fsmith

I have gotten good mileage with my SH-AWD since I bought it in November, but not as good as others have been reporting. This past weekend the temperature was finally 70-80 degrees and I drove 350 miles from Boston to Maine and back, and saw a dramatic increase in mileage. I averaged 36mpg on a couple of 50 mile segments of two lane road doing 40-50mph (with some opportunity for EV mode) and 33mpg on a couple of 120 mile segments of highway doing 70-80mph. These numbers are at least 10% better than any previous mileage I've seen since November. So is it likely the temperature after the Northeast winter, or the gas companies changing their blend, or both?

neuronbob

Probably both. I have noticed a gradual increase in mileage as well, as evidenced by my Fuelly chart.

After my well-documented experience during the winter, I can now see why manufacturers tend to release their hybrid cars in warm climates first, then start selling in flyover country, often in the spring or summer. Temperature kills mileage in hybrids.

getakey

I know we discussed this before, but what do you think the disadvantage of Hybrids in winter versus ICE?
Seems like the main issue is warming up the ICE and it runs less efficient in cold weather for both Hybrid and ICE. I don't see how Hybrid mileage is going to be any less than ICE in winter except maybe for weight.

I guess what you are saying is that Hybrid mileage suffers more than ICE compared to published EPA mileage rather than suffers more than the comparable ICE

Malibu Flyer

I am no engineer so others may have a more technically informed explanation but I have heard that the poorer mileage is a combination of several things. First and foremost is that the lithium batteries are not as efficient in cold temperatures --they don't hold a charge as well. This means more charging by the ICE. Second the car runs solely on the gas engine until the engine warms up. In temps well below freezing that means an extended period of time until the EV kicks in. Lastly, in the winter there is likely to be more power draining accessories running [seat heater, heater on high, defroster etc.]. These likely drain the 12v battery quicker than in more benign climates. So, once again, the gas engine needs to kick on more often. All subtle differences, but add them up and they probably make a noticeable difference in gas mileage. I have seen similar complaints about the Tesla.

For me, all this mileage stuff is noise in the background. While my mileage [averaging 28+ for 6,800 miles] is better than the PAWS, my main focus is on the driving characteristics of the torque-vectoring and instant acceleration. That's is why I love the Sport Hybrid!

getakey

^ I totally get the issues. All I'm saying is that take the Electric engines out of the picture and there is no reason mpg should be less than ICE other than weight. Now add Electricity back in and there will be some advantage getting the car moving from electric motors even if not as efficient in cold. Getting the car moving is where hybrid has advantage.

All the heater, etc runs off 12V battery same as in ICE. ICE has same issue. Now if you told me that there is a heater to make lithium batteries operate in a certain temp range, then that could contribute to lower mpg.

I have a full EV and am well aware of climate control effects on EV range. What is also interesting is to watch power consumption in accelerating from 0 to 30 compared with power consumption at steady at <70 mph speed. Much harder to accelerate even to a modest speed than power car at 65mph.

hondamore

You can add to Malibu Flyer's list the fact that gasoline blends in the winter are designed to prevent freezing and light/burn easier in freezing temperatures which decreases the efficiency of the ICE as well. I noticed a 20% drop in fuel economy in my RL during the winter months.

getakey

you guys need to move to Calif. Never heard of these winter issues

Malibu Flyer

Please don't tell folks to move here......the traffic is already overwhelming!!

The worse day of the year here is the day of the Rose Bowl when our great weather is showcased to tens of millions of football fans. I'd prefer to keep the nice weather a secret!!!

To all you folks in Boston, Cleveland etc. it actually can snow here......at least one dusting on the beach every 50 years. It can last at least a few hours before is disappears.

MNH

I really hope this isn't true in the RLX SH. Since there is no traditional drive shaft connected to the rear axle in this vehicle and only two electric motors are used to power the rear wheels, this would mean that in inclement winter weather AWD would be unavailable for a potentially extended period in advance of the ICE achieving temp stability.

If accurate then I'd suspect a front and center disclaimer as to this shortcoming (or 'feature' some might opine) in the owner's manual.

Can anyone confirm the above assertion that the SH rear wheels cannot be driven until a particular ICE operating temp is achieved? As a would-be cold weather owner, this would/should clearly be a prominent consideration if it were true.

Having said that, I suspect the SH mileage efficiency drop in cold weather isn't very different, proportionally, to similarly powered ICE only vehicles (as long as germane differences are accounted for). The PAWS is obviously a good reference here, except that the extra weight and perhaps other drive system influenced characteristics further taxes the SH ICE beyond where the PAWS ICE is pushed under the same environmental conditions when the electric motors aren't being used efficiently, or at all.

I guess it's also possible that rear wheel electric motor thrust is somehow being influenced by cold weather. Is it possible that the electric motor control logic (whether discrete or integrated into a wide band ECU in this vehicle I don't know) is being influenced in some manner by cold weather conditions so as to provide reduced electric motor assist in terms of forward thrust? Perhaps influenced parameters affect only the front electric motor or all three of the electric motors... I would assume, based on all the rave reviews of the SH's surefooted handling in snow that rear wheel torque vectoring is very much available at that axle when required.

Regen is likely affected by inclement weather, too (rolling resistance is certainly increased in snow, so harder breaking must be necessary for the same regen charge). There are probably a variety of factors that adversely impact fuel efficiency in the cold...


Good stuff. As long as rear axle torque vectoring is available very shortly after startup in *all* weather conditions!!

I personally wouldn't be wholly interested in the RLX if it lacked either the performance characteristics or its excellent fuel efficiency. It would probably still be on my list of vehicles for consideration, but not right at (or very near) the top.

getakey

^good point on the AWD not available in low temp if cannot be used until ICE warm. That would be a bad tradeoff.

Also does anyone know if only source of cabin heat is ICE (radiator heat)?
Many hybrids have heat pump and/or resistance heating.

hondamore

I believe the electric motors can/do work immediately in cold weather, but the car won't enter full electric-only mode because of cabin heater requirements as well as the ICE being needed to help charge the lithium battery.

getakey

Not Full electric makes sense, but should have AWD active.

What charge level does ICE come on if warmed up and driving electric only. I'm assuming this would only occur in slow stop and go driving.

On a side note, I have a "Hybrid Garage" (RLX PAWS and i3). Bet my i3 can beat you 0 to 30

MNH

Yup, this makes sense...

fsmith

NOT true. The electric motors and the torque vectoring work immediately, even while the gasoline engine is running to heat up the cabin. They work because the system never lets the lithium ion battery get below a normal charge. I think Malibu Flyer meant that the gasoline engine runs constantly while cold and so there is no EV-only mode, not that the electric motors don't also run as requested for torque vectoring or acceleration.

neuronbob

This is correct. I can personally attest to this. All the electric motors work immediately, no matter what the temperature is, powered by the ICE. It is pure EV mode is not available until the engine reaches operating temperature. This car is ALWAYS AWD except when in pure EV mode (in which case it is RWD), or in cruise mode (i.e. not accelerating) on the highway, when it is FWD.

Edit: Oh jeez. I see all the hybrid owners have hopped into the discussion.

Colin

Yeah, I think the biggest problem in cold weather is the need for heat and a loss of efficiency in the Li-On batteries.

fsmith

Also, the power from the electric motors does not seem to be diminished in any way in cold weather. Though I did not try to actually measure anything, the acceleration provided by the rear wheels seemed every bit as strong when starting up at below zero temperatures this past winter as it is now in warmer weather. And the performance and handling seem identtical. If cold weather is affecting any aspect of performance (other than gas mileage), I couldn't see it. This is just anecdotal and technical folks may know more.

Also, I agree about the value of the SH-AWD being the performance and handling and power, not the mpg. I started this thread because I was curious about how my mileage might be better in warmer weather and so took some readings.

Colin

I'm thinking the amount of power delivery wouldn't change, just the duration of the boost if the batteries have less juice.

Malibu Flyer

I believe hondamore is correct. While I haven't driven in snow yet so I can't confirm the AWD, I am pretty sure that the torque vectoring works even when the engine is cold. It just won't use solely the rear electric motors. I will check tomorrow.

Ken1997TL

Moving parts simply do not turn as efficiently in colder weather. In addition, you have more resistance on the road surfaces, tire traction and if you don't monitor your tire pressure it can possibly be too low as well.

A few percentage points here and there add up

George Knighton

Well...I think you guys have just about covered it.

LOL....

We're just going to get better fuel economy in the warmer weather and climates, for a combination of all of the reasons noted above, the two big ones being the "winter fuel" problem in northern States, and the need for the J Motor to run long enough to warm up and heat the interior.

I believe that the reason that I always got better fuel economy this past winter than most people got is because more of my driving can be done in EV mode on my usual commutes.

Because of traffic and stops that I make, I will tend to take US routes instead of Interstate most of the time, which means I'm commuting at 45-60 mph, not 70-80.

Even at 55 mph, if you look down on level road, you might be surprised that your car is in EV mode.

neuronbob

This is the most important thing to remember about eSH-AWD. It is for performance and handling, not fuel economy. The improvement in the city fuel economy is a pleasant happenstance.

Once more people join the Sport Hybrid family, though, we will have to point people here or to the original fuel economy thread to alert them that mileage will be lower in the cold, and the reasons why. I also think a clear statement of what cold weather does to mileage to this car should be added to the owner's manual. This will mitigate disappointment.

I'm now ready for next winter with a engine block heater and foam pipe insulation to block some cold air from the engine compartment. (I spent way too much time reading hybrid forums this past winter, can you tell?)

RLX-Sport Hybrid

I hit 34.4 mpg today. This is the first time I broke into the 34's for 90%+ highway miles. Overall each tank is consistently staying in the 30-33mpg range (including the occasional poke of the go peddle for enjoyment purposes only of course).

hondamore

I'm still stuck in the 31 mpg range for mostly city driving (7.6 litres per 100 Km for Canadian owners). Considering the moments of "silly aggressive driving" that I enjoy from time to time, I am absolutely thrilled with the mileage thus far.

George Knighton

Right. Let's keep our perspectives.

You said "stuck at 31-something."

Stuck at 31-something?

It's great.

:-)

hondamore

My bad, I should have elaborated.

The point I was making is that I have been steadily getting better and better gas mileage as the weather warms up, so I've improved from the 29 mpg I was getting to 31 or 32 now. We've had a cool spring up here (daytime high temps in mid 50's F) and really haven't warmed up to summer temperatures yet, so I feel my mileage will improve further once summer arrives and so, for now, I'm stuck at 31 mpg. No complaints about the mileage, I was more complaining about the temperatures around here and looking forward to crazy great mileage once it warms up.

George Knighton

Mine is slowly improving, but my problem is that most of my 14,000 miles on the Sport Hybrid were over the winter.

I've seen a marginal lifetime improvement to something like 30.5.

But it's going to take all summer and fall to make an impact on the winter mileage that I've racked up.

hondamore

I drove my wife and parents to a family reunion yesterday putting around 50 all city miles on during the process. With the seniors in the back (gushing with praise over the roominess of the back seat), I drove in a more sedate manner than normal and achieved nearly 37 mpg (6.4 litres per 100 km which converts to 36.76 miles per US gallon). The warm temperatures (mid to high 70's here) have made it easy to exceed the Transport Canada fuel economy ratings (8.0 l/100km or roughly 29 mpg city) and more than make up for the 28 - 30mpg I was getting during colder weather.

neuronbob

Sorry for being AWOL. Work has been kicking my ass lately.

Eh. I'm now getting 26 per tank despite achieving 30-34 mpg on freeway commutes into town. It's gradually increasing. It'd be useful for folks to post full tank mileage instead of individual trip mileage, or better yet, post your data on Fuelly if you track it like I do.