Hybrid Battery

If you had the air conditioning on and the ambient temp is high, then the A/C compressor will consume considerable power from the traction battery. Once the traction battery SOC gauge drops down to two red (or pink) bars then the engine should start to charge up the battery. This is normal behavior.

 

The traction battery typically doesn't drain much, if at all overnight. If it drops from full green bars to 1 bar purple, then you may have a problem (or you left the car on).

For me, it appears to stay the same. Any decrease is usually unnoticeable.

 

Dropping 2 bars overnight is not unusual. I've seen it as well and the car was definitely off all night. It seems to be a case of the ECU recalculating what the actual battery SOC is upon the new start. Others have reported the same effect as well.

 

it goes down to 1 bar... at 1 bar it's really only down to 50 percent charge or so.. and when it's full with all green bars, it's only about 85 percent carged... so you're only useing 35% of the battery.

if you have 1 purple bar, the engine will run untill it hits 2 bars or 3 bars.. then shut back off..

if you have two bars, the engine will kick in when you let your foot off the brake... or may kick in ( depending upon accessories you have running) till hit hits 3...

if the pack gets too high, it waste power by forcing you into EV mode...

it's very very very self regulating.

only worry if it never charges back up past 3 bars... ( for multiple days)

 

To pull together the others' comments, the car manages the battery quite well on its own, babying it to prevent over-charging or excessive discharging. Some of us pay close attention to state of charge as we try to eke out the best fuel economy possible, but that's not necessary for those who choose to drive normally. Enjoy the ride and trust that the car is doing its job.

 

One way that the Prius driver can screw up is to shift to N (instead of P or leaving the car in D) when sitting in traffic or a drive-through line, etc. While the car is in N, the hybrid system cannot charge the traction battery.

If you have the A/C compressor on then the traction battery will quickly discharge, perhaps beyond the point that the system can recover. So, avoid the use of N in normal driving.

If you go through a car wash where you need to shift into N, I suggest you make sure the A/C is off.

 

That leads me to a question...How do you set up the car when going through one of those car washes that pushes the car along a track and the wheels have to spin? Must you leave it ON and either in N or D?

Thanks!

 

I wasn't sure whether the wheels spin or not - I haven't used one of those car washes in years.

Another rainy day in PA...

 

If you press the power button from off twice then select neutral the wheels will be free to turn and the engine wont start. I would leave the AC off in this mode. At the other end, select park then with your foot on the brake press power button again, the car will go into ready mode.

You can also select neutral while in ready mode but if the battery runs low it can't recharge.

 

Personally, I've never been in a car wash that took so long that running the A/C drained the battery

 

Mine defaults to recirculating air when I turn on the AC.

 

Find something else to worry about. This is normal. 2 bars represents 40% charge. The car will keep the charge state between 40% and 80%. This maximizes battery life.

 

The AC turning on recirculate is good, and should happen except when the outside air is cooler than the inside air.

From right at just below the green bars, I was able to run my AC for about 25-30 minutes before it hit the first purple bar. Ambient temperature was over 90º, and the AC was set around 77º.

The lower you set the temperature, the harder it works and the quicker it will eat your battery.

If it's hot and sunny where you are, invest in a sun shade for your front window and a good tint job. The glass in the Prius (at least the sides and rear) are pretty good at rejecting heat, but some tint could help quite a bit. Leave a window cracked if you can, and park in shade if you can.

When you start out on a hot day, roll down the windows to flush out the hot cabin air. Turn the AC on and set it to fresh air for a couple minutes. When the hot air in the cabin is flushed out and is about the same temperature as the outside air, roll up the windows and leave it on fresh for another minute or two, then turn on recirculate.

It's also a good idea not to set the AC on full blast (down to a really low temperature) if you'll be comfortable with it at a higher temperature. The temperature setting just controls the speed of the fan, apparently. In 100º weather here, I can be perfectly comfortable in my car with the AC at 75º.