You will always use the 100 in the equation, because you are trying to calculate 100% of the remaining battery. You put the % of battery used in the denominator. In my example, I started at 90% battery & went down to 78%, so I put in 100 / (90 - 78), or 100 / 12 for the last part of the equation.I think you mean the formula like this:
[(Miles Driven in Step 3) / (Average miles per kWh efficiency in Step 3) ] * 100 / (Percent Battery Used from Step 1) = Estimated Battery Remaining
Assuming that the efficiency indication of the car is correct, the charge percentage indication is correct, and the battery will always indicate 100% for a full charge, even after years of degradation, I think this estimation may make sense.
But when the battery gives a lower percentage than 100 for a full charge, then you have to put that percentage instead of the 100. In fact you can also start this with a non-full battery by using the initial charge percentage minus the final charge percentage as (Percent Battery Used from Step 1).
Gotcha. A better way to write the equation is:I meant if after some years you start with a full battery, but that fullness is indicated only by 98% (which happens for some BEV's), then you have to take that 98% into account in some way, as the 2% loss is already in that number.
You are assuming a degraded battery will stop @ 50%, thinking it is fully charged. If a battery degrades about 2% - 3% a year, are we seeing Ioniq's stopping at 97.5% now? I've driven my eGolf for almost 2 years, and it still says it charges to 100%.I am afraid this is not enough. Suppose after 10 years of degradation the full battery is only 14 kWh and it indicates that fairly by an initial 50% percentage. Then according to this last formula for a trip from full to empty you would calculate 14 kWh * 2 = 28 kWh, which is not true in that case.
If the "fully charged" percentage goes down over the years, you won't have to calculate anything. If it stops at 70%, your battery is at 70% capacity.There are different systems for different brands for this. Some indicate the percentage of the current capacity, then in all years always a fully charged battery is 100% by definition. But some others also let that percentage go down over the years. I am not sure how the Ioniq handles this. If it belongs to the former category, the last formula seems OK. If it belongs to the latter, then you need to do something with that percentage < 100% too.
Yes, that could be the case if they exactly do that system, but still I would like to be sure it is not a mix of the two systems. And you rely on the figures generated by the car anyway, so there will always be a doubt whether these figures are correct.If the "fully charged" percentage goes down over the years, you won't have to calculate anything. If it stops at 70%, your battery is at 70% capacity.
Personally, I used Google Maps to get a better "miles driven for trip". In respect to efficiency & state of charge... we kinda have to assume it isn't lying to us. There is no way to calculate battery capacity if we can't trust the numbers the car provides.Yes, that could be the case if they exactly do that system, but still I would like to be sure it is not a mix of the two systems. And you rely on the figures generated by the car anyway, so there will always be a doubt whether these figures are correct.
I am driving a 2015 eGolf, which has a 24.2kWh battery, with a little over 21kWh usable. I'm very interested in an Ioniq, if the battery looks like it will hold up (since I prefer to own my cars for a long time). I expect the degradation can't be any worse than my eGolf, which has no thermal management. I'm running new numbers today, since I'll have to average out a few readings to get an accurate number.This is a bad outcome if you find an estimate of 21 kWh for the battery for which the usable part is 28 kWh. This would make this method not usable to find differences such as 2 or 5%. Are you sure the input numbers were correct?