2002 Prius New Traction Battery but now low MPG & odd noise?

We bought a 2002 Prius a couple of years ago with 91k miles. It ran great until July 2013 when the HV battery needed replacing. We put in a ReInvolt battery and were good until a month ago when error codes popped up indicating a bad HV battery with cell banks failing. ReInvolt, now owned by Dorman Electric, replaced the battery under warranty.
Upon driving home from the repair center I noticed an odd noise behind the right side of the dash which sounds to me like an electric short. This sound is only made when the car's gas engine is between 2500 and 2800 rpm. I can consistently reproduce this especially by driving up any incline and hold 2750rpm (where the sound comes up the loudest). There are no error codes showing in the main computer (using a ScanTrip II unit).
Fuel economy was a solid 44 to 45.5mpg with our usual mix of city/highway driving. On certain roads where I've learned how to drive the car so it will stay on EV only for a particular section it no longer will. It never stays in electric-only for very long. My fuel economy has dropped to around 38.5mpg.
I am concerned at the significant drop in fuel economy but more so at the noise behind the right side of the dash which sounds like an electrical short.
I plan to take the car back to the repair shop which was authorized to install the Re-Involt (Dorman) battery; however I'd like to maybe have more information to give them. (Anything to keep the diagnostic costs down! A hybrid mechanic at over $100+/hr adds up really fast!)

 

The 12v accessory battery is in great shape - 1yr old Optima glass mat battery. When the shop tested the SOC on the traction battery they also checked the 12v battery and found it to be very good.

 

I'll try for an audio sample and post it if I get anything usable.

Yes, I too thought about something resonating due to the rpm; however the type of sound combined with the recent premature failure of the traction pack after <1yr and subsequent lower fuel economy has be considering that it may be something else.

As for driving - I'm comparing to previous travel along the same roads in my area where I've learned quite well how the car should perform. I'm one who notices every little squeak and rattle, check my fuel economy on every tank (with my non-hybrid car as well as my wife's Prius). I know how often and what parts of which roads the car should be on electric only versus having the gas engine kick-in. The on-board fuel economy readout isn't entirely accurate, but where it was showing a consistent 43/44mpg it now shows 38/39mpg.

 

Well, my wife's Prius broke down today after I stopped in at my second job to work for a brief period. It started, then the gas engine shuddered and shut down after about 10 seconds throwing an error code P3191.

I am attaching an audio file from my iPhone where you'll hear the buzzing/arcing sound as the car gets up to 2700rpm.

Now waiting for the tow truck to arrive... :-(

It won't take the .m4a file..

 

Well, how about an update! The buzzing sound is gone. It may have been a loose mount but that's all that could be found so far. Everything electrical checked out fine. The car stalled because the computer told it to shut down. The error code indicated that the car didn't start properly (?) and cut off the fuel supply forcing a stall. Of course the car didn't fail once for the shop even after they drove it extensively. A fuel pump spectrograph showed that the pump was working just fine. I replaced the MAF after finding one from Dorman for $52. So far the car is running and not stalling.
I am concerned though since having the new traction battery pack installed (warranty replacement from Dorman after the ReInvolt pack failed just shy of 1yr old) my fuel economy isn't as good as it was prior. We were getting 43mpg in normal mixed city/hwy driving but now I'm seeing 39mpg even after replacing the MAF. What's odd is that two long trips this week of 250 miles each (separate days) saw 48mpg and then 47mpg. It's the driving around town in the usual places where I'm concerned at the apparent falloff of fuel economy. Maybe the O2 sensor should be replaced next. The car has a fresh engine oil/filter change, transmission oil/filter change, new air filter, new MAF, and even a new cabin air filter.

 

Having worked with electronics for over 30 years I can say a component shorting out does have a unique sound. This was similar to what I heard -

The cause was found to be a bad 12v accessory supply cable which had been rubbed through the insulation on a metal frame in the lower dash.

My real reason for replying here after a year and a half is to report the Dorman battery is now failing after only about 15k miles and 18 months with repeated P3006 and P3012 codes. It seems the ScanGauge 2 can only read SOC on the Gen1 Prius and not Delta SOC. I am seeing the SOC change by more than 60-70 points. Does anyone know if this is normal behavior?

 

The car is located now in the Frederick, MD area. I sold the car just before Christmas after having some maintenance work done - inverter coolant flush, transmission flush, oil change, serpentine belt. Unexpectedly one month later it began repeating P3006 codes and then P3012. The shop which has it now (Dynamic Automotive) says the pack is bad and not just the cells indicated by the P3012 code.

So a brief history & lessons learned: A Re-Involt battery was installed in July 2013 but failed in June 2014. Dorman Products (who bought Re-Involt in October 2013 and appointed David Taylor from Re-Involt to run their new Dormany Hybrid division) handled the warranty replacement of the battery pack in July 2014. The Dorman replaced battery pack failed 18 months later in January 2016. Dorman will not replace the pack under any warranty since they point back to the original purchase with ReInvolt which carried an 18-month warranty unlike Dorman which now has a 3-year warranty. From my experience anyone buying a Dorman battery may very well need that three year warranty! Mine lasted only a mere 18-months and 16,000 miles! I now look back and kick myself for ever trusting Re-Involt and (not by my choice) Dorman. So disappointing!

 

No. I do feel very bad and want to try and help because we sold him the car at a discount since he's been out of work for a year and the family needed transportation. Many friends and family actually pitched in to buy the car for the family. It was a reliable vehicle for us so this battery failure after only 18 months and 16,000 miles was totally on expected.

I am absolutely appalled that two batteries from Dorman, or Re-Involt, were bad. I am utterly disappointed that they have failed to stand behind their product.

 

The closest thing I see on the ScanGauge site is a battery charge and discharge reading.

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