How accurate is the "CHRG" bar?

In my experience, the charge bar is fairly linear and represents the number of amps (or power) going into the battery at any given time, from 0 amps all the way to the right to 100 amps all the way to the left, since the bar goes from right to left.

Prius wouldn't exceed the charge rate because you will overheat the battery or the inverter.

I can be very steady on the brakes and stay within 90-100 amps during situations where I have to brake in a short distance.

 

I don't know that it's beneficial to aim to max out the charge bar, ie: press the brake harder than needed, to increase that bar. The battery will get charged with normal behavior, and I believe the more you can reduce acceleration and decelerations the better for your battery. Both heavy discharge and recharge can be detrimental to battery life.

Basically: drive like your brakes are shot

 

Yeah sometimes an unexpected red light or traffic ahead is at the proper distance where you can stop using regen only, but you must saturate the charge bar almost fully. If you need to stop, why not?

 

The full charge bar represents 100 amps, and not less. No portion of regen is hidden.

 

For so-called "unexpected red lights" applying brakes hard to shave the excess speed and then releasing them and braking at 100% CHRG will charge battery more then braking linear or braking at 100% CHRG and then braking hard.

I am getting better judging the right amount of initial braking needed

 

yea at 7mph i think you get no regen.

 

Skoorb, you may be interested to know that on a steep downhill today and a red light at the bottom, I had about one opportunity to try this.

I maxed out the charge to about 90 - 95 amps, but once friction brakes engaged the amps dropped to 70 - 85.

Unfortunately you can brake (at such a force) for so long before stopping, so I can't really tell if the transition causes the drop in regen (the number of amps), or if it is by design that when friction brakes take over that there is slightly less allowed regen.

 

Damn, that makes total sense...I never thought about doing that.
Usually when the light changes really quick and I have to brake really hard, I cuss and yell because it is such a waste of energy!!!
Thanks for the tip...I love PriusChat

 

I got lot of details in this forum..
Thank you

 

Yes, at least as a thought experiment, that is correct. The reason is that you're maximizing the time during which you're sending amps to the battery. Energy stored is the product of amps to the battery times the duration in seconds that you send those amps times the voltage. In this case, the voltage is approximately fixed (~201.6V), as are the amps (~100 A, the maximum the system can regen). So to maximize the stored energy, you want to maximize the time you spend in regen. The way to do that is to slow the car down very quickly at first using the friction brakes, leaving you lots of room to slow down at exactly the regen limit for as long as possible. No matter how quickly you're slowing down, the friction brakes will do the stopping below 7 mph, so that range doesn't matter.

It's a similar idea to timing stoplights; if a light turns red ahead of your car while you're going 35 mph, you're better off braking early and coasting at 15 mph, and hopefully arriving at the light just in time for it to change. If you stay at 35 mph, you'll cover the remaining distance more quickly, and the light won't have changed by the time you arrive at it, and you'll have to slow down well below 15 mph - and likely stop. (Of course, if it does change quickly, then by slowing to 15 mph, you've lost all the great momentum you had. But the bottom line is that the ideal way to time a light is to immediately slow down to the highest speed such that you arrive at the light just in time for it to change - continuing at a faster speed means that you will have to slow down more when you reach the light.)