no power at all

YOu need professional help.

One should NEVER use a hybrid vehicle as the "donor" in a battery jump.
The little battery is not meant to run a "real" starter motor.

 

Sounds like you almost completely fried the inverter. But almost burning down your whole house is nearly as bad as completely burning down your whole house.

So to clarify:

With the car off completely, when you try to READY the vehicle with the key and brake pedal, you get no love. Car remains off, no lights, no sounds, nothing. Then you hookup the Prius to a donor battery like a jumpstart, and you actually can READY the vehicle except you have weird light issues?

If so, my money is on him reversing the jump leads. The fuse at the 12v battery is probably blown, making it so that the car can't start without a donor. Replace that first, it is in the red plastic bits covering the terminals. You need to have the hatch open to access that area. Easiest to do when the car has power, open the hatch, then shut it off.

Then your next problem is what to do when the car is READY. My guess is that the 12v inverter rail is destroyed by the reverse jump start. If this is the case, you're looking at about $4K USD to repair. You can find some in the junkyard/eBay for about $600 to $1000 and it will take a day to install. Not an easy fix.

This is wrong on many levels. A "hybrid vehicle" could mean many things. They make a mild-hybrid Chevy Silverado pickup truck with a yuuuge battery. It can jumpstart things. The Prius has a tiny battery but that doesn't effect the jumpstart ability. Once the car is READY, the battery is essentially out of the loop. It is used as backup only. The main HV battery is providing up to 100A on the 12v rail in addition to what you can pull from the battery. Way more than most starters actually require. The CCA (Cold Cranking Amps) ratings on batteries are not meaningful in the Prius since the Prius will give you 100A when it is -20 or +40 outside whereas a starting lead acid battery will not.

I have jumped many bug diesel trucks with the Prius, and the Prius is the crown jewel that will start in almost any weather since the draw is so very very low.

The key is to be overly cautious with your hookups or leave that to technology. I only jump people through a pair of "smart cables". Basically just some relays and voltage sensors. You hookup the leads in any order, and it detects which is positive and which is minus. Additionally the leads are not hot when connecting so you never get sparks (i.e. voltage spikes) and on normal cars since you connect to the battery less chance of an explosion. For $20, very good assurance on any vehicle from a $4000 repair.

Any modern vehicle is run by a HAL-9000-esque series of computers. A bad jump can kill any number of them and they aren't cheap. You can't fix it with bubble gum.

Your dad owes you about $1K to $4K for his impatience. Let that be a lesson to him.

 

Would you happen to have a link for such a product?

 

I doubt the 12v battery itself is fried. Lead acid batteries can take a beating of reverse voltage, usually by emitting toxic fumes for a short period.

Look at this portion of the schematic:



Note the 4 arrows. The bottom 2 arrows are in the fusible link block at the 12v battery. If you don't know what I'm talking about go look there. It is not just a wire attached to the battery. It is a plastic fusible link assembly attached to the positive side of the battery. Inside that thing is a 120A fusible link and a 5A replacement fuse. Then the 2nd arrow from the top is the main fusible link under the hood good for 100A. My guess is that one of the 2 main fusible links (2nd or 4th arrow) is blown. That's a replacement piece, a few dollars from Toyota. That's why your Prius isn't READYing without a jump now.

The second problem you have is when the car is operational. This is what the real damage is. Could be one or more of the ECUs are fried ($700+ each generally) but usually the inverter gives its life to protect the ECUs in a reverse voltage scenario which is a $4k dealer repair. $1k repair if you are really mechanically inclined and can do it yourself. No guarantees that after you fix the inverter nothing else is damaged.

The car was electrocuted. Something has died. If it was quick acting enough, maybe just the fusible links. Then the inverter would go. Then the ECUs would go.

So first I would (with the hatch open and the car off) measure the 12v terminal on the battery. It should read 12.6v or higher. Then measure past the big red box on the battery and it should measure the same as the battery. Then measure the fusible link under the hood by the jump point. Both sides of it should measure the same as the battery. If at any point it doesn't standard deductive logic will lead you to the fault. Once you have that problem sorted, your car should be in the same state as it becomes after a jump start. Then that lengthy debug process can start, but hopefully some codes will be thrown or can be read. Who knows it may be driveable just quirky from now on...

But one step at a time. Get it so that you don't need to jump it each time to make it READY.

This is what I have:

Code:

https://www.amazon.com/dp/B002RRZX06/?tag=akeyuk-20

I have had them for a long time and used them very frequently. As I mention all over PriusChat, my 2006 Prius is my "Mountain Goat". We use this to go skiing all the time. It is parked for 12 hours outside in a blizzard in temperatures below zero. Perfect skiing weather. Also the worst possible weather for a lead acid battery. Many times after getting back to the parking lot, there will be a stranded motorist or two or three, usually in the larger vehicles (that need more CCA to start their dino-sucking engines). The little Prius can start even the heftiest of diesel trucks. And since it only flips a couple relays and primes the brakes, it will READY the car even with a completely dead or shorted cell. A very frozen battery will still READY the Prius. I have actually had one guy refuse my offer of a jump start when he saw I would be jumping with the Prius. Didn't want his truck to get cooties I guess. So I jumped his friend's Jeep and the Jeep jumped him. Whatever.

Now I also carry one of these:

Code:

https://www.amazon.com/gp/product/B00ZZKGXEC/ref=od_aui_detailpages00?ie=UTF8&psc=1

I have successfully used it to jump start a large Chevy Suburban in a parking lot. The kind with 2 aux batteries under the hood because the engine is so yuuuge. Started right up, no problems. 99.9% of the time I use it to re-charge cell phones while traveling and thought the jump start "feature" was a terrible prank. But it really works. And if it can start a dead Suburban, I think it will start any of my little cars.

Pardon the code tags, but PC keeps trying to make them embedded media tags and it doesn't work... Trying to be smart...

 

But that is part of the reason for my comment. Let me re-phrase......so you can pick that statement apart too:

The "average" owner of a hybrid vehicle should NEVER use it to jump another inoperative vehicle.
That is a bad thing to do.....on many levels.

If you REALLY understand electricity and electronics, you can make an intelligent judgement about when it is and is not appropriate.
Most people don't have that level of knowledge.

 

NO. You should not replace ANYTHING based only on a guess.

Either get it checked out by a professional.
Or get a multimeter and make some tests.

 

the 12v sounds dead, but wait a few hours and put a meter on it with the car off. then call us back with the voltage reading.

 

I really REALLY hope that you weren't connecting that load tester while the car was RUNNING, in the ready mode.
It was intended to be used on the battery by itself, disconnected.
The charging system won't like that huge load being thrown on it all of a sudden.

14.4 is too high. 11 is WAY too low.
Something is definitely wrong there.