Unable to determine the cause of the triangle warning

Did you:

1. Load test the modules - A good cell can deliver a high current for a short time and recover to nearly the same voltage when the load (use both filaments of a halogen headlight).
2. Did you measure the series resistance of the modules - A capable, Prius aware OBD2 can read these values out from the Battery ECU.

Any module that behaves differently from the others in these tests is bad and will cause error flags to be set.

JeffD

 

This means your battery is overheating which can weaken additional modules.

JeffD

 

You probably have one or more modules with a high series resistance. They get hot when the battery sources or sinks current and their voltage fluctuates widely setting the flags.

JeffD

 

Get a Mini VCI cable and Toyota Techstream software. The cables are available on ebay or Amazon for $25. Without Techstream you are trying to fix your car in the dark. With Techstream you can look at live battery data while under charge and discharge. Weak module pairs will stand out with larger voltages swings.
Static module voltage does not give a complete a picture of module health.

Charge test : Engine on, set parking brake, car in drive, step on gas and brake fully. Your car will just sit still and charge. Give it about thirty seconds to a minute. The weak module pair voltages will rise faster and higher than the rest.

Discharge test: Car on and warmed up, engine off, set parking brake, car in reverse, step on the brake, give it a little gas but not so much that the gas engine turns on. The car will sit still and discharge the battery. Give it about a minute. The weak module pairs will drop in voltage faster and farther.

Brad

 

After you run the "Health Check" there are a couple of other things to look at. Some of the codes will have little snowflake Icons. Clicking the icon will get you into the freeze frame data. This is where you will find the sub codes. Another check is to click on the battery category on the left side of the screen. This will lead to the live battery data. Run the discharge and charge test!

Battery Blocks are pairs of modules. So block 10 will be the 19th and 20th modules. The Toyota repair manual and most people on Prius Chat will tell you the count starts at the battery ECU.

In my experience the count starts opposite the battery ECU. You will find a module 1.3 volts below the rest. Let us know what position you find it in.

Let The flames begin.

Brad

 

Doing a load test on a module using both filaments of a halogen headlight would detect this as well.

That indicates that the module has been overheated and should be discarded. The adjacent modules may have been aged by the added heat as well

Yes, that is the easy way to get a resistance measurement, but it is for two modules in series. I am surprised that the bad module didn't show a higher resistance.

JeffD

 

In what position did you find the bad the bad module? To match Techstream what side of the pack did the count start on?

I agree get rid of the bulged module. When I reassemble a Gen II pack I remove the compression tubes and plastic end plates from the metal case bottom. Fill the compression fixture with the modules and tighten the end plates. Flip the modules upside down. Set the case bottom on the modules and install the million mounting bolts.

I have seen Techstream report a range of 19 to 23 milliohms for internal resistance. With such a small range I have not found it of much use.

Brad

 

Sorry to chime in, since I don't have answers, however this is one of the most instructive posts I have seen. I picked up a thing or two about techstream and HV batt.

 

You need a way to charge and discharge the modules. As Jeff said a Halogen headlight can be used as a load. Most use a RC model charger to charge the modules. I have used a 12 volt lead acid car charger on the lowest 2 amp setting. Since its voltage is much higher than the module it will put out 30 amps. I limit the charging to ten second bursts. Modules should be clamped while charging to prevent swelling. Get the modules charged to 7.5 to 8 volts. For a good comparative test you want the modules to be at the same SOC (voltage) at the start of the load test. This is done by connecting the modules in parallel. I use a really fine 30 ga wire wrapped around the terminal studs. I get the fine wire my stripping the insulation off an old extension cord and using just one strand. The fine wire will act as a fuse in case things go bad. Let the modules sit overnight while connected in parallel. You will also need a volt meter to run the load test. Alligator clips on the voltmeter lead would help. Hook up the voltmeter and the the headlight to a module. Time how long it takes to drop to any given voltage. I would use 6 volts. Another option is to run the load for a set amount of time ( a minute) and record the ending voltage. All of this is just comparing the group of modules that you start with. The clunkers will stand out.

The codes in your car should clear on their own after a few driving cycles. Techstream has an eraser icon at the bottom of the screen also. It would be informative to run another charge and discharge test on your repaired pack. The results could show how long you have until the next module replacement.

Brad

 

Man, I wish I'd seen this before I rebuilt my pack! It was quite a feat to get those modules and end cap back on the pack! Now that I see your method, it seems so obvious, LOL!