Battery Not Full ??

My Prius normally leaves room for more regen, but rarely I will do a ton of braking after a 50 mile cruse and get it to go green. But mostly you always want room to do more regen, so you hope it never tops out.

 

On my 2010, I have seen it fill on up all bars only when using regenerative braking while descending hills of at least several hundred vertical feet. When the road flattens out, it is fairly aggressive about burning off the top two bars to make some room for the next descent.

Driven normally, it should never fill up on the flats because this would preclude any regenerative braking on mountain descents, which some of us drive frequently. But you might be able to trick it into filling up more with a series of regen stops from high speeds. I see no point in even trying.

 

If it's anything lke the '07, the onboard computers will keep the battery state of charge between 40 to 80%. normally, 80% will ot show full bars. Likely there's no problem.

 

As lenjack says, the Prius tries to avoid ever having the battery full or empty. And in fact, the icon on the MFD only represents part of the battery, since it will never go below 40% or over 80% of the battery's actual capacity. It maintains these limits to extend the battery life, and is the reason your battery will outlast the life of the car.

(Unfortunately, this only applies to the big traction battery. The little twelve-volt lead-acid battery will probably have to be replaced once every four years or thereabouts, the same as the 12-v battery on any other car.)

 

As everybody wrote, Prius is trying to keep the charge level to the target SOC (state of charge).
So, it does not want to be full.

Ken@Japan

 

Ken;

Our V, which is typically driven short duration commutes (seldom more than 7-9 miles round trip), my wife informs me stays at or near the Top Bar almost continuously.

Live in a flat area, with normal driving speeds around 30-50 MPH (but probably only average around 20-25).

Anything to be concerned with?

David (aka Blind Guy)

 

What book says that all bars should top out? Time to toss out that book for one with good information. As the others have pointed out, the Prius tries very hard to keep the battery at about the 2/3rd position on the display. That way the car has power when it needs it, but still has room for regenerative braking.

Tom

 

Short drives require the engine to run to heat it up. While the engine is running it charges the battery and supplies power, so you will find that short drives tend to result in a higher SOC. In cold weather the effect is even more pronounced.

Tom

 

Tom;

THANKS, with assistance like yours I'm slowly beginning to understand the characteristics of this vehicle!

David (aka Blind Guy)

 

I was going to start a new thread for this question, but it seems appropriate to ask here: what happens if the batt tops out (all bars green) and you still have a mile or two to go downhill? That is exactly my situation every day, as I descend 2000 feet from my home to the freeway. I have noticed that a strange thing happens to the engine once the battery tops out if I keep it in brake mode going downhill - the engine revs up very high - so high in fact that it is disturbing (I don't have a tach so I don't know what the actual RPM is). At that point I always take it out of brake mode because I am afraid of over-revving the engine. I use the brake from then on to the bottom of the hill. Can anyone verify that this behavior is part of the design? I guess that since it can't regen into a full battery pack, it reverts to downshifting the variable transmission?

 

If you want to learn just about all there is to know about the Prius ... from the real world experience of an owner now on his 3rd Prius ... go here John's Stuff - Toyota Prius and more

Don't worry about what the display says about your charge level. The computer in the car is not going to let the batter go under or over the optimal range for the battery. The simplest thing you can do in learning to drive or understand a Prius is

"Just Drive It"

I have been reading stuff on this forum since I bought my first Prius (I am now on my 2nd) and I would suggest one thing to you ... ignore most of the (often wrong) information you see here.

There seem to be too many people here whining and crying about some feature or noise or something on their Prius which is DIFFERENT than what they were used to before they drove a hybrid. Just drive it and don't sweat the small stuff.

 

The high speed operation you hear is MG1 spinning the ICE to waste energy. MG1 uses the ICE as a big air pump. Friction from the pumping burns off excess energy as heat. It's completely normal and not harmful.

Tom

 

Not suppose to charge to 100%. Designed by Toyota engineers to stay (roughly) between 20%-80%.

If you want the engineering details, here ya go: blank

In a nutshell (as to why not 100%) -

[FONT=Arial, Helvetica, sans-serif]"At the upper extreme[/FONT][FONT=Arial, Helvetica, sans-serif], there is a good reason not to go to 100%. For most of the charging cycle, this prismatic pack is about 85% efficient in storing electricty, with the remainder dissipated as heat. But as you get closer to 100%, more and more of the electricity coming in gets converted to heat and the cell temperatures start to rise rapidly. If continued, the electrolyte could boil away, (read pack damage). Now modern 'smart' NiMH chargers try to prevent this by watching for this rise in temperature and turning the charging off. This helps but is not perfect. So Toyota chooses instead to set a maximum charged level of 80%, cutting back the charging current from either the ICE or from regeneration as you get closer, until it accepts nothing and the ICE has to revert to compression braking."[/FONT]

 

The only time my battery topped out was when I was in North or South Carolina, and we were going down that mountain that is about 7 miles long downhill, I put the shift lever into B and coasted all the way down, and had all bars!
Its such a good feeling when you have all bars!

 

when the battery indicator show's full, is it at 80% battery or 100%?

 

80%. The indicator shows the operating range of the battery, not the entire theoretical range.

Tom