SoC drains to two bars every other night

Check if the inverter coolant is working good by checking the coolant turbulence. See the video at 5 min and 25 seconds.

[ame=http://www.youtube.com/watch?v=-yf6eCeV4M8]2006 Prius Inverter Coolant Change - YouTube[/ame]

 

Yes the ac should be icy cold. These cars have a very good ac system.
Your right again it does have something to do with the core issue.
Sounds like the Hybrid Battery has a bad cell or cells but not bad enough to throw a code yet. Be careful because this scenario is very hard on the Inverter.Makes Inverter run twice as hard and that's the expensive part.

The dealer can do a cell check for $125. That's min diag charge.
And I would like to have them open up the hybrid cell cover and check
carefully for interconnect corrosion in there too.
Also reply to my request on inverter coolant turbulence check please

 

I second that. A weak inverter coolant pump plus a weak HV battery cell would stress the inverter. If the inverter goes, it will be expensive to replace.

 

Whoa! Hold on to those inverter thoughts! If there is no triangle warning, then the HV battery is at a high enough potential with low enough internal resistance to provide the current X voltage that the inverter needs to operate properly. And if the pump wasn't working, the car would throw P0A93 for high temperature well before getting too hot to cause damage.

Don't waste your money on a dealership diagnostic of the HV battery, because if it is not showing a code, they will take your money and tell you it is fine.

I just skimmed this thread, and I don't see any hard numbers regarding the 12V battery. A Piece of S**t 12V will reveal itself readily after the car has been sitting for a day or two. If the HV battery ECU loses power, then it will easily show the SOC behavior that you are seeing. Please at least run the standard test described here:

http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html

Weak A/C: sounds like it is low on refrigerant. That is a job best left for the dealer or hybrid-specialist (Mellors Automotive in West Melbourne for example).

 

+1

 

+1
Get yourself a yellowtop optima 12V aux battery too ... not the OEM, which ages way too quick. Then come back & tell us all is fine with the world. You have an 04 (as we do) ... and you still run the OEM? Your lucky it made it this far. BTW - this issue / fix has now officially been repeated 500,802 times. Here's to hoping that all your Prius problems will be this easily remedied.

 

What? The x into what? The Inverter software is not that elegant. How many posts here have you seen people riding around with a dead inverter pump probably for days weather permitting only to end up stranded on the highway. The inverter won't throw codes until its so overheated it crowbars and shuts the car off.

First you say don't waste your money on the dealer than you end up saying go to the dealer for the ac.

Given the age of the car A quick peek into the Hybrid battery box is well worth the $$$. Its old and we don't know the history. I've seen many posts here concerning corroded interconnects. If the car sat for a few months that alone can corrode the interconnect. And they can check for any bad cells with TS software. A ride around the block with the Techstream laptop hooked up will tell the tech if its charging properly also.
Saves the op alot of time and head scratching.
And they can do any TSB software updates the car may need. And check the ac.

If the op had Techstream software we could help him but until then its all
supposition and checking things off the list.

I stand by my original recommendation to take it easy on the car because its not right.

 

Ed, no one at a dealership will open up the HV battery case if there are no codes. A bad cell/module, or high resistance at corroded contacts, pops P3000 and P3011-P3024. Very few techs would even know what to look for in Techstream as far as a weak pack. Just read the http://priuschat.com/forums/gen-ii-prius-main-forum/95641-power-loss-low-battery-during-climb.html thread where it took Toyota over two months to decide that a weak but non-coding battery needed replacement. That's what I mean by a waste of money for HV battery diagnostics. And there is just no way that a weak pack can damage the inverter, given the 125 amp fuse in the service plug.

The A/C, on the other hand, is not appropriate for a first-time DIY repair attempt. It is also hard to find shops that will work on it due to the non-standard compressor oil. If it is not operating up to snuff, then getting it serviced now for a couple hundred could save over a thousand on a new compressor.

Mainly, I just wanted to encourage the original poster to make absolutely sure that the 12V battery is not the problem. Once that is confirmed or denied, then we can encourage OP to explore diagnostic options. I urge a visit to Mellor's as a place to get paid-for help.

 

Checking inverter coolant pump is 30 seconds thing. Pop the hood and unscrew the cap and look at the liquid.

Checking the 12v battery voltage is also easy by touching the MFD. Those are the easy ones to rule out first before going to harder stuffs.

 

But how does a bad 12 volt aux effect the SOC when the car is off?
The op states when he shuts the car off he has X blue bars. When he turns the car on in the morn he has loss of Hybrid charge. The Hybrid battery is disconnected form the car when the car is not ready as you well know. Where does the aux drain the Hybrid is this situation? It can't put that much of an instantaneous load on the Hybrid the very second he goes into ready reflecting charge loss. Not buying that.

I do fully understand it affecting mpg's over the course of a commute as the car struggles to charge and unchargable battery.

Having said that I think his aux is toast too anyway but please tell us how that affects the Hybrid pack when the car is not READY.

 

Maybe the weak 12V got the ECU confused while car was not in READY mode. So the HV battery did not really lose charge, just the ECU was reporting bogus numbers.

 

Right, if the battery ECU loses memory from the prior trip due to 12V sag, then it will start fresh at low SoC. Anyway, yet another person gets us all stirred up and then never comes back to let us know how things turned out

 

Hell of a reach there. And first I have seen mentioned on PC.

But easy to test. The op should put the car on a 12v battery tender overnight.
They cost $30 and the op can get alot of use out it anyway.
I use mine all the time.
Start it up in the morning and see if the soc on the hybrid sagged. I bet it does.

 

Perhaps they eventually realized that it was not draining while the car was off but rather was draining rapidly after the car was started. A lot of people make this mistake. I've seen numerous posts where people claim they are loosing large amounts of their HV battery charge while parked for a few hours etc. It usually turns out that they were wrong about when it actually took place.

 

Absolutely right. When the ICE is warming up during S1, it only produces 3 hp. The rest is filled in by HV battery until it can no longer (34hp max). Then the ICE is forced to run with additional emission. Prius was programmed to prioritize emission before efficiency and safety before emission.