Do batteries decline from age or mileage?

no one really knows. it's a crapshoot. i would keep the one i liked better. have to say though, the '064 was a beast, then they started taking something off the ball after that.

 

Yes, batteries degrade from age and use (mileage). Too many variables to tell which is worse, heat cycles, number of deep discharges, cell construction anomalies, ambient temps, ad nauseum.

 

More than one question here.

I don't think "Do Batteries decline from age or use" is an either/or answer.

Batteries WILL decline with age. Use is another factor that can impact batteries. Keep the battery in use actually can be good. Non-Usage can impact batteries negatively.

I disagree with this:

The only thing I partially disagree with is the addition of the word "mileage".

For a battery which is a non-mechanical, chemistry based component, it really has no connection with mileage, for the Prius's hybrid battery standpoint, mileage translates directly into operational time. More mileage- potentially- equals more time in operation.

But that isn't even necessarily true as the connection between time in operation and total vehicle miles can be skewed by HOW the vehicle is being used. Long highway trips may rack up higher miles in shorter time. You could have less miles on the odometer but more time in operation if you do a lot of city driving.

So I would say age and use....mileage only partially reveals- possible- time in use.

To the OP?

With that minimal of a mileage difference, personally I wouldn't even factor in the hybrid battery. What I would try to ascertain is which one is in the best shape all around. Which would probably be the newer one.

They are both Gen 2 so I suppose you could switch the batteries. But switching older with less mileage with younger with more mileage is no guarantee you are picking the walnut shell with the pea under it. It's still a vague gamble. You could be picking the wrong one regardless.

So really I would base my decision on which Prius I felt overall was in the best shape, and which one I personally liked better if there are trim or accessory differences.

My observation has been that The Hybrid battery can fail, but it can fail at 110,000 miles or 250,000 or more, and there is really no good way of predicting which range you might be in when it happens. So in my opinion? 40,000 miles difference isn't worth basing your decision on. Which one do you like best? Which one is potentially in better shape overall?

 

I agree with The Electric Me in regards to battery's lifespan is not based on its mileage and that how fast a car will age is not necessarily based on years or mileage. To accurately assess a battery chemical life span /age the voltage under load is rough estimator with the higher voltage under a standard load indicating a healthier battery. The condition of a battery's seal and material integrity can roughly be determined by the battery's container/shell - cracks or oxidation of the shell or connection posts are a bad sign. Other hybrid component concerns like the battery inverter and cooling system are equally as important. As always one must also consider the condition of the non hybrid components as well too and whether those components are doing okay too.

If all conditions are equal the generation 1 Prius is statistically more likely to have a failure than a generation 2 Prius because of its age this is due to environment exposure. If the generation 1 has had better care (e.g. less/no accidents, mostly garaged ) than the generation 2 then the generation 1 may last longer. Generation 1 is built more like a normal car and is easier to fix and maintain as a DIY hybrid than the more sophisticated Generation 2; However, there are were less Generation 1 Prius made than Generation 2 Prius so finding used parts for a Generation 2 Prius should be easier and cheaper. Given that the the CARB warranty has or is about to expire for both cars - a hybrid mechanic assessment might be useful here.

 

should be an easy choice now.

 

Following the advice " Use it or lose it."

 

Actually, I think it is.....keep the one you like the best.

 

If the use patterns have been similar, I would keep the 06.

Put another way, IF the only differences between the cars are age and mileage, age matters more to the big battery in the usual situation. Running up and down mountains every day would be an exception.

 

Running up and down Mountains effect the Hybrid battery? How so..

 

If hills are big enough Prius tends to drain the battery to minimum on the uphill and charge it maximum on downhill. Those charge discharge cycles will wear the battery. On the steady driving on the flat road battery gets used very little.

But there are other factors that affect the battery life as well.

 

That's good to know. I go over two mountains going and coming from work. I do have the original hybrid battery... with 235000 miles.... I do notice battery going to minimum on uphill driving...

Thank you.

 

That's what keeps running through my mind, reading this thread. One of our sons is always talking us into runs up a local ski hill. Well, not that often, but I try to duck it. We've gone up there twice this year: I don't know what's worse, the climb or the descent.

 

Even if driving that route would cause 100 times faster wear rate on hv-battery doing something couple of times a year or even a month would mean basically nothing. And it’s probably going to be something like 10.

I would say desert heat is the worst especially if it’s parked on the sunlight. Since the heat will effect it even when you’re not driving.

 

Mendel,
I would not worry about twice a year.
Every day is a different story. I'm blanking on the PC member name, but a very knowledgeable EE from Santa Fe, NM who started a battery refurb business would describe two failure modes of traction batteries: one would be a module or two failed; the other would be an aged pack throughout. The latter situation was noted in commuters who worked in Los Alamos and drove up and down a mountain every work-day.*

These drives can be a double whammy. Not only does the battery cycle to its full extent, the rapid charge/discharge leads to over-heating.

*I used to drive up to Los Alamos every week. There are actually two routes available -- the car route and a 'truck' route. I learned to take the truck route, and with some effort could reach the top without draining the battery. On the way down the battery always reached 'full', but at least it took a little longer to occur. Most people would not make the effort, or even know that it mattered.

Addendum: Seilerts is the fellow.
I should point out that nothing is know of the failure rate; only that IF an generally exhausted battery was seen, it was a from a mountain commuter.

 

I drive these two mountains 5 days a week.

 

From what I can understand heat plays a much bigger role in the battery life than hills or usage. Nissan Leaf owners have also confirmed this, the highest rates of failure are in Arizona and Texas, relatively flat states. I live in a valley in a four season climate here in British Columbia. There are numerous hills, mountains, and even a couple of ski hills Prius drivers run on here. My dealer is in a city with a hundred thousand people, there are many Pri's here including numerous taxis. To date there have only been two gen2 battery failures in total! One was a high mileage taxi, the other sustained 'water damage' to the battery and had to be replaced. I'd imagine this is a failure rate of well under one percent, not bad....

 

All mountains are not created alike. But if you want to extend the life of your battery, learn how to drive without rapid full discharges or charges. I'm happy to report that our 'mountain' Prius is a 2004, closing in our 200k problem free miles. It has always lived outside, mostly in the sunny and quite warm state of New Mexico.

 

Do you keep the cabin cool with air conditioning? Good to hear about your 2004!

 

Always on long drives. It is a safety issue for me, since I get sleepy in hot weather.