Nx450h HV range display

[guildford]

Has anyone worked out how the 450h+ determines what figure to show for HV range.

On a full tank the hv range claims about 500 miles. However if I start driving in HV mode the range drops rapidly (eg you drive 100 miles and the range now says something like 350 miles) … however if you then fill it up you will only have used 9l or so … so it doesn’t seem to be anything to do with real falling fuel economy.

I guess the range is based on 45l fuel (ie ignoring the 10l reserve) but I can’t work out why the stated range doesn’t reduce at a rate similar to the miles actually driven.

[Harrier Man]

It doesn't make sense does it? I've noticed the same thing but I'm hoping that this is a temporary thing that will sort itself out once the car refines a better mpg after a few fill-ups.

Over the journeys I've completed (a mix of short and long, motorways and rural) the app is displaying a wide range of mpg figures. If the car is using the same data to calculate the HV range, I'm not surprised it's a bit confused.

[RXtoNX]

I had the same situation today. Left Birmingham with a range of 285 miles showing and no EV range. After arriving at our local petrol station and covering 165 miles all obviously in HV mode, rather than showing the expected range left of circa 120 miles it was showing 56 miles. Just to add to the confusion it only took 36 litres to fill up and the range then showed 522 miles🤔.

I can only conclude that the range calculation is based upon historical mpg including EV miles, and therefore makes an assumption that the % EV driving will be the same as historical, but as the tank gets lower it uses the current mpg to adjust the calculation. Doesn’t explain why I could only get 36 litres in the tank though unless it omits a reserve range as the tank gets lower.

Very confusing and can’t be relied upon as an indication as to whether you can make it home or not before filling up.

My RX was the opposite, the fuel tank always showed more fuel in the tank than the remaining range suggested🙄

[guildford]

I can’t work out any logical explanation. I did wonder if it was something to do with their confusion in some situations between miles and kilometres ie some of the figures seem to be out by a factor of around 1.6 

I just find it incredible that 9 months after a car has been on the market that an organisation the size of Toyota/ Lexus seems incapable of resolving such basic errors.

[guildford]

On a long motorway drive with a full EV Battery, I let the HV range run down to 0 to see what happens.

a) The Fuel light came on when the HV range claimed 20 miles to go. This is at odds with the manual which says it should come on with 2 gallons left in the tank and I hoped the car might realise it had more fuel in the tank than it thought.

b) However, the range continued to drop at a rate in excess of the miles driven and when the range hit 0 the car turned to EV mode and said refuel. I did refuel and the car took 44 litres (according to the manual the tank is 55l).

 Two days later I refuelled again and this time the HV range on a full tank came up as 367 miles (previously it had always claimed more than 500). This could be something to do with the vehicle "learning" from an empty tank or I suspect it was following a software upgrade. On a positive note the range now goes down as you would expect as you drive.

However, although this is one step forward it still doesn't explain how a car that seems to do 40-45 mpg and has a 12.1 gallon (55l)  tank only has a hybrid range of 367 miles.

I'm guessing the tank may not be size it claims in the manual (or certainly the usable volume isn't)

[Las Palmas]

Seems that Lexus software has not improved since 2017. In the little tank we have it tells that the range is 500 km when just filled up. drive a bit more than 400 and empty light comes on. Never trusted to drive a lot of km after that so do know if reserve is actual close to 100 km, but when filling up again the 500 km will again be stated as the range.

[Zotto]

The problem with hybrid with ecvt is that, if you have no more fuel , it's quite a catastrophe, as you discharge traction Battery and and that point after refuelling, you can' restart car anymore. To avoid this, the left range indication is very pessimistic to force users not to end fuel. Using a plug-in may complicate more the estimate range. My simple rule is to consider to to absolutely  fuelling  below "zero" range, even if there could be made many miles before total disaster. Besides, a fuel pump working with no gasoline circulating risks to break with another expensive repairing.

[Ken R]

Don't quite know how this works as I fiiled the tank this week and got an indicated range on 501 miles. Have since travelled 70 and yet range says 348 and the fuel gauge has reduced by one "bar". ???

[RXtoNX]

Ken, see my post above of Sept 25th. 
 

General consensus appears to be that it has something to do with the calculation down to the reserve tank, which there could be some truth in if you consider the amount of fuel my fill up took🤔