Battery Not Full ??

[Blind Guy]

Tom;

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

David (aka Blind Guy)

Originally Posted by qbee42

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

[rbarline]

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?

[Old Bald Guy]

Originally Posted by artieb

Got about 1100 miles so far batt. indicator has never been full all bars on, just today moved up a total of one higher but still one or two bars to be full ,is it braking in, cycling etc. book says all bars should top out???....... I love this car.........

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.

[qbee42]

Originally Posted by rbarline

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?

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

[codybigdog123]

Originally Posted by artieb

Got about 1100 miles so far batt. indicator has never been full all bars on, just today moved up a total of one higher but still one or two bars to be full ,is it braking in, cycling etc. book says all bars should top out???....... I love this car.........

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%) -

"At the upper extreme, 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."

[That_Prius_Car]

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!

[SlowTurd]

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

[qbee42]

Originally Posted by SlowTurd

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