Gas Mileage Went Down 11 MPG

My milage and how much charge i get always drop when it turns cooler in central California on my 2013 prius plug-in. Cooler here as not very cold. Same for this year. Most my trips are about 5 miles out and i plug-in most of the time. I went 2000 miles at 255 mpg in oct./nov. But dropped to 750 miles on the next 2 fill ups. My long trip not plugging in winter mpg is 47-51 and summer 51-56 with the best late spring and late summer with no a/c or heater needed . Temperature will drop my charge range from summer of 11.1-12 miles and winter as low as 9.1 miles. I wonder what really cold does to the charge range.

Posted via the PriusChat mobile app.

 

Made the run from Phoenix to LA yesterday afternoon. Strong (40 to 50 mph) headwinds and blowing sands. Overall mileage on full tank 37 mpg. A few weeks ago I made the reverse trip LA to Quartzite with a similar tail wind. 68 mpg @ 77 mph (right on the cali legal limit )

 

You really think it strange that winds affect a vehicle that gets a lot of its efficiency from its aerodynamics?

 

Temperatures don't just directly affect the battery, or hybrid system, or engine. The car has an ambient temperature sensor, and as temperatures drop it intentionally changes engine and hybrid system behaviours. Delaying/reducing engine shut-off, for example. It's sort of an edict from on high.

You can reduce the effects, by for example: lowering cabin temperature setting. Setting the vent system to Auto and then lowering cabin temp setting is a one-two punch I find will push the car to cross the engine shut-down threshold, especially when halfway through warm-up.

And on top of that is the direct effects: greater heater demands, coolant taking longer to warm.

 

All cars get worse gas mileage in the winter, except plugins - They tend to get less range which amounts to the same thing.

You can't have the magic without a complicated system powering it

 

I have a new theory on poor winter mileage. I have noticed with the scangauge that ICE coolant temp will drop very fast when the engine turns off, especially if I'm venting the heat into the cabin with the heater. I have a lot of stop lights and stuff where I will lose temp and it spends a lot of the drive at around 160F instead of 195. I figure it's probably not as efficient at that temperature. And the battery can be 20-30 degrees cooler as well on some trips - I would imagine the same is true of it.

It's probably more pronounced on a hybrid because the engine being off causes the coolant temperature to drop in ways a regular car wouldn't experience.

 

I know the Gen 2 Prius actually had a thermos bottle to keep the coolant warm. I have not noticed that on my Gen 4, though.

 

It is simple, buddy. All you have to do is select climate automatic and leave it there. Then all you ever need is to alter the temperature to suit and turn it off/on as required, just like your old car.

 

wah-wah. i go from about 16 in summer to 12 in winter. that's all back roads 30-40 mph.

 

I don't understand. Well at least the temp setting: that's always your prerogative; you pick a temperature. Or am I misunderstanding?

Fan speed: yeah once you set a speed it's locked. To unlock just hit auto again.

 

Auto Eco for climate control will help you get your good mileage even in PWR mode. It sets fan speed, which vents, and recirculated or fresh air to meet the temperature setting. Front defrost also turns off Auto.

Set your temperature to 32 as the "keep awake" temperature

 

My mistake, set the temperature as required, Then press Auto!
If you try to change the fan speed in auto you will take it out of auto, but shouldn't if you alter the set temperature while on auto to the best of my knowledge.

 

I think, if you set the fan speed while in Auto, it's takes the fan speed off Auto, ie: the fan speed is locked, at whatever you set. But mode will continue to be automatically chosen, say vent, vs high/low, vs heat, vs heat/defog. If you set a mode, then that too is locked, at whatever you set. And that's more-or-less all Auto does, if I'm not mistaken.

 

I think Coast needs to RTFM Page 515.