Yes but in the TCH (and probably the NAH) the battery gauge is calibrated so "full" is the 80% and "empty" is the 40%, or whatever those percentages are. So you can see the gauge go to the limits. It just won't let the battery go beyond them, and makes it difficult to even reach the limits in "normal driving".

Every time the KW needle is in the white, energy is being drawn from the battery. Since most of the time the ICE and the electric motor are running at the same time, what comes in from running the ICE goes right out running the electric. This is why during most driving the charge indicator hovers.

When in EV mode or under heavy electric usage, the charge indicator goes down. Right before it hits empty (Which I have been told is not really empty) the ICE turns on to give the battery a charge.

When the KW needle is in the blue, the charge is going up, but this only happens when breaking or coasting.

The only time I have ever seen a "full" charge is after coasting down a long (mile+) slope. Even then, it doesn't stay at full for long because the system is balanced to stay in the top third during normal driving.

Why? I'm not sure.

Today I faced the dead battery situation after coming back from a
long vacation (5 weeks). The car was off before I left but the
manual asks to disconnect the negative terminal from the 12V
battery before a trip longer than 2 weeks which off course I did not
do.

The hybrid battey leaks power even when the car is off to keep some
electronics alert I guess, and eventually drained out. Since the
car was off the ICE did not trun on to recharge the battery.

Then the 12V battery discharged I guess due the same reason
and when I arrived the car was silent. Even the the doors did
not recognize the key fob. However, it had the good sense to
automatically unlock the doors before going dead. Otherwise I
would have been in a complete mess. (Even could not have
gotten it towed from the garage without some damage)

Anyway, jump started it from the second car which thankfully
being only an uncomplicated ICE car, had enough juice even
after 5 weeks. Just used the procedure in the manual.
The NAH started fine, the ICE immediately came on.

I thought everthing was fine. Was surprised to see the hybrid
battery showing half charge - that is where it was when I
left the car. So I disconnected the jumper cables.
Then the surprise. The ICE shut off when the CAT converter
was warmed and the car again went dead.

So had to jump it again. This time found the hybrid battery
at negative charge as it should be - not the half charge. This means that
the battery charge reading was not reset when the car first
went dead or even during the initial ICE-on phase after the first
jump. This incorrect reading lead to the ICE shutting
off when the CAT warmed and the car going dead as a result.
This is definitely a bug in the firmwire of the car.

The second time the ICE stayed on while the hybrid battery
charged and I drove aroung for about 5 miles while the battery
went to full charge. Things were OK from then on.

So the trick is to run the NAH at > 40 mph from the initial
jump while the ICE is warming the CAT. Otherwise if you
go into EV mode after the first jump, and the battery has not
charged, you may stall at an intersection.

Even if the doors didn't automatically unlock you still could have used the physical key inside the fob to unlock the doors manually.

That is true if the locks have a completely mechanical override.
I am not sure of that. If they are electro-mechanical then they
will not work with a dead battery. I tried the boot release lever
on the dash to open the boot when the battery was dead and
it did not work. I will figure that out the next time the battery
goes dead

I'm considering getting the NAH, but frequently take multi-week business trips and I'm concerned about the battery going dead. I'm not sure how I'm going to get the long term parking attendant to disconnect my battery cable.

But independent of that, if when you jump the car it thinks the battery level is ok, but it has been drained, with what you described above, wouldn't you have to worry about the ICE turning off at some stop sign or traffic light before you can get to a road where you could drive 40mpg? From your post it sounds like if it does you probably wont be able to restart the car.

If the behavior you described with the car not knowing the battery drained is typical, you might need to jump the car once, let the car realize the battery and reset itself and then jump the car again.

This dead battery thing has me nervous. I'm also looking at the TCH. They have an interactive site that discribes the car and one of the things is mentions is Toyota doesn't recommend you leave the car unused for more than 2 weeks. They say something about if you do, your car might not start and you will need to contact Toyota.

-Bruce

Bruce, the NAH and TCH are the same car, just a different wrapper. You are concerned about abstract situations. Leaving the car running or in a cold garage in winter for two weeks will affect any car. I have the NAH for almost 1 year now and I drive it just like all the other cars I have owned. If your high voltage battery runs down, the car will just run the gas engine until the battery is charged, you don't have to do anything. If the 12v battery runs down, you jump start it. (yes a few additional steps are involved but the jump start is the basic need) On public forums you will find the exceptions in regards to battery issues. The hybrids are all new <10 years so not many issues will show up. When cars first were first developed you probably found many issues with wheels or tires and so on.

I have left my car at the airport parking garage in the winter for more than a week with no problems. I have never had a problem with cold weather effecting the battery. My car always starts. The only difference is that your mileage will go down in the winter 2-5 mpg.

I think all you need to do is disconnect the +ive 12V battery terminal
before leaving the NAH at the long term parking lot. The 12V battery
in the NAH is easily accessible from the trunk. It would have been
good if they just provided a concealed switch.

Haven't looked at the jump starting instructions yet. But, I wonder -- can one of these 12V charges (that plug into the lighter) be used to recharge the 12V battery if it dies?

Thanks

Hand calculated numbers, not trip computer data.