Do I need a new battery?

[HooptyPrius]

Hello everyone,

I am the proud owner of a 2007 base model prius. The car has been terrific thus far, but recently I have been noticing a slight drop in performance as well as some other bizarre issues I cannot figure out on my own. I thought I would post on these forums in an attempt to figure out if anyone was experiencing similar symptoms in their Prius.

My Prius has approximately 24,000 miles on the odometer. I drive on the highway to get to work which is a 30 mile roundtrip from where I live. About three months ago I began to notice that my battery was behaving irregularly. When I get to work, I will park the car and the battery display will show that the charge is in the green. I'll leave the car parked for 7 to 8 hours while I am at work and when I come back outside and start the car, the battery shows a low charge (purple). I double checked to see if maybe I was leaving lights on or anything else that would drain the battery, but at this point I am 100% certain this is not the case.

When I get back on the freeway to go home, I will sometimes run into bumper-bumper traffic. Because the battery is low, my car will start the engine in an attempt to charge the battery, but when I tap the brakes, the engine will seize. This doesn't seem to be good for the engine. The engine is basically seizing 10 times a minute.

Is it normal for the battery to drain if left idle for 7 hours? Could there be something else that I am missing which is causing the battery to drain? Should I take the car into the dealership? I'm guessing the battery is still covered by some sort of warranty.

For reference, I used to average about 47.5 mpg. I'm not having difficultly maintaining 44 mpg.

Thank you for taking the time to read my post. I'd appreciate any feedback.

[john1701a]

Originally Posted by HooptyPrius

Is it normal for the battery to drain if left idle for 7 hours?

In 5.5 years, I have never seen that. Something isn't right.

With the car off, there really isn't any source of drain... normally. A relay is suppose to disconnect the battery-pack when you press the power button.
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[HooptyPrius]

Originally Posted by john1701a

In 5.5 years, I have never seen that. Something isn't right.

With the car off, there really isn't any source of drain... normally. A relay is suppose to disconnect the battery-pack when you press the power button.
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Hey John,

Thanks for replying to my post. I actually used a PDF tutorial from your web site to change my cabin air filter a few weeks back. There's a lot of really useful information on there.

I think the thing that is most alarming for me is that it's not irregular drainage but everyday I pull into work with a full charge and like clockwork the battery will be in the purple when I get in the car after 5:00. Is the best course of action to go to the dealer and see if I'm eligible for a new battery under warranty?

[john1701a]

Originally Posted by HooptyPrius

Is the best course of action to go to the dealer and see if I'm eligible for a new battery under warranty?

Yup. That's an unusual enough situation that they'll easily see it as irregular behavior too and want to dig deeper to find out why.
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[richard schumacher]

Are you *certain* that you're shutting the car OFF when you leave it? Do you lock the car every time you leave it? (Don't be insulted, this happens a lot.)

What do you mean the engine "seizes"? As part of battery charge management it's perfectly normal for the engine to start and stop repeatedly, especially if you tap the brakes.

[john1701a]

Originally Posted by richard schumacher

What do you mean the engine "seizes"?

I read that as just a typing error, where "ceases" was the word meant to be used... which would just be the arrow on the Multi-Display stopping, not an actual RPM to 0 situation.
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[donee]

Hi Hoopty..,

Of course your engine is not siezing. Siezing is a very specific mechanics term which means the engines locks up, usually because of lubrication failure, and cannot be turned. The only remedy for siezed engine is to completely disassemble it and hammer out the pistions, and the remachine the surfaces and replace a bunch of parts.

The operation you are seeing with a low battery in stop-and-go traffic is normal. This is typical of what is called a BAS hybrid (Like a Malibu Hybrid). Once the battery gets charged up to have sufficient margin, the car will let you EV for the short go periods, again.

[Flying White Dutchman]

go to your dealer and dont wait.

see what that brings you

[richard schumacher]

Originally Posted by john1701a

I read that as just a typing error, where "ceases" was the word meant to be used... which would just be the arrow on the Multi-Display stopping, not an actual RPM to 0 situation.
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Ah. Thanks, that should have occurred to me.

[john1701a]

How many people use the word "break" instead of "brake"?

There's a big difference in meaning!

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