Double prius 2004/2008 traction battery swap

I have a 2008 which is working great. Monitoring the battery levels on the screen it doesn't look any different than it has for the last 7 years.

We were preparing to start looking for a junker, possibly a Prius, since our older daughter will be driving in about 5 months (wow!). Then a 2004 with a dead traction battery dropped in our lap - someone we know that no longer lives in the area but the car is at a local dealer. The usual codes that confirms it is the battery and not something else like the inverter. They don't want to deal with getting it fixed, but I've drilled down to the battery on my 2008 several times (documented elsewhere on this forum - I run a 4500 watt inverter directly from the traction battery for home backup power) and am mechanically inclined so I have no worries swapping out the battery myself. So for $400 for the car and $1300 for a rebuilt battery with gen 3 cells, hopefully we'll be golden. Has 130k miles so I'm hoping to double that for many more years.

But, I don't want to drop the money on the battery until I'm certain that is the only problem. So, I've decided to swap my 2008 battery into the 2004 to see what happens. If I still see codes I'll have to decide to fix that too or get my money back by reselling it as-is. If it runs I'll leave the 2008 battery in the 2004 and order the rebuilt battery for the 2008.

I'll document my progress - hopefully with no problems - here.

 

The 2008 crossed over the 150k mark not long ago. Sure Toyota might help - but not necessarily. If it just needs a battery and they don't want to help I'm willing to drop the $1300 to get it moving again. It is all a gamble and I'm willing to roll.

 

Ok, just double-checked and it is a bit more. The company I'm looking at (priusrebuilders) charges $1350 plus about $200 for shipping round-trip (new to me, old back to them).

Used gen 3 cells, tested and matched. 1 year/15k warranty. They have a $950 option with gen 2 cells and 6 mos/7500 warranty which I'm not interested in. Or new gen 3 cells for over $2850 and a longer warranty.

 

I have yet to see much proof of that. Sure there will be some failures, and people tend to post failures online much more than successes.

 

That will mean a lot more work, and would increase the chances of an internal failure (connector, etc). Buying one already swapped out with 3G cells, tested, and warranted, makes more sense for me. Sure, I have the ability to do the technical stuff but real life intrudes with other stuff that needs to get done...

 

$650 to $1k more would have some advantages, but since the primary purpose of this car is a learner for my daughter I would prefer to keep the cost down. I won't be happy if I sink that extra money and she totals it 6 months from now. If I was going to be the primary driver it would make more sense.

 

I agree. From my first post, above:

 

I forgot to mention yesterday that I towed the car home yesterday afternoon. Luckily it moves even with the error condition so it was easy to load and unload from the tow dolly. The car is just about in the shape I expected - some stains in the interior, 3 of the 4 tires are new (or fairly new), and the plastic cowling is heavily damaged. However, all of the exterior metal is perfect from what I can see.

My street is currently closed (bridge closed) so that gives me a 1 1/2 mile test track with several good hills and turns, with only neighborhood traffic to worry about. I reset the codes by pulling the 12 volt battery lead and on my first lap the traction battery quickly climbed from 1 bar to full bars (usual for this problem) and then entered the error condition again. Reset the codes and it did the same thing in the same spot on an even shorter lap, just as I hit the gas for a big uphill. It ran well before the codes were thrown - then the engine revved higher, there was less power, and the battery fan turned on high (also usual for this problem). So I'm confident the powertrain is good and most likely there is nothing else wrong other than the battery. My only worry is there is a noticeable valve tick.

Next up will be a battery swap with the 2008 to confirm.