Help! Battery is dead!

Sounds like there's a decent chance you fried your 12v battery, which is used to start the car. I'd look into getting a new one. From what I've read, there's also a fuse you might need to get checked out.

 

I believe the 12v battery is between $180-$220, depending on location. Not sure how much the fuse costs, but if you don't know how to check it, I'd take it into a shop or dealership where they know about hybrids and have them check. Just describe what happened and they'll probably have a good idea what to look for.

 

1) Never jump any car with your Prius, there is a good chance of frying a $4000 inverter if you hook up the cables badly. I use a portable Jump pack instead, $40

2) There is a fusible link ($60) that may have fried first, as designed. To my limited knowledge that will require towing to the dealer for most owners, but here is a thread with instructions How to change Fusible link under hood | PriusChat
And the part Fusible Link - Toyota (82620-47040)

3) If you have damaged the 12 battery, you want an AGM battery with JIS posts and external venting. The buzzword for that is S46B24R expect over $150 (the Toyota dealer will have an 82 month warranty, last I knew)

 

From the linked thread:

 

Check the fuse on positive connection of the battery. With a bit of luck, you may have blown that. Use an Ohmmeter to check for continuity, don't just look at it.


This picture is taken from the back seat looking back.

 

The main 120A fuse referred to by 3prongpaul is (I believe) the white square block immediately to the right of the 5 amp fuse in the picture of post #7.

 

in the hatch.

 

not sure, but it never hurts. disconnect the negative lead and put a rag around it in case it accidentally moves.

 

Check your resting car battery voltage. If it's below about 12.2V, your battery is bad (good batteries should be above 12.5V when fully charged). To me it sounds like your battery was probably really close to needing replacement. The additional stress of the jump likely reduced the capacity past the point where it can start the car. If the car starts fine when jumped from another car, it points to everything being okay except the battery. If the inverter wasn't working properly, I would expect the check engine and other lights to come on.

As others have stated - never jump start another car with the Prius. The only car a Prius can jump start is another Prius.

 

This is actually not true. Resting voltage is only one metric to give a picture of the state of health of a battery. In isolation, all that that resting voltage shows is the battery is low and could do with being charged up. I'm not saying the battery is a picture of health, or indeed not toast, I'm just saying you can't make that statement based on that one metric.

The voltage under load is a more telling metric to use.

Also, a good AGM battery fully charged (and rested for a min of 2 hrs) can be in the range of 12.9 V - 13.2 V, but if it was in the range of 12.7 - 12.9 V that would be no worries either. It just indicates a bit of wear. 12.5 V indicates something in the realm of half charged.

 

I agree that there's a lot more to measuring the battery's capacity than just the resting voltage. For the Prius, if the 12V can supply the 200-300W the ECUs draw for a few seconds before the inverter starts without a serious voltage drop, the car will start. However the OP is likely not a battery expert. If the car was driven in the past few days for a decent amount of time, the inverter should have charged the battery up to full capacity. A fully charged 12V lead acid battery with a resting voltage of 12.2 volts is bad. That certainly does not mean that if it has a 12.3V resting voltage it is not bad. In that case I would do a load test as you suggested. Most of those who have reported the voltages of their batteries that would not start their Prii have reported in the 11s.

 

I agree with (almost) everything you have said. The prius will start (with that initial load you mentioned) right down to 10.5 V, however this is the territory where the "weird" things start to happen.

I was simply stating that the you cannot make the statement 12.2 V = bad.

You have now added all the assumptions you did not state to qualify your statement.

It is not good to make sweeping statements based on assumptions without stating your assumptions.

People who come here may not have the background to weigh up what is said, to "read between then lines." You make the statement "If it's below about 12.2V, your battery is bad" and people will take that at face value and lock that away as fact.

One example of your assumptions:

While the statement stands on its own as true, you have no way of knowing the battery was fully charged, it was not stated, and is quite different to the statement you made in your post, which is why I challenged it.