[PacDave]

So, there's a hybrid display mode that lets me watch the battery output and input in kW. I have been successfully driving with a light foot in order to keep the engine from switching on all the way up to 75+ mph, but I'm curious as to approximately whereabouts I can expect the computer to switch it on, based on kW output.

Anybody know or have a guess at the battery's (lets say near fully charged) maximum output in kW before the engine kicks on? I am sure this is dependent on tons of factors, like accelerator input, speed, temperature, etc, but has anyone tracked or got a guess at (using a feather light foot on the accelerator) when the computer decides to start the engine?

Second question: How many kW can the capacitors handle when braking, before the ablative brakes/pads engage? Anybody tracked maximum input? Obviously when you've gotta stop, you've gotta stop, but I have a light foot on the brakes as well, I'd like to know just how light it should be to recapture the maximum amount of energy.

I drive with a fairly light foot on the accelerator and I almost never cause the ICE to run. As you drive the car more you’ll get a pretty good feel for it I think.

I do not believe that the regenerative braking charges capacitors. It is directly charging the battery. I always try to anticipate stops. I take my foot of the accelerator as early as possible and a lot of times I shift into L to slow the vehicle down and then use the brake pedal right near the end. Some people drive 100% of the time in L but for me that doesn’t seem the most efficient.Believe it or not, for most efficient operation it’s better to let the car coast down to stop than using the regenerative action but most of the time that’s not possible with other impatient drivers around.

 

[PacDave]

Im not so sure. Cruising on the highway takes less power than starting off from a dead stop. The only real problem with a faster discharge is the internal resistance of the cells producing heat. But the Pacifica has a capable thermal management system to control that. In most conditions I bet that’s not even really needed.

Just remember that wind resistance increases exponentially. Wind resistance at 75 mph is 4x as much as it is at 37 mph.

 

[PacDave]

So? The issue is total sustained power output, and if that's bad on the battery. Call me crazy but I have a feeling that an automotive high voltage battery was probably engineered with freeway speed travel in mind.

I wasn’t commenting on that. I was simply saying that at some speed (probably lower than most people would expect) the power required to simply keep the car at a constant velocity will likely exceed the amount of power to take off from a dead stop.

But I think I agree with @stop-eject. Driving the car at 75 mph is probably harder on the battery than driving at lower speeds. It’s true that automotive high voltage batteries are designed for heavy charge/discharge rates but that doesn’t mean it’s necessarily good for the battery.

 

[PacDave]

Ya my point is always that everything contributes to degradation. Everything. Once a battery is created it’s just a slow march toward its inevitable death. The question is do these use cases, like freeway speed driving, really cause more degradation that anyone is likely to notice. We have no data, but I’m going to suggest it’s probably no. If driving at freeway speeds in EV mode causes 0.00005% more degradation than driving at city speeds, then you’re right that it’s worse, but you’ll never notice over the life of the vehicle. So I think these discussions just aren’t useful when we have no useful data. And if that was really the case why wouldn’t Chrysler have set the switchover speed to Hybrid mode to something like 55mph? If they were worried about battery longevity over that 10 year warranty you’d think that would be prudent. But they left it up at 80+mph. So just drive your van and don’t worry about it!

Is the “switchover speed” fixed? Is it the same whether climbing a hill, descending, or on flat ground?

 

[PacDave]

Possible. I don't usually drive at that speed. I'm normally around 110kph. It will also vary with outside air temperature, wind, tire composition and pressure. But my memory is telling me I rarely see that close to 50kw output when cruising. Generally below 40kw. Maybe I'll go test that again today.

But my main point still stands.We spend a lot of time saying what's good or bad or whatever for these batteries when we really don't know. And don't really have any good information to offer. Lots of people do lots of things, convinced that they are changing the world (or at least greatly extending the life of their battery), but the vast majority of it is bunk, and could even be doing the opposite! Like people that force close all the apps on their iPhone thinking they are doing good, when in reality they are hurting their battery life. I say drive the van and leave the engineering to the engineers. Sure they aren't perfect and everyone makes mistakes, but they know a lot more about these things than someone who read 1 article on Battery University and is now an Internet Battery Expert.

Of course in reality even if you like to force close all your apps on your iPhone, the extra drain it puts on your battery to reload the apps when you want to use them is likely minuscule.

 

[PacDave]

But my main point still stands.We spend a lot of time saying what's good or bad or whatever for these batteries when we really don't know.

Well we really do know. Pretty much anything whether it be mechanical or whether it be electrochemical or whatever will wear out and it will wear out faster the more we push it toward its limits. The thing we don’t know, for example, is how much faster the battery will wear out by driving the car at the highest speed permitted by the designers. It is probably not a huge amount but if someone wants to drive 60 mph on the highway instead of 75 mph, then go for it. You will probably increase the longevity of your battery by doing so just as you will probably increase the longevity by driving 45 mph instead of 60 mph. It’s just that the difference in most cases is probably not enough to worry about for most people. The manufacturer of the car designed it to go 75 mph because it will. And they offer a 10 year warranty on the HV battery so they must be pretty confident that the amount of extra abuse the battery receives at 75 mph will not be enough to matter much even if you do it for ten years.