2012 Prius struggling during first 10 minutes during high heat

You could try Dr Prius (phone app). It requires an OBD Bluetooth dongle; Carista worked well for me, with an iPhone. Simple assessment looks like attached.

 

Too many factors to give any real diagnoises....
It does seem like your hybrid battery is weak. Is it original?
It seems this issue began when you stayed in the city. The hybrid battery
does take longer to charge up with city driving.

Have you had the egr system cleaned? Changed the air filter?

Since you don't want to do any work on it, you need to seem a good shop that
is familiar with the Prius and get a diagnoised performed.
Mostly what you'll get here is "guesses" as to what it could be. And it will only
fustrate you.

Since you don't want to do any work on it, you need to find a good shop that
is familiar with the Prius and get a diagnoised performed.

 

Yep, sounds like a weak traction battery. If the cooling fans in the traction battery pack has never been cleaned out - now probably a good time to do that and make sure it's operating correctly. It's probably too late but it sounds like a couple of weak cells in your traction pack. Your entire pack recharges back up in about 10 minutes, then your symptoms goes away. Once you park the car overnight the cycle repeats. If you don't blast your AC, the draw on your pack is lessen and you problem will probably go away for now.

Hope this helps....

 

Air conditioning often works harder (draws more power) in the first few minutes, assuming the car is parked outside in sunlight.

Try a trip without A/C.

My guess (and it really is a guess without direct diagnostics) is that your A/C load vs. a hot cabin is enough to make a "fair" battery act like a "poor" battery.

After those first few minutes, the A/C energy demand slacks off, and there is more available for other duties.

 

If I watch the "A/C watts" PID on my ScanGauge while driving, I see the car often drops the compressor power to zero when I ask for any more than modest acceleration.

Some old mopars and the like would have a "WOT Cutout" in the A/C clutch circuit, for the same reason.

So I'd like to think it isn't the A/C sapping too much power when you're actually trying to accelerate....

 

That's because you had windows closed in the parking lot and the battery pack was hot. Upon first using the car Use the air conditioner to cool the battery pack. The status you describe is protection from heating the battery up more

 

BTW, do not plug it aftermarket dongles into the OBD Port.

 

I can imagine, that something like this would happen, if the HV-Battery is simply too hot.
The system is not allowing to charge or discharge the battery to protect it.

The effects - the ICE hast to do all the work to accelerate the vehicle, and it is reasonable weak engine
And after taking the foot off the accelerator, the ICE has to slow down the vehicle too - without charging the, still too hot, battery, so it is revving up and not going down to idle.

Does this sound plausible?

Mat