Possible Hybrid Battery issue?

Could you let us know how many miles you have on your vehicle.

Is it mostly city driving?

 

Does your decline in MPG coincide directly with noticing your battery in the green more often? Was it a dramatic change?

What about tires? 2nd set? 3rd? What size, brand, inflation, etc? And brakes, do all wheels turn freely? Have you ever had the brake drums cleaned?

There will be some loss in battery efficiency over time, but it would be subtle. Only when a module is near failure and there is a constant effort to keep the block pair in balance would MPG decline significantly.

 

Odometer reading now?

45-48 mpg is quite good. Is it possible that your local gasoline formula has been changed over the years, to include a greater proportion of ethanol which has lower energy content?

If a traction battery module was bad, then you would see the master warning red triangle and an MFD warning icon appear. However it is certainly possible that traction battery capacity is declining which is why it is easier to charge the battery up to the 7-8 green bar level.

You could try disconnecting the 12V battery for a few minutes, for fun. That may make the "indicated" mpg per the MFD improve for a short while, until the vehicle fuel consumption history is restored. That action will not impact "actual" mpg measured by keeping track of miles driven and gallons of fuel pumped.

 

The Hydroedges likely aren't as LRR as the OEM. Might be a factor.

 

Hi Rae.

I don't think seeing green more often is of itself enough to indicate a bad (or nearly worn out) battery. I'd also be looking into how well the battery powers the car in EV mode (flat road under 35 MPH). If the battery is really bad you'd also expect to see the SOC drop very quickly when running EV and the ICE keep coming on, even if you are ultra light on the go pedal.

One other thing to consider is the rear vent fan that keeps the battery cool. Even though you don't normally hear it running it does run at a slow speed most of the time. Before I cleaned mine out it was pretty badly clogged and my battery was probably getting hotter than it should. One effect of the hot battery is that the car tries to limit the use of the battery, so you can end up with a 7 bar green SOC but it's still reluctant to run in EV mode and use that charge. So just possibly that could be part of the problem.

BTW. In any case think the 12V disconnect "reset" is a good idea. I remember one other poster here had a similar problem with his SOC always green and he said the battery reset thing worked a treat.

 

I was thinking the same thing, but she said she's got 65k on them so I don't think they can account or any recent issues.

BTW. That's great wear you're getting out of those tires Rae.

 

Hey Rae Vynn,

I can't comment on the slight mileage drop, but just some reassuring observations about gentle driving and green bars...

I only use hypermiling techniques in my car, so I'm almost always at 5 or 6 blue bars (sometimes 4 when I've been bad :-D). The few times I've seen "normal" drivers use a Prius, they always get 7 green bars at some point in their trips. If you're accelerating gently and not actively using EV or a glide to drain the battery, it'll charge the SOC right up.

My dad once took my car just for a short drive (to the post office or something like that). When he came back I was shocked to see I had 7 seven green bars.

One woman at church to whom I recently gave a Prius driving lesson turned on her car for our little session, and the car was at 7 green bars from her previous drive. She told me she tries to drive it conservatively, though she had no knowledge of how to activate a glide, or EV, so she meant my gently using the gas.

I remember in cold weather before I had the Scangauge, and I didn't know about stage 4, that the engine wouldn't shut down one day (stage 3) so I just kept on the accelerator nice and gently. By the time I got to my destination a few miles away, same thing, 7 green bars.

I think a lightfooted approach will tend to show that more. With a heavier foot you'll invoke more battery assist, whereas with gentle acceleration more energy will constantly be flowing to the battery during the continuous pulses.

From reading Luscious Garage's site, they recommend cleaning the battery fan every 60k miles like uart already mentioned. At 85k if you haven't done it yet you may want to get that done, might be quite hairy in there!

 

What is the meaning of this color change with the SOC bars?I have never noticed a color change, but then I don't monitor this page! Could someone please explain this to a newer owner. I don't recall this in the manual, but I may have missed it. This car has a lot of things to read about! Hal

 

When the 12v was swapped out on my 2006 (both times) I did not experience a drop in fuel economy. In fact, 6 tanks were above lifetime average, 2 were below, & 1 was average.

The first time it was hooked up to a tender in the shop so I didn't lose my settings. The 2nd time was a failure so at least some (I don't remember which) were lost. IMO disconnecting the 12v won't help your situation.

 

Their color is redundant with their number. It's just eye candy.