Prius only getting 39.6 mpg-Is it time for a new hybrid battery or can I wait a while longer?

I drove around like that for a couple months in an '09 battery was corroded to hale.

 

Bought a brand new Toyota Panasonic battery.

 

39.4 MPG is fine... Nothing wrong unless you have other symptoms.

I've solved this before on people's cars by simply boosting tire pressure for Summer months.

Or it could be worn out tires, or buying the wrong kind of tires.

Engine tune up might help too...

As for hybrid battery and 12v that can impact MPG, but we need you to get battery data for that via Toyota Techstream on an old laptop and a Mini-VCI dongle or by an OBD2 code reader via phone apps: Panlong OBD2 Scanner Bluetooth OBDII Diagnostic Tool Car Code Reader Turn Off... | eBay

 

do a battery life test with doc prius, it might be something else bringing your mpg's down.

can you detail when, how much and how fast they have fallen?

have you done a 12v load test?

 

that should fix it

 

But I thought you said you had the battery fan running full time.

 

low tyres can overheat the battery, as we well know.

 

It's amazing how many people's old Prius I've worked on with just over 20psi of tire pressure. And don't get me started about how many people wait till an oil starvation warning light starts blinking before they get an oil change.

 

... somebody's dicking around with the gasoline.

I do a lot of road trips. I've seen a lot of things. Colorado unleaded, January of 2012, I went Edwards, Colorado to Salina, Utah, on a single tank, steady state 80 mph, bursts to a hundred. California unleaded, I barely make North Las Vegas from Los Angeles, on a single tank.

Moment I run my tank dry, top off outside California? I'm seeing a 7-10 mpg improvement. Change the air filter, do all the maintenance you can do? In the end you'll discover, it's the gasoline.

We've been targeted. Always with the little games, policy community wants us out of our hybrids, into gay-guy EVs -


Samuel, '04 Ruthiemobile

 

I'm going to post on this soon but I've had very weird experiences in this regard.

For a couple years I got high 30s and low/mid 40s.

Then my battery started to go (wearing down to 1 bar frequently, esp in hilly areas), and my MPG suddenly improved. I recently took a 17k mile trip into Latin America, and I suddenly started getting the best mileage I've gotten in over 10 years, averaging in the high 40s to mid 50s.

During the trip I had someone look at my battery. All the cells were reading in the 6s. The guy cleaned the battery up and charged me a diagnostic fee, and recommended replacing when I get back to US, but not sure if I should do that or just ride it until it dies. In spite of the cleaning (which was loosely correlated to the MPG improvement) I'm still getting the replace battery triangle light, which pops up randomly once every couple weeks and goes away. But the mileage is good and car drives normally except for super hilly areas which are rare in my neck of the woods.

Not sure if the improvement was related to the cleaning or some kind of ECU 'strong battery state' reset.

 

or just the gas