Got a prius, should be interesting to mess with....

[ps2fixer]

Yea, slight improvements in design in each item really adds up in the long run. I'm sure the areo is probably slightly better, the engines on their own probably are slightly better, besides the electronics being better and I'm pretty sure the newer electric motors are higher efficiency too. 1-3% here and there really adds up. I think the biggest gain is the battery tech though. Size doesn't matter an insane amount, it just needs to be big enough for worst case situations and whatever charge/discharge allowance they target for longevity of the battery. Pretty sure Lithium Ion is similar to the NiMh where keeping the charge below 100% and above 0% most likely around 60% is the most ideal for longevity.

I'm sure the window tint helps a ton. If it reflects so much, I wonder if it works on painted surfaces too, say the roof. Don't know a whole lot about window tints though. Logic tells me the most reflective paint would likely give the best results, but that's more visual light, and most of the heat is in the IR range.

[Phase]

Originally Posted by ps2fixer

Yea, slight improvements in design in each item really adds up in the long run. I'm sure the areo is probably slightly better, the engines on their own probably are slightly better, besides the electronics being better and I'm pretty sure the newer electric motors are higher efficiency too. 1-3% here and there really adds up. I think the biggest gain is the battery tech though. Size doesn't matter an insane amount, it just needs to be big enough for worst case situations and whatever charge/discharge allowance they target for longevity of the battery. Pretty sure Lithium Ion is similar to the NiMh where keeping the charge below 100% and above 0% most likely around 60% is the most ideal for longevity.

I'm sure the window tint helps a ton. If it reflects so much, I wonder if it works on painted surfaces too, say the roof. Don't know a whole lot about window tints though. Logic tells me the most reflective paint would likely give the best results, but that's more visual light, and most of the heat is in the IR range.

ioniq has 40 percent thermal efficiency on the engine. whatever that means

and the tint doesnt reflect much. they arent as glossy as old school tints. modern ones have a more matte finish and they absorb the heat, rather than reflect

ive thought about white plastidip all over the car, but that would still be a few hundred dollars and that stiff loves to peel and flake...

[ps2fixer]

Thermal efficiency for an engine basically boils down to potential energy in (gas energy content) vs mechanical work output. 40% of the gas is converted to work. The prius engine in my car is 37%, a typical gas engine is more like 25%. Diesels are 40%+

The excess energy is the heat going into the engine, exhaust, the actual pumping effect of moving the air, etc.

I was going to mention that you can get white paint, but your profile pic looks like it's a nice car, so probably not really an option lol. My dad's done similar with an old buick he used to drive. He did it because the clear coat was already gone and the paint was starting to rust a little. It worked well enough for him, but it was a $200 beater car he fixed and drove to save it from the scrap yard.

[Drifter]

Originally Posted by ps2fixer

Yea, slight improvements in design in each item really adds up in the long run. I'm sure the areo is probably slightly better, the engines on their own probably are slightly better, besides the electronics being better and I'm pretty sure the newer electric motors are higher efficiency too. 1-3% here and there really adds up. I think the biggest gain is the battery tech though. Size doesn't matter an insane amount, it just needs to be big enough for worst case situations and whatever charge/discharge allowance they target for longevity of the battery. Pretty sure Lithium Ion is similar to the NiMh where keeping the charge below 100% and above 0% most likely around 60% is the most ideal for longevity.

There have definitely been incremental improvements across the board, but I think the EPA's revised MPG labeling and the CAFE credits for A/C efficiency have really helped spur large changes in air conditioning system efficiency. And your Prius is largely responsible!

In 2008 the EPA revised their MPG testing in large part because American drivers weren't getting close to the advertised 60mpg city, 51mpg highway from their gen2 Prii.

Let me step back some and explain the EPA's dynometer mpg tests:

The city mpg test was created in 1972 and was based on rush hour traffic in 1972 Los Angeles. It involves a number of stops and starts with glacial acceleration and generally stays under 30mph except for 2 cycles up to a top speed of 56 mph (the rate of acceleration is equivalent to a 18 second 0-60 time). The overall average speed is 21mph:


The highway test was created in 1975 (1 year after the 55mph national speed limit) and was based on rural highway driving, not interstates. It simulates a 10 mile drive which averages 48mph, again with very slow acceleration (the initial 0-35mph takes about 30 seconds):


Few people drive like that, fewer still do so without air conditioning/heating, in exactly 75F windless weather, and fewer still on premium 93-octane ethanol-free gasoline. So in 1983 or 1984 the EPA crunched the numbers and decided to keep using the same tests (they were mandated for CAFE standards) but to lower the city mpg label by 10% and highway mpg label by 22% to more closely reflect what average drivers - those not employed by the environmental protection agency - were achieving in the real world in the days of the 55mph speed limit.

These 1970s tests were the very same ones the Prius took in 2003-2004, achieving 66mpg city ("corrected" to 60mpg with the 1980s correction factor) and 62mpg highway (corrected down to 51 mpg with the 1980s correction factor). Many people were irate when they were getting 40-45mpg in the real world and the gen2 Prius was a very hot-seller so it attracted lots of (negative) attention. But the EPA (repeatedly) tested Prii and verified the window sticker. By law Toyota couldn't advertise anything other than the EPA mpg, even if they had wanted to be more conservative.

So for 2008 the EPA added 3 new tests. A high(er) speed test with a bit quicker acceleration:


A 95F outside temperature city test with the AC on, maximum fan (or 72F if equipped with automatic controls), recirculated air:


And finally the original city test, but this time performed in 20F outside temperatures.

In 2016, the EPA added a few new correction factors to try and lower mpg labels a bit more on hybrids to match what average drivers achieve.


Anyway, long story short is that before the 2008 EPA a/c mpg test automakers really didn't pay too much attention to the efficiency of AC systems. Why should they care if their customers used more gas as long as the system was cheap, reliable, and cooled the cabin quickly? But that test, along with the Obama administration's tougher CAFE standards (which offered credits for A/C improvements), helped focus their attention on a/c efficiency.

[ps2fixer]

Interesting charts. I suspect my prius is showing it's age since I'm having to do somewhat extreme driving to just hit the corrected EPA figures (46mpg combined). Maybe I have a weak module in the battery pack or something causing issues. I don't have a blue tooth adapter for OBD2 since I rarely use my cellphone for stuff like that. I have a OBD2 to usb adapter though if there's a pc/laptop variations of software that can pull the figures for the module health.

There must be something going on, maybe the cat system is getting plugged up, it has been flagging a cat inefficient code so the cat isn't burning off the exhaust gases as well as it's expecting, or the secondary o2 sensor is bad.

I have a 2nd prius that has some title issues I need to get fixed up. Maybe I should swap the hybrid battery from that car just to see if it effects anything. It's a 2009 instead of a 2006 so a little bit less age on the battery, and if I remember right it has less miles too.

I suspect swapping the battery to lithium ion wouldn't work very well with the stock setup since the charging process is a bit different. I know some had lithium ion as an option, not sure if that was newer generations or this one included that too, thinking it's the 2010+ era though. Maybe I can run across a wrecked 2010 prius and swap over some parts to "upgrade" this one.

[Drifter]

I got this cheap bluetooth obd2 connector which works with my (android) Dr. Prius app: https://www.amazon.com/Veepeak-Bluet...dp/B011NSX27A/

For free, the Dr. Prius app itself lets you monitor nearly useless bar-graphs of the individual cell voltages. For a fee you can run more involved tests to diagnose potentially bad cells and/or estimate remaining battery pack life. I haven't purchased one yet, but I think it is like ~$10 to test on 3 cars or ~$20 to test on unlimited cars.

Your gen2 never came from the factory with a lithium ion battery although Toyota did test it in the gen2 and ultimately decided to stick with NiMh ( https://seekingalpha.com/article/161...-for-the-prius ).

The gen3 plug-in Prius uses lithium ion.

Gen 4 generally uses lithium ion, but Toyota still uses the higher weight, older technology NiMh batteries in the awd Prius because it assumes the AWD prius will be used in colder climates (where NiMh outperforms Li+). I've read that certain Canadian Prii also use NiMh for that same reason.


Dr. Prius does offers a Lithium Ion "upgrade" battery pack for ~$2200 with a 2 year warranty: https://projectlithium.com/products/...placement-pack
It is relatively new so we haven't seen any independent long term results.

[Phase]

Curious to what month this year they are going to announce the final gen 5 prius. Excited to see what they want to do with it

[ps2fixer]

Yea I heard about the app, just sucks I can't buy it for a laptop and just use the usb based adapter I already have. I've always been a fan of hard wired communication over wireless. The other factor is, I have no payment info stored on my cellphone, not a fan of having that data roaming around either lol. Might seem overly cautious, but it's still not enough, I had my main bank debit/credit card number stolen somehow and the thief charged around $250 on it. I got most of the transactions reversed since it was caught quickly. I always use guest checkout online or even better paypal so the idea is the credit card details aren't stored anywhere, but either some site that forced me to make an account stored the info, or some site stored it even though I checked out as a guest and clearly the site got hacked and the info sold.

Over seas I heard they get one time use numbers, or they can set a limit per month for the number for monthly bills. Never heard of anything like that in the USA though. Sounds perfect for online spending. I think storing personal info of customers should be illegal without express permission of the person. There's no reason a company needs to keep your address, credit card info, etc after a transaction is completed besides to spam the person with promotional material which pushes me away from those companies as I hate spam/ads. I give a junk phone number to stores when they ask, saying no thanks gets annoying, every time they have to ask. I guess I should do similar for email since it's getting annoying always saying no to that question too.

[ps2fixer]

Ok, car acting really weird now. Been going 40mph a bit and today I decided to go 40mph the whole time where possible, more back roads, avoiding the express way and such. To town it was things as normal, hybrid mode and cruise down the road. I ran to get a fill up and the car didn't go into the hybrid mode where it shows charge and discharge cycling back and forth It dropped my mpg to like 50mpg indicated at 40mph while charging. Once the battery hit about 74% it kept the engine running but idled it down to about 1200 rpm (was 1280rpm) and it drove about a mile like that, then it killed the engine for another little bit before it went back to charging. Trip home from the gas station it did the same thing. In car screen said 66.7mpg which seems to be a massive jump up, like a lot more than just areo drag difference.

I'd think if it's going to use the battery, wouldn't engine off EV mode be better? I could force it to do that, but I figured I'd let it do it's thing.

Fill up was done at a different gas station, was pretty low on gas this time, 12.5% filled to 97.5%. It seems like I got a bit more gas in it this time than before, or the slower driving hasn't helped mpg hardly at all, which I really doubt. Screen indicated 52.7mpg

Trip home going 40mph the whole way with the strange charge/discharge cycle going on it showed 66.7mpg since I reset it at the gas station.

Now for the bad news, the scan gauge is really acting up lately. The average has been going to 2808 quite often, mainly when I scan through the gauges, like to look at the gas level. Not sure what's going on, or how to clear the memory out since there's clearly corrupt memory (hopefully not the flash memory for the firmware).





I've sent in a support question to scangauge, hopefully they know the issue, maybe it can be reset and be self corrected. If I don't go through the gauges, it seems to work fine. The fuel it said I used was pretty much spot on. Figured I'd reset it at the gas station since it's been messing up some so didn't do any calibration.

Anyway, the 66mpg is the highest I've had for a trip so far and the key was 40mph instead of 45mph which normally gives around 50-55mpg depending how far I go. About +17% better mpg for going about 12% slower is pretty crazy. I'm not sure if it's the coding in the car for how it functions at the lower speeds or what. I don't think the areo would have that large of an effect. I mean, going 45mph vs 55mph I'm seeing 50-55mpg vs around 46mpg. Something is at work here, but not 100% sure what. I think at the slower speeds, I'm probably getting closer to what the speed vs mpg chart says. I guess I should see how my numbers compares to the graph for the different speeds so far.


40mph - 66mpg vs 85mpg on the chart (77.7% of chart)
45mph - 50-55mpg vs 72mpg (76.4%)
55mph - ~46mpg (up to 50mpg for a very long trip) vs 64mpg (71.9%)

I guess the numbers seem to line up, I guess I just underestimate how much the cold start uses, or my coasting isn't done the greatest. Pretty interesting that the trend is slower I go, the closer to what the chart says I get. I think that would suggest part of the problem is areo.

Also I had the car fully warmed up, and it didn't want to kill the engine for a coast again, so I hit the EV mode button, it just beeped at me and didn't kill the engine. Not sure why it's being goofy like that.

Anyway, I've been trying to push this car to it's limits on mpg to really learn where my mistakes are and such. I still have a hard time beating 25mpg for the first 5 mins of a cold start trip.

Note that on the pic above, it's a warm start at the gas station but I idled for about a minute resetting the gauges and such, not used to the car yet and almost forgot to reset the trip. It was in the charge mode and the last bar is where it was in discharge mode but kept the engine on. It seemed like I had it in hybrid mode before going around 40mph (maybe it was closer to 45) and I was seeing pretty consistent 65-70mpg on the screen.

Anyway, tips on this new mode I stumbled into would be great, I don't think I've seen it before. If the programming is really this much better for the lower speeds, I really thing getting the gear ratio so this logic can work at 45mpg should give solid gains then at those speeds.

Seems like I'm always learning something new with this car lol.

[Drifter]

How hot was it? If the battery temperature gets too high it won't turn off the engine.