IS300h mpg

[Ken83]

Hi guys,

My wife and I have clocked about 2k miles in our 2014 IS300h F Sport and we seem to only be averaging 37-39mpg.

I exepected quite a bit more from the car so wondering if I’m doing anything wrong? 

I read somewhere that accelerating reasonable quickly but not flooring it and then releasing the acellerator, then pressing back down gently so the car goes onto electric is an efficient way driving. I do this whenever I can but figures still stay in the high 30s only. 

Since we got the car I fill it back up every week and work out the average cost per mile. On Sainsbury’s petrol at around £1.24 per litre I consistently get around 15-16p a mile which I don’t think is not bad but could be much better if I made it into the 40s. 

Car is mainly used for school runs with some stop start traffic with the wife. At weekend I put it on the A13 to go in and out of London but again once you get there it’s stop start again. 

Wondeing if anything wrong or this is normal. Before I bought the car I looked at the ‘realmpg’ site where individuals post their mpgs and it calculates an average. On there it was 48+ which was part of the reason I bought it. 

Any advice would be helpful before I approach dealer. 

Thanks

K

[Jayw13702]

If this is your first hybrid then it can take time to get to the 40s+ figure.

I’ve been driving them for about 7 years now, it took me about 6 months the become a little smoother and get the figures I was happy with.

I build my speed rather than accelerate and then cruise. As soon as I’m heading downhill at a speed I am happy with I am off the throttle and coasting/recharging.
I find I am thinking about how I drive a little more, looking at the lights/traffic ahead and trying to keep it as smooth as possible, that sometimes means I’m not a quick as I used to be. On a long run I’m sat at 75mph with the cruise control on where suitable. However I’m getting early 50’s mpg around town and close to 60mpg on a run.

Stick with it, you will see your figures climb [emoji6]


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[matt8]

An F-Sport's wheels are not as efficient.

I get about what you're getting in my F-Sport too.

[LordByronUK]

The wheels alone should only make a minor difference, I average 50-55mpg year round on 17inch wheels in my luxury spec IS. Try the following:

- Use eco mode around town to stay on the Battery as much as possible. You should aim to fully deplete the Battery when in town. If you've always got a full Battery, then that's a good indicator you're doing something wrong!

- Use pulse and glide for 40mph and below roads. Get to speed, lift off then gently back on the pedal with just enough juice from the Battery to hold speed.

- Aim to do all your stopping using just regen braking (i.e. try to always slow and/or come to a stop with the needle within charge, but never bottomed out). When the needle has hit the bottom of charge, you'll be using the real brakes as well to stop.

- Try rolling as much as possible, and braking as gently as possible. 

- Use cruise control as much as possible

- Get up to speed fairly briskly, and try to maintain speed, avoid slowing down and speeding up as much as possible. This is why Prius drives always keep their distance.

Do all these things, and once they become habit, you should start to average in the mid to high 40s. Hope that helps 🙂

[Jayw13702]

- Use eco mode around town to stay on the battery as much as possible. You should aim to fully deplete the battery when in town. If you've always got a full battery, then that's a good indicator you're doing something wrong!

I hardly ever run my IS to full depleted, I seldom run it below 50% and most of the time it is about 70-80%, and I am averaging 50mpg around town.
Depleting the Battery means the engine then has to kick in to recharge it, thus costing you mpg.
I do agree about eco mode, mine lives on that when in town/A roads, on a run I switch to normal, especially on motorways



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[LordByronUK]

On 10/23/2019 at 3:43 PM, Jayw13702 said:

 

I hardly ever run my IS to full depleted, I seldom run it below 50% and most of the time it is about 70-80%, and I am averaging 50mpg around town.
Depleting the battery means the engine then has to kick in to recharge it, thus costing you mpg.
I do agree about eco mode, mine lives on that when in town/A roads, on a run I switch to normal, especially on motorways



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The engine is always acting as a generator for the Battery, so as long as you're moving you can deplete the Battery and it won't affect overall mpg. What you're referring to will only negatively affect average/overall mpg if you're stationary and the engine needs to recharge the Battery. 

If you're never depleting the Battery, then you're just wasting free fuel from built up charge. Also, I believe it's good for the health of the Battery to run through complete discharge/recharge cycles.

[Thackeray]

On 10/21/2019 at 10:03 PM, Ken83 said:

Car is mainly used for school runs with some stop start traffic

I would suspect that school runs will keep the fuel consumption high, assuming the distance is fairly short. It will get worse as the weather gets colder!

But don't worry about it. My long-term average is about 44 mpg but for a couple of months last winter my mpg figure went down to around 30 mpg (can't remember the actual figure and can't find the forum post I wrote about it.) I was doing four-mile journeys from cold; the outside temperature was close to zero; the heater was on, the air conditioning was on, the lights were on; the windscreen wipers were often on; the heated seats were on. All of this took extra fuel with a cold engine.

The minute by minute fuel consumption graph in the car showed that for the first five minutes after starting from cold, the car was only getting about 20 mpg. After ending the trip before the engine had had time to fully warm up, I was just going through the same process again a couple hours later.

Even in traffic the engine will keep running if it still needs to warm up to provide heat for the cabin. (You could turn off the heater but I wouldn't bother - it all averages out over the year.)

By contrast, cruising on motorways in temperatures around 20, with just me in the car and minimal luggage, the dash mpg display is usually in the upper 50s or sometimes low 60s. On a 20 mile trip I've even seen it above 70 mpg. I was so surprised by this I checked on a map to see what the altitudes were at the start and end points. Sure enough, imperceptibly, the trip ended at a lower altitude than at the starting point; not exactly down-hill all the way but presumably enough of a decline overall to take the mpg over 70.

But these highs and lows mean little. If you're keeping the car, it's really the annual figure that counts and it looks from websites like spritmonitor.de and fuelly that most people get mid-40s in the long term.

[Jayw13702]

The engine is always acting as a generator for the battery, so as long as you're moving you can deplete the battery and it won't affect overall mpg. What you're referring to will only negatively affect average/overall mpg if you're stationary and the engine needs to recharge the battery. 
If you're never depleting the battery, then you're just wasting free fuel from built up charge. Also, I believe it's good for the health of the battery to run through complete discharge/recharge cycles.

If the Battery is depleted then the engine has the work harder to :
A) recharge the Battery
B) power the car.

Without looking at the Battery monitor I can tell if the Battery it low whilst driving as the engine is working harder in order to push that car forward, the also feels like more slippage from the transmission as well.

I’ve had 5 hybrids now, done close to 600,000 miles in them and never encountered a Battery fail. I’m no expert on Battery technology but I know what works for me.


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[MattK9797]

Best I've got so far is 49mpg over an entire week of commuting. But on 1 trip to work I did hit 60mpg.

[ganzoom]

On 10/24/2019 at 9:54 PM, LordByronUK said:

Also, I believe it's good for the health of the battery to run through complete discharge/recharge cycles.

Not for the type of cells used in these cars (or any current hybrid or EVs).

Just drive the car like you would any other when it comes to gentle acceleration/deceleration and your see 45mpg+ all day long, on M-ways runs at legal speed+10% your see 50mpg, go 10% below the speed limit and your see 60mpg.

Overall half sensible driving should see 45mpg longterm on the IS300H, the most important factor in mpg is not the car but the driver, go haring up every traffic light in order to practice an emergency stop and your be lucky to see 30mpg, when I took a loaner IS300H sport out for a blast my favourite local B roads I saw less than 20mpg. 

 

At the same time I've seen nearly 50mpg from my old Nissan 350Z which had a NA V6 petrol on a long run.....

....but on a the same local B roads, not much better than 10mpg if you're really going for it :). 

 

If your not getting over 40mpg in a IS300H on a day to day basis, you need to see where how you can adapt your driving technique. 

[MONTIMAR]

My car has averaged over 55 MPG during 12000 miles of ownership. BUT. 90% of my driving is on A/B roads and very few short trips from cold. Under certain conditions the car is capable of amazing fuel cons. I often see over 70 MPG in the summer months with slow moving holiday traffic. My driving profile is ideal for a Hybrid as I  only do about 10 miles before hitting a 30 limit where I use Battery power before hitting the open road to re-charge the Battery before the next village. How you drive and your driving profile is the key to good MPG.

[Hadrian]

We don't use ours for short trips, so it's mainly used on dual carriage and motorways.  I seem to get a steady 52-53 mpg.

I use it in eco mode most of the time, unless I need to overtake quickly.   I did once have it up to about 60mpg after a reset

and driving from Essex down to the New Forest.

I don't consider that too bad, considering I only get just over 34mpg from my 1600cc Ford Bmax auto.

[Jayw13702]

Over the last week or so my MPG has dropped like a stone, I’ve been struggling to get 39mpg and that’s when I’ve been driving carefully, also the hybrid Battery has been cycling from fully charged to discharged quite quickly, for my car this is quite unusual.

I know the weather and outside temp can make a difference with MPG but it’s not been that cold, certainly not to have this much of an effect of consumption.

From experience I had narrowed it down to two things
1) the 12v Battery being dodgy
2) the hybrid fan filter.

Having tested the 12v that was fine so I set about getting the bloody fan gauze filter out.......




Yep, it was fluffed right up!! That’s only 25,000 miles worth of use as well.

I cleaned it out with a hoover, put it all back together and took the car out for a run. No exaggeration it’s like driving a totally different car, fuel consumption within 10 miles has gone from an average of 39mpg to 45mpg and the hybrid Battery feels a lot stronger, it doesn’t deplete as quickly.



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[matt8]

2 hours ago, Jayw13702 said:

Over the last week or so my MPG has dropped like a stone, I’ve been struggling to get 39mpg and that’s when I’ve been driving carefully, also the hybrid battery has been cycling from fully charged to discharged quite quickly, for my car this is quite unusual.

I know the weather and outside temp can make a difference with MPG but it’s not been that cold, certainly not to have this much of an effect of consumption.

From experience I had narrowed it down to two things
1) the 12v battery being dodgy
2) the hybrid fan filter.

Having tested the 12v that was fine so I set about getting the bloody fan gauze filter out.......




Yep, it was fluffed right up!! That’s only 25,000 miles worth of use as well.

I cleaned it out with a hoover, put it all back together and took the car out for a run. No exaggeration it’s like driving a totally different car, fuel consumption within 10 miles has gone from an average of 39mpg to 45mpg and the hybrid battery feels a lot stronger, it doesn’t deplete as quickly.



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Same thing you did a mini tutorial on before right, Jay? Or is this something different you've now cleaned?

[Jayw13702]

Same thing you did a mini tutorial on before right, Jay? Or is this something different you've now cleaned?

Same as before, this was done as an emergency as I didn’t have a lot of time, I’ve got a GoPro now so I’m going to run through it and put it on you tube


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[reeac]

I don't understand how you can deliberately run down the traction Battery. My understanding is that it's charging is controlled automatically in order to ensure that there's always sufficient charge to keep the 12 v auxiliary Battery charged,  to be able to start the ICE and to cycle the batteries  state of charge so as to promote its longevity. Have I missed something?

[Jayw13702]

I don't understand how you can deliberately run down the traction battery. My understanding is that it's charging is controlled automatically in order to ensure that there's always sufficient charge to keep the 12 v auxiliary battery charged,  to be able to start the ICE and to cycle the batteries  state of charge so as to promote its longevity. Have I missed something?

You can’t deliberately run down a traction Battery to zero, on the display it will show 10 or 20% but in reality the Battery will be holding more than that. Conversely when the display reads 100% it isn’t fully charged

When the display reads 20% the engine will kick in and start recharging so as keep the 12v system running, that’s why if the 12v Battery is dying the traction Battery will cycle from full to empty frequently and a lot quicker than normal. The reason being the traction Battery will be topping up a Battery with faulty cells.




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