2007 Prius Replaced 12V battery, worked initially but now won't start

For the past year or so my 2007 Prius would randomly have starting issues. in such cases, a quick jump would get it going again and it would be fine for the next 3-4 weeks. This week, however, it got to the point where it would not start with a jump so I took out the 12V, had it tested, purchased a Optima yellow top and installed it.

Upon installing the yellow top the Prius started right up. I went back and forth from work, and then picked up my son from school, came home and when I turned the car off it completely shut down; as in no "door open" light, no beeping, etc. After that, it would not start on its own. I tried jumping it again (from the fuse box) and as soon as I connected the negative cable to the ground bolt the car turned on. I then tried driving around for about 40 minutes to see if that would charge but the same problem persisted (turn the car off and it completely dies and does not respond to a button press). One thing I noticed when driving was that the power button did not have the normal green light (even while driving).

Any thoughts here? It feels like the system is not communicating with the 12V, could that be a fuse issue?I am not the most mechanically inclined so I was kind of excited when I replaced the 12V battery and the car started because I figured I saved myself $150 from what the dealer quoted to replace the 12V, i'm hoping that there is a simple fix before I take it in to the dealer? Thanks for your help, this forum has been a valuable source of information over the years.

 

Thanks for the quick reply! How would I go about charging it and how do I know when its fully charged?

 

I bought the 12V battery at Pepboys, not sure if they do charging.

Just to be clear, when you say the wiring harness and bolts might be loose are you talking about the 12V battery, correct?

So, when I drive it after getting it jumped, is the 12V playing a roll at all? After driving around for 40 minutes I was approximately one blue bar away from getting to the green, is that separate from the 12V?

Thanks for your help.

 

When I say I'm "not mechanically inclined" that's a fancy way of saying I know next to nothing; when you say "negative to ground connection" is that the cable connecting the negative terminal to the chassis; if not, what is it?

Along those lines, after I jumped the car, I went into diagnostic mode and the 12V battery read out showed that it was at 14V, does that mean anything? When the car is running, is there anyway to know if the 12V battery is functioning properly?

I literally bought the battery today so the terminals are as clean as they are going to get. Everything looks good on the positive terminal (I tightened the nut, the plastic plugs are clicked in, etc); the negative cable has some tape on it which i'm guessing is from the previous owner (i've had the Prius for about 6 years and this is my first battery issue), otherwise it seems to be snug on the terminal (though, it is difficult to get a wrench in the right position to really tighten it). Would it be worth it to buy a new cable for the terminal?

 

I installed it (seemed easy enough from all the tutorials on this site).

 

That's a good idea, i'll start over and try doing it that way.

At this point, do you think the 12V still has a charge (I bought it new today and probably only drove 15 miles on it); in other words, should i look into getting it charged (if that's the case, can I jump it)?

 

Took everything out, tightened the negative connection and put it back together, noting...sort of. The power button blinks orange and the interior lights come on though they are dim.

The other thing I noticed is that the positive terminal is pretty warm and I started to get a sulfur (rotten egg) type smell. I'm wondering if there might be a problem with the battery itself. I took everything out and will bring the battery back to Pepboys to get it tested.

 

As far as I know everything is correct; The positive is on the left and connected to the large positive wire harness and the negative is on the right (closest to the bumper) and connected to the negative cable which, in turn, is connected to the body. At this point, i'm rooting for a bad battery as that would be the easier fix. ;