When using brakes how do you know

yes, around 6 mph i think. also, if you watch the hsi when braking, the harder you press, the further the line moves to the left. if it goes all the way, you're friction braking.

 

If you want to know for sure, get a scangauge and use xgauge and set one to monitor mechanical brakes and one for battery amp. The HSI is not completely accurate. When the battery gets too hot, the regen cuts out and mechanical brakes kick in even though the regen bar is half way.

 

Close enough.
The transition from regenerative to friction brakes occurs at 7 mph, assuming you are using the regen brakes when slowing down.

 

i know, it's amazing, isn't it?

 

I think you misread. Regen braking basically kicks as soon as you hit the brakes. It's "friction" braking that kicks in at 6-7 mph for the last few feet of stopping distance. And this assumes you slowed down by pressing the brake pedal a little and didn't wait until the last minute. Obviously, if you hit the pedal hard, friction braking kicks in right away. If you watch the display as you press the brake pedal, you'll see the indicator start moving to the left. This is regen braking. When you get to 6-7 mph, the friction brakes kick in even though the display might still only be at the halfway point. At least that's how I understand things.

 

Regen is available at all speeds above 7 mph, unavailable below.

Are you using the HSI display so that you can see the CHG portion of the bar? If so, a reasonable first approximation is that you are using all regen when the bar is not pegged to the left. The available regen braking force varies considerably with speed, producing moderate braking force at low speed but only light force at highway speed. (Battery power limit sets the regen braking limit. Force equals power divided by speed.)

But as Cproaudio mentioned, this is not the whole story, you need added instrumentation to see the rest of it.

 

Oh, and AFAIK, when you're going downhill, the car is regen braking even if you don't press the brake pedal. This is why the Prius can navigate down a lot of hills without ever having to use the brake pedal, unlike most other cars.

 

when i post a question, and come back to find a bunch of responses, i only read the last one.

 

You are actually using regen braking anytime your foot is off the accelerator (up hill, down hill, no hill) and not on the brake. It is designed to simulate a regular engine's braking effect. With your foot off of the gas, you can see a small line on the CHG indicator - that's the regen kicking in, unless, as mentioned, the traction battery is at or near full charge and other variables (Temperatures, etc.) are in play.

 

I'm not sure it's all-or-nothing with the brakes. If I've washed the car,and it's sat a day or two, built up some rust on the rotors: I'll hear some noise from the brakes regardless of speed.

 

Here's proof that friction brake kicks on even though the HSI shows regen only. I believe this is done to protect the battery during extreme temperature. It didn't show on the video but it was 108f that day. I've seen this issue when the outside temp as low as 95f. This only happens when I parked the car in direct sunlight for longer than an hour. Look at the lower left scangauge. BRK monitors the friction brake. Normally, the BRK shows 0.00 when no friction brakes. During extreme temperatures, it shows 655. Not sure if it's the scangauge's fault or OBD-II's fault. When friction brakes is activated no matter how small, it'll show above 0.01. This is how I know the friction brakes have activated during supposed regen only braking. Typical moderate braking shows about 0.3-0.5. Hill start assist takes 1.5 to kick on.
Amp monitors amperage gain or loss. - means regen. During regen, you'll see somewhere between -99 amps and -20 amps depending on how hard you pressing the brake pedal. At cool temperature, during full regen but just shy of friction brakes activating will generate -70 to -99 amps.
In this video I never pegged the CHG bar while braking. The Amp meter showed less than -16.1 amps of gain at the most. This is the same as lifting the foot off the gas pedal without applying the brakes. When I did apply the brakes, the regen never engaged. Friction brake is what slowed down the car.

 

did you have the software flash?

 

Yup

 

I have Scangauge envy...

 

My uneducated take is it uses a blend of the two, maybe in varying proportions.

 

From what I have read when you apply the brakes and it goes into the charge area on the indicator scale for about the first half of that is is using the braking motor and the very end half of the charge indicator is actually when the brakes kick in and recharge.

 

According to the Toyota description the friction brake pads are moved "to the discs" but no pressure is applied. This is to "get ready to brake if needed".

So it sounds like we have advantages AND disadvantages living where it actually gets -cold- in winter.

Advantage - battery will probably not have overheating issues -ever- (max. summer temps of around 30C or about 80F).
Disadvantage - warmup can take awhile in winter. Oh yeah, and then there is the ice (solid water type) and snow.