ratobuza

Couple of days ago had one of those rare moments when you see the hybrid battery completely full. Was surprised for several reasons:
- this was after a relatively short highway drive on flat terrain (as a side note, I had a burst acceleration where i left a model 3 in the dust - probably base model lol)
- was -7C (20F) outside
- my 2013 GS450h has 170K km (105k miles)

I guess that's good news though and wondering how often other owners see the the hybrid battery full and under what circumstances.

Another question for the members is if anyone changed the eCVT and diff oil as I don't see it referenced in the maintenance guide but some dealers recommend it @ 60K miles

Im2bz2p345

Wow, that's a rare sight. I have only seen it once or twice on my 2013 as well. It's been only during longer stretches and going slightly downhill.

The car is has no much power built up that it's just waiting to release when it gets to 7/8 or more full. I'm glad you were able to capture a picture of it.

~ im2bz2p345

Hues10

Yes, when going downhills in the Blue Ridge mountains. Interesting when going downhill, you are not coasting as you would in a normal car, and thus, you do not need to brake as much. One comment on your picture, why L/100km? Is there an option to show km/1L? That way, the higher the bar, the better the gas mileage. Just looks counter intuitive to me. In the US, do we even have an option to display Gallons/100 miles? I have always determined gas mileage as miles per gallon.

I know, the Metric system……..

ratobuza

Yes I've seen the battery full in downhill situations which makes sense as even coasting without the brakes recharge the battery - but highly likely you'd brake at least now and then to keep speed. What suprised me was this happened on flat highway at below freezing temps

Re mpg in the US vs l/km I guess both are OK depends on preference in mpg you want the bars as high as possible in l/km as low as possible lol

bclexus

I seem to recall pulling into the garage with the hybrid battery displaying 6/8 or 7/8 but the next day, or maybe two days later, after cranking-up and backing out of the garage the hybrid battery was displaying only 2/8 or 3/8. Is it typical for the hybrid battery to lose that much storage over a night or two?

On second thought, I think the hybrid battery actually starts the ICE, so that would take some battery storage (maybe one or two bars) to crank the engine.

[Note] I'll have to pay closer attention to this to be sure because sometimes I'll float through my neighborhood in EV mode before arriving at my house which of course would use up some battery storage.

bclexus

I found that if I pull into the garage with the traction battery at 6/8 or 7/8 it's usually either at the same level or down just one notch after I crank-up the following day...so it retains the charge level adequately. When driving and using the traction battery I've found that it is pretty quick to discharge yet it's pretty quick to recharge too.

With no firsthand experience until just recently I would have thought the charge/discharge pattern would likely be; relatively slow to achieve a near full charge but rather slow to discharge (much like a typical tool battery is), but that's not the case...

ratobuza

In my personal experience it looks like the hybrid battery is both charged and discharged rather quickly, couple of minutes really, which seems normal for a small 1.9kwh buffer battery like our hybrid system uses. I think that the very conservative battery charging/discharging with 20/80% threshold is designed to maximize lifecycle rather than performance, which is both a plus or a minus depending where you look at it I also noticed a preset algorithm in the hybrid ECU which seems to favor a full 20/80 cycle rather than partial cycles (ex if in a discharge cycle and battery reaches 4 or 3 bars it still seems to go down to 2 bars even if ICE already started recharge)

bclexus

ratobuza - Very Interesting!

If I understand it even partially (to some casual or small extent); complete 0/100/0% cycling would not be good for the hybrid battery and would likely be damaging to the battery. So, cycling between say 20% (empty) to 80% (full) provides for adequate buffering or safeguard protection of the battery. I presume this is accomplished by purposely limiting the minimum and maximum voltages, so that some of the hybrid's capacity is intentionally left unused.

I suppose there is no published cycling method data specification sheet or algorithm pattern blueprint available for the hybrid ECU's hybrid battery charge/cycling system? I assume that would likely be proprietary information and not made publicly available, which begs the question - How were your able to notice a preset algorithm in the hybrid ECU which seems to favor a full 20/80 cycle rather than partial cycles (exampled by - when in a discharge cycle and the battery reaches 4 or 3 bars it still goes down to 2 bars even if the ICE has already started recharging)? That pretty much is a telltale indication that the ECU is controlling the cycling percentage - almost certainly on both the charge and the discharge side of the matter. Again, as I understand it - very interesting!

bclexus

ratobuza - This research paper (article link below) supports and parallels your view and understanding of the hybrid traction battery's optimal charging cycle.

Real-world study for the optimal charging of electric vehicles

Lwerewolf

It's actually 40/80%. Falling below 40% makes the car drive in turtle mode - no throttle assist whatsoever.

bclexus

Lwerewolf,

Fascinating! But I have not experienced this 'turtle mode' you speak of. Can you be more descriptive in defining what exactly you mean by 'makes the car drive in turtle mode'?

Falling below 40% [causes] no throttle assist whatsoever - from what power source? No assist from the traction motor - do you mean EV Mode is not available? I'm confused.

Since 3 bars (3/8) is below 40% and 2 bars (2/8) is only 25% I have not detected this 'turtle mode' at 3/8 or 2/8 unless you mean that EV Mode is just not available, which is fully expected and not surprising. But even at 2/8 the drive power has not perished any compared to well above 40% (e.g. 6/8 or 7/8). I guess I need some help to understand your perspective.

Does using a Drive Mode other than ECO (e.g. Normal, Sport or Sport+ Drive Mode) in any way alter the charging parameters any, or allows the car to drive with greater power?

703

0 bar is 40%.

bclexus

Ah, never would have thought that!

Attempting to comprehend this...

So, at 0 bar (equaling 40% or below) the motor and battery system isn't accordingly shut down completely, however there's no throttle assist. Yet, it still might be able to provide enough function to move the car a little, which one could refer to as 'turtle mode'. Maybe...

ratobuza

Thanks for the link bclexus - interesting article! Regarding your question on how did I get the impression on "forced" 20/80% cycles by the ECU is simply by observing the battery status while driving. I noticed that more specifically after driving in EV mode for a while in either stop/go highway traffic or constant cruising @ below 40mph in a residential area, in the context of battery just being depleted for a longer period - say starting from 8-9 bars all the way down to 3-4 bars with no ICE intervention. In that circumstance i noticed several times when ICE started at some point say 3 bars due to speed increase or need to accelerate that battery still continue to deplete to 2 bars even while ICE was on, followed of course by the gradual battery recharge back to 8-9 bars

Im2bz2p345

Interesting! I should really do more reading on our traction battery or Toyota traction batteries in general. I always assumed 0 bar was 20% SOC.

I find Prius forums a great resource with knowledgeable folks on traction batteries (of course they are different size & recently Toyota has pivoted to using LION vs NIMH in some vehicles).

My hope is if the GS450h ever makes a return, we get a lighter weight (and one that takes up far less space) LION battery that can propel the vehicle on battery only power for quite some miles on its own. I wouldn't mind plugging it in if I could ride around town to do chores in pure EV mode.

Regarding "turtle mode" - I have not experienced that unless my vehicle runs through an automatic car wash where you have to keep the vehicle in neutral as that depletes the battery rather quickly and doesn't allow the ICE to recharge. I make sure to turn off the A/C or other other high draw devices before entering the car wash. I've had the vehicle down to one bar doing that and my biggest fear is getting stuck in a car wash if the line! It does affect the acceleration and makes the car feel "bloated" because the engine is working hard to restore power to the traction battery.

~ im2bz2p345