GOT HYBRID BATTERY QUESTIONS? ASK AWAY

It takes a little while... But the best number to pay attention to is "Voltage Diff." That number needs to be down near 0.15v for the car to operate normally without warning lights. I suspect you can do that by changing one of the two modules in block # 12.

 

Thanks! So should the "blade voltage" shown affect what I buy? I see some sellers guarantee a 7.8-8.0 voltage and others a 8.2.

 

Where are you in SC? I have over a thousand modules and can easily match your needs.

The voltage match isn't nearly as important as the capacity match. Any good module will get your HV battery to a reasonable working condition. A bulletproof battery would require a capacity test of each module so any weak ones could be replaced with modules matched to the average capacity of the remaining modules to minimize the chance of failure.

An 8.2 volt module is a module that has recently been under charge. 7.8-8.0 modules have probably been sitting for a week or so after being charged. I can make a module read whatever voltage you want, which is why (by itself) it's not an accurate indicator of health. Even a good module has a small amount of self discharge. A good module should still be 7.5+ volts after sitting unused for MONTHS. I've seen a brand new Toyota HV battery still have 7.6+ volts on every module even after being on a dealer shelf for almost 2 years. A bad module(s) will typically show itself by self discharging significantly more than the other modules in the battery. Sometimes in less than an hour, sometime over a couple days..

 

I am in the upstate, between Greenville and Spartanburg.

 

What information do you need from my pack to find a match? I did order a Prolong reconditioning package to hopefully help the pack as well.

 

I read a post but can't find it now. It was an experiment you did on swapping a random module. You recorded all the data on techstream. I was wondering if you ended up trying the prolong charger to see how it affected the data.

 

That was probably this thread:

Just Another HV Battery Thread and Experiments | PriusChat

It seems so long ago, I don't remember off the top of my head about what I did with the prolong following that build.

 

I can typically match very close by dates and miles. Your modules will have a serial number stamped on the top. The first 4 digits are the date code. If you don't have access to that yet, I can use the build date of the car. Most (original to the car) modules are about 2 months older than the car.

 

Okay the first four are 107J on all modules so I'd guess these are original modules (I bought the car used so I wasn't sure). The car mfg date is 07/08 on the door frame. I have 157,000 on it. There is quite a bit of corrosion on the terminals. How do I know which is block twelve?

 

People have fixed problem packs by disassembling and cleaning up those terminals.

 

So I tested the voltage in each module and they are all between 8.10 and 8.16 EXCEPT module 23 in block 12. It was 6.83.

 

So the module date 107J is July 10, 2008. For a Gen 2, number the modules 1-28, starting with the module furthest from the ECU end of the battery, so Block 12 will be module 23 and 24. Or, the 5th and 6th module if counting from the ECU end.

 

I was wrong about the terminals. They were clean. The corrosion was on the bus bars and nuts. I put them in vinegar and it cleaned them up. I was wondering if it's a good idea to nickel plate them. I have access to the tools to do so.

 

Each module has (6) individual 1.2 volt (nominal) cells inside. Your #23 module has a failed cell. Very typical.

 

How do I test the capacity of each module?

 

This is also the norm. I usually install a new harness, which is called Wire Frame #2, which is available from Toyota for about $60. You need to take a good look at the ECU socket and the harness plug. There is very often corrosion issues, which will need to be resolved. A new harness helps since it eliminates any corrosion problems at the male plug. ECU pin corrosion is a bit more challenging and often requires another ecu.

Although I don't do it, nickel plating does a great job of preventing the corrosion you're seeing.

 

Does this mean one cell is dried up and could be rehydrated?

 

Some people use light bulbs and timers. I use 28 electronic charger/dischargers that use a 10 watt load and measure the exact amount of mAh discharged from or into each individual module.

 

Anything is possible, and there are some threads on the site about doing it. My recommendation would be to not invest the time or effort. If modules were rare to come by or super expensive, it might be worth trying. It's kind of like trying to make your own Snickers bar, when all you really need to do is run down to a nearby store to get one.

 

Here is a picture of the ECU socket and the wire harness. I can see why you replace the harness.