Greetings all,

MY first post!!! Yeah!!!!

I suspect that my '07 HiHy, Limited, 2WD 156K miles HV battery pack is getting weak and will need to be replaced. The gas mileage has decreased from 25 mpg to 20 mpg. On the Nav Screen with the battery status, the battery will not get a full charge, I am missing the top to green lines on the battery, (the screen that shows all the wheels and both motors). I did see the battery screen get one of the green lines yesterday, but did not stay there very long. I have noticed that it seems the engine is working a little bit more, like a small load on it. With all that said, I am doing my research now to find the best place to purchase the HV Battery Pack. Any and all information on finding a company will be greatly appreciated, plus any other info.

Thanks

 

The battery gauge behavior you describe is normal and desirable. Routine operation into the top two green bars is a sign of degradation. The system works to keep the battery at about 57% SoC. If it fully charged the battery, there would be nowhere for the regenerative braking energy to go, and efficiency would be lost.

I would investigate other factors first. Excessive use of cabin heat, especially defrost, forces the engine to run longer than when operated in more moderate climates and can adversely impact economy substantially.

 

Thank you S Keith, I understand and I bet it is excessive use of cabin heat as I noticed the MPG decrease when it got in the low 20's here in the Tulsa area. I have only been here about 2 years and came from So Cal where the temps hardly got in to the 30's. So my question is how does the cabin heat work?? I was assuming it was using the motor coolant. Just seems to me that the engine seems to be under some kind of light load....but I could be wrong....taking a 500 mile round trip this weekend and will see what happens.

 

It uses motor coolant like a non-hybrid. The defrost setting in particular forces the engine to run full time to drive the compressor, which has a notable impact on economy.

NiMH does not perform well in extreme cold. It discharges fine, but it progressively restricts charging as the battery temperature drops below 50°F. At 20°F, it's charging at a much lower current than usual. This causes the SoC to drop and shifts more load to the engine until the battery warms and normal operation can resume.

All NiMH hybrids begin to perform like non-hybrids the colder it gets.

Once the engine is at full operating temp, and the battery is above 50°F, normal operation should resume. I expect it will perform fine on your trip provided you don't stop for an extended period (several hours) before resuming.

 

S Keith,
Thanks for the info, it was the cold temps that caused the decrease in gas mileage, drove it on a 240 Mile trip and once she got up to temp the mileage went back to normal......so I am relieved that I dont need to spend money on a HV pack.

 

Glad to hear it.

 

Thank you so much for your valuable contribution to this thread. Read before posting next time.