Regen adjust?

[Pegasus_]

Hello all.

Having owned an all-electric car before getting the Prius, I'm used to somewhat more aggresive regenerative braking. (Plus I like the additional recovered energy. ) The inverter on my electric car allows me to adjust the amount of regen (and torque!) via an attached PC.

I found an article that discusses making this mod to a Prius: http://autospeed.drive.com.au/cms/A_2392/article.html but the author doesn't give wiring details.

Does anyone have the service manual for the 2007 Prius that could flesh this out a little more? Or better yet, does anyone know if regen is adjustable via the computer service mode screens??

Thanks!

[qbee42]

There is nothing to adjust. All of the braking on the Prius is done with regen, until it gets down to about 7 mph, at which point it is too slow to effectively use regen. If you want more regen, push harder on the brake peddle.

Tom

[JimboK]

<div class='quotetop'>QUOTE(qbee42 @ Jun 29 2007, 04:38 PM) [snapback]470254[/snapback]</div>

All of the braking on the Prius is done with regen ... [/b]

Doesn't hard braking at speeds >7 MPH also engage the mechnical brakes?

[ken1784]

<div class='quotetop'>QUOTE(Pegasus_ @ Jun 30 2007, 04:17 AM) [snapback]470200[/snapback]</div>

I found an article that discusses making this mod to a Prius: http://autospeed.drive.com.au/cms/A_2392/article.html but the author doesn't give wiring details.
[/b]

His vehicle is very low-tech 1999 original Prius, and the mechanical brakes were always engaged when he pressed his brake pedal.
The 2004-2007 Prius is now very sophisticated and most braking was done by regeneration above 7 mph.

Yes, it is adjustable by brake pedal value.
Attila's study shows the value 17 is the best.
http://vassfamily.net/ToyotaPrius/CAN/brindex.html

Ken@Japan

[hobbit]

Also, see http://techno-fandom.org/~hobbit/cars/bp/ for some figures
and operational discussion on the system. Basically, there's 10-20
amps of "drag" with no feet on either pedal, and if you begin braking
with a slowish risetime you get up to 100 amps of pretty much pure
regen all the way up to that 7mph or so transition point. In the '04
and later prius, the hydraulics aren't touched at all unless/until
needed.
.
You can also play with "B" at speeds < 20 mph for a little extra
drag regen, but really, it's almost exactly like touching the brake
pedal. Only difference is that the rears don't preload.
.
_H*

[MPG > HP]

<div class='quotetop'>QUOTE(hobbit @ Jun 29 2007, 07:40 PM) [snapback]470438[/snapback]</div>

...You can also play with "B" at speeds < 20 mph for a little extra drag regen...[/b]

I thought that "B" was for engine, not regen braking. When I use "B" I can definitely feel the IC come on, though probably with fuel off. Will have to check this with my ScanGauge.
- Gary

[efusco]

<div class='quotetop'>QUOTE(MPG > HP @ Jun 30 2007, 01:38 AM) [snapback]470515[/snapback]</div>

I thought that "B" was for engine, not regen braking. When I use "B" I can definitely feel the IC come on, though probably with fuel off. Will have to check this with my ScanGauge.
- Gary [/b]

You're correct, Hobbit was being intentionally brief in his comments. Using B will increase regen drag marginally but it will also use ICE compression to slow the vehicle. It is not recommended to use B mode in any but a few situations such as very long steep downhill runs where the battery would top off quickly just using the brakes.