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I know it has regenerative braking, but at what point are the break pads used? The power / recharge gauge on the left doesn't say, so I was curious if the needle was half way or or all the way down did that mean it was using more than just regenerative braking to slow the car down. Or, maybe it always uses the break pads. I don't really know.
 

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Below 10mph and above 60% brake pedal effort (approximately) blends to friction braking.

If your slowing at a steady deceleration and your regen kW starts dropping off then its handing over to friction. Same as when your regen meter maxes out and you demand more braking.

So whenever your slowing and not gaining electrical charge its using friction brakes.

If case you havent seen this

 

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You sure about that? There's more kinetic energy to convert back to potential energy between 50 to 40mph than there is from 20 to 10mph.
You need to use your common-sense here.. there are many factors.

If your still slowing and your not generating nearly any electricity then your slowing using friction. Try it - Target a specific kW regen value like 10kW and maintain it and you’ll experience what I’m talking about.

For a true understanding, test drive an i3.

It regens to a stop; then you’ll understand how much energy is still available at these lower speeds..

If you want specific function description of the braking system and the many factors involved, refer to this Tech Authority document.. but note it does define that regen is “not active below the minimun regen speed”..

https://www.dropbox.com/s/iydk8w455jjechz/Brakes Function Description.pdf?dl=0
 

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You need to use your common-sense here.. there are many factors.

If your still slowing and your not generating nearly any electricity then your slowing using friction. Try it - Target a specific kW regen value like 10kW and maintain it and you’ll experience what I’m talking about.
Oh, it's common sense alright. And a simple understanding of Newtonian physics. When you say "If your slowing at a steady deceleration and your regen kW starts dropping off then its handing over to friction," I assume you're meaning you believe it's the friction brakes. I'm simply saying that it's not accurate to say that there's the same potential energy available, as you slow at a steady deceleration. That's just physics. Of course there's less kinetic energy converted to potential energy. That doesn't mean the conventional brakes have engaged.

Put your van in L. Watch the display as you take your foot off the accelerator. You'll return more energy to the battery when slowing between 50 and 40 than you will between 30 and 20. That's without touching the brake pedal. It's simple physics. There isn't as much kinetic energy to recapture. It doesn't mean the conventional brakes have engaged.
 

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Oh, it's common sense alright. And a simple understanding of Newtonian physics. When you say "If your slowing at a steady deceleration and your regen kW starts dropping off then its handing over to friction," I assume you're meaning you believe it's the friction brakes. I'm simply saying that it's not accurate to say that there's the same potential energy available, as you slow at a steady deceleration. That's just physics. Of course there's less kinetic energy converted to potential energy. That doesn't mean the conventional brakes have engaged.

Put your van in L. Watch the display as you take your foot off the accelerator. You'll return more energy to the battery when slowing between 50 and 40 than you will between 30 and 20. That's without touching the brake pedal. It's simple physics. There isn't as much kinetic energy to recapture. It doesn't mean the conventional brakes have engaged.
Sigh, so much for common sense.

Do you think this is what the Op is asking? I’m sure they want to get into a broad and technical, math intense discussion over the whens and when-nots of regen..

There is a point when the HCP discontinues regen. That is the handover point.

Its 10mph, and above the max regen capability. Simple.
 

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I know it has regenerative braking, but at what point are the break pads used? The power / recharge gauge on the left doesn't say, so I was curious if the needle was half way or or all the way down did that mean it was using more than just regenerative braking to slow the car down. Or, maybe it always uses the break pads. I don't really know.
I think it always uses the brake pads at some point to come to a complete stop. But using the pads at such low speeds probably won’t wear them down very fast. My brother-in-law has had a hybrid for over ten years and he’s never had the brake pads replaced. I think if you go easy on them they will probably last the life of the car.
 

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You sure about that? There's more kinetic energy to convert back to potential energy between 50 to 40mph than there is from 20 to 10mph.
I just checked and found that the relationship between speed and kinetic energy is exponential. A vehicle going twice the speed of another has four times the kinetic energy.

So, naturally, in a steady deceleration the energy generated by regenerative braking will drop off pretty quickly as you slow down. Most likely the more pedal pressure you use to stop the earlier the mechanical brakes will start to fade in.
 

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Oh, it's common sense alright. And a simple understanding of Newtonian physics. When you say "If your slowing at a steady deceleration and your regen kW starts dropping off then its handing over to friction," I assume you're meaning you believe it's the friction brakes. I'm simply saying that it's not accurate to say that there's the same potential energy available, as you slow at a steady deceleration. That's just physics. Of course there's less kinetic energy converted to potential energy. That doesn't mean the conventional brakes have engaged.

Put your van in L. Watch the display as you take your foot off the accelerator. You'll return more energy to the battery when slowing between 50 and 40 than you will between 30 and 20. That's without touching the brake pedal. It's simple physics. There isn't as much kinetic energy to recapture. It doesn't mean the conventional brakes have engaged.
I just checked and found that the relationship between speed and kinetic energy is exponential. A vehicle going twice the speed of another has four times the kinetic energy.

So, naturally, in a steady deceleration the energy generated by regenerative braking will drop off pretty quickly as you slow down. Most likely the more pedal pressure you use to stop the earlier the mechanical brakes will start to fade in.
Both of your are absolutely correct..

But peak available energy isn't alway the most useful. It is better to harvest energy at a lower linear value over a longer time than to generate peak loads - You have the entire area under the exponential curve that you can opt to use.

20 sec of 20kW = 400kJ
3 sec of 80kW = 240kJ

But this question wasn't the question asked. This is what our common sense should dictate.
 

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This is what I was responding to.
Ok, i’ll bite. The op doesnt seem involved anyway. :nerd:

I feel if you followed my example that my statement would be true.

Ie: Hold 10kW regen slowing to below 10mph and it will drop off; no amount of increasing the deceleration rate will bring it back up to 10kW or higher.

My use of the phrase “steady deceleration” wasnt referring to g’s but rather a regen rate.

I thought this was the hangup.. Because holding a steady gforce deceleration would make that statement false.

It’s not necessarily correct. This is a forum—we talk about things.
Wasn’t there a formula that describes the state of forum conversations by W. Boltzmann; S = k log W :wink2:
 

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Both of your are absolutely correct..

But peak available energy isn't alway the most useful. It is better to harvest energy at a lower linear value over a longer time than to generate peak loads - You have the entire area under the exponential curve that you can opt to use.

20 sec of 20kW = 400kJ
3 sec of 80kW = 240kJ

But this question wasn't the question asked. This is what our common sense should dictate.
I agree completely. That’s why I start braking early and with a light touch at first gradually increasing pedal pressure as the van slows down. That is my attempt to create a more steady regenerative charge when braking.
 

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Ok, i’ll bite. The op doesnt seem involved anyway. :nerd:
I am here reading the comments and enjoying the discussion. Feel free to keep going :nerd:. I didn't realize the braking algorithm was any more than pedal is pushed in more than x, so use friction brakes. It is nice to find out I may never have to change the pads though. One less thing to fix is good in my book.
 
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