Four Blue Bars after short test drive??

The battery being at 4 blue bars is not necessarily a problem. There can be a recalibration cycle that happens, such that the battery will suddenly change its SOC due to temperature change, or just sitting for a while. (This is different from the large swings seen just before a HV battery is about to go.) If it took a couple of minutes to force charge it, that is about right.

What did the MFD say for MPG's?

But, you should definitely notice the engine shutting down after sitting at a stop for a short while, usually about 10 seconds if it is not in Stage 4 already. If it doesn't, there is a potential problem with the 12V battery. Given that the owner is of the oblivious type, I would not be surprised that the 12V battery is original, has a shorted cell, and the engine is running trying to charge it, but can't get to the proper voltage. So check that first.

 

Dropping a couple of bars SOC is not uncommon when taking a short trip with the engine cold. If you force charged the battery to full-8 green bars then it may have even been turning the engine to dump some charge. You should have stopped at 6 or at most 7.

 

Sounds very normal. The red triangle was probably because you did not step on the brake before shifting to D? H

 

Your experience seems rather normal. Engine, catalytic converter, and defroster settings all can force the ICE to run, even with a middle SOC. The computer algorithms are constantly trying to keep a middle SOC, but they're hardly perfect. Optimally, you'd never seen green bars except on a downhill. What really bothers me is when it's showing green at the start of a downhill - doesn't it know the route? Well, no, it has no idea.

What would worry me is if the SOC quickly bounced between the extremes. Another worrying condition would be stopping the car with high SOC, and having it low the next time it's started. Obviously a constant low SOC indicates trouble.

 

The red triangle and message is normal if the door is open, the ignition ON, and the transmission is not in Park. Maybe there's a problem with the door-open sensor?

 

IME the SOC can drop fairly rapidly when the car is on the cold side because the car tends to pull more juice out of the pack to allow the engine to warm up w/o as much load on it, the pack itself can be on the cold side, which will lower it's apparent voltage, and having cold oil/trans fluid/grease just adds to the energy required to move the car down the road.

 

Your looking at this all wrong.

Being green all the time is bad. Its bad in the sense that either your driving condition warrants constant on/off of the pedal or you don't know how to properly drive a Prius. Its sure not a yardstick of battery health.

The first thing you try to learn to get good mileage in a Prius is keep it from a green charge. Lots of turtles.
Green charge means unnecessary motive energy was wasted in regen getting it hyper charged. When my wife drives the car and could care less about hyper she's always in the green and gets 44 mpg's falling off a log.
When I drive it I can get 52 and never in the green.

A really good hypermiler never see's green. Always in the blue. And its not good thing to consistently stow the car with a green battery.

 

There is an excellent facebook entry from Luscious Garage about diagnosing and replacing an HV battery.

Repair of the Day - Gen 2 Prius HV Battery P0A80 | Facebook

 

Stop worrying! The car is acting perfectly normal from what I have read through all your posts. The MFD triangle that went away is not a problem. It is because the door was open. And Wth was the car in N? Don't do that. Leave it in D and unless you live on a mountain, it should never see B mode either. P-R-D are the only places it should ever be in 99.9% of normal driving.

Green bars are bad. The battery wants to stay blue. This prolongs the HV battery life. All green bars is 80% and too full. 1 purple/pink bar is 40% and is too low. In both cases the car will spin the engine. When 80% full, it will spin the engine and waste energy to bring the SOC lower into a sweet spot. When 40% it will charge up to 3 bars then shut off.

The Prius is not an EV. Coming from a GenI, you should know this. You will get worse mileage in most situations driving in EV mode, anywhere. It is fun to creep, but it is detrimental to MPGs. Even with a very healthy fully charged battery, you will only get a mile or so out of the HV battery. It is essentially a big buffer, it is not meant to be the main motive power source.

Also keep in mind the Prius is built for the lowest emmisions, not the highest miles per gallon. It is just a perk. So when you start the car, after 7 seconds (sooner if the HV battery is less than 3 bars, cold, or hot) the engine will start. Even if you don't move. This is part of the "warming cycle" and there are 4 stages. When the engine shuts off, usually 1 minute later at normal temperatures from a cold start, it is in Stage 4 and considered in normal drive modes. Before that the engine will be running rich to warm up faster. It burns fuel just to heat itself and the coolant loop. While in this mode, the car does not want to use the ICE to drive the car because it will emit worse emissions. So as you move around, most of the power is coming from the battery, even though the ICE is running. Only if you NEED power, like stomping on the pedal, will the engine reluctantly rev up and help but then go back to warmup mode. So if you are driving, before the engine shuts off for the first time, your battery will drop like a rock.

 

What 2K said:​

 

A very simple measure of battery health is to look at battery temperature. A battery which only shows minor thermal rise from normal driving is a happy battery.