Car running on ice/gas despite full battery

rodeknyt said:
The dashed line represents where the pedal detent is, not where the end of the blue arc is.
Click to expand...
As shown in the graph from the manual that Weave presented above, the detent or "click" is meaningful only in ECON Mode. It's too bad Honda couldn't figure out how (OK, spend the bucks) to adjust the detent position to signal ICE activation for the other two modes, too.
 
Viking79 said:
No, according to studies I posted in that thread 4.05 V is between 80 - 90% for NMC for charging. If you measure voltage with no load and it shows 4.05 V SoC is about 85%. It is not linear, you can't do 4.05/4.2
Click to expand...

See picture below. I usually stop at 340v (340/84=4.047v) on a full charge but on that day it went up to 342. I attributed this to one or all of three reasons. Ambient temp was 96, I might be out of balance as I only fully charge twice a week and/or I took the reading right after charging was completed.

Never the less the Emergency Response Guide says max voltage is 352. Open circuit voltage is not linear as it relates to SOC but it is most accurate near the top and bottom of charge state. For that reason I believe we are in the 96% range.

As Wayne said we don’t know what Honda’s secret sauce is. Their mixture of nickel, manganese and cobalt might lend to different capacity and charging parameters. I was going to look around for some of their patents or patent applications, but my 4 year old wanted to wrestle so I never got around to it. :)

2018-07-16 09.50.22.webp


Sent from my iPhone using Inside EVs
 
OP here, in both their was no switch that I noticed going from blue to while or in between, the card went into while odometer very quickly after start.

1) Can be explained with my drive starting with a small down hill, and with sports mode and four chevron regen and full battery. The car had to run ICE to expel additional power. This does not happen usually as I drive in normal mode, where regen is pretty low.

2) Is still problematic, as the ICE ran in low speeds < 30mph for about 1.5 miles, then high speed about 80mph for 6 miles than again at < 25 mph. This happened for around for 11 mins with full battery. I had a pit stop, where I stopped and restarted the car and then it ran in EV in Sports mode. So this baffles me.
 
Try using normal brakes and not paddles for a bit after starting off. I'm wondering if the battery is full if it's smart enough to just use all friction when braking in that case. That seems to me to make more sense than having the brakes regenerate electricity and then having to run the engine to dump it.
 
AnthonyW said:
See picture below. I usually stop at 340v (340/84=4.047v) on a full charge but on that day it went up to 342. I attributed this to one or all of three reasons. Ambient temp was 96, I might be out of balance as I only fully charge twice a week and/or I took the reading right after charging was completed.

Never the less the Emergency Response Guide says max voltage is 352. Open circuit voltage is not linear as it relates to SOC but it is most accurate near the top and bottom of charge state. For that reason I believe we are in the 96% range.
Click to expand...

The Voltage is correct, but that isn't 96% SoC. Again, it is more like 85% as battery SoC is not linear with voltage so you can't just take 4.05/4.2 volts. Look at the charge curves on pages 4 and 5 of this study: http://www.mdpi.com/2313-0105/4/1/11/pdf
And draw a line from 4.05 volts and you will see it is about 80 to 85% SoC for those two NMC cells.

Yes, it is sort of linear in that region, but again, not accurate to take 4.05/4.2. If you did a linear model you would have to say 3 or some other non-zero value as the bottom, so you would take (4.05-3)/(4.2-3) which would be 87.5%, but this still doesn't really fit. It is not safe to assume a linear relationship for Li-ion, which is why people model this behavior to get more accurate SoC based on Voltage.

Here is another chart from battery university that shows 4.05 V corresponds to about 80-85% SoC.
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

If Honda charge to 96% we might have longevity problems with the batteries. Charging to 85% puts them right in that sweet range for NMC and it should last 5000 cycles or more. I imagine this battery will last life of the car barring other failures. I know at least one Volt was around 150,000 EV miles (Over 400,000 total miles) and didn't have any real capacity loss or pretty minor.
 
weave said:
Thanks. I've yet to "floor" it personally.
Click to expand...

You know what? I don't think I have either! That's my new goal tomorrow. Let's see what this baby can do!

But don't worry. It'll be only once.

That said...I told my wife to put it into Sport mode when she knows high acceleration is necessary.
 
You must log in or register to reply here.
Back
Top