Prius beeps after being turned off, then won't start

Never mind the main battery. Has the 12V battery ever been changed?

I don't know about the beep, but the jumping and everything else certainly sounds like a failing 12V battery. The displayed battery bars tell you nothing about that, they refer only for the traction (main) battery.

As for warranty, the expensive main battery should still be under warranty, but the 12V very likely will not.

 

You can't.

 

Almost the only battery that is the right size, shape and technology as the Toyota battery is the Optima Yellowtop D51, but it has the wrong sized posts, elearnaid sells a conversion kit, with and without the battery. Free shipping to the US makes it appealing if you have the time.

Toyota Prius 12 Volt Auxiliary Battery with install kit for 2004 - 10

 

This is totally normal charging behavior for the main battery. Remember the state of charge shown on the screen is for the main high voltage battery and does not tell you anything about the state of charge of the 12 volt battery. It is the 12 volt battery which boots the computers which then start the car. Prius has two electrical systems. A high voltage system which includes the main or traction battery which drives the traction motors and a low voltage 12 volt system which runs the computers and other low voltage accessories.

 

If you have, or can pick up a digital volt meter: check the voltage of the 12 volt battery. A good battery should read at least 12.6 volt. Lower, it might be salvaged with an overnight charging regimen.

Assuming it's the original 12 volt battery in there, I would just get it replaced, regardless of outcome, soon. It's gone a good distance, more than most. Look on it as an expendable. If you don't want to fuss around, the original battery model is your best bet.

 

And by the way... the car has a target for the big battery of 2 blue bars.. not full. That way it has some headroom to regenerate from a future use of braking. It also doesn't want to fully charge the battery since this greatly reduces it's life. As you have seen a downhill run on the brakes can give you lots of green bars, but the car is going to look for a way to productively use those as soon as possible to be ready for the next braking.

 

if it's covered under warranty, why not have the dealer do it? if not, you can order the optima, wait for it to arrive, install it yourself and save a few bucks. time is money! all the best!

 

Beeeeeeeeeeep = "you left some cabin lights on or a door open" or "help, the 12V battery is dying".

 

This has been happening to me for quite some time now. Its not the 12v Battery in the back and its not the system battery. I have had mine checked a few times now at 69.00 per diagnostic. Personally I think its a sensor in the key cartridge slot is not registering that the key has been removed., so technially the car is still "on " in a dormant acc mode. It happens randomly to me, but what i have noticed is that when i get in the car start it back up and move the car and park again SOMETIMES this works. BUT in the event of failure it is best to always have an inexpensive fully charged battery 12 V starter pack from sears, its a quick and painless start and you are never worried anymore. It happened to me last night, and i was off and running in a few seconds. It hooks nicely to the battery in the trunk and you ground it on the metal tie town hook.

 

This has been happening to me for quite some time now. Its not the 12v Battery in the back and its not the system battery. I have had mine checked a few times now at 69.00 per diagnostic. Personally I think its a sensor in the key cartridge slot is not registering that the key has been removed., so technially the car is still "on " in a dormant acc mode. It happens randomly to me, but what i have noticed is that when i get in the car start it back up and move the car and park again SOMETIMES this works. BUT in the event of failure it is best to always have an inexpensive fully charged battery 12 V starter pack from sears, its a quick and painless start and you are never worried anymore. It happened to me last night, and i was off and running in a few seconds. It hooks nicely to the battery in the trunk and you ground it on the metal tie town hook.

 

I'm having the exact same problem. It's only happened to me 2 times but it's still frustrating. Has anyone replaced the 12v battery and had this problem again after?

 

Then clearly the 12V battery *is* at fault; either that, or the cables at the battery terminals or the negative cable at the stud connection. A dealer's battery tester can be set (or interpreted) incorrectly for a Prius battery, indicating a false pass. It would be fine for the starter in a conventional car but not for Prius' electronics.

To easily test the 12V battery yourself see here:
http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html

If it fails this test perhaps you can convince the dealer to give you a credit on a new battery for having messed up their $69 diagnostics.

 

So I did try the diagnostic tips in the link above a few times since my last post. Currently I'm getting 10 v before a load is placed. So no matter what the dealer says the battery is toast. I have it hooked up to a charger that will go to trickle mode once the 12v is charged up. One thing I noticed is as soon as I take the charger off, the battery registers ~12.3 v but then rapidly decreases to 10.3 v while in maint mode with no load on the battery. Maybe I didn't let it charge long enough to hold onto the charge? It was only 15 minutes, but charger went into trickle charge mode so assumed the battery was full. I'm trying over night this time to see what happens

SGH-T959 ?

 

Just a general question: How often do we change the 12V? When it dies?

 

You can run the above test to get an idea of the condition. I have an 06 that I bought in January 06 and I changed the 12 volt 2 months ago, as a precaution since voltages at the vehicle signal check step after being left overnight were getting marginal (high 11.x volt range).

Yours is probably due to replacement soon, if it's not already bad.

 

In almost any car, any time over 4 years is borrowed time.
In a Prius, only those which have been run completely dead do not last 4 years.
If you are planning ahead, the Optima recovers from a deep discharge better.

Toyota Prius 12 Volt Auxiliary Battery with install kit for 2004 - 10