arnolddeleon wrote:0.8kWh sounds about right for an hour of charging at 100V. There seems to about 200 watts of car overhead/inefficiency when the car is charging leaving 800 watts for the car. If they had reclalibrated for 120V we would get a nice round kWh. Does the car switch to only 1 hour increments at lower SOC? That would be a bummer because that's where you need more information.
I drove from full to turtle today to confirm couple of key metrics, but I'm too tired to post all the data I've gathered. What I can say with some certainty is that 1 hour on the 120V charging display corresponds to about 840 Wh. The display shows half hour increments in the upper part of the range, but they are not displayed in the bottom half (below 12:00).
arnolddeleon wrote:From what I gathered at the meeting the SOC is at best a guess when the car is running and under load so getting and displaying very precise numbers is going to near impossible but I'm ok with that. I would be quite happy to have any gauge that is repeatable and accurate to with a 2 to 3% (N.B. I'm trying to use precise and accurate carefully).
Based on my turtle experience last month, I had a hunch that Nissan used pack voltage to estimate SOC values. If I recall Kadota-san's slide correctly, he mentioned that in his presentation as well. As GregH said couple of months ago
, pack voltage can plummet rather easily when the battery is below the knee, which roughly corresponds to the very low battery warning. In my experience, sharp pack voltage drop can trigger premature onset of power limited mode. I would be careful with the accelerator pedal and either avoid going uphill or at least slow down considerably on inclines after the LBW and particularly after the VLBW.
arnolddeleon wrote:The question that driver needs to answer is "will I make it". The current reality is the battery pack doesn't store enough energy to make this a moot question. This leads to the fundamental need for a gauge that behaves in a somewhat consistent manner so the driver can *learn* what *their* range is. I suspect most drivers don't think of trips in miles (until they start driving EVs). What I've learned in almost 10 years of driving a RAV4-EV is that I need a certain level of SOC from certain locations to get home. I could plan future excursions from those known points. BTW I think the DTE (Distance To Empty) indicator is a useful addition, it is just not sufficient. The unfortunate mistake was to make it so prominent and not give us a percent SOC meter that we can read as easily.
Yes, I agree completely. To Nissan's credit, they tried to make the DTE indicator easy to use. However, it would have been a prudent design decision to include a simple SOC meter display option as a fallback. Just in case their rather simplistic DTE algorithm should prove to be inadequate in the field.
Based on my trip today, I'm pretty confident that the rock bottom on the 120V indicator is 25 hours. Turtle mode is getting very close when the 240V indicator ticks over from 7:00 to 7:30 hours. The two indicators (120V and 240V) on the charging time display don't move in lockstep, they appear to be calculated separately.