Braking. What happens after the battery is full?

rposton · 03-21-2006, 07:15 PM

From what I have read in other threads in this forum, D captures more kenetic energy than B, and sends it to the battery. The purpose of B is when the downhill is so long that your foot might get tired pressing the brake pedal. Since such a hill would max out the battery, the ICE is used to help control the downhill speed of the car. Also, friction brake comes into play at about 10 mph and less.

Therefore, my question is...

You go down a long hill in D, and your battery bars max out to the top, and you are traveling, lets say 50 mph, what does the car do with your extra kenetic energy? Does it,
1. start using more of the friction brake?
2. spin up the ICE and use it even though you are still in D?
3. somehow change the excess kenetic energy into heat energy and dump it into the coolant, which then can be used to warm the cabin, or wasted via. the radiator?

kkister1492 · 03-21-2006, 07:21 PM

The ICE will engage to use up the extra charge. This happened quite a lot on our trip in the Rocky Mountains last year.

DaveinOlyWA · 03-21-2006, 07:24 PM

you will stop charging the battery and start using your friction brakes more

**efusco** · 03-21-2006, 07:25 PM

Yup, it's pretty dramatic actually. I experienced an 80% SOC twice this past week and was able to watch the ICE spin up to over 3000 RPM and the amerage drop to -1 while braking on a downhill! I tried releasing the brake and reapplying to see if I could get the regenerative brakes to reingage to absolutely no avail. The ECU will go to some pretty extreme measures to prevent any overcharge even at the expense of lower fuel economy.

hyo silver · 03-21-2006, 07:44 PM

Going up a big hill in summer, I drive a little slower, and turn off the air conditioning. Going down a big hill, I drive a little faster and crank up the cooling to take advantage of the 'free' electricity. This gets tedious on low rolling hills, but in mountain passes it seems to help the efficiency. (My daughter tried to apply this technique to the music volume, but I don't think it has the same effect.

)

I love the regenerative brakes. No more warped discs for me!

rposton · 03-22-2006, 10:23 PM

I like the idea about wasting excess electricity into the music.

The Prius has enough, but it would be nice to add a way to, once the battery is full, to store additional electricity as extra heat in the coolant on less than 45 degree days, and then circulate it through the engine and heater core of the car.

I guess somebody, not me, could convert the roof to an airbrake, like on the back of an F15 Eagle.

Thanks for the replies. I learned something.

-Roy Poston

DaveinOlyWA · 03-22-2006, 10:37 PM

man i agree 100 %. i have had situations when i am maxed out on a charge, still got a ¼ mile of downhill left, and my CANVIEW says im DRAINING the traction battery!!!

man i HATE THAT. whats worse, since doing the 50P update, my max SOC seems to only be 75% now...anyone else notice this??

SirGreen · 03-22-2006, 10:42 PM

I think I would turn up the AC or the heat.

DaveinOlyWA · 03-22-2006, 10:49 PM

Quote:

Originally posted by SirGreen@Mar 22 2006, 07:42 PM
I think I would turn up the AC or the heat.

[snapback]228843[/snapback]

not me... but i do plug in the ipod, laptop, cellphone....

rbarline · 10-15-2009, 03:40 PM

Quote:

Originally Posted by kkister1492

The ICE will engage to use up the extra charge. This happened quite a lot on our trip in the Rocky Mountains last year.

How can an ICE engine use up any charge? I don't think ICEs can do that. There must be a better explanation.

03-21-2006, 07:15 PM	#1
rposton Senior Member Join Date: Feb 2006 Location: Nashville, TN Posts: 108 My Car: 2006 Prius Model: Package: #8 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	From what I have read in other threads in this forum, D captures more kenetic energy than B, and sends it to the battery. The purpose of B is when the downhill is so long that your foot might get tired pressing the brake pedal. Since such a hill would max out the battery, the ICE is used to help control the downhill speed of the car. Also, friction brake comes into play at about 10 mph and less. Therefore, my question is... You go down a long hill in D, and your battery bars max out to the top, and you are traveling, lets say 50 mph, what does the car do with your extra kenetic energy? Does it, 1. start using more of the friction brake? 2. spin up the ICE and use it even though you are still in D? 3. somehow change the excess kenetic energy into heat energy and dump it into the coolant, which then can be used to warm the cabin, or wasted via. the radiator? __________________ Roy Poston Car's name is "Ruth". Ruth is an '06 with Package 8, with all the etc. that the dealer could add on. Ordered in 9/05, arrived 12/23/05, took delivery 01/07/06.

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03-21-2006, 07:21 PM	#2
kkister1492 Join Date: Dec 2004 Location: Fremont, CA Posts: 354 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	The ICE will engage to use up the extra charge. This happened quite a lot on our trip in the Rocky Mountains last year.

03-21-2006, 07:24 PM	#3
DaveinOlyWA 3rd Time was Solariffic!! Join Date: Apr 2004 Location: South Puget Sound, WA Posts: 12,382 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 24 Thanked 122 Times in 104 Posts Friends: 10	you will stop charging the battery and start using your friction brakes more

03-21-2006, 07:25 PM	#4
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 17,255 My Car: 2004 Prius Model: Package: #9 Thanks: 50 Thanked 263 Times in 158 Posts Friends: 37	Yup, it's pretty dramatic actually. I experienced an 80% SOC twice this past week and was able to watch the ICE spin up to over 3000 RPM and the amerage drop to -1 while braking on a downhill! I tried releasing the brake and reapplying to see if I could get the regenerative brakes to reingage to absolutely no avail. The ECU will go to some pretty extreme measures to prevent any overcharge even at the expense of lower fuel economy.

03-21-2006, 07:44 PM	#5
hyo silver awaaay Join Date: Mar 2005 Location: Vancouver, BC Posts: 10,733 My Car: 2004 Prius Model: Package: Base Thanks: 47 Thanked 154 Times in 109 Posts Friends: 63	Going up a big hill in summer, I drive a little slower, and turn off the air conditioning. Going down a big hill, I drive a little faster and crank up the cooling to take advantage of the 'free' electricity. This gets tedious on low rolling hills, but in mountain passes it seems to help the efficiency. (My daughter tried to apply this technique to the music volume, but I don't think it has the same effect. ) I love the regenerative brakes. No more warped discs for me!

03-22-2006, 10:23 PM	#6
rposton Senior Member Join Date: Feb 2006 Location: Nashville, TN Posts: 108 My Car: 2006 Prius Model: Package: #8 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	I like the idea about wasting excess electricity into the music. The Prius has enough, but it would be nice to add a way to, once the battery is full, to store additional electricity as extra heat in the coolant on less than 45 degree days, and then circulate it through the engine and heater core of the car. I guess somebody, not me, could convert the roof to an airbrake, like on the back of an F15 Eagle. Thanks for the replies. I learned something. -Roy Poston

03-22-2006, 10:37 PM	#7
DaveinOlyWA 3rd Time was Solariffic!! Join Date: Apr 2004 Location: South Puget Sound, WA Posts: 12,382 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 24 Thanked 122 Times in 104 Posts Friends: 10	man i agree 100 %. i have had situations when i am maxed out on a charge, still got a ¼ mile of downhill left, and my CANVIEW says im DRAINING the traction battery!!! man i HATE THAT. whats worse, since doing the 50P update, my max SOC seems to only be 75% now...anyone else notice this??

03-22-2006, 10:42 PM	#8
SirGreen Join Date: Feb 2006 Posts: 75 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	I think I would turn up the AC or the heat.