Stuck in non-moving traffic, went from 6 blue bars to 2 purple bars in 10min.

Pretty typical, especially for a older hybrid.

 

With the AC on, that's normal.

 

If it took 10 minutes with AC on, I would say that is not bad for a 12 year old car.

Engine typically comes on when you go to 2 bars.

 

I spent an hour in below 10mph traffic yesterday, lots of stopping, and just creeping along while leaving a fireworks display at Buffalo Springs lake in West Texas. What you describe is almost exactly what I experienced as well. Outside air temp was still in the low 90s at 11:30 during that crawling exit! I was nice and comfy with ac set to 76, and once I cleared the traffic, the battery got back up in the 5-6 bar range for the rest of the trip home.

 

what was the temp and dewpoint?

 

The AC compressor runs off of the HV battery.
Along with the power used to just creep along in EV mode, why would you think that this is unusual ??
It isn't.
10 minutes is a long time.

 

Used to have the same problem before reconditioning my battery pack... Basically as these packs age they lose capacity due to crystalization issues inside the pack. You break up that crystallization by doing three increasingly deep discharges and recharges. In most older Prius that will restore a battery running at 50% capacity back up to 96% capacity. The science of it is here: BU-807: How to Restore Nickel-based Batteries – Battery University

And the gear to do the work without pulling the pack out is here: hybridautomotive.com

 

For a 2nd Generation Prius, that is indeed perfectly normal. I’ve experienced similar. It does depend on many factors, including how hot it is (both outside and inside your vehicle) that specific day, how long you’d been driving, whether your A/C was on auto or manually set to “minimum life support”, and the TRUE state of charge of your traction battery when you encountered the congestion.

You’re more likely to encounter this phenomenon in hot weather - but, it’s perfectly normal.
Note that even at the purple bars, you’ve still got about 40% state of charge on the HV battery.
Perfectly normal.


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