Green Battery Display?

<div class='quotetop'>QUOTE(TedSeachord @ Jul 11 2007, 08:51 AM) [snapback]476731[/snapback]</div>

No, and it shouldn't under normal driving conditions. The Prius will charge to the top of the bar chart only under special circumstances, such as braking down a long hill. Think of the battery in the Prius as a flywheel that temporarily stores a small amount of energy for later reuse. When you step on the brake, energy flows into the battery. Step on the gas, and energy flows out. The Prius wants to keep the battery at middle charge, so there is always room for energy to flow in and out. If the battery charge gets too close to the top, the computers on the Prius will tell it to use more electricity and less gas. When the battery gets too low, it does the opposite.

Tom

 

I hit green bars twice, the day after I picked up the Prius. (Road trip to NY.) I have yet to hit low-charge purple, however. I tend not to really pay much attention to the bars now; I'm more often looking at MPG.
But I still don't know how I feel about the concept of using the battery as little as possible, to achieve better MPG. I do try to glide, whenever I can... but in stop and go traffic, I seem to hit lots of regen deceleration, which I figure must help make up for any discharging I cause, say in garages or parking lots, or flat roadways, when driving a bit on battery-only. I'll often see a one or two bar recharge gain, on gradual decelerations, with no ICE arrows helping.

 

I've only seen green a couple of times, mainly on downhills as expected. I see purple all the time, but I'm running the A/C full blast -- it's been 100-115F here.

 

<div class='quotetop'>QUOTE(Danny Hamilton @ Jul 3 2007, 03:49 PM) [snapback]472480[/snapback]</div>

Hi - I'd also be very interested in the answers to these questions. I have had my 2007 Prius for about 3 & 1/2 months and really don't want to have to jump the battery so would like to know what might cause it to totally run down. Am I correct in understanding that I really don't need to worry if the Battery Bars get down into the purple ones? Thanks for any guidance you all can provide.

 

<div class='quotetop'>QUOTE(Danny Hamilton @ Jul 3 2007, 04:49 PM) [snapback]472480[/snapback]</div>

1. The traction battery will not charge when the Prius is in N. Don't put your Prius in N. Except for some very specialized situations, such as getting dragged through a car wash, there is no reason to ever use N.

2. See above. Don't use N.

3. See both of the above. The Prius will complain via the MFD, then eventually shut down.

4. See 1 & 2 above. It will shut down, but you can start it again. Repeated use will discharge the battery. If you run the traction battery down, your Prius will have to be towed to a Toyota dealer where they can use a special high voltage charger. You don't want to ever have to do this.

In case I didn't mention it above, don't leave your Prius in N. Stay in D or Park, and all will be well.

Tom

 

<div class='quotetop'>QUOTE(David Beale @ Jun 30 2007, 05:54 PM) [snapback]470767[/snapback]</div>

I've only had my Prius 3 weeks and I've seen the green bars at least 6 times during this period. (Only 7 bars, not 8 yet. No long enough hills here.)

I beg to differ on this as well. Acceleration is the hardest thing a car has to do, and an electric motor is always more efficient than a gas one. I usually accelerate very gently (when possible) to try and stay in electric mode during acceleration and so far I've averaged 53 MPG, so it must be working. I also back off the accelerator pedal when cruising then press it gently again to either glide or go into electric-only mode to maintain speed. Depending on the terrain and battery SOC, it usually works. (If not, the ICE just comes right back on again.) Maintaining speed is very easy to do and an electric motor will use very little power to do it on a relatively level surface. This is how I can go miles in electric-only mode despite the puny battery.

This is probably where EV mode could get you into trouble: if you use EV mode for acceleration, then accelerate pretty hard, you'll use quite a bit of battery energy which of course the ICE eventually has to replenish. What I'm not sure of is if the engine is more efficient acting as a generator or driving the wheels during acceleration. (I'm thinking the latter, due to how the computers behave.) But then, if you accelerate too hard, EV mode will auto-cancel, so I guess it's not worth worrying about too much.

 

<div class='quotetop'>QUOTE(Nicole @ Jun 6 2007, 12:16 PM) [snapback]456720[/snapback]</div>

If the car is warmed up and you treat the accelerator like there is a raw egg (in the shell ) between it and your foot you can get it up to 25 mph. I managed to do this this morning after I got a green light and no one was behind me, my destination was only a half a block.

 

<div class='quotetop'>QUOTE(Inches @ Jul 14 2007, 11:30 AM) [snapback]478667[/snapback]</div>

I almost daily get up to 41 MPH on battery alone, then at 42 the engine kicks in. The furthest I have driven on just battery is 5 miles, and by the end I was doing 20MPH down from 40. In town I try to run on just battery, with just spurts of gas when needed where the road rises. Once the battery level reaches 4 bars, the engine will kick in more frequently. From a dead stop I can get it up to 40 on just battery without the engine ever kicking in when the battery is full green. In these situations is where I gain back lost MPG from all the highway driving I do. My overall is 47 MPG since day 1. My highest has been 59, the lowest 41. Currently it is sitting at 49 MPG.

 

You will never see the top bar appear, nor will you ever see the bottom bar disappear.

Y'all are worrying way, way too much here. The car is behaving as normal. The controller keeps the battery within the optimum range it needs for safety and longevity. The display is just an indicator, and really has no meaning to you, the driver. You can't control what it does with the battery, not really, so just drive the car.

 

<div class='quotetop'>QUOTE(Pegasus_ @ Jul 13 2007, 11:19 PM) [snapback]478523[/snapback]</div>

What you forget in this equation is the inefficiency of storing and retrieving energy from the battery. i think I've heard it quoted somewhere around 30% efficient, (%70 loss). So for every 10 joules of energy the ICE generates that is used to charge the battery, you only get about 3 joules out to drive the car forward. It is much more efficient to never put that energy into the battery system.

 

<div class='quotetop'>QUOTE(chuck_k @ Jul 14 2007, 11:17 AM) [snapback]478684[/snapback]</div>

This is false. I see the top bar appear every day on my way downhill from 7,600' to 6,000'. You just have to coast a lot for it to happen. I've also seen the bottom bar disappear going the other direction.

That said, I agree with the rest of your post - i.e. don't worry so much about it.

-Sean

<div class='quotetop'>QUOTE(Inches @ Jul 14 2007, 10:30 AM) [snapback]478667[/snapback]</div>

Folks, driving on battery power alone should never be a goal. If it happens great, if not that's fine too. Remember, the only way that battery got any stored energy to being with is because the ICE put it there (either directly or indirectly). ALL of the energy for the car - ALL of it - comes from the ICE. Converting it to battery and then back again into the motor has losses, so it's better to never have to do it in the first place. The point of having the battery is to catch energy that would otherwise be lost entirely.

The goal of pulse and glide is to either run the ICE where it's most efficient or not at all.

-Sean

 

<div class='quotetop'>QUOTE(TedSeachord @ Jul 11 2007, 05:51 AM) [snapback]476731[/snapback]</div>

OMG.... HOW CUTE!!!!!!!!!!!!!!!!

 

<div class='quotetop'>QUOTE(ACD @ Jul 14 2007, 10:12 AM) [snapback]478681[/snapback]</div>

How do you get it up to over 40 MPH without the ICE turning on?? Do you have the EV mod?? Even with that in the documentation says the ICE will kick in at around 34 MPH.

 

Me too. I assume the battery in question is the Hybrid?

 

correct