Ah. Note how I have the same name over on Prius Chat. You don't.

My point over there was, I find it almost impossible to believe that failing to connect that cable wouldn't trigger an instant code when the car is turned on.

 

 

This just happened to me bought a new battery
Two days later same thing with new battery interstate
So far thinking about checking battery voltage

 

I have thoroughly read of all the threads on this subject in this forum, as well as several other forums, as of September 2016. Thank you to everyone who has posted, especially srivenkat's posts #163 and #166 circa 11-Oct-2014.

So, I ordered the Exide Edge FP-AGM25. Initially, I had ordered the Optima 8040-218 D35 YellowTop. However, due to the terminal orientation and lack of a vent connection, I canceled the Optima order after finding this sage advice, buried 2/3 of the way through this thread:

The Exide Edge FP-AGM25 Flat Plate AGM Sealed Automotive Battery seems to fit the bill. The terminals are correctly oriented for the 2009 Camry Hybrid. This battery appears to have a vent connection hole on both sides, and apparently the unused side may be plugged. It is uncertain if the vent elbow connector mentioned in #166 will be included with the battery. (UPDATE: if your battery distributor does not include the connector then you need to find a BMW standard elbow connector, as recommended here... "Vent tube - All Exide AGM batteries i’ve seen use BMW standard vents... If your battery didn’t come with a vent elbow, you can purchase the Dorman 924-254 vent kit.")

Parts ordered:

1. Battery - Exide Edge FP-AGM25 (it probably only makes sense to order a heavy battery from Amazon if you have a Prime membership)
2. Elbow connector - I ordered the Dorman 924-254 Battery Vent Tube from Amazon. Any BMW standard vent connector should work.

Removal and installation of the battery is straightforward. Just a few notes regarding the installation process:

1. I connected a spare 12V battery from a lawn tractor to the hot lead and trunk grounding point (prior to removal of the OEM battery) in order to avoid any computer error codes post-installation.
2. Carefully remove the temp sensor from the OEM battery. The entire temp sensor bracket pops off the OEM battery. Then, you will need to peel back the yellow sticker and gently pry the glue around the sensor. Finally, hot glue the temp sensor to the top of the new battery case.

Specs via Battery Connection: Exide Edge AGM batteries (including the FP-AGM25) are designed for both starting and deep cycle applications.

 

After reading through every single post on this thread, pages 1-22, I just have one question:

Does Power Cycling the TCH entail the starting of the engine or just the electrical system?

I am very grateful for the informative posts but I realized that no one really answered this question specifically.

 

You go through 3 complete cycles.Off>Ready>Off.
Btw, Optima now sells vent kit for Yellow tops. 2009 model is exactly same as my 2007 and Yellow Top Optima fits in just fine.

 

Thanks ukrkoz.
I feel really silly asking, but could you elaborate for the uninitiated on how exactly to power cycle? Engine on, off? I just want to clear the 'Check Hybrid System' off the display panel.

And as far as venting is concerned, I opted not to worry about it. The TCH is driven by my dad, who drives on average 3-5 miles/day. Venting doesn't seem to be an issue, at least not enough for me to go that extra mile to rig the battery for. I'd worry more if he was driving 20 - 40+ miles/day, but he is retired and drives less and less these days. All I did was stick the sensor on top of the battery with 3M thermal tape. Seems fine.

His mechanic actually scared him into thinking the battery can blow up without venting, but I assured him (after thoroughly reading every post here)--especially with the way he drives (very little, not far)--he has nothing to worry about.

 

The "Check Hybrid System" is caused by Hv ECU not sensing the thermistor in the Temperature Sensor. I have once used a 2.5K ohm thermistor built into a harness to ward off this code.

 

You should be having above 14V reading when you place the terminals of your voltmeter across the terminals of the aux battery (IG ON), if that is not happening, then you may have a faulty DC/DC Converter. The DC/DC Converter is inside the HV battery pack and is cooled by the battery blower fan via the black duct that runs from the fan to the battery. You also may want to check the fuse in the HV relay assembly. I think the resistance is 0.2 ohms measured when taken out.

 

What Ikefor is saying is that there is no generator charging 12V battery. It is charged off traction battery and maintained at specific threshold charge, lower level being 11.7V.
Complete cycle is to press and hold brake pedal, press and hold Start button, until ready light comes up in the cluster. Release brake pedal, press Start button until system turns off. Repeat 2 more times. That is 3 power cycles.