Folks - so new owner of a '13 450h with 36k miles. I AM familiar with hybrid driving - my other car is a Volt, but, i'm not getting the MPG i was hoping in the Lexus - driving in ECO, i'm getting around 24.5mpg. Searching the forum, i began reading about sometimes there can be issues with the propulsion battery, especially after the 12V battery has been changed, and an ISC reset might be necessary. I found the instructions for it on the forum, and have tried to follow for about 20 minutes, but i'm not sure if i've done it correctly and was wondering if anyone could give me some pointers. Here's what i did..:

Sat in the car, AC blasting, trying to wear the propulsion battery down quickly. It didn't take two long, but on the main display, I could only get the battery down to 2 bars before the engine would come on and start charging again. I wasn't sure if it was critical to get to zero bars, or how to do that at that stage given the engine had come on and began recharging, so assuming that was good enough, i went on to the next step.

Turning off everything electric in the car that i could, I then pushed the brake down, and then the gas all the way. Alternating, 40 seconds on the gas, then lift on the gas for 10 seconds, then back on for 40 - always with the brake pushed down. The car would rev up and charge. Just looking at the small dash display, once the battery got past about halfway, I noticed the battery indicator would come on in addition to the engine - meaning the car was using both battery and engine power. Once I got to this stage, it took me a long time to further charge the battery. Repeating the process, i finally got to 'almost fully charged' - on the small dash display the battery was never fully filled, just about the + - icons. I continued for a while - i notice the engine would rev differently - initially when i'd step on the gas, it would rev up, but after a few seconds it would drop down to a very low rev. However, I tried for around 20 minutes, and couldn't get the battery fully charged. I quickly checked the battery on the main display (wanting to keep it off) and I was still 2 bars short of a full charge, but I couldn't seem to get it any further using this technique. Did I complete the ISC reset? Is there a way to know if it was successful?

thanks in advance!
-Matt

 

Hi Matt.
See, that's not quit knowing hybrids, Toyota hybrids.
Battery indicator should NEVER go below two bars and ICE should start up to charge it. Normal.
Sitting revving engine doing this and that, will NOT fully charge battery. You need to roll down, with battery at about 80%, very long steep hill, to actually hit the full green mark and, most likely, in B mode, as it charges faster. In B mode, charging current is three times that of regular regen braking. 30 A vs 10 A.
So you are not happy with mpg. Understood. Questions do I have though:
1. what exactly is your normal drive? Terrain, traffic, distance, ALL of it. As it has huge impact on mpg.
2. driving style.
3. vehicle load.
Those are likely three most important factors that influence mpg.

 

thanks - yeh, i am new to Toyota/Lexus hybrids - what i really meant was i'm use to taking advantage of things like regen breaking - coasting along, not aggressively accelerating, monitoring the road ahead for gentle breaking etc. - efficient driving. I am not use to how/when the charging occurs, and its various limits, as the Volt is all electric until the juice runs out, then it switches to its gas 'range extender'.

What is B mode, is that available on a '13 450h?
In terms of your questions - that's why i was thinking i should be doing better....
1. Typically flat, mostly slow and go traffic, typically around 6-9 mile trips on average.
2. Driving style - as mentioned above - while i'll quicken up with traffic (as i don't like to give hybrids a bad name by having everyone forced to drive slowly behind me) mostly i'm very gentle - ease on the gas, avoid the power zone, let off and glide as much as i can, monitor road ahead to avoid sharp breaking etc.
3. Load - its either just me (190lbs) or me and my boy (add another 55lbs) - nothing else in the car except for my mints!
thx,
Matt

 

Being able to cruise a lot on battery power only is one way to get high mileage, which can take some patience and the right roads. This is possible when you are <= ~42mph AND operating within the 1st eco zone. While cruising in your flat areas, try to avoid drifting up into the second eco zone if possible, this will force an engine start and possibly start charging the battery (try to save battery charging for regen, or when driving at higher speeds). The second eco zone is only applicable when using the EV button below 25mph, and not normally helpful.

The eco mode will "soften the response" of the gas pedal, and reduce fan and A/C load of the climate system. I've typically only found this helps when needing to use the climate system a lot, but the softer response on the gas pedal, not sure if really helpful. I've found that being too sluggish to accelerate is counter productive. Not advocating burning up the tires, but reasonable accell up to near 35-40mph (the sweet spot) and ease off into bottom of first eco zone momentarily (right at point of regen, this will allow an engine stop), then slight ease on again staying in first eco zone is a good approach.

Flats and downhills are great of course, but ups and downs are better than long (even gentle) uphills, avoid them as they keep the engine running. Toyota hybrids prefer to keep the battery charged over max efficiency, and will do so all the time if you let it. Have to coax the efficiency out of it sometimes.

 

Yeah, Toyota hybrid is fairly unique.
Ok, so you have all but one, indications to have good mpg. Now, here I am, guy who had two hybrids, Camry and Highlander (same as RX H power train) and each one aced on mpg.
One that I do not like is short trips. Thing is, ICE will run until the EVAP system is warmed up to a certain required temp. That usually takes about 4-5 miles. That said, here's your 6 mile range, with 80% of it taken by warming up whatever it needs to warm up. I am not saying ICE runs continuosly - it simply runs much more, than after it's all warmed up.
Toyota hybrids are known not to ace on short trips.
I averaged 30-32 mpg in my Highlander but on 31 mile one way commute.
Next. B mode. B stands for braking. As in - engine braking. I was on my Camry and Highlander. Now, I saw some remarks that RX H may actually not have it, what would have been surprise, as Prius also has it.
In B mode, engine is turned off and vehicle is slowed down by air resistance, when bled through the cylinders, flow controlled by VVT-I. It is normally suggested to use when rolling down hills. I used it much more extensively for pre-braking car before red light, stop signs, entering corners. I used B mode as much as I could, I sorta really liked it. So look down by your gear shifter, if you have position marked as B. Toyota says you can drive in D or B position, long drive is not recommended in B mode. How long is too long is not specified.
Ouside of short trips, possibly in city traffic (which is another mpg killer), I see no hindrances to you having better mpg.

 

My Camry hybrid had the B mode and I used it a lot as well. In my RX450H, I use the S (sport) mode in a similar way. When the light up ahead turns red, I let off the gas and move the shifter over to Sport mode and it initially moves into "4th gear" out of 6. I know it doesn't really have 6 gears since it's a CVT but just pretend it does. Then I continue to downshift (regen braking) as I approach the light until I need to use the brakes to stop. Then I shift it back to "D". I don't know if it charges any better but it does slow you down, charge your battery, and you get to pretend like you're driving a manual transmission. It also comes in handy if you need to slow down or stop suddenly.

 

Yeah, so I was right that they moved away from B mode on some RXs. B mode charging produces higher amperage, as compared to regular regen braking. I was - rightfully - pointed out once that charging gauge does not show any higher charge when in B mode, but then who knows what that gauge actually shows. I know beyond doubt and have B mode article on this at toyotanation, that B current is 32 amp vs 10 during regen. Also, from experience, I could clearly charge battery faster using B mode.
Never used it in concurrence with regular brakes application. Slopes, pre braking entering sharp turns, pre braking before stop or red.

 

That said, they also have newer RX H-s coupled with regular automatic transmission.. I know nothing of that. No experience.