Author Topic: Value of 1 bar of battery display  (Read 892 times)

RustyK

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Value of 1 bar of battery display
« on: February 03, 2023, 05:24:15 AM »
Hi All,
Have been trying to establish the approximate capacity of the bars displayed on the user interface.
Have been using the following to test (engine is OFF) and car is in EV Ready mode.:
AC=off and set to LO, all lights off, Fan Speed = MAX, audio off, time measured to drop from 6bars to 5bars in seconds. Average time to drop is 230 seconds.
Assuming Max fan blower=250W+Background usage=100W for about 350W total.
I do this after a drive to ensure the 12V battery is charged.
Estimate that 1 bar = 0.028Kwh = 28Watt Hour.
Does this seem reasonable? if this is the case the bars displayed only represent about 1 third of the battery capacity (0.28KwH).
Comments welcome!
Regards.

Marco1979

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Re: Value of 1 bar of battery display
« Reply #1 on: February 03, 2023, 05:51:35 AM »
Interesting test! The accuracy comes merely from your power estimate of 250W and 100W. I donít know whether these are realistic. Does anyone know?

What I also notice is that the top 1 or 2 bars are almost never used except when driving down mountains. Also the bottom 2 are always there, the engine kicking in to charge. So I suppose that maybe those 10 bars are not evenly spread across the battery range. It would be interesting to see if 5 to 4 and 4 to 3 also takes 230 seconds.

shufty

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Re: Value of 1 bar of battery display
« Reply #2 on: February 03, 2023, 07:04:52 AM »
... I've never seen less than 2 bars but frequently see 10 (no mountains involved  ;D
)
Tbh I've never thought the bars were an accurate measure of anything really just an indication of charge left, which as you know is up and down all the time.
MY22 Jazz EX - Sunlight W

Kremmen

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Re: Value of 1 bar of battery display
« Reply #3 on: February 03, 2023, 07:18:48 AM »
Same here, the only time I think it's accurate(ish) is on a journey after the battery has had to be charged when the meter has dropped to 3.

It then tends to rise and fall between 3 and 7
Let's be careful out there !

Marco1979

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Re: Value of 1 bar of battery display
« Reply #4 on: February 03, 2023, 08:47:04 AM »
I like to check the distance covered between rises and falls. E.g. when cruising at 90 kmph (56 mph) on a warm day you see it drop from 7 to 3 while being in EV mode in around 800 meters. Then the engine kicks in and it needs around 1000 meters to get up to 7 again. This ratio (800 : 1000) tells me something about how efficient I drive.
Unfortunately I do not own a Scangauge or anything; if I could figure out / read the amount of power the electric motor would develop, I could also calculate battery performance from these distances (including speed and EV power, obviously). Moreover it would also tell something about wear if done regularly e.g. every year. Or check efficiencies in summer versus in winter. Or... Or...

I can imagine Honda puts a low strain on the battery and uses not very danse battery packages. An EV would have 1 cycle (charge - discharge) every let's say 100 miles, while the Jazz does this every 1 or 2 miles. So across the entire life span, HEV's have had much more cycles than EV's.

Lord Voltermore

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Re: Value of 1 bar of battery display
« Reply #5 on: February 03, 2023, 10:09:46 AM »
I dont think you can accurately assess the capacity of bars in relation to  the wattage consumption of 12volt systems such as fan blowers, radio etc ,aircon ,headlights etc.   These take power from the the small 12volt battery. The power used by the 12v battery  is topped up by  the HV battery, so will indirectly deplete a bar in time, and require more petrol  to top it up again. But   the traction motor also shares  the same 'Bar 'and  will take the lions  share of a 'bars worth' of power when active.  And this amount of consumption  tends to suggest the bars represent a large and relatively vague measurement  subject to fluctuations in precise  accuracy.
  I have never yet been able to predict  when EV power will recharge itself, or not. Sometimes the engine starts when there are still plenty of bars, other times it does not start  even when there are only 2-3. bars

I dont think waiting to see how quickly 12v systems alone  would drop a bar   would give a meaningful or accurate measure. You could probably tell using more sophisticated measuring instruments,  but the bottom line is  that any unnecessary use of heating, aircon etc comes with a small fuel penalty. Which will reveal  itself as a change in mpg.
« Last Edit: February 03, 2023, 10:19:17 AM by Lord Voltermore »
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Kremmen

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Re: Value of 1 bar of battery display
« Reply #6 on: February 03, 2023, 10:18:33 AM »
TBH I don't really care what the bars are reading as long as the car is working, which mine is.

I've seen 10 bars come up after an overnight stand and no charging but that soon drops to 3 after a few miles.
Let's be careful out there !

John Ratsey

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Re: Value of 1 bar of battery display
« Reply #7 on: February 03, 2023, 02:17:55 PM »
I've always assumed that each bar equals 10% of the battery capacity.  However, the minor flaw in this logic is whether 3 bars, for example, covers the range from 21% to 30% or from 25% to 35% as we need to know the charge level when the display changes the number of bars. The normal gauge range of 3 bars to 7 bars implies that the normal battery operating range is 30% to 70% or perhaps 35% to 7% percent. Such operation is plausible given that most of the wear on the lithium battery chemistry is caused by operation at the two ends of the charge range. I've got a dim recollection that someone claimed that the Car Scanner OBDII app could read the HR battery charge level. If true then this would improve our understanding of the gauge.
2022 HR-V Elegance, previously 2020 Jazz Crosstar

Lincolnshire Rambler

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Re: Value of 1 bar of battery display
« Reply #8 on: February 03, 2023, 06:19:54 PM »
If the hybrid drive train results from Hondas F1 knowledge then I suspect the control of the HV battery is very sophisticated and doing lots of things . I would imagine the controls ensure s the HV battery sees 10 or 1 bar  at some described point based maybe on optimising the battery life. If you accelerate with  an enthusiastic foot from several roundabouts (as on the A43 past silverstone ) the HV battery can show 3 bars or 9 , and has nothing to do with giving it the beans !! I expect the PCM figures load and battery temperature maybe driving style as well based on accelerator position / brake use . It must figure the actual cycle use of the HV battery and add itís own conditioning cycle into the mix ? My last long (500 miles return ) journey in summer with 30 C heat and climate control on auto 19C all the time gave 73 mpg on A1 M11 M25 M2 to Kent and 71 mpg on the return leg .. figure that Ö.??  😆😆😆. Outside of our group of users this level of tech isnít appreciated !

richardfrost

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Re: Value of 1 bar of battery display
« Reply #9 on: February 04, 2023, 09:01:07 AM »
You lot have too much time on your hands.

Lord Voltermore

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Re: Value of 1 bar of battery display
« Reply #10 on: February 04, 2023, 09:39:52 AM »
Yeah sometimes there is too much information.

   I have carried out a detailed analysis on how I spend my time overall and  on the various instruments and accountancy possibilities on the Jazz  and have concluded...  - Nah  Only Joking.  ;D    Ignorance is bliss.    As long as I can still pay the bills its enough to know the Jazz is better than most cars. 
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nowster

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Re: Value of 1 bar of battery display
« Reply #11 on: February 04, 2023, 11:51:02 PM »
According to the CAN bus, 10 bars (full) on the display is 89% charge on the battery. I've not in the short time I've been monitoring yet seen the battery go below 25% charge.

Kremmen

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Re: Value of 1 bar of battery display
« Reply #12 on: February 05, 2023, 07:14:34 AM »
Which battery though ?

I've had multiple instances where I've been sitting on 3 or 4 bars, trickle charged my 12v battery and next powerful it's gone up to 10 bars.
Let's be careful out there !

Jazzik

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Re: Value of 1 bar of battery display
« Reply #13 on: February 05, 2023, 09:49:09 AM »
  :o Then I think you have (secretly) connected the trickle charger to the HV battery... ;D

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Kremmen

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Re: Value of 1 bar of battery display
« Reply #14 on: February 05, 2023, 10:08:18 AM »
That would be a good trick via the 12v terminals :)
Let's be careful out there !

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