questioning dealer service advisor

My *best* average hi-way MPG is 46. Without running the AC. Always. And forever. With a new hybrid battery. And plugs. And PCV. And tires inflated to 42 PSI. And intake filter.

Now what would it look like if you were trapped in a field of white with nothing but your own thoughts and a Gen II Prius for a thousand years? A million? A billion? A trillion eternities? And then - quite suddenly - thrust into the world of light and sound and smell. Writhing in a body that has seen nothing and everything for a trillion eternities. Has thought every thought for a trillion eternities. With yellowed, strange corneas that has seen God and the devil a thousand times over. A billion times over. Recited every story and nursery rhyme until the rhyme *is* you.

And then you get "only" 50 MPG? Why...I think you would go insane.

And claw your eyes out.

And then....then...probably thank God you got the mileage that you did.

/just my $.02

 

Hi rmacguy. It sounds like your traction battery is still working ok, but has possibly lost some of it's capacity. The truth is that most traction batteries wont just suddenly fail, but rather just gradually lose their amp-hr capacity as they age.

To limit warranty claims I believe that the bar is set pretty low as to how much capacity the battery can lose before it throws a code and is "officially" faulty. Tests have shown that the battery can lose quite a lot of it's capacity (well over 50%) without greatly effecting the MPG for most driving regimes.

If you're still under warranty then no doubt the dealer won't act until there is absolute certainty that the battery is faulty and it throws an error code. This is fair enough though, I know my battery has less capacity than when it was new but I'm still happy enough with how it drives. There are definitely some driving measures you can adopt to mitigate the impact of a slightly weak battery if you want to try them.

If you're not under warranty and you want to foot the bill for a new battery then just ring around a few dealers and get some prices. I'm sure you'll find someone that will happily do it.

 

With a specialized code reader (even with TORQUE app and ELM adapter) you can read individual voltages of HV battery blocks. If one of them is significantly different than the others, you have a problem. Also, the internal resistance of each block can be read. There is also a parameter called "Total time of battery being too hot" but I'm not sure whether is this parameter cumulative over battery life or shows time since car has been started.

Also I second on very slow capacity decrease over time. Not a big deal.

- Alex

 

OpenElectron.com offers a Traction Battery Health Monitor that plugs into the OBDII port and records battery data; SOC, Amps, Battery Module Pair Voltages, Resistances, Temps, etc. You plug this in and drive while it records. You remove the microSD card and copy the file to your PC.

This will give you a current baseline for your battery. You can record your battery data periodically and compare against your baseline.

Send a copy of the file to Nitin at OpenElectron.com and he can analyze it against his database of Gen II batteries and give you his opinion of its current health.

I also agree with the others that you are seeing a decrease in battery capacity.

 

I assume your odometer reading is 135K miles so your car is not covered by any Toyota warranties.

Suppose your mpg has dropped 4 mpg because your traction battery is becoming marginal. Are you willing to spend $3K to have a new traction battery installed??

 

Where can I get what you are taking?

 

i know a lab in miami.

 

Change Inverter coolant.
And transmission fluid.

 

There's no point in clearing codes that you don't have. If you do get codes, you can clear them after you read them.

 

hang on, where have you been for the last trillion eternities?