So long story, 1 year ago I bought 2007 TCH with 224000 miles (against my wife's advice) .. .in May at about 234000 , I got dreaded P0A80 Replace Hybrid Battery Pack and P3014 Battery Block 4 Becomes Weak.

I bought a cell online and replaced the bad cell. battery ran great for 6 months, but now in December 2017 at 244000 miles I have the P0A7F Hybrid Battery Pack Deterioration. This seems to have happened as the temperature in western NY has dipped below 20 degrees F for the past week. P0A7F happened about a month ago, then went away for 4 weeks when we hit a warm patch, and is back again, coincidence ?

My thought is that could be either total end of life for the battery, but would be worth replacing the Battery Smart Unit to see if that fixes the issue. Problem is can seem to find that part online anywhere.

Anyone know where I can get my hands on one ? Any other ideas ?

Thanks, New to forum

 

Hard to find as most are kept with the packs for drop-in replacement. Nobody wants to have to disassemble half the pack to drop-in a replacement battery. More importantly, waste of time and money. It won't do anything for you.


Smart unit failures have their own set of codes. Battery codes mean problem with the battery.


Welcome to the game of "whack-a-mole" that is DIY battery repair. In addition to the one module that failed due to low voltage, you likely had a dozen or more that had very low capacity and needed replacement. You've now experienced the next weakest module failure out of the other 33, and it might even be the one you dropped in (can't tell you how many bad ones I've seen on eBay).

 

S Keith, Thanks for the reply. I feared that the ECU's where hard to come by.

So if I get a DTC output of P0A1F that would point to the ECU correct ? I need to get it on an intelligent tester to be sure.

 

Not necessarily. In order of likelihood:

Battery smart unit
Auxiliary battery
Wire harness or connector
IGCT No. 2 fuse


A P0A7F is tripped by:



Internal resistance of HV battery is higher than the standard (1 trip detection)
Difference in the capacity between battery blocks is larger than the standard (2 trip detection)


Given the history of your pack and my experience with the Camry battery, either or both of those conditions is infinitely more likely than a failed smart unit.


When you pulled the pack last, did you clean ALL bus bars?


Did you tighten all terminal nuts to 48 in-lb?

 

Yes we cleaned the bus bars. do you suggest next adventure, short of replacement, is open it up and test/re-balance the cells ?

 

You didn't state if you torqued all terminal nuts (68 of them) to 48 in-lb. It's extremely important.


The issue is the amount of work involved in actually assessing the health of the modules is either somewhat expensive, time consuming or both.


If you can afford to invest some, purchase a Hybrid Automotive value reconditioning package ($469 + shipping). This will allow you to TRULY balance the pack at 100% SoC, automatically drive the battery cooling fan and discharge the entire pack with light bulbs. As you discharge the pack, you will measure all modules at various target voltages while they are under load.


By the second discharge, the outliers will start to matter, and you can decide where to draw the line on which modules to replace.


Charges can take 24-30 hours (assuming an ultimately strong pack) and discharges can take 16 hours. At least two cycles will be necessary.


It can take a full week.


Alternatively, you can:
Disconnect the 12V battery for 2 minutes
Reconnect the 12V battery
Start and idle the car until the ICE shuts off.
Put the car in "N"
Turn on lights, HVAC blower, rear window defroster and any other big electrical loads possible.
Continue discharging this way for 10 minutes AFTER you get the "N" warning.
Power off car.
Disconnect 12V
Allow the battery to sit for 10+ hours, 24 hours better.
Measure all module voltages. Replace all modules less than 0.05V from maximum except for end modules, they are often 0.1V less than maximum.


The above is coarse and inexact; however, it's better than nothing, and you get pretty decent confidence.


Please read this post documenting my experience with a 144K mi pack from Tucson:


https://www.greenhybrid.com/forums/f...16/#post262723


It needed 14 modules replaced for what I would regard as a reliable DIY repair. Note that NO modules had failed cells and the lowest voltage was 7.59V. However, you can see that several modules had EXTREMELY low capacity AFTER reconditioning.

 

Thanks for the insight. to answer your question I did not torque the terminals to a specific value. Think it would be worth going back in and just do that ?

 

It's a lot of effort to do that, and I suspect it's very unlikely to solve your problem, but it could pay off.

 

I think I might have my hands on a replacement battery from a wreck, about 4 hours drive from here. does anyone know where I might be able to sell my old battery core once I've done the replacement ?

 

You need to check with the source. They may require your old battery as a core.


Where are you?