Gen 3 "Happy Battery" icon???

Happened only once in almost 2 years in my car driven in city on a mostly flat terrain. I understand that is actually not healthy for the traction battery.

 

Well its kind of like weighing yourself, you dont weigh yourself everyday, maybe once a week. so look at your display every week not every minute, it just doenst makes sense.

 

I have had mine for 7 months and 7000 miles. I have had full battery 3 times (for a short time).

 

I have owned my 2012 Prius since March 23 and I have already hit full battery once for a short time. there is a long downhill into my neighborhood that requires braking and that is where it happened.

 

If you search on this forum you will find all kinds of posts explaining the battery indicator.
A synopsis -
All bars lit - your battery is around the 80% charge level. The HSD will try to get it back down to about the 60% charge level, including by "wasting" power. So while having all bars lit may at first glance be "wow good", it really serves no purpose. It IS an indication the HSD is working.

Less than all bars lit but more than no bars lit - normal operating level of charge. It will cycle up and down, and can do so in a matter of a few minutes (the battery doesn't really hold much energy compared to the energy it takes to move the car down the road).

One or no bars lit - this is an indication you have "run out" of usable battery charge. You can get there climbing a very steep mountain pass, or by using A/C cooling while in "N" for example. You shouldn't tempt this level of charge too often, though if reached in normal operation (the use of "N" is NOT "normal" or recommended) it won't case any harm. The actual charge level with one or no bars is about 40%, so there is quite a large "buffer" built in.

Keep in mind that the HSD historically has been very good at protecting the battery.
Operation involving taking the charge level very high or very low is avoided by the HSD. The reason is -
Taking the charge level too high will result in overcharging at least one cell (the cell with the lowest capacity) which can result in overheating it and the loss of electrolyte. This will reduce the capacity even more, and will eventually result in a dead cell if the cycling of charge level is allowed to continue.
Taking the charge level too low will result in fully discharging the cell(s) with the lowest capacity and then -reverse charging- them. This will destroy those cells.

So the HSD operates between a high of about 80-85% charge and a low of about 35-40% charge. This ensures a long battery life. The charge display is calibrated to show 100% -usable charge- or actual 80% charge with full bars and 0% -usable charge- or actual 40% charge with one or no bars. You might say the display is fooling the user, but it displays "usable charge", not total charge. So it's telling the truth!

So don't worry about the charge level, the HSD will keep it in the "right area". I'll step on Nissan's toes and say "Enjoy the ride".

 

I use my brakes so infrequently that my ICE has to turn on to provide charge to the battery all the time. I've had a full battery icon about 5 or 6 times in the past month of owning it. I do live in hilly terrain though, and some of the hills require engine braking, or constant regeneration braking to get down safely.

The reward? Going to the gas station once or twice a month instead of once or twice a week.