Author Topic: Fuel Recommendation vs Low Fuel Light  (Read 2839 times)

guest9814

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Re: Fuel Recommendation vs Low Fuel Light
« Reply #30 on: November 06, 2021, 04:17:41 PM »
What I find odd is that on the 2 occasions I've used a CTEK to fully charge the 12V battery after not using the car for a couple of weeks, on next powering up the battery segments go right up to max then tail off during driving back to the normal 3 to 6 variable segments.
This mentioned in user manual on page 138
When car used for 30 minutes HV battery will by cycled many times from 29% to 70% or less depends on conditions but at the end of this drive cycle HV battery will be the same ~30-40% SOC (so mayby not charge level concern but balancing liion pack because if pack unbalanced pack will stop working with hybrid system check error on dashboard) - liIon battery have very low self discharge rate and when car not used almost not discharges.
Another story if for some reasone when car in ready state driver moving from Drive (D) to Neutral (N) in this case  ICE engine will stop charging HV battery and HV battery may by discharged by car loads such as A/C (directly uses HV DC) seat heaters and rear window heater (powered throught DC-DC converter that suply charge to 12v system) below the point when car can start ICE to recharge HV battery.
Loock on Toyota recommendation for hybrids (but they mention both batteryes just because many their hybrids uses HV NiMh packs this ones have huge self discharge rate in comparison with LiIon packs -
https://mag.toyota.co.uk/coronavirus-toyota-hybrid-car-maintenance/
They simple asked to turn on car to ready state for 60 minutes.

guest9814

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Re: Fuel Recommendation vs Low Fuel Light
« Reply #31 on: November 06, 2021, 04:33:52 PM »
I'm not convinced that continually topping up a few litres at a time is making any real difference.

It's probably just fooling the fibometer into reporting higher mpg. The only true way is to calculate by brimming, or to the pump nozzle 'click', and doing the maths.
I drived 327 kilometers to get 2 bars of fuel meter go off then fill up to full tank (i let the fuel pump on gas station to stop automaticaly) - managed to fill up 10.8L.
Afterward i fill up after 335km and get 11.1L but this time i added to 3/4 of tank "95" RON gasoline with 98 RON, managed to get from this tank 930.7km and computer still judge that on remaining gasoline i can go another 150km
But that was in end of month and i heard about fuel price jump so filled up - get this time 30.7l to full tank (trip A 930.7KM)
I dont think filling to the first click auto stop on the pump is consistent enough between pumps for  precise comparisons on small quantities over a short period.    With a fast pump the filler neck on the car may fill up with fuel faster than it can  drain down into the tank. Especially when its almost full  . The pump detects this backlog of fuel in the filler pipe as a full tank and clicks off early. After a few seconds maybe half a litre or more of this trapped fuel  will have drained down into the tank.  With a slower pump there is no such backlog and you can fill up with that much more  fuel. Seems like you have used more for the same distance, but you haven't really.

The only way to do it accurately is to brim the tank until fuel is literally visible in the filler neck.  But this is not very safe, especially in a  hot climate where the petrol may expand.

Sound like your local  petrol is  using some dubious additives.  Even before it is adulterated further by criminals.

If there is a risk of a very bad batch of petrol it makes more sense to buy little and often.  If you add 10 litres of bad petrol to 30 litres of 'good' petrol you may never know.  Add 30 litres of bad to 10 litres of good and you'll know all about it. :o
Sorry but this kind of game with new car and plastik fuel tank is dangerus !!!!
All fuel tanks desigened this way that they have space for expanding fuel, if i brimm to the cap i risk damage fuel tank and charcoal canister, this will cost me too much.
I get twice almost identical ammount of fuel when refueled with almost full tank and i used same pump on same gas station.
This enough for me


Expatman

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Re: Fuel Recommendation vs Low Fuel Light
« Reply #32 on: November 06, 2021, 05:04:05 PM »
If you use the first click stop for safety but measure consumption over several fill ups then any potential errors will be minimised. The more fill ups you use for the calculation then the more accurate will be the mpg.

guest9814

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Re: Fuel Recommendation vs Low Fuel Light
« Reply #33 on: November 26, 2021, 07:00:13 PM »
Just found  Fuel recommendation on engines.honda.com
https://engines.honda.com/support-and-service/fuel-recommendations#gas



John Ratsey

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Re: Fuel Recommendation vs Low Fuel Light
« Reply #34 on: January 06, 2022, 08:42:36 PM »
Today I travelled about 6 miles after the miles remaining hit zero before putting 37.66 litres into the tank. The low fuel warning came on with about 30 miles of journey remaining and mental arithmetic indicated that 5 litres of fuel (the handbook says approx 5.3 litres remaining when the low fuel warning came on) should be good for at least 50 miles. And that's roughly how it worked out.
2022 HR-V Elegance, previously 2020 Jazz Crosstar

nowster

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Re: Fuel Recommendation vs Low Fuel Light
« Reply #35 on: January 06, 2022, 10:20:40 PM »
Just found  Fuel recommendation on engines.honda.com
https://engines.honda.com/support-and-service/fuel-recommendations#gas
Those are for small (lawnmower type) engines, but many points are still relevant.

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