There isn't one and even the battery percentage is only an approximation. The % is the battery management systems best estimate of state of charge but it can go up or down as the ambient temperature changes. Then the GOM estimates how far this charge will get you based on how you last drove it and the temperature. Some cars further adjust the value if you set a destination in the nav according to the type of road. So if you drive like a granny then charge the car it will estimate a long range. If you drove it like you stole it then it predicts a short range. If it's cold out it reduces the estimate and if it's warm it increases it. Simples.

 

There isn't one

@Gt6k I think the guage that @Ben Cole is talking about is on the right in this picture:-

John

 

Thanks for your reply. I know how the GOM works, thanks anyway.



When you say "the BMS' approximation", do you mean the same way every other device with a battery "approximates"? (What we all actually regard as the charge level)



Anyway, the question was about the relationship between the gauge and the percentage. I don't believe that there is no relationship (as you claim).



For starters when the SOC is 100% the gauge is "full" and when it is 0% it is "empty"........a relationship.



If you're saying that the point at which each bar disappears is at a different percentage day to day, then this is what I want to know.



If they were set on this type of gauge, I don't know why Hyundai didn't just put a 20 segment range and have each segment correspond to 5% 🤷‍♂️

 

Hyundai call it a SoC gauge in the manual, but it is really just a rough sketch of what a gauge might look like.
Again from the manual, the 2 red bars at the base are stated to be where the vehicle speed is limited, say <= 4% SoC. Above this are 16 white bars, assumed equal in value, thus giving 16x6%=96%.
Accordingly, the 2 division marks on the vertical scale would be "1/3rd" at 28%, and "2/3rds" at 64%, which roughly fits your observed value...

 

That makes sense, but in reality it’s not how it works. I don’t see any limitations until I’m on the last bar (or no bars). I see turtle mode at roughly 8-12 miles range which is 2-3 kW or about 5%. And that’s only 1 bar.

 

I've always found that battery gauge to be pretty accurate, it mirrors the battery percentage on the EV range screen.

 

There are 18 bars, so each bar is very roughly 6%. So if you want to say that 6 bars are 33% then yes, except it won’t drop to 5 bars until it hits 27%. And it won’t drop to 4 bars until it hits 21% so I can see where the OP is coming from, it should have been on 5 bars, but I have to say I don’t use that gauge, I drive to the range guesstimator which I have to be honest,

I’ve always assumed was 50 miles wrong because I could go into my hotel at 5pm when the air temperature is 12C then come out to get in the car at 5am, when the air temperature is 0C and it’s drops by 30-50 miles. It’s just living with a BEV.

 

There are 18 bars, so each bar is very roughly 6%. So if you want to say that 6 bars are 33% then yes, except it won’t drop to 5 bars until it hits 27%. And it won’t drop to 4 bars until it hits 21% so I can see where the OP is coming from, it should have been on 5 bars

Yes, this is the issue. I wish I could use it to judge charge levels in 5.55% steps (100/18) but this isn't the case. Since it's calibrated differently I presumed there must be a rationale behind the change .

 

Sorry I thought you meant the GOM when you said fuel gauge

 

I take your point, however I've found my percentage discharge perhaps a little more linear. That is is, miles/percent to be reasonably consistent.

Anyway, since nobody has actually been able to succinctly answer the question, I am embarking on a fact finding period.

I will watch my %, GOM and gauge and note the changes at each bar drop.

Just stopped for a cup of tea on my drive home, so far I have:

Start 88% 16 bars 217 miles
83% 15 bars 200 miles
78% 14 bars 186 miles

#geek 😁

 

Just in the unlikely event that someone is interested 😉......


Start 88% 16 bars 217 miles
83% 15 bars 200 miles
78% 14 bars 186 miles
72% 13 bars 171 miles
65% 12 bars 154 miles (might have been late noticing this drop)
61% 11 bars 143 miles
56% 10 bars 130 miles
50% 9 bars 116 miles
44% 8 bars 101 miles
38% 7 bars 91 miles
35% 6 bars 83 miles

Then it went odd. Going back and forth between 6 and 7 bars, the first was due to regen coming off the motorway but after that all on the flat.

7 bars 34% 82 miles
6 bars 34% 83 miles
7 bars 34% 82 miles
6 bars 34% 81 miles
7 bars 33% 81 miles


Got home with 7 bars 33% 80 miles.

163 miles at 4.3m/kwh according to the car.

 

More linear than I expected.