Car running on ice/gas despite full battery

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.

 

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.




Sent from my iPhone using Inside EVs

 

That there folks is the comment of the week!

 

Haha he has his priorities straight! And I truly mean that.

 

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.

 

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.

 

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.