2007 Prius - Check Engine, Red Triangle, VSC Lights - 12 volt battery issue?

Tampaite,

Value is obviously in the eye of the owner, but I have a little thumb-rule. If I have a car I like and it meets all my needs, I figure if I can maintain the car for an annual cost equal to or less than what 2 new car payments would be, then it's worth keeping. Can a new car be had for less than $500 a month (48 months)? So I guess in my case, as long as I can maintain my car for less than 1k per year, it's worth keeping.

If you're looking at a 5 year period, do you think you can maintain the car in your desired condition for 5k or less? Also, with a 5 year horizon, I would definitely have a GOOD HV battery planned in the near future. This alone will reap benefits due to reliability, mpg, etc.

Your options for a very reliable (5 year + timeframe) HV battery are most likely limited to a new Toyota battery, a battery kit from 2k1 toaster with his cylindrical design, or one of mine built using 2015/2016 Gen 3 or Gen 4 modules.

 

The typical HV battery failure starts as mostly an annoyance with 'every now and then' faults with only minor changes to how the car behaves, progressing to where the car is very slow to accelerate and eventually progresses to where it won't let you drive the car anymore. Unfortunately, during this, it tends to try to continually charge the battery at every opportunity. I've seen the cars driven for weeks during the early stages, but you just never know when it will hit that next stage. Could be weeks, could be hours. If you decide to drive it, just be a bit more gentle than usual. Heavy acceleration will cause large current draws, which triggers the fault more easily. Some have driven the car with a code reader attached so they can reset the codes on the fly. I've done that when testing older batteries, but use an android app and a Bluetooth wireless adapter instead of a hardwired code reader.

The more significant your commute, the more you may want to look into a rental. No one wants to be stuck on the side of the road, or have a car go kaput in the middle of heavy traffic.

 

From Bisco: always have the trouble codes read, before going to all the hassle of testing the 12v health.

For me anyway, it is a lot quicker and easier to test the 12v at the jumpstart point under the hood than to drag out my old laptop, etc. to see codes -- which as someone else mentioned may or may not be reliable.

 

the 12v only boots up the computers, it is almost unnecessary.

 

And what happens if you try and force charge it?

 

Given your latest posts it sounds like you should replace the 12V battery, then see how the car does.

 

You could use a lawn mower battery as a substitute to do your testing, they are cheap, they come in different cold cranking amps but would probably get you going.

 

Lots of someone elses have mentioned that lots of times, but have you ever seen it backed up? It would be straightforward to do: get the codes, learn what they are saying about the car, then test for the conditions they report and show that the car does not have them. I have yet to see such a post. The posts I do see generally read like cozy rationales for not investing the effort to read the codes and learn what they mean, so naturally they don't lead to finding out anything that could support or challenge the premise; that seems to be sort of the point.

Now I'm not talking about cases where an ECU contains a voltmeter, as many of them do, and reports a code that actually means "hey, volts look a tad low from here". Those cases do happen (and, it bears emphasis, provide absolutely no support for the idea that the ECU has been "confused" by the battery into reporting "unreliable" codes—what they support is the idea that the ECU has done exactly as it's programmed and reported a code that means exactly what it says).

I'm also not entirely ruling out cases where somebody has truly, honest-to-Pete, flattened a battery (there was a recent thread around here where somebody measured 4 volts open circuit). Since the logic circuits used to build the ECUs are likely designed for 3.3 or 5 volt supplies (and their onboard regulators probably need a volt or so of headroom), I at least wouldn't be shocked to be shown some erratic behavior in an extreme condition like that (though, it must be said, I still haven't been shown the kind of erratic behavior we're supposed to believe is so common, where the ECU correctly carries out its whole complex communication protocol to deliver codes to your scantool exactly according to spec, and only the codes are bogus—not even in those extreme cases).

But those are extreme examples, not representative of all the threads around here where there's a pile-on of posters competing to sound the most all-fired certain that there's no point asking the car what it's trying to tell you because the battery's some fraction of a volt below 11 so the ECUs can't possibly mean what they say. In those cases I'm pretty sure there's confusion involved, but not on the part of the ECUs.

-Chap

 

In post #5 the OP reported that the car logged DTC P0A80. Eventually he will determine whether the traction battery has failed; and if so that would be evidence that the codes reported in post #5 were valid.

 

And to follow on from what Chap just posted, because most people don't have the skill or equipment to conduct the diagnostics, nor have an understanding of how the computers talk to one another, and to them, it seems the information is incomprehensible. They then frantically try to make sense of what they see, by coming up with all manner of theories. The trouble is most of the theories are nonsensical.

If people followed a methodical diagnostic procedure, and understood what they were doing, it would become clear in a very short time where the problem or problems lay.

Here is a classic example of a poster who has received quite clear DTC information telling him exactly what is wrong, but chooses to not believe that and allow himself to be lead on a wild goose chase hoping against hope he will not need a new HV battery.

 

No matter how you spin it, P0A80 will have the same meaning, even after a new 12v.

 

The opinion here is that ALL "rebuilt" batteries are a gamble, some less than others. Even those with longer warranties only include the battery, not installation. The best third-party solution right now for DIY is the kit of new cells sold by @2k1Toaster for $1600 shipped. @ericbecky put 4000 miles on one. He then removed it & traded in that car for other reasons. I have not seen any negative experiences reported with this kit.
See my signature for details.

 

I am thinking there is a shop TampaPrius...somebody help me here

 

Yes, you are correct. Make sure you or the mechanic who fixes/replaces the HV battery cleans the fan.

@TampaPrius.com or Todd at Home - Tampa Hybrids Inc. - (813) 241-5307

Before dropping money on some janky rebuilt with a 30 second / 30 feet warranty (whichever gets you further), why not see what Todd or @TMR-JWAP can offer you. Pretty sure SC is fairly close to FL.