2008 Prius with 280K mile - Failing Traction Battery - Options

I bought this Prius used in 2016 with 243K miles. It now has over 280K miles.
Engine runs good and burns little oil (not excessively). Occasionally I get P0420, P0300 and P0304 engine codes. This has been going on for years, and they clear and the car runs for a while without them. Long enough to pass smog with no issues. I recently installed new plugs and coil packs. I am thinking the fuel injectors could be causing the misfire codes. In any case I can't really notice the misfires, and the car appears to run normally.
MPG's have been declining over the years and averages in the mid 30's right now .

In other words, the car runs decent but not perfect. I have another smog check due in December.

Sunday, I got to see the red triangle of death for the first time since I got the car along with the VSC, check engine and ABS lights.
I was able to clear it with one of my OBD2 scanners. Unfortunately, I didn't plug in the VEEPEAK to see the actual hybrid code before I cleared it.

Running Dr. Prius it showed the three battery temps in the red:



I let the car sit overnight. The next day I connected Dr. Prius again and ran the battery test. It shows poor balance on block # 10:




Going up a steep hill, I noticed block 10 seems to be lagging behind, confirming the diagnosis:



The red triangle of death has not reappeared, although all three battery temps eventually get in the red.

Now, given the age and condition of the car, I am a little hesitant on spending top dollar on a Toyota OEM battery pack or the premium Lithium replacement.

Should I get one of those reconditioned packs with a (transferrable) warranty?

Also, what happens if I continue to drive the car? So far the red triangle has not reappeared. I am going to clean up the battery fan tomorrow in hopes it improves the cooling.

Thanks in advance!

 

Good idea! It would be great if that's the culprit. And the fan is filthy -
I really like the car, it has been good to me, so I don't want to deal with replacing a module or cells and then have it fail again after a short while.

I don't mind the drop in MPG's, I just treat it like an old Corolla at this point. It still beats my parent's 2014 Corolla in MPG's!

I may just try to see how much longer I can drive it before the battery pack completely gives out.

By the way, I am not sure this is the original pack. It may well be. I will look at the labels when I take it apart tomorrow for fan cleaning...

 

Yes, I only know the Hybrid Pit in Buena Park. They did a great job cleaning the EGR system on my 2015 a couple of years ago.

If someone on the forum can recommend an outfit or person in Southern California, preferably near Palm Springs, that would be awesome!

In regards to this 2008 Prius, I remember checking the Carfax and Toyota Owners website and the car was well maintained and a lot of expensive work had been done on it when I got it at 243k. Always a good thing.
The car has more than exceeded my expectations!

And yes, I think this car will definitely go past 300K and maybe even 500K. It's got what it takes to get there.

OEM battery packs have gone down in price, I believe. So I may be able to get one for less than 2K and install it myself.
I could sell the old battery to recoup some of the costs...

 

Crazy thought: I should buy one of those Project Lithium packs and put in on my 2015 Prius. Then take the NiMH pack (still good at 130K miles) and install it on my 2008 Prius!

That is if they are plug and play. They may not be, although the cells/modules are probably similar...

On the other hand, my 2015's battery is still under warranty for another 20k miles.
Somewhat related question: Is there a way to accelerate failure of this battery before 150K miles, so I can have Toyota replace it under warranty?

 

Yes, and the actual PL battery is listed as compatible for both Gen 2 and Gen 3, so it may just be a matter of adapting a harness to fit either car.

As for the warranty, I would have to forgo it on the 2015 if I install the PL pack. But at 130K I would hope it would still be good for at least 50K or so.

Out of curiosity, I did run the Dr. Prius battery test on my 2015 and it passed with the exception of the battery temp, which it said it was running warm (I live in the desert). Maybe it's on the way out too. In that case, I would have to prove that to Toyota to get a replacement...

 

Ok. So I watched a few videos online and I think I have it figured out.
The Project Lithium sells the core with the cells sans case. I can install these on my 2015 and then the original modules/cells can be transferred to the 2008 reusing the battery enclosure and hardware in both cases.

This would be a weekend project at a minimum, but I have experience as an electronics technician, so it's definitely doable..

I would end up with a state of the art Lithium battery pack on my newer Prius and at the same time breathe new life on my 2008 by transferring the NiMH cells from the 2015...

 

Good idea. Specially here in the California desert!

It would be a win win to get the 2015 battery replaced and then use it in the 2008...

 

I ended up getting a new OEM battery from the dealer. Best price I could get was $1773, which is pretty good considering the prices I saw from some refurbishers.

Installation took me a whole afternoon but I worked methodically and double checked everything. Car runs like as champ. I can't believe how smooth it drives now. I'm very happy with the end results!

 

And yeah, the car burns oil but it has not gotten worse since 2016 when I got the car and it has always passed smog. So I'm confident it will pass again this year.

 

Thank you! It was quite a week researching all available options and then calling all dealers within 100 miles to get the best price.

Then hoping that all would go well during the installation. I hardly got any sleep the night before the install! Tomorrow I'm returning the core.

In all, everything went smoothly. More so than I had expected..

 

I got mine at Longo Toyota in El Monte. Great folks. Refunded my deposit immediately after old battery was received. No questions asked.