I purchased my new NAH on June 29th here in Phoenix. I'm starting to learn some "tricks" to keeping my energy history / mileage display above the 40 mark, but I'm looking for a few more tips since many of you are beating that. I don't really want to do anything wacky like driving 45 in a 65 and it doesn't sound like many of you are doing that anyway, but it does seem like I need to adjust my driving to get the most benefit out of the hybrid engine.

My first 5 minutes are always lousy sub 10mpg due to warming up the engine and cooling down the cabin. I always have to keep the AC on here with the summer temperatures usually over 105. I haven't tried adding air to the tires. I'm worried about cranking the PSI on the tires to the max due to the heat here and big elevation changes when we travel north. It's 6000ft from Phoenix to Flagstaff and I don't want to risk ruining a set of tires to save some money on gas.

I'm really struggling with traffic lights. Accelerating from a red light, I can keep it in EV until about 15mph and then the gas engine kicks on. Once I'm at a cruising speed around 40mph I can back off on the throttle and get EV turned back on. I just can't seem to get it from 15mph to 40mph in EV unless I let it take 2 minutes to get it up to that speed. Is there something I can do to bridge the gap?

So far I've been getting the best mileage by accelerating a little past my cruising speed and then backing off on the throttle and letting it slowly drift down to my cruising speed. Say I cruise around 45mph, so I would get up to around 50mph and take my foot off the pedal until it's about 48mph. The hybrid drive generally takes over when I do this (not EV mode, but the ICE is not active on the monitor). Then I add a little pressure to the pedal with the electric gauge hovering between 0 and the first tick mark. Gradually the car will start slowing down to say 43-44 and I start to gradually speed it back up again. The ICE will kick in and I continue repeating the procedure. I don't accelerate hard to get back up to speed, but I try to get there in maybe 15-20 seconds. I can often get the mileage indicator to stay pegged at 60mpg for about 3-8 minutes at a stretch depending on how level the road is. I don't seem to get as high a mileage on the indicator when I use the cruise control versus this gradually slowing method.

Someone mentioned in another post about using a trickle charger to charge and test their battery. Could this be used to give me a "poor man's" plug-in hybrid? With my current driving method, I rarely can get the battery indicator above about 70% and often I see the engine on the energy flow meter turning on just to charge the battery or run the electric motor. Due to the heat I usually have to let the vehicle sit and cool down for a couple of minutes before I can start driving, so it looks like I'm often burning about 10-15% of the battery before I even get moving.

I'm also curious about the dual zone climate system. Does the passenger side fan not change speeds? We were fiddling with this on a trip this past weekend and my wife couldn't seem to get the system to work very well. When I had it set to 72 and she had it set to 76, we couldn't tell any difference in the temperatures or fan speeds from the vents on either side.

Any and all advice is appreciated.

 

I'm not convinced that it actually pays to stay in EV mode when accelerating away from a light; use the ICE for what it is best at, and let the electric motor help maintain your cruising speed once you're there. All the power comes from the ICE in the end, anyway. Plus this will be less annoying to the folks behind you. I'm not recommending jack-rabbit starts, just reasonable, moderate acceleration.

One of the better tricks with stop lights is to avoid sudden braking (which prevents the regen from happening) by looking a little farther ahead. This has the added advantage of being safer.

But the biggest factors seem to be speed (especially on highway), temperature, and trip length (percentage of time spent in warmup). Standard tricks like combining trips (to minimize warmup penalty) are the most effective. In AZ, I suspect that parking in shade whenever possible would also help.

I don't think you can make an effective 'plugin' out of the NAH using the current batteries; they just aren't designed to give it that much pure EV range.

Welcome, and good luck!

 

Welcome Stephen, unfortunately the poor mans plug in will not work because the battery does not have enough capacity to give you any advantage in mpg. The full charge will diminish within minutes. Yes a full charge does make the ev engage and remain even during higher accel pressures but again only for a minute or two. Sward's advice is sound but i always try to stay in ev mode as much as possible but only when i am sure that the recharge will occure on the highway. I don't notice as big a hit to FE when recharge occures at 55-65 mph as I do when im stopped in traffic.
Good luck.

 

Good point about planning ahead (when you're on a well-known route) to do the recharging at an effective time (i.e. not when stopped at a light). Likewise, you don't want to come to a long downhill grade when you already have a full charge - there won't be any capacity left in the battery for the additional charge.

Tricks like that help get the last few percentage points of efficiency out of the system, although I'm not sure the gains are very large (compared to the big things like speed, temp, and a warm engine).

When I first got my NAH, I tried some test runs with different driving styles, such as trying to extend EV mode as far as possible, but the effects on my mileage were minor. Temperature changes made a much bigger difference.

 

With regard to traffic lights. If you can get a car rolling to 15 or 20mph off a dead stop, you're doing well. That is the when the most gas would be used by an ICE only car. Personally I try and get the car rolling via EV to these (15-20) speeds, let the engine kick in, and go with the flow. Then back off as much as I can. It doesn't take much power to maintain speed.

BTW, Every so often I accidentally experience a condition where the battery really wants to move me. I can't reproduce it, but when it happens I have very little pressure applied to the gas pedal, and the car keeps accelerating. It's actually kind of fun. The battery has to have a good charge for it to happen. I wonder if anyone else has experienced this.

I believe you may have read an earlier post of mine regarding a trickle charger. That was advice for the 12V battery only! Never attempt to charge your hybrid battery (it's several hundred volts). The advice for charging the 12V battery was given to troubleshoot a potential problem someone may have been having with the 12V battery. This battery is just a simple lead acid type found in any car. Although the NAH 12V battery is quite hard to cross reference (I tried). I hope its a deep cycle battery (it's not needed for starting). If not, IMO it should be.

 

The above are all good tips.

To the OP: It's been stated many times on priuschat that trying to force EV mode or accelerate via EV isn't necessarily the most efficient.

Read http://www.autosafety.org/article.php?did=854&scid=77 about pulse driving and http://www.cleanmpg.com/forums/artic...-fe--1224.html. Notice that the pulse involves using the ICE to accelerate and not staying in electric.

Wayne Gerdes, author of the above article was one of the hypermilers who set this record http://www.post-gazette.com/pg/05220/550484.stm.

When messing around >42 mph, I'm not convinced the OP is driving the most efficiently. In theory, the ICE must run (or at least spin) above 42 mph to keep up motor generators from going over their RPM limits.

 

Just got my 08 NAH. Less than 30miles on it, so have some additional newbie questions related to this topic.

Should the battery charge meter ever read full? What circumstances would get it there?

Also, when does the electric power meter climb above 50KW?

Thanks!
Eph
40.4MPG on the way to work this morning!

 

Hello and Welcome.

The charge meter doesn't represent full or empty as ether extreme would damage the battery. The system is balanced by the computer to hover in the upper third to quarter during normal use. You can fill it to the top by coasting with mild breaking down a long (several miles) downward slope, however it will quickly even out again. I have also seen mine hit the bottom. The engine comes on until it is over half way again.

When the power KW meter is in the white you are using the electric along with the gas engine for accelerating or maintaining high speed. I guess it would only hit the top if you slammed on the accelerator, which is not advised. Once in a while you feel a slight loss of power, usually around 50 miles per hour or so, which is when the computer diverts power back to charging the batteries. This sometimes feels like a transmission shift even though the NAH doesn't have a conventional transmission. Don't be surprised, it is normal.

 

Do you mean the upper third to quarter of the blue region? Mine seems to be pretty close to halfway in the blue region most all of the time. Of course, as I said, I've only gone 30 miles!

Thanks again!

 

First off, thanks for all the great tips.

I watched pretty carefully this morning, and you might be correct.

My battery was very low this morning and the ICE stayed on to charge the battery for about 15 minutes during my drive to work. I have one long flat section where the speed limit is 40 and another one right after at 45. When I was at 40mph the ICE powered the electric motor to the wheels and when I was at 45 the ICE ran directly to the wheels. In both cases it continued to charge the battery. While it was at 40mph the mpg meter hovered around 35mpg, and at 45mph it bounced around between 45 and 50mpg. It appears the ICE is more efficient around that speed (at least while it's charging the battery).

Cephraim's question about going above the 50kw mark. I drove up to the Grand Canyon last weekend and there's about a 5-mile section with a very steep grade you have to climb. Doing around 65-70mph, power from both motors were driving the wheels. I'm pretty sure it climbed to around 80-100kw during that section. On the way back coming down that section, without touching the brakes, it put my battery level all the way to the top of the meter.