driving on battery power alone

[andrew_mar]

Hello

I've owned a 2007 Camry Hybrid for two and a half years now.

One of the big features of the TCH is that it can (supposedly) drive on battery power alone at speeds up to say 40 km/h or so. However, in my experience, I cannot get my TCH to go on battery power alone unless I very gently press on the gas pedal and slowly accelerate, if I'm driving around a parking lot or in stop and go traffic on the highway. Otherwise, if I'm constantly accelerating from a stop at a traffic light, the car invariably will kick into gas to accelerate at a rate acceptable to the traffic behind me.

Is there an issue with my TCH? Or, does battery-alone only work when you're accelerating slowly or on your way down a hill?

Thanks
Andrew

[JeffB60014]

The batteries only produce about 50 HP. That is not enough to accelarate from a dead stop. The hybrid system is designed to maintain speed on battery alone, not start unless you are prepared to go very slowly from a light.

What you are describing is perfectly normal.

[Droid13]

Yes, perfectly normal. If you enjoy driving on battery power only, you've probably figured it's easier in summer than winter. Having the climate system in ECO will help, off altogether is best. Accelerate moderately briskly to 60kph and release gas pedal. Re-apply gently to try to maintain speed. For some reason its far more likely to slip into E than if you only accelerate to 40kph.

[98CamryLE]

I have found that it will allow me to accelerate using the battery alone only in certain circumstances- but it does not happen often. I must accelerate very slowly- which is fine on side streets but not if other cars are behind me. It must be on level ground or on a street that is heading downwards, the engine must be at or very near normal operating temperature, the cabin needs to be at or near the desired temperature, and the battery must have a good charge. If all of these things are happening, and the hybrid god(s) are smiling on my individual car- it will accelerate on battery power alone.

It really never happens when the temperature is below 30-40 degrees Fahrenheit.

[ekpolk]

Originally Posted by Droid13

Yes, perfectly normal. If you enjoy driving on battery power only, you've probably figured it's easier in summer than winter. Having the climate system in ECO will help, off altogether is best. Accelerate moderately briskly to 60kph and release gas pedal. Re-apply gently to try to maintain speed. For some reason its far more likely to slip into E than if you only accelerate to 40kph.

The maximum "stealth" (electric only drive) speed is 42 mph (although per my ScanGauge-II, mine seems to max out at 37-38 mph, NOT kph). This is an inherent design feature in the HSD cars. It results because of the gearing of the PSD (essentially the core of the tranmission). If the car were permitted to go "stealth" over 42 mph, it would result in an over-revving of MG1 (the smaller of the two motor-generators, driving the centershaft of the PSD).

Go to the link below to see a very neat, interactive depiction of how the parts of the PSD work with one another. Go half-way down the page. You can move those sliders with your mouse. Slowly slide the left-most one (representing MG2 rpm) upward, and watch the speedometer. As you hit 42 mph, you'll see you reach max rpm for MG1.

http://eahart.com/prius/psd/

As for the climate control, other than turning the AC compressor off in cold weather, I'd leave it on. I do realize that you're in Canada, Driod, so your climate is very different from mine, where combating HEAT is the main climate challenge. Remember, the traction battery is cooled by "used" cabin air. The battery cooling intake is that large vent scoop on the shelf behind the rear seat. In the Prius, it's a vertical affair at the right rear passenger's outboard shoulder. Anyway, if you try to save gas in hot weather by shutting off the climate control, you may deprive the traction battery of sufficient cool air. If you do so, the computers will scale back the "involvement" of the traction battery, reducing the system's overall efficiency, and ultimately lowering your mileage.

Back to the OP's question, yes, what you describe is normal (unless you're getting system warnings, which you did not indicate). Having owned and driven both the Prius and the TCH, I find that the Prius is much easier to "maneuver" into stealth mode, and much easier to keep it there. The TCH strikes more of a compromise between performance and economy, and seems to be programmed to start the ICE much more willingly than the Prius which is clearly programmed more heavily in favor of fuel economy. Be subtle, steady and gentle with the TCH's throttle, and you'll get the hang of milking it along in stealth mode. A good specific technique is to accelerate to a couple mph/kph ABOVE your intended speed, and then "back down" to that. That gets me into stealth very frequently and easily.

Finally, don't get overly frustrated with it. The computer weighs many variables, most of which you can't directly see when deciding whether or not to go stealth(hint: get a ScanGauge...). If coolant temp is too low, for example, even if you do everything right, the ECU will keep the ICE running. And so on.