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Discussion Starter #1
The state of the battery on the prius is always in a state of flux. I'd imagine there are times either going up hill or accellerating alot, where your going to drain the battery to virtually 0, or at least eliminate it as a power source. When that happens your basicly driving a 2,800lb car with a 76hp engine. I imagine, to top it off, the system might decide it will charge the battery at the same time which means that might place a 10hp load on the engine, bringing you to a grand total of 66hp for a 2800lb car.

Anyone go up a big hill and notice this? Now I know this was noted for thos who try to test it's max speed because after hitting above 100mph or more the battery gives out and yougo back to the true (extended distance) max.

Now I drove a 55hp Yugo (when they existed) and that was a 1800 lb car and I know up a hill steep hill it was a matter of gear and engine reves to get it up in a speedy fashion.

Surely some one must have a driving route that at one point drains the battery, so what happens and can any one describe the gasoline engineonly performance, or state that the charging of the battery only occurs at steady speeds and not when performance is demanded from the car?

I'll assume no one drove thier Prius up Mt. Washington if no one ever encountered this situation.

One more question, does charging occur not only during brakeing but also while cruising?

-Lee
 

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Yes, the Prius has been up Mt. Washington and up the Grapevine in CA and other such heavy climbs. Unless you've got a fully-passenger-loaded Prius and you're trying to go 85MPH+ up the Grapevine, you've got plenty of passing power to go around all the other cars that can't go up that long steep grade.

Read some owner reports here:
http://autos.groups.yahoo.com/group/toy ... 010253404/

without a major mechanical failure, you cannot drain your HV traction battery to 0%. I think the lowest reported is in the area of 30% (read with a ODBII scantool) where the battery stops providing power.
The speed limiter isn't so much the battery unable to keep up, but that the transmission cannot handle those speeds (prevents overrevving of the electric motors).

Yes, the engine recharges the hybrid battery while driving, besides the battery getting charged by your coasting/braking.
 

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ltsnyder said:
Surely some one must have a driving route that at one point drains the battery, so what happens and can any one describe the gasoline engineonly performance, or state that the charging of the battery only occurs at steady speeds and not when performance is demanded from the car?

-Lee
Your logic is what most people would expect from the Prius... that it would eventually lose power because it depends on a resource, the battery, which has limited capacity.

The short answer is that Toyota also considered this problem very carefully, and solved it to my satisfaction.

I did my best to drain the battery on a brutal drive with three people in the car and vacation baggage, while going over the 70 mile long Coquihalla Highway in British Columbia. I kept the speed above 75 mph, and often above 90 mph on the drive from Merritt to Hope, the first half a gruelling ascent. The battery went down to two red bars and even down to one red bar at times. At those times I thought, 'Ok, now I've got it', and pushed it even harder. But no luck - I couldn't drain the battery, and I couldn't get the car to a state when it wouldn't accellerate right back above 90 mph any time I wanted to, going uphill.

I know I will never be in a situation where I will need performance better than I got that day, so I'm satisfied.
 

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Discussion Starter #4
but the level of the batter is not the real issue . . .

Going up Mt Washington etc, all that matters is that you are running off of Interal COmbustion Engine power only, thus your performance is ICE only.
Do you notice a difference?

-Lee
 

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My understanding is that the 2004 Prius engine has a max output of 76 HP vs 70 for the 2001-03 model. So it should be able to hold a higher uphill speed after the HV battery drains.

Anyway, Mt. Washington is big for the East coast, but tiny for those used to the Rockies. It doesn't challenge any modern car.

Although there are closed course races up Mt. Washington where the cars do over 100 MPH, for a normal drive it's mostly under 35 MPH with a few straight areas where you might go 50-60 if you ignore the speed limit. Anyway, with the 2001, you can drain the battery about 1/2 to 2/3 of the way up. After that it's just engine power. The engine provides plenty of power to do the aforementioned speeds. But there is a significant difference in feel. Without the instantaneous response of the battery, you must wait up to 2 seconds for the engine to "spool up" when you suddenly request more power. It's initially odd, but you eventually get used to it.

There's a possibility that the 2004 is programmed to run the engine at higher output when the battery is low and the accelerator is less than fully depressed. This would allow it to maintain enough charge for instantaneous response much farther up the mountain.
 

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ltsnyder said:
Anyone go up a big hill and notice this? Now I know this was noted for thos who try to test it's max speed because after hitting above 100mph or more the battery gives out and yougo back to the true (extended distance) max.

Surely some one must have a driving route that at one point drains the battery, so what happens and can any one describe the gasoline engineonly performance, or state that the charging of the battery only occurs at steady speeds and not when performance is demanded from the car?

-Lee
See here http://www.priusonline.com/viewtopic.php?t=2266
 

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Calling anyone who has gone up the hill on I 84 outside Pendelton Oregon. That is one awful hill. I have only gone down that hill and that was scarey enough for me. In my drive from Helena MT to Olympia WA I went over 4 passes and never even came close to challenging my Prius. 75 mph up hill still had power and the battery was not even close to empty the lowest I got was 2 bars at the top of Lookout pass after which I nearly filled the battery. Stelthing at 65 mph is way cool.
 
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