Just a quick question - Toyota Nation Forum : Toyota Car and Truck Forums

beach808boyz · 09-08-2006, 04:34 AM

I was wondering when does your car switch from only the battery to the engine?
I've noticed when i drive it occurs relatively quickly only at 5-10 mpg and even on reg acceleration.
I thought i read somewhere that's why that the engine kicked in at around 30 mph.
is something wrong?
thanks guys.

Sallyspal · 09-08-2006, 08:58 AM

Quote:

Originally Posted by beach808boyz

I was wondering when does your car switch from only the battery to the engine?
I've noticed when i drive it occurs relatively quickly only at 5-10 mpg and even on reg acceleration.
I thought i read somewhere that's why that the engine kicked in at around 30 mph.
is something wrong?
thanks guys.

Your TCH is designed to run on battery only (for short periods), internal combustion engine only, or a combination of both. There are many variables that determine when the ICE engages. Probably the most frequent is the need for extra power, even at slower speeds (such as an uphill climb). Another important factor is the need to charge the traction battery. Your TCH is not designed to run on battery only for any great length of time. You probably have noticed that the ICE will come on soon after you start your car in the morning. This is to help warm up the catalytic converter and also helps circulate various fluids. Its a pretty complex system. You can read more about the technology on Greenhybrid.com.

maynard160 · 09-11-2006, 08:45 PM

The following are the conditions under which I've seen the engine come on:

First thing in the morning to warm-up, like Sallyspal said

Any heavy dipping into the gas pedal (you gotta really baby it to stay on the elec motor)

Anytime above 40 mph (not sure about going down hill. too flat here. but I was told it still stays on going downhill above 40. Can anyone confirm?)

When the battery gets to what appears to be about 3/4s low

I dont think you have a problem. Hope this helps.

beach808boyz · 09-12-2006, 03:56 AM

hmm yeah that does help. i was just wondering if i could run on the battery more to maximize the mpg. b/c 90% of my driving is in city and total driving for the day is only 5-6mi max. LOTS of stoplights and bascially no freeway until the weekends. thanks guys.
i got a question tho
are your batteries fully charged?
i don't think my battery has ever been fully 100% full it always hovers around 3/4 full
how are yours?

Tideland Prius · 09-12-2006, 04:57 PM

NO! Contrary to popular belief, running solely on the battery actually reduces mileage. The reason? It has to get recharged somehow and given that a normal (i.e. not a crazed hypermiler) will probably not maximise regeneration on a hill, or if you simply live on a flat area of the country, most of the recharge will come from the engine. There are energy conversion losses so you will take a mileage hit by using the battery more often.

The best way is to glide as much as possible. This means your engine is off AND there's no arrow to or from the battery. This little nirvana (haha) means no fuel is used AND no battery power is wasted either. Also, by not coasting (arrows from wheels to battery), you're not slowing down as much so you can maintain your speed for a longer period.

Lastly, you'll never see a fully charged battery unless you go down the mountainside or simply maximise regen on a short, steep hill. Also, a full battery on the screen isn't a full battery in real life. The battery meter shown is actually a small window of true battery SOC (state of charge). An empty meter is 40% true SOC and a full meter is 80% true SOC. This is to maximise the ilfe of the battery. In short, yes it's normal to be at 3/4 (~60% true SOC).

Lastly, the engine does spin at above 42mph but I'm not sure if it uses any fuel.

Phew, hope that helps!

Sallyspal · 09-12-2006, 09:34 PM

Quote:

Originally Posted by beach808boyz

hmm yeah that does help. i was just wondering if i could run on the battery more to maximize the mpg. b/c 90% of my driving is in city and total driving for the day is only 5-6mi max. LOTS of stoplights and bascially no freeway until the weekends. thanks guys.
i got a question tho
are your batteries fully charged?
i don't think my battery has ever been fully 100% full it always hovers around 3/4 full
how are yours?

Sounds like my commute. I have been averaging 37 - 38 mpg driving about 8 miles daily roundtrip on local streets with stoplights; and an occasional spell of highway driving if my job requires a longer trip. I am driving more conservatively now, but unless I am bored, I don't use "pulse and glide" or any other hypermiling techniques.

At 3600 miles I am noticing an improvement in mileage (the car is breaking in) and I hope to be able to reach and sustain 40 mpg tanks in the near future. You'll do fine as long as you are patient and willing to learn from your TCH.