Hybrid battery levels

You are referencing the battery SOC, charge bars. Yes, it can be completely charged and the top charge bar is 'pink' but it is not easy nor recommended:

• Drive normally on top of a 150 m tall hill until the charge indications are 'normal'.
• Driving fast as is safe, descend the hill in "D" and brake gently to control the speed.

What you've also done is added about 5-10C to the traction battery temperatures and generate a small amount of gas in the modules. This increases the pressure inside the battery while at the same time, heat weakens the terminal seals. If the car was already in a warm area, the battery modules can leak a little gas and electrolyte leading to traction battery failure.

The recommend approach when descending a hill is to use "B" or engine Brake to control the descent speed. The engine will absorb the excess charge protecting the traction battery and keeping it from heating. But also moderate your hill climb speed.

The ideal hill climb speed is that of a large truck going up the grade. If no trucks around, watch the energy flow and slack off if the car is drawing energy from the traction battery. You want to ascend the hill on engine power, not drawing traction battery power. A low traction battery will require more engine power at the top to replace the charge and that heats the traction battery.

Bob Wilson

 

Yes, what you describe is normal behavior, and no, it will not charge itself to a "full" level after being low; as Bob describes, it only will get to full if you're descending a long hill, or otherwise doing a lot of (regenerative) braking and not very much use of the battery.

The battery wants to be right in the middle of the normal range; this way, it has some power if you need it (either to avoid turning on the engine for low power needs, or to provide a boost for high power needs), and can absorb some power without wasting it (when stopping or slowing the car, typically; but also while warming up the engine). So it will never charge fully, but only to close to the middle of its normal range.

Also, the top bar is not pink in the 3rd gen; it's the aqua-ish color no matter how many bars you have.

 

I would say that when there are 2 bars left and the second bar is almost depleted the petrol engine kicks in. It will charge you to 3 bars. If you are driving with a speed that the electric engine can take over the petrol engine will charge to the third bar and turn off.
Charging full can be done like others said, only by regenerative charging by breaking. When the battery reaches full it turns on petrol engine breaking. It's equivalent to B on the shit stick.
When you drive on a highway or any other road where the petrol engine has to be engaged all the time your battery will get charged but it will leave you 2 or 3 top bars not charged.
The battery will discharge by itself even if you are not driving, if the car is ON and you are just parked somewhere. Of course it won't discharge quickly but still it's a good thing to mention so you won't get worried cause it's normal.
Also if you will be going to a non toyota service, keep in mind that they might not know how to deal with this car and get your battery discharged below 2 bars like I had. You can lose your battery if discharged completely so you should try not getting it bellow those 2 bars.