Car dead, no dash lights on.

My alarm bells started ringing as soon as you said you jumped the car.

Assume you carefully read the section in your handbook on how to jump start a Prius? Failure to follow the instructions will result in you frying the computers which could result in the symptoms you're experiencing as well as the possibility of very expensive repair.

 

is there a fuse? $3,000. hybrid battery would be under waranty.

 

I'm also wondering if you're on the original 12volt battery? If so, that can cause weird error messages when it starts to fail (usually at around 4-5 years or 80k miles). However, incorrect jumping has prematurely ended the life of many a Prius, esp if the terminals were connected to the wrong place or the wrong way round and especially if the car doing the jumping revved its engine! The Prius has a much 'smaller' 12 volt as it is only required to boot up the cars computers rather than crank the engine as in a tradititional car. This is also the reason why it is difficult to realise when the 12v is failing (no slow cranking).

You might have blown the internal fuse or the 12 volt might be so damaged internally that it just can't hold any charge. You might want to test the 12 volt battery off the car first as it's the cheapest fix.

 

You may have to leave the jump battery connected for up to 5 minutes so that your discharged 12v battery recovers sufficiently to allow adequate computer voltage.

 

He's right you know. The Prius 12volt charging is much slower than in a traditional car. Where it would take 15 minutes in a normal car, it would take about 2 hours in a Prius. Best way is to charge the 12volt with a charger and test its voltage to see if it's all ok.

 

This is only when your charging the 12v battery from the HV battery. If you connect a jump battery (the correct way round) the car should be able to be made ready strait away, no need to wait for a charge. As soon as the car is ready the 12v will start to charge from the HV battery, this then as you correctly said only charges slowly (about 4amps) or over 10hrs to fully recharge a flat battery. Again you are correct that the battery would be best charge off the car, but at 4amps max charge rate for this battery it will still take at least 10hrs.

 

If the 12v battery is extremely discharged, a jump battery sees that battery as a high load and will cause reduced voltage for a period. Real world experience validates what the book says about allowing a few minutes.

 

I disagree, The jump battery "if in good condition and state of charge"should be capable of supplying at least 350amps (typical small battery cold cranking amps) at 10volts. If you put that sort of current into the Prius battery it would fry it very quickly. I would be amazed if the current flow to the Prius battery when discharged to the point of not being able to light the dash was above 25amps and this load on a good battery would only bring it down a few tenths of a volt. Remember the battery is not trying to turn the engine over as in a normal jump start and people have reportedly made ready a Prius with a couple of lantern batteries.

 

also remember you don't have OO wire gauge from the front fuse panel to the battery in the rear. I am not arguing the point, I am simply reporting direct experience.

 

The wire from the front panel to the 12v battery is protected by 120amp fuse at the battery, so it must be reasonably substantial, but any resistance in this wire would reduce the current flow further unless the car was jumped directly to the battery at the rear.

 

I wonder if the OP got his car going? Was it the 12v? Was it a major problem? Hope they pop back and give us all an update so we can all learn from this.

 

Glad you got it sorted. The Prius 12v is its achilles heel. It will slowly fade away giving no real indication of this until one minute it just goes causing all sorts of weird error messages. A cheap peace of mind hint would be to replace it every 4 years unless you like messing about with volt meters etc. Oh and regarding jump starting - NEVER EVER offer to jump start your neighbours car with your Prius. Your neighbour will think you're miserable, but you really would ruin your car. A Prius can't jump another vehicle and it can only be jumped itself if you follow the instructions in the manual very carefully.

How much did you pay for the new 12v out of curiosity?

 

So pleased for you that it was the 12v battery. It sounds like you have a real rip off dealer though, the battery is under $200 and the belt is less than $15 and 10mins to fit. Still I can understand your relief.

Your neighbor obviously connected the correct way round, but as you now know it rely does pay to check very carefully when trying to jump start the Prius and it is well advised not to jump start another vehicle.

Please do not let this put you off the Prius you have many good miles left in your car.

John.