Okay, I bought my new/old '04 back in Jan, during one of the most remarkable winters we've had here in WV. I was quite pleased with the mileage driving about in temps down in the negatives and single digits and lots of snow. I even used the prius to tow my little saw mill through the mountains of PA in early Feb, and still got in the high 30s carrying a light trailer and driving in snow. Very pleased, and man, was I ever looking forward to the warm weather when I knew that my high-40s to 50-ish was going to magically jump into easy-to-maintain-50s and maybe even a 60-ish tank from time to time. But alas! No joy! I have a very difficult time even managing to hit a 50 average, it's almost like it was easier to hit a 50 average in the inclement weather. So, here we go: - Have you read This Thead Yet? --YUP - What fuel economy are you getting and how are you determining fuel economy? (trip computer or manual calculations) Using the trip computer, getting in the low 40s to MAYBE 50. - What fuel economy are you expecting and why? in the 50s. Because I was getting this mileage during the cold heart of winter, without working very hard for it. When I drive the mrs's '08, I can keep it in the 50s without much effort, and in the 60s with some more careful attention. During the winter, I was routinely getting better mileage than she was, and now she's waxing the floor with me. - What are the approximate outside air temps? 40s to 80s. - How long are your trips? Daily ~50 or so. Weekends involve multiple 140+ mile trips. Through the mountains. - How much of it is city vs. highway? Roughly what's the average speed in overall and and of each segment? Is there a lot of stop and go driving? I do very little city driving. Probably 85% is highway, in the city (what little driving I do, mileage is in the mid-30s). - What region/state are you in? (if you haven't set your location in your profile) WV, Va, Pa. - What's the terrain like of your drives? (e.g. flat, gentle hills, steep hills, etc.) Yes. (flat, gentle hills, steep hills) - Is your oil overfilled? (i.e. above the full mark on the dipstick) Nope. How old is your 12v battery? What is the voltage reading of your 12v battery after sitting over night? (Method Here) Errr, 11.2 EDIT Actually, just checked it at 9.4v. Battery is probably original. Have you had your alignment checked? Any pulling or abnormal tire wear? Alignment adjusted after wheel bearing replacement last month, was bad, now good. No abnormal tire wear. - Are you using the factory tires and wheels? If not, please indicate tire make, model and size (e.g. Goodyear Assurance Fuel Max 185/65R15). stock size, very worn goodyears on the back, local tire shop snows in the front. - What are your tire pressures? 35-front 33-rear (checked often) - Make, model, year, engine and transmission of previous car? (e.g. 08 Honda Civic Si 2.0L 4 cylinder, manual transmission) What did you actually get on the same trips/commute? (Please give us actual numbers, not EPA ratings.) '98 subaru outback, actual 25 consistent, occasionally 27/28 (against a gps, not odo, as the odo lies). - How are you trying to drive (e.g. trying to stay in electric only?) and how hard are you braking? Trying my best to stay as electric as I can, ice oftens comes on with any pedal pressure at all, stays on, find myself running on the ice going /downhill/ with >50% of battery available. I brake gently. Very. - Are you "warming up" the ICE (internal combustion engine) by letting it idle after powering on? Errr, no, not really. - Are you driving using D or B mode? I've used B about 3 times in my life, descending long grades with the trailer on, never used it with single passenger load. Though the car does act like B is engaged on long descents. - HVAC settings? Are you using the heater, AC, auto mode, etc.? If using auto, what temp is it set to? Never used auto. I've used the A/C a few times lately when the temps went into the 80s. Normally, I run 'lo' at 70, fresh air. - If reporting a mileage drop, did anything significant change on your car (e.g. accident, hit a curb or big pothole throwing off alignment, oil change/other maintenance/repairs, changed tires or wheels, etc.) or your commute? No accidents/pothole slams, etc.
Being completely uneducated on the subject I'll offer my two cents worth - I recon its the snow tyres/tires on the front. Have you tried normal or summer tyres on the front? I ask because I suffered severe mpg reduction when I replaced my front tyres a few weeks ago. To cut a long and boring story short, the new (but wrong) tyres were replaced with the correct energy saving tyres by my dealer and now my mpg's are back where they should be again. They and I couldn't believe that tyres could make such a difference to the mpg's but they obviously do.
Your 12v battery looks a tad low, is it the original? If so, yours would be six years old, which is on the high side. Its voltage is supposed to be greater than 12v. Most people run 42/40 on the original stock tires. This higher pressure gives you better mileage and in my own experience doesn't have noticeable impact on ride comfort.
Yeah, It's actually much worse than that. I went out and checked again (after driving in to work this AM) the voltage I posted was from the first time I checked it a while back, Granted, the interior lights were on, but it came up as 9.4v, (14.2v running). ICK! New battery time. have to wait a week to order the yellow-top kit. Need new tires also. Thanks for the hint.
How about me? All other info being similar, I run 43-45 psi in frt and rear, rarely drive on highway, and avg almost exactly 40 mpg. I live in north east Cincinnati, and have seen it "touch" 42 mpg. I use synthetic oil (I work at a Toyota dealer and get it for free) and have made sure the oil level is "proper". All the techs in the shop attribute it to my "lead foot" but I feel like I'm driving it very easy. I have a corvette, so if I want to drive fast, I'll drive the Vette. However, while commuting to and fro I want better gas mileage. HELP! I want to see 50!
I actually use B all the time. I also notice that if the battery charge indicator is almost full and green, my mileage goes down, which makes sense, but why would the desired appearance of the battery charge indicator be green, if the ice is working harder to recharge the battery? Or am I just nuts.
Stop using B - unless you are going down a mountain road somewhat like that out of Yosemite. From what I've read I thought that B throws away energy rather than sending it back into the battery - which means that the engine has to run other times to charge the battery. I believe it is more efficient to use the ICE than the Generator for propulsion due to losses involved in charging the battery. Cheers
B is for Bad mileage. Don't use B unless you actually need it (for safety when descending long mountain grades). Also to the OP: How fast are you driving on the highway? After you replace the 12v battery (< 10V means your 12v battery is done), you can get the best highway mpg by staying under 65 mph. I get up to 54 mpg by staying under 65.
why do you drive in B? who drives in B? does the manual say to drive in B? did someone where you work tell you to drive in B?
Another question you must add is what type of gasoline do you put in? For me Ethanol blend decreased MPG as much as by 5. I got better MPG after flushing the Ethanol blend completely. Grille blocking can improve MPG even in the Spring. Just be careful not to cover up completely or closely monitor using an OBDII reader.
No, I didn't mean I back out of the garage, and place in "B" but almost every steeper downhill, I place in "B" to recharge the battery, instead of braking.
B mode will still throw away some energy through engine braking I think. Unless you don't have capacity left in the big battery I think using the brakes would be most efficient on downhills. If you've got green bars, go B. To the OP, I think you need to change your 12v battery and stop trying to run on the electrics only.
You get less energy in the battery by using B than you do by normal regenerative braking. http://techno-fandom.org/~hobbit/cars/b-mode.html
timkf1, the *only* time to use B is while coming down a long grade, when you would otherwise need to ride the brakes for more than several seconds. cpm, it would be noticeably easier to get better MPGs with higher tire pressures, in front up to the max pressure shown on the sidewall of the tire and two PSI less on the rear. This will also make the ride harder and change the handling; the tradeoff is your call.
It just occurred to me (for some reason) that I guess the Prius allows people to really run their batteries really low and have all sorts of weirdness besides the supposed mileage hit (I don't know since I haven't experienced it first hand) since the 12 V doesn't start the ICE at all. On a regular car, you'd notice the starter it turning over very slowly or not at all due to a weak battery. I guess the Prius has a much wider allowable range of the 12 V battery for "starting" and operation, although not necessarily properly. Hopefully the 3rd gen or future gens will have some warning indication before it gets into the car going wonky phase.
Hobbit performed an experiment where he removed the 12v battery from the car. Result - the 14v from the DC to DC converter will still power the 12v buss. http://techno-fandom.org/~hobbit/cars/prius-12V/
Okay, I haven't yet replied, as I haven't been able to order the optima kit yet, next week hopefully, then I'll know more. I'll post again after I replace the battery and run a tank through.
Okay, just a FWIW, I replaced the battery with the optima kit. Nice kit by the way. Just need to sort out how to recycle the OEM battery now. Ran a tank through it. No great improvement. Seems a *little* better. Not like her '08 though. I suppose that's fair, my '04 has 100K more miles on it. Still 'seems' like the ICE runs more often than it needs. other annoyances have cleared up though.
