpg showed 59.4, which is the highest I've ever had by a country mile. I've checked the readout from time to time against my brim to brim calculation and the readout is accurate within .1 or 2 of a mpg so I know the 59.4 was there or thereabouts.  This is the first car I've had with such an accurate readout although my trusty 17 year old Yaris although not quite so close is also within 2 to 3% so maybe it's a Toyota thing!. 

Anyway this morning I thought great, I wonder if I can keep it in the high 50s.  Switched on with 7 bars showing drove off our short drive ( a couple of car lengths) and the ICE kicked in.  Our drive slopes downhill and at one end of our road (50 yards) is a long downhill slope followed by a level stretch approx. half a mile.  Display showed that after the initial firing of the ICE it quickly switched off and I coasted most of the half mile down the slope and on the flat maintaining 30mph.  Result 44.5mpg!  Where did I lose 15mpg!!!

This evening I took it out for a short run.  It showed 44.1mpg after the morning journey; the ICE fired up immediately (7 out of 8 bars on the Battery level indicator) but by the time I got to the other end of our road (approx. 300 yards and dead level ) the ICE had switched off and I was in EV mode and quickly regained the mpg I lost when the ICE initially fired up and maintained 44.1 for the 2 mile journey I did. 

The point of the above is I have absolutely no idea why my mpg was so good and I've come to realise that there are so many variables with the hybrid system that  there's no point worrying about other people's mpg unless the mpg is wildly out . Today it was 30C, I'd taken the car out for a 20 mile run this morning then left it outside in the sun so the car and engine bay were warm, which is ideal for the ICE and batteries; on other days and especially in the winter I may drive well over a mile before the EV kicks in and I may be pushed to get 30mpg.  On Thursday I did a 300 mile round trip mainly on the motorway with a lot of 70mph cruising and the occasional blast to get into the outside lane.  My mpg was 32.6 but on the same motorway journey the week before I averaged 37mpg and I don't think I drove too differently.  Why?  Heaven knows! 

This is also my first hybrid and as others have said getting used to a different driving style e.g. quick acceleration up to desired speed then lift off and maintain speed, takes time but in the meantime do what you're already doing and enjoy your wonderful RX:-)

Finally one tip, which somebody mentioned on the forum recently is that if you're parked up listening to the radio etc. switch to EV mode.  I also turn off all other electrics e.g. air con, fan etc  I've found this does have a real impact on mpg.

[mrdoofa]

When the car is cold it’ll always start up on the ICE even if the hybrid Battery is full to get everything up to temperature, once warmed up and with plenty charge in the Battery you should be able to accelerate very, very gently up to about 20mph on electric power alone (assuming level ground). If I accelerate to 30-40mph then ease back on the throttle so you are coasting then gently reapply just enough to maintain momentum and I can run on electric power alone at those speeds but the Battery soon runs down after only a mile or 2. The car also saves fuel by shutting down the ICE when standing still unless the Battery is charging or other demands are placed on the system such as air con or heating, mine switches off around 80% of the time, also the initial acceleration to get the car moving is done by the electric motor so saves fuel by overcoming that initial inertia.

The thing that has to be remembered is that it is still predominantly a petrol vehicle with an electric assist, not the other way around, also Lexus hybrids are more performance hybrids than economy hybrids. Perhaps the biggest tip is to drive smoothly, hybrids really benefit from this, accelerate to the desired speed briskly then just feather the throttle coasting as much as possible to get maximum economy but not maximum fun, I enjoy the power and acceleration too much!!! My experience is based on a GS450h so the characteristics of the RX maybe slightly different but just give it time and allow yourself to adjust to the way a hybrid drives, they are a fantastic piece of engineering.

To give you an idea of fuel consumption I went from an LS430 to the GS450h, day to day the LS430 averaged 20mpg whereas the GS450h averages 33mpg, on a run the LS430 would average 30mpg whereas the GS450h averages 40-45mpg. The LS430 is only a bit bigger and heavier and has a 4.3 V8 which gives 289bhp, the GS450h uses a 3.5 V6 with electric assist to give 342bhp so although it has more power and the acceleration is much quicker and livelier the fuel savings are significant. I love it.

[sorcerer]

Thank you guys, lots of food for thought there, much appreciated.

[sorcerer]

Woohoo, just been out to a job and the onboard display says that I've managed to get a best of 41.7 and an average of 38.3mpg on the journey there and back  😀

I am now officially one happy chappy!

[rich1068]

So what did you do differently?

And sorry but someone is going to have to tell me what ICE stands for.

[sorcerer]

12 minutes ago, rich1068 said:

So what did you do differently?

And sorry but someone is going to have to tell me what ICE stands for.

Internal Combustion Engine (or sometimes In-Car Entertainment).

I literally did just what the others advised. Quickly up to speed and then just ease off the loud pedal slightly to initially coast as much as possible and then maintain speed, then rinse and repeat - I believe some call the method of driving 'pulse and glide'.

[Mr Vlad]

Yippee and well done John.

Oh to me ICE most definitely stands for In Car Entertainment. Those who use it to short cut the car engine are copy cat lazy gits lol. I've been into ICE for 30 years and those initial's have been used for car hifi for decades more.

[mrdoofa]

I’ve always known ICE as in car entertainment or that cold stuff you get in winter!!! I’ve never known it mean the engine before but I carried on the theme on my post anyway. Really glad you’re enjoying your hybrid now.

[ColinBarber]

2 hours ago, sorcerer said:

I believe some call the method of driving 'pulse and glide'.

P&G is an extreme form where you accelerate to a higher speed than desired, come off the accelerator and then lightly touch it so neither the ICE or electric motors are running so you just glide, and allow the speed to slowly reduce until you are going below your desired speed, then repeat. Not really a recommended method, especially in the UK where you are going to upset the drivers behind you.

[rich1068]

Well I'm glad I could ask the question no one else dare! 

I keep trying the method described above but I'm still at the booting it stage 

[mrdoofa]

The instant power on tap is too addictive!!!

[sorcerer]

3 hours ago, mrdoofa said:

The instant power on tap is too addictive!!!

That is indeed very true, but because we haven't had the car long I'm still playing the game of trying to get the most mpg  

[rich1068]

My two previous daily drivers were the IS300 with the 2JZ and a V70 2.5T AWD. I haven't needed to do anything to see an instant 10mpg improvement! The Volvo in particular was very thirsty.

[Ian M]

Likewise, 10mpg better than my IS300 SportCross.  But economy was not at the top of my wish list when I bought the RX.

 

[RobinGBrown]

Another point, and this is from driving my RX400h which is not quite the same: tyre pressures make a big difference

Recommended for the RX400H is 32 but I had to put it up to 35 on the Hankooks that came with it to get any form of decent mpg from it

As others have said, there's definitely an adjustment and learning period. Nowadays I find that when I switch back to my RX300 I have to really put my foot down to get it moving like the 400.

[Hangie]

Basic thing with Lexus hybrid is to not confuse them with plug-in ones. In RX you got small batteries which can provide 49bhp when engine is off.

That why you can't accelerate in EV mode or drive fast - there just not enough power. In EV mode just think like you got 49bhp under the bonnet and 2000kg of mass.

 

As was mentioned trick for economy is to accelerate to 40-50 area and keep it steady. Then you can drive for 1-2 miles on Battery only. Eventually when you are in traffic just be very gentle with it and you can also very slowly roll forward on electricity only. 

 

[sorcerer]

1 hour ago, Hangie said:

Basic thing with Lexus hybrid is to not confuse them with plug-in ones. In RX you got small batteries which can provide 49bhp when engine is off.

That why you can't accelerate in EV mode or drive fast - there just not enough power. In EV mode just think like you got 49bhp under the bonnet and 2000kg of mass.

Thanks for your input Krzysztof, I do appreciate it but in this case it's not the answer. My disappointment was coming from comparing my car with other cars that are exactly the same, so yes, 49bhp and 2000kg, but so are the other cars I'm comparing to and they get better results than me, so I was wondering just why and how it is that I can't achieve the same results as they can.

As it happens, I think I've got it cracked now. Most of my 'in town' driving is now being done in ECO mode and it's now returning 37mpg and above quite regularly and I'm also seeing that it's using EV mode much more. One thing I wish the designers had done was to make it so that the green EV light comes on every time it's actually running in EV mode and not just when you manually press the EV button.

[Hangie]

Oh I must missed that you were comparing to other RX. 

As for EV light, on GS there is an customisation you can make. In my case EV light comes on when car is in electric only mode. Check your manual maybe it is there too on RX.

[Ala Larj]

On my GS I've changed the settings so that I have a rev counter instead of the eco thing gauge. As soon as it goes into ev mode the revs drop to zero.