Im2bz2p345 - This is an interesting read that can add to our knowledge:




lexnewbi Says:
NateJG responds with the following:

Your car is acting Normal (not the Normal as in "it is normal for a 99-year-old to die soon", but Normal as in "it is normal for a healthy athlete's heart rate to beat slower than that of a Couch Potato").

In order to prolong the traction battery's life, the computer maintains its state of charge at a conservative level. You're seeing that as 6 bars.

The state of charge is maintained so that - in the event that you're decelerating downhill, or braking - and the battery is at that 6-bar level, the battery has the additional charge capacity (read: ability) to accept the additional charge and keep the car acting "normal" to you, the driver.

You WILL see the next one and even two bars lit during downhill stretches.

To help eliminate any likelihood of damaging over-charging of the battery, you may also feel/hear the engine (ICE) raise in speed during those long down-hill-fully-charged situations -- whereupon the computer will use the MG1 to 'waste' energy by spinning up the engine to, in effect, "Bleed Off" electricity that would otherwise overcharge the traction battery.

On the other end of the spectrum, once your traction battery depletes to the two-bar level, the ICE will start and cause MG1 to charge the traction battery - UNLESS YOU'RE SITTING IN A CAR WASH IN 100 DEGREE TEXAS WEATHER AFTER GETTING GROCERIES AND LEAVING YOUR TRANSMISSION IN NEUTRAL WITH THE ENGINE AND A/C RUNNING - because the MG1 needs to have something to pull against (read: Park, Drive, or Reverse) in order for the MG1 to generate electricity).

If you're still of the "gee, I'll see how far I can go in electric only" phase (it took me almost two years), you will likely not see the charge approach 7 or 8 bars; but once you've decided to simply drive the car as though it was, well, a Car - you may/will find occasion to see the top two bars lit (since the car will try to maintain 6 bars when in routine driving).

Lastly, you have the last two bars of capacity hoping that you, during the time that it takes for the traction battery to wear down those last two bars, discover the dashboard message to "take the car out of Neutral" - else the traction battery will deplete to a level insufficient to spin up MG1 and start the engine.

P.S.: I did a little test tonight - sat with the A/C, headlights, seat heater (yes, it's summer here too), and blower blasting - IN NEUTRAL - until the bottom two bars were the only ones lit.

After the next-to-last bar went out (leaving but one purple bar lit), a message on the dashboard told me to take the car out of Neutral. I did (put it in Park) - and it took several minutes for the battery to charge up to three bars lit.

During that time (charging) nothing I did to the throttle (as in "floored it") made any difference on the engine's speed. Once the battery charged to three bars, I was able to quickly charge it to four bars by "brake-torqueing" it with part-throttle.

Helpful?

 

Thanks for sharing - good explanation. I've personally never seen the battery under 2 bars as ICE starts at that point to recharge, and never keep it in neutral as I know it's not charging in that position.

Like most folks here most of the time the top charging stays at 2 bars lower than completely full on dashboard (which i understand is 80% SOC) although i get the additional 1 bar charge (1 left empty from top) when using sport+ and rarely full charge

Someone was saying 0 bars charge is 40% SOC which is surprising - wondering what the SOC corresponds then to 2 bars left, when ICE kicks in

 

[QUOTE=bclexus;11243086]Im2bz2p345 - This is an interesting read that can add to our knowledge:



Your car is acting Normal (not the Normal as in "it is normal for a 99-year-old to die soon", but Normal as in "it is normal for a healthy athlete's heart rate to beat slower than that of a Couch Potato").

In order to prolong the traction battery's life, the computer maintains its state of charge at a conservative level. You're seeing that as 6 bars.

The state of charge is maintained so that - in the event that you're decelerating downhill, or braking - and the battery is at that 6-bar level, the battery has the additional charge capacity (read: ability) to accept the additional charge and keep the car acting "normal" to you, the driver.

You WILL see the next one and even two bars lit during downhill stretches.

To help eliminate any likelihood of damaging over-charging of the battery, you may also feel/hear the engine (ICE) raise in speed during those long down-hill-fully-charged situations -- whereupon the computer will use the MG1 to 'waste' energy by spinning up the engine to, in effect, "Bleed Off" electricity that would otherwise overcharge the traction battery.




Thanks for the explanation. I posted an enquiry about this a while back and nobody seemed to know the answer
Brake Regen with a full hybrid battery? - ClubLexus - Lexus Forum Discussion
idk how effectively it discharges the battery.. that being said i wasn't driving under normal conditions lol. having a personal track day, 10hour drive, mountain range, nobody on the road, hard on the brakes, hitting apex and accelerating out. but when the ICE kicked in on my way down, I started to get paranoid about over charging the battery. when braking at speed, the rpms would rev as high has 4~5k. Odd feeling accelerating out under those conditions, rpms drop to 1k and then increase according to throttle input. back on the brakes rpms jump up. Against everything I'm use to.
I was hoping the engineers had a way to divert the charge, rather than bleed it off. I'm sure I was putting way more into it

cheers

 

That was an interesting read. I guess I didn’t think about it too much that at speeds above say 40 mph, the car keeps the engine and battery working together to maintain six or more bars consistently (as in highway driving), but anything else, it runs the battery down to that two bar level before the ICE kicks in to recharge. I also did not know the battery does not recharge while in neutral. Have never taken it through the car wash, so not in neutral ever. Off topic. Does anyone use the brake hold feature much? When I first got it, I got stuck two times at a long wait when some error message pops up. It popped up exactly when I was supposed to go at a light so I didn’t read it, and when I pressed the gas, it wouldn’t budge. Man that was frustrating and I am sure the people behind me were not happy either. I still rarely use it somewhat because of that.

 

I seem to recall reading somewhere (maybe it was your post) that someone was using the brake hold feature and it would not release when they pressed on the accelerator, thus being unable to move (for I'm sure what seemed like a very long time) until it finally released.

I've tried the brake hold feature just to test it and see how well it works. It worked well but I don't use it. I don't use LKA or Cruise Control (with or without radar) either, preferring to be in full control rather than only partially in-control. The only thing I use that operates without my control is the Auto High Beam feature.

 

[QUOTE=JGB93;11244612]That would feel really strange and counterintuitive to what you've always been used to experiencing.