Should the battery fill completely?

Mine does.

 

The car always try to keep the state of charge (SOC) at a level (something like 80% of the displayed battery) that keeps enough energy in store to move the car with the motor, and at the same time, keep empty space available to capture energy when you use regenerative braking (every time you brake progressively). If it was to charge the battery completely (with the engine), it would not be able to capture this free energy, which would be therefore lost.

The battery has two roles: provide power to the motor to avoid running the engine in inefficient manners, and to capture back energy from the generator while braking.

You may see the battery completely full at some times, but it is rare (depending on the terrain). For exemple, if you go down on a very long slope, you may completely charge it with regenerative braking; then the car will try to go back to its ideal SOC.

Note: To ensure a long life of the battery, the real SOC is always kept between 40 an 80% of its capacity. Hence, what you see on the screen as an empty battery is equal to a real SOC of 40%, and what you see as a full battery is really a 80% SOC.

 

I almost posted this exact question this morning, as I have never seen my icon full on my 1 week old Prius.

I found another thread on the topic, and it seems like the consensus is as stated here; 40-80% is normal, rarely you may see it full.

 

I see mine all full every time I come home because I have a long drive down a hill about 4 miles 7 klm

 

I don't know, but defer to others with far more experience. All I can say is that in 6 months or so, I have never seen mine full. Almost full, yes. Totally full, not yet.

 

I drive all over different terrain and the only time the battery will show completely full is after a long decent on steep hills. The car does weird things when the battery is really full (still no more than 80% even though it shows full on the screen) and will run on electric only upto about 45 mph. It goes as quickly as when you have selected EV mode but doesn't cut out until much higher speeds.

I believe the car isn't too happy having a full battery and will try to reduce the level back to its 'happy' level as quickly as possible. There are many technical reasons for this but I won't bore you with them.

Don't worry about damaging the battery though as the car is programmed to look after itself.

 

I have had mine up to the top bar a few times. Very easy to do around Brighton. Lots of steep hills and reasons to put the brakes on. I have wondered if there is a bonus bar in the two little lugs at the top of the display

 

Well put, I have had my car since July and have only seen if full a few times. It does make sense to keep it off full for normal driving so when you do experience a long down grade you capture that free energy for most of the trip. I would love to do the "plug in" upgrade but, at the cost they want, I would never recover my money back. Also, has any one replaced the original batteries with Lithium? Is there a significant battery capacity increase?

 

It'll fill completely if you go down a hill long enough and the last bar is a slightly different color (salmon).

 

Not on my car. They all are the same color

 

We had this huge debate a while ago.

 

Agreed--I even posted a pic from my car in a thread a while back, as did another member.

 

Go to the last post on page 5 (the current last page) for the summation of what is going on. Pics are on pages 4 and 5, I believe.

 

Which thread are you referring to? The one linked above only has 2 pages.

And the last post in that thread makes statements that conflict with what I experienced (as indicated in post 41).

 

Ive had my car for a little more than a year. So far my battery was 100% only 2-3 times, after coming down from the mountains. I thnk that the battery rarely is 100% full because it is always in use, assisting the engine during acceleration etc

I think.

 

It takes a long steep hill to get it to show 100%/all bars showing. The hill that does it for me is over a mile long and rather steep. You have to brake virtually all the way down.

 

But it's not conclusive. If I'm sitting in Stream's car and I can see it but he can't then it's user color perception that's at play. If, on the other hand, I can't see it in his car and he can see it in mine then some Prius have it and some don't.

FYI: My headlights weren't on when I noticed it.

The number of posts per page can be customized, hence it may be different between members. It's best to refer to post number rather than page number for this reason.

 

Top bar is NOT 100% full. It is 80%. Keeping the state of charge between 40 and 80% will extend battery life to maximum.