Do older hybrid battery packs heat up more than newer ones?

What exactly makes you think that the temps you are seeing is NOT "normal" ?
Charging and discharging creates heat. The faster the current flows, the more the temp goes up.
The ventilation is there not to keep it "cool" necessarily but to keep it from OVERheating.

 

A thermal camera will help with a problem like this... Are all temp numbers the same on Dr. Prius app? Usually if it's not a ventilation failure, the heat is from one of the 168 cells wired up in a series. When big amps move through a failing cell it creates a lot of heat. Once you get it up to 130' again use a thermal cam to find the source of the problem.

 

Since others can’t answer

Yes a aging pack can have an increase in internal resistance and thus heat but in your case you would do well to figure out if a cell or two has failed or if the ventilation fan is plugged

that is all

 

It's not that we can't answer that question, it's that the question is not relevant to this particular problem.

 

Hey I've been tinkering with my Prius because it seems to have an heat issue with the battery as well. Did you look at the resistance rates also for each module?

This is the crap I've been dealing with, and I'm not too far from you in the OC with my own woes. I'm using Hybrid Assistant.

I think I've narrowed my problem down to a bad 12V, will find out tomorrow (discharge/charge rates all over the place on the screen, bad fuel economy). The fan on Hybrid Assistant will spin down on Level 6 and it sounds like an aircraft landing in the cabin when it gets that hot.

 

If you know anyone who's a home inspector, they have 'em...

 

Ignoring al the other variables. yes....absolutely..... an older battery heats up more with use than a newer equivalent battery.
As batteries age, their internal resistance goes up. This is true for ALL rechargeable batteries. It's not quite accurate but think of it like 'friction'. As electrons go in and out during use on an an older battery they have more 'friction' to overcome and this translates as heat. Ultimately this manifests itself as a battery that is failing to do the work that is required. Doesn't matter if this is a NiMh AA cell in a flashlight. or a whole pack of them trying to move a car down the road.
Cells get old and fail. How and when can be quite variable depending on the hugely variable issue of use.

 

I had already tested the 12V battery (followed the procedure above as well) and assumed it was good as it passed the signal tests above with NO codes. I'm used to seeing a battery fails and the dash lights up like Xmas, but I guess with hybrids it doesn't happen. I happened to take the 12V battery Autozone for a test. It tested at 99% capacity, yet the screen stated that the battery still failed load test (I'm thinking a cell in it probably died).

This kinda makes sense, because as my hybrid battery is charging/discharging, I'm noticing the levels fluctuate everywhere.

The resistance range for my first module set is really high compared to the rest.


The local Toyota dealership has a sale on them this month (wonder why, summer all batteries dying) so gonna get me a True2 AGM Toyota. I've been driving the car for about two years, and my gf three years before then so maybe its the 12V battery.

 

The levels fluctuate as the car runs and the battery charges/discharges. When I replace the 12V battery tomorrow, I'm assuming it will stabilize the gap.

 

@2GenPrius, the 12 V battery has nothing to do with what you are seeing in the HV battery. You are wasting $200-$250 chasing that.

@Brando714 and @2GenPrius, The value of the charge/discharge Amps is not high. The voltage levels of the green bars will always be moving up and down while the HV battery is in use. The way the app displays the bars exaggerates the difference. Your screenshots show 0.13/0.14/01.7 V which is well within specs.

@Brando714, I'd be wanting to verify that the temperature is actually in the region of what is reported by the temperature sensors. I think somebody has already suggested using an IR thermometer? That's what I'd be doing.

Is it possible for you to get a photo of how the three temp sensors are mounted inside the battery?

 

BUT a higher internal resistance likely means a LOWER maximum current flow, both charging and discharging, which will mean less available stored energy but not necessarily higher temperatures. Might actually be a bit lower.

HOWEVER...... if some of the cells or modules fail in such a way that their resistance actually is LOWER, then overall current may go UP and that cell might overheat.

I don't think that a thermal "camera" is necessary to detect hot spots.
A hand held IR thermometer should do the job. Even the ones from Harbor Freight seem to be reasonably good.