Gen II codes P01AF P3030 P3056

Sorry, I didn't recognize it as a call sign. I see now.

Thanks for finding those torque specifications. I am the obsessive type who torques just about every fastener when I do these projects.

I located a nice (professional-grade) 10A battery charger to keep the 12V going. It has a 'maintainer' setting (unlike my little Craftsman) so I no longer need to worry about overcharging the 12V.

 

Thanks for the independent verification of that torque spec!

 

As speculated by usnavystgc, I was being overly optimistic that my problem was only corrosion. The good news is that I haven't found any bad modules yet!

The problem was self-evident once I got around to pulling the voltage sense wire connector off the ECU. (I procrastinated as it was very difficult to remove on my first attempt. Now I can see why.) Here are pics of the connectors from the voltage sense wires and into the ECU.
Note that pins 22 & 23 (bottom right) on the ECU side have broken off and are stuck in the receptacle on the right.

The connector looks burned. What could cause this? I would expect there to be minimal current flow through the voltage sense wires if eveything is working properly.

Input from anyone who has fixed this problem before would be appreciated. Otherwise, I'll try to fabricate some new pins or make an auxilliary connector for the broken connections.

 

Thanks for the suggestions. After looking at the connectors under a microscope, I agree it is not good to reuse. The pin spacing appears to be standard 0.1" (2.54 mm) so I am considering replacing the ECU side connector with a standard right angle header and putting a corresponding female receptacle on the wire side. I would be forced to keep the same pinout doing this so I would not end up with any higher voltage potential on adjacent pins than what Toyota already has. (If we consider the rows, I believe we must have some adjacent pins with >14V differential but I presume they have ensured the full ~210V are well-spaced apart. I'll reverse-engineer the pinout tomorrow out of curiosity.) I have all these types of standard electrical components and I would say they are higher quality (e.g. gold-plated rather than tin-plated) than the Toyota connectors. I hate to replace the entire ECU just due to a connector.

 

Thanks for the input. I have actually changed my mind again. I'm going to follow BritPrius' suggestion and fix it properly. 3prongpaul offered a pretty good deal on a used (known good) ECU and the harness with the receptacle connector. Even though I hate trashing the ECU, the price makes it not worth the risk even for someone as cheap as I am.

 

I have seen one or more threads where the "overvoltage" problem was reported. I was thinking that after the rebalancing step, I would use the chargers to discharge each module to something like 8V before tying the modules together. It seems that should be a standard part of this process but it is not mentioned in the threads I have perused.

 

Does anyone here know what level trips the overvoltage error?

 

Thanks again! That is a good data point. 8.9V actually sounds like a pretty strong voltage to me as 1.4V is considered fully charged for a single NiMH cell (i.e. 8.4V for a 6-cell pack) in most applications.

I understand the reasoning for keeping the battery in that range in normal usage. From a practical standpoint, I just want to avoid taking the time to discharge the modules more than necessary. I would run some experiments to find the overvoltage threshold but R&R of the bus bars and battery pack is a bit too difficult to justify satisfying that curiosity.

 

It's been a while since I have provided any update. I have not finished the project yet but am making steady progress.

On the voltage sense connector front, I received the ECU and harness from Paul. (Ordered on a Friday and had it sitting on my doorstep on Mon when I got home ... can't ask for more than that.) Here is a picture comparing the old and new ECU connectors. (I leave it as an exercise for the student to determine which is which )

Here is a pic of both new connectors ... all clean and shiny!


The replacement ECU is now installed in the pack. I finished one 3-cycle round of balancing on the 28 modules. I am running additional cycles on 11 modules. I am pretty confident I can get them all at least 6.0 AHr.

Regarding discharging to avoid the Prius seeing an overcharged situation, I am expecting this will not be a problem (per usnavystgc's observations). After 3 weeks of balancing, the modules I hit initially have a nontrivial amount of self-discharge that have dropped their voltage to the middling range. Unless I top everything off, there should be no problem. I am curious as to why others have seen this issue ... perhaps they topped off their pack before installing? Or they had enough chargers that they did the process so quickly that the self-discharge was insignificant?

I am wary of excessive current flow when shorting the batteries together if the voltages differ by much, e.g. over a volt. I am planning to take a day and manually charge and discharge the modules to a moderate voltage (and within 0.1V of each other) before I short them together in parallel. I considered a first step of using a resistive load from one terminal on each module to a common bus in order to limit the current. However, it does not seem anyone else has gone to this trouble and others have good luck with the process so I presume there is no significant heat damage due to using the small battery internal resistance (~20 mOhm) as the only current limiting.

Thanks to everyone for the continued advice and assistance with this project!