Hybrid system Malfunction (Visit Your Dealership)

To find out things, which often is better than insisting the things you haven't found out must be the way your common sense says they must.

Booster packs are frequently used to boost conventional cars whose starters draw well over 100 amps. The duration is brief enough that the battery clips do not reach any troublesome temperature.

You skipped right over the 100-amp spike shown in post #101 (for a gen 2, courtesy of mr_guy_mann, who was interested in finding things out).

The spike is shown, but also quite instantaneous, a small fraction of a second, visible only as a vertical line in the trace. A spike that brief will hardly have a detectable effect on the battery clip temperatures.

The trace proves the presence of the spike (when the car is jumped from a source that can provide it). That does not necessarily prove that the car would have failed to start, or gone 'haywire' in any way, if jumped from a source with a lower current limit. That would be another thing to find out. There are plenty of things electrical that may draw a tall spike of current when the supply can source it, but will just draw a lower figure for a bit longer if that's what's available.

Surely there is a current limit too low for the start to succeed, but what that limit is could be another thing a person could systematically find out, and that might take less time than getting a lot of armchair PriusChatters to agree on what it must be.

 

I was thinking about like a minivan with rear air, very common system. I am not an expert on car a/c.

 

In a minivan with rear air, there's a pair of refrigerant lines running from the engine bay back to the rear A/C unit. That's exactly what the Prime does with the battery pack. The difference is that the Prime just moves that refrigerant through lines in the battery pack and then returns it to the engine bay. In the minivan, the refrigerant goes through an evaporator coil that has a fan blowing air across it. So the minivan system has at least two additional parts(usually more), takes up a lot more space, and wouldn't cool the battery pack nearly as efficiently as just running the refrigerant through a closed loop that has metal fins attached to pull heat directly from the battery.

I guess you're just going to have to trust me that the system in the Prime is way simpler and more reliable than what a minivan might use. Just because it failed in this one case, doesn't make it less reliable overall. In this case, there was apparently a manufacturing defect in one of the refrigerant lines that let the refrigerant escape. That could just as easily happen to a rear A/C unit.

 

The issue is more with the pack design apparently not being serviceable for individual components.

 

Yeah, the fixability would be rough depending on exactly where the leak is. If it's on the outside edge where the refrigerant comes in or goes out, it might not be that bad. But if it's in the middle? That would likely mean having to completely disassemble the pack and pulling out all the individual battery cells to get at the leak. I can understand why Toyota views that as non-serviceable(especially since it should be impossible for it to fail* without the battery also being severely damaged at the same time - like in an accident.

That being said, if mine somehow failed outside of warranty(wonder if a refrigerant line failure would be 3 years(car), 7 years(hybrid system) or 10 years(battery)?), I would absolutely try disassembling the battery to separate the lines(taking all HV precautions, of course), then take those lines to an A/C shop to see if they could be fixed. Even a used battery pack at that point might be $10k.


*excepting manufacturing defects which should show themselves almost immediately

 

I figured out most of it in the meantime, and trust you. I just learned from you the battery pack assembly is a unit with the refrigerant lines. That’s sort of what I was wondering about. Not stating an opinion but definitely have one now that it’s better explained. I wouldn’t have expected it to be made that way.
Somehow it seems unlikely a new car needs refrigerant lines replaced, and I have well experienced doubts the dealer really was telling it like it is. Do they ever, almost?