Prius battery replacement question

[cloudy]

Back in 2016 I determined that a second car was needed for me/my family. After a bunch of research I determined that the best fit for my needs was a gen 2 prius. I wound up with a slightly mistreated, but mechanically sound 2004 Prius with 288000 km on it for $4000 AUD. A real bargain at the time and even better by today's standards.
8 years on with regular servicing and nearly 350000km on the clock it's still going strong. In that time I have replaced the HV twice with junkyard batteries from wrecked Prius with lower mileage. It would only be once, but I think the first battery was not the >100k km the junkyard promised. In both cases after selling off the old batteries/cells I was only out of pocked less than about $500 AUD.

Anyway, while fuel is over $2/L, I'm really liking having a car that only uses 5L/100km and only cost me 4K to buy.

Cheers

Hey cowardlyDuck, sorry to restart an old thread but I have a few questions about your Prius.

I also have an australian gen2 (2008), but the battery is original, 226,000 km on odo. Fuel economy is around 5L/100km, maybe slightly higher than it was a few years ago.

How did you decide when to replace the battery, did the car stop suddenly or were there warning signs before it stopped?

How did you go about sourcing a used replacement from wreckers, did you have to buy the whole car or do they just let you remove bits from the car in the yard for cash?

Dis you ever consider building your own (lithium) pack to replace the original NiMH version? Or buying a new after market prius pack?

I've found some videos on YT detailing how to replace the HV battery so was planning to do it one day. Just trying to work out how long I can kick the can down the road, or if I should source a spare battery now.

 

[offGridDownUnder]

sorry to restart an old thread

Perhaps an admin can move this to it's own thread, so more people can benefit from the answers?

@neptronix @amberwolf ?

 

[neptronix]

^-- wish granted

 

[cloudy]

here is an older thread where I asked a similar question:
Prius Gen2 battery replacement and conversion
I'm just seeking a bit more information from owners about how these cars behave as the battery ages and eventually dies.

 

[Cowardlyduck]

Hey there, happy help! And thanks Nep for looping this in!

How did you decide when to replace the battery, did the car stop suddenly or were there warning signs before it stopped?

Look up the red triangle of death....if you don't see that or a check engine light there isn't really any way to tell apart from dismantling everything and checking IR on each cell. Not worth it!

How did you go about sourcing a used replacement from wreckers, did you have to buy the whole car or do they just let you remove bits from the car in the yard for cash?

You want Findapart: Wreckers used Car Parts, Auto Parts, Motorcycle Parts, cheap parts locator
Just put what you need on there any it will go to most wreckers around Australia. Just pick the one with the best reputation and lowest price. It's a gamble no matter what do not worth fretting over and just go for it. Most wreckers these days won't let you pick through their yards any-more unfortunately due to insurance costs and liability risks.

Did you ever consider building your own (lithium) pack to replace the original NiMH version? Or buying a new after market prius pack?

Yes, but not to replace, just to run in parallel. Plenty of companies were making packs like this back when the Gen 2 was still being sold. They would spoof the car into thinking it was out of fuel so it would run on electric only, then the lithium pack would feed the NiMh pack to run the car. From what I've seen they worked ok, but couldn't go far, fast or accelerate very hard at all.
All those companies stopped making/selling those mods years ago for the same reason I never made anything.....it simply isn't worth it. For the same money spent, you could almost buy another Prius or at the very least a whole bunch of fuel.

IMO there is a sweet spot with modding cars these days. They need to be old enough to be cheap enough to buy, but not so old as to have most parts rotting out/falling apart. Typically that is in the 10-20 year range. They need to have less than 250k km on them or be a car where high kms doesn't matter so much....i.e. large capacity 4x4.
And most importantly, the mods need to makes sense....i.e. in my case I'm glad I never did add batteries, solar panels or any other significant mods to my Prius.
It's now 21 years old and has 355k km on it. The suspension has sagged to the point that the underbody scrapes the top of speed bumps if there are 5 ppl in it. The underbody plastics are all torn up. All the paint is faded or peeling on the roof/rear. There are numerous bad scrapes, dents and scratches. It has never driven the same since one of the front wheels met the gutter very hard one day....even after multiple wheel alignments....I suspect something is bent.
The biggest issue now is it is chewing oil fast. I have to top it up every few thousand kms. I'm contemplating selling it while it still runs and I can still get something half decent for it before it blows up.

Had I put a ton of mods/effort/work into a custom battery setup.....I would now be essentially locked into buying another gen 2 prius to move it all over to....so I'm glad I didn't!

All that being said.....for a cheap runabout car....if all you need to do is replace the NiMh battery, it is worth it IMO.

Hope all that helps!

Cheers

 

[cloudy]

Thanks so much for taking the time Cowardlyduck. I think I'll just run it until the red triangle comes up, I looked it up and it sounds like it still lets you limp home (no towing required).

I do have an OBD2 connector but couldn't really get much useful info out of any of the apps I downloaded for it. It definitely did not check IR. I tried "Dr. Prius" and "Torque (lite)"

That findapart website is gold, I had no idea such a thing existed. It sounds like there is no point in buying new replacement parts for a car this old, so it makes sense to try and salvage a battery for it from the wreckers. It blows my mind that these batteries last as long as they do, they are relatively small so likely get flogged pretty hard at high discharge and charge rates.

 

[cloudy]

Did you notice any improvement in fuel economy when you changed out the battery @Cowardlyduck

 

[Cowardlyduck]

You won't be able to see IR with any OBD2 port/scanner. It would only be possible with a multimeter or IR measuring tool directly on an opened battery after removing it from the car....hence why it's not worth it.

No real change to fuel economy after changing the battery either.

Cheers