Torque Pro - Questions related to my readings

looks good to me, how many miles on her?

 

Nothing there that would worry me. As long as your battery bars continue to respond slowly and not change quickly, you're doing pretty well. If you were in California, you would be just out of warranty depending on when the car was originally sold.

 

I'm not sure why leaving it sitting for a day or so should cause it to react any differently than normal. Do you mean it loses bars during the time you have it turned off? If that is the case, I think you may have a problem. How quickly does it go from purple to green? Rapid changes in State of Charge are not a good sign. I believe some people have the mistaken impression that green bars on the MFD mean that the battery has not lost much total capacity. That only means that it is nearing an 80% SOC of its total capacity at this particular time, a total capacity which may have been considerably reduced from the time it was new.

 

That is one of the signs that the battery is nearing the end of its useful life. I agree with what @davecook89t wrote.

What seems to happen is that the battery has reduced capacity due to a combination of normal wear on the battery and a growing imbalance in the states of charge of the cells. Yours looks pretty well balanced, but the chemicals inside are still aging. When you get the purple bars after it sat for a while, I'd guess that you probably parked it with a fairly low state of charge, then (being in Iowa in the summer, which I know is even worse than Florida) you hit the AC and it runs like mad, pulling down the battery, and then you start driving which also drains the battery even more while the engine warms up. That's about as hard as a Prius battery can work. And your battery is getting to the point where they start to fail, but many go way way longer.

The two best options that I see for you involve deciding how to prepare for what may happen a few months or maybe a year from now. It's hard to predict how long you have. Many people buy time for the battery by reconditioning it with a Prolong grid charger. But that is a sizable investment. The other viable alternative is to save up for a new battery and drive it till it fails. You never know. It might still last quite a while.

 

I suggest you read up on the Prolong charger threads. It sounds like your car would benefit from one. If you're going to use one, now is the time rather than waiting for the battery to throw a code. Nothing to worry about yet, but preventative maintenance is usually a good thing.

 

I have never worked on a Prius HV battery but have been an electrician and did you ever notice that when you buy a crimp style terminal no matter how big or small they are always plated to guard against corrosion. If it were me I would install all new plated hardware.
You will need a proper torque wrench to do this.

 

We heated up a vinegar (5% acetic acid) and salt solution, placed the bus bars in the pot of solution and stirred for a couple of minutes.

Then rinsed with tap water. They came out pretty clean

 

I do not know of one, but I haven't googled it. I won't repeat the suggestions given, but they are good.

Seems like a good idea to me. Quicker than cleaning, too.

This is more what I would try if I was broke. It works.

However, @padroo mentioned crimp connectors and that reminded me that the wires often corrode inside the connectors. I lived for 10 years on the windward side of a small island. It was amazing how the corrosion could not only get into the connections in our whole electrical system, but the corrosion would work its way under the insulation along the whole length of the wire. So check for that if you do open up the battery case in the future. There are tiny little wires gong to sensors for voltage and temperature that are sometimes the actual cause of battery codes when the battery itself is OK.

 

It looks like Toyota used plated bus bars in the Gen 4 batteries by looking at the John Kelly videos from Weber University.

Like Jerry mentioned about corroded wiring, usually high quality stranded wire is tinned for corrosion.

 

I assume the wires are multi-strand? If so I'd be concerned that hot vinegar-salt would work it's way up the wire under the insulation via capillary action. Both are corrosive to copper, especially the salt. I would omit salt.
A simple rinse would not get rid of that. I'd would minimally give it a good soak in a weak sodium bicarbonate solution to neutralize the acid, then soak and rinse again in clear water.

 

Shame on Toyota for not using a more high quality bus bar on the earlier Prius. I always looked at Japanese electrical and electronics as being the best in the world. Looks like they saved a dime and now you spend dollars.

 

Toyota already has cars that regularly go 250k miles, if they made them more durable, they would be screwed. They have to break!