Just bought it a couple weeks ago. 126k miles... 27 mpg with air conditioner at 75 degrees and blower at three bars... struggles with hills and revs like crazy to make modest accelerations. No check engine lights... OBD2 Android scanner won't read at any rate....

What's going on?

 

Check your oil.

Brakes dragging?

Do CEL and IMA lights come on when key-on/engine-off prior to starting?

What's the battery gauge doing?

Swing by O'Reilly and have them read your codes for free.

 

It does that recal thing pretty often. Every time I try to accelerate it wants to charge. It does auto-stop (a lot) but it's not reflected in the fuel economy. It's usually at 4 or 5 bars. Like the charge is there but it doesn't want to do anything with it. 25 mpg with air at 75 degrees, mix of suburban, rural, and highway traffic.

The oil is full. 80% lifetime according to the display. I have no issues with the breaks that I can tell.

At key-on/engine off: the IMA light comes on briefly... the battery and oil lights stay on... the CEL light stays on a few seconds, then blinks a few times and disappears.

 

key-on/engine-off is to confirm the lights actually work. They can go inop.

Low oil can cause the car to feel like it has a rev-limiter or be gutless without an accompanying low oil warning light.

With the frequent recals, it sounds like it's almost certainly the battery.

The charge is there, but it's not everywhere there. When you demand assist, one of the 11 voltages the car monitors drops too low and triggers a recal. The 132 cells are all in series, and they can easily go out of balance as they age and deteriorate.

A grid charger MIGHT buy you some time, and it's a good tool to have moving forward with a new pack. I recommend the Hybrid Automotive Value Reconditioning package. It has a solid track record for several years now. There are no guarantees that it will work, but it could buy you some time to save for a new replacement.

Another thing to check is your 12V. Have it load tested at an auto parts store. A weak 12V may put a heavy load on the DC-DC converter - not enough to account for what you're seeing, but 12V health on a hybrid is critical.

 

If I do need a new battery, are the higher capacity new batteries better than OEM capacity?

 

Not really. They're all higher than the HCH2 cells at 5.5Ah. As I understand it, the 8Ah is a "performs like" type of rating for the older vehicles that had higher resistance cells.

 

Right it seems like the question is whether the hybrid system can manage itself well enough to make use of the additional capacity (of course if you used a grid charger to top off, I figure that would be a major boost with a high capacity battery of say, 15 "free" miles). It might be useful in areas with a lot of hills. Personally I think auto-stop is a waste except in city traffic and there ought to be a way to disable it... everywhere else that energy would be better spent to accelerate at low RPMs.

 

No, and you need to adjust your expectations.

The amount of usable stored electrical energy in the hybrid battery is about the same as the total capacity of the 12V battery. Imagine trying to run a 3000# car on a single 12V battery.

Your idea that disabling auto-stop would somehow benefit you in other ways is also a non-starter. The amount of energy needed to start the engine is very very small.

 

The IMA could be going but if it was completely gone the light would be on. On my first generation HCH even when the battery was essentially toast my mpg never dropped that low.

Your comment about "revs like crazy" suggests you might (also) have a transmission problem. The CVT has a clutch in it and if that isn't fully engaging the transmission could be slipping. That would definitely knock the MPG down. A CVT with a slipping start clutch most likely isn't long for the world.

 

Pas,

That's an excellent point, and I should have thought of it. I got fixated on the festival of recalibrations.

OP,

Check your CVT fluid level. It should be in the zone on the dipstick. Note that you check it with the car OFF on level ground.