Just Another HV Battery Thread and Experiments

CB,

I purchased my Techstream off ebay several months ago. This is a copy of the listing I used. I run it on a 64 bit laptop with Windows 10. Just click on the thumbnail to enlarge it.



It's worked very well for me. It can be used on either 32 bit or 64 bit computers. 32 bit would be easiest to install, but if using a 64 bit computer, there's just a extra couple steps in the installation process. I have found that it's best to disconnect the laptop from all wireless signals prior to starting the techstream software when hooking up to a car. If it sees the computer is connected to a wireless signal, it tries to update the software and will not go any further.

 

I was able to pretty much get the battery reassembled last night. The wire connectors and the ECU terminals all looked to be in good condition. I didn't see any corrosion on any of them. So that's a good thing. I didn't go crazy with the thermal sensors on the bottom, since I may end up taking it apart again. I just clipped them in place and attached the third one to it's module using a dab of contact cement for now. Hopefully I'll be able to install it in the car tonight and do a bit of testing. I didn't use the serrated nuts that were previously installed. I used all new stainless nuts that I had available

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Got a bit sidetracked, but I was able to get the battery installed into the car today. I took it for about a 10 mile drive, and put the hammer down a few times to get a high discharge rate and got on the brakes to get a high regen rate. The highest logged discharge was 172 amps and the highest regen was 104 amps. After the drive, I parked it for about an hour and performed a load test. Sometimes the first load test immediately after installing a HV battery can be a bit weird since the car hasn't exactly gotten a good determination of the true battery state of charge. The main thing I look at is the module voltage curves and delta v curve.

 

Maybe this will be a bit more clear on the screen captures. Remember, this was just a straight up module replacement.
Nothing special was done to match voltages or capacities. Just replaced the obviously defective module.
Notice Block 9 is no longer an issue. Looking at the charts from the 10 mile drive, it's actually Block 2 now that may be an issue down the road, Block 2 all by itself accounts for 1/3 of the total delta V.
I'm going to drive it for a couple days and then do another load test. Then pull the pack out again and perform the cycle testing of all 28 modules. Then we'll see how the load test looks.



done

 

Here are the charts from the first portion of the test drive. I think it was showing to be about 6 km.
Notice on the graph of the 14 block voltages, the green line is the lowest reading by far. That is Block 2. All the ups and downs are from me going heavy throttle and then braking trying to put the largest load possible on the battery to see if it would code out. Updating block 2 would definitely tighten up the delta V graph. Not gonna do it tho. This is a simulation of what a typical repair job might look like.

 

Dxta,

If you have an android phone, get two free apps called Hybrid Assistant and Hybrid Reporter. It would also be best to get a OBD 2 Bluetooth communicator called OBD Link LX. This communicator costs about $50 but it's also one of the best, as opposed to a $7 generic that probably will not work with the app. I bought the OBD Link LX because it's what was recommended by the app developer. The app itself is not perfect on some of the real time driving screens, but I only use it for the load testing and block voltage graphs.

 

I was able to drive the Prius only a small amount over the weekend and then 22 miles to work this morning. I did a load test when I got in the employee parking lot. This was around 5:30 am this morning. Notice in the first screen capture that Block 9 is now holding a higher voltage than the others as the battery is being depleted. Notice on the second screen capture (delta V graph) that the upper line is actually block 9. The average voltage is skewed toward the lower voltage due to 27 of the 28 modules being significantly lower than block 9. Then in the third graph, it now looks like block 10 could be the next "whack-a-mole" to show up.

Although the graphs look sketchy, the car drove very well. There was no seat of the pants evidence whatsoever that the battery could be considered marginal.

 

I drove the car 22 miles home after work. I let it sit about 2 hours while the wife and I did some errands. Did another load test after we got home. It seems like the more I drive it, the better block 9 is working. How long before the next "Block x becomes weak" is triggered? Regardless, I probably wont be able to keep this battery in the car for more than another week. Once I pull it, I'm going to cycle test all the modules and tehn get it back in the car for testing ASAP so we can compare before and after.

 

Here's todays load test. There's been about a 100 miles since the last test. This will probably be the final test for this stage of the experiment. The block with the replacement module is consistently outperforming all the others by a significant margin. The graph with the module voltage curves is about 0.061 volts per division. All the remaining 13 blocks are in a relatively tight voltage range. The next stage will be cycle testing all the modules using the CQ3 chargers.