johnlocke said:
Could you explain how you go about changing the Hx value? It might be useful for us to know how to change it and how to improve the value. It might at least explain why it changes and what the effect is on the battery.
it would be easier if you read my blog. have several entries talking about this. it also provides a lot minute details.
Part of the reason is top end balancing. the balancing is based on the voltage of the highest cell. going beyond this will cause damage to the cell if allowed to charge beyond the high end cut off, right?
Problem is that when this cell hits it, the other cells are at a varying distance below the top. This is where you see differences in GIDs and ahr.
Now keep in mind; cell balancing goes on all the time but the current is very small. This is part of the reason why the charge lights remain on after the charge has essentially ended. There will be times when the charge will reinitiate because cell balancing dropped the voltage of the highest cell sufficiently to restart it.
So top end balancing becomes critical if you need the maximum range. BUT, if you don't need the range, using the middle range of your SOC is the recommended method for increasing your long term viability. I The best way to attain good balance is deep cycle charging but must be done every day for at least 3-5 days in a row.
http://daveinolywa.blogspot.com/2016/05/april-2016-drive-report-after-36000.html
a few things to take note of; the voltage delta at 57% SOC. Now seeing this at full charge is not unusual but at half? that is good balance.
Before the experiment I was at 59 ahr, 92 Hx, Kwh available 20.0
This pix was taken after the update that shows the date so that is obvious but you can also judge by mileage as well.
60 ahr.jpg
here is pix from LAST year. now my stats suck right? same car, same pack, same driver, same location so what changed?
I was simply charging with a profile that likely resembles yours. charging maybe 4-5 days a week, never hitting full charge or rarely hitting full charge. SOC ranging from 20 to maybe 85% but mostly in the 30 to 70% range.
This screenshot was taken on the first full charge after only 8 days.
FINALLY; I mention this last because if I mentioned this first, you would (like most here) stop reading. I believe the LEAF BMS was reprogrammed to hold more back to enhance longevity but will also allow a deeper charge if it feels you need it. So by driving a lot of miles in a short period of time, I think I am fooling the LEAF into thinking I am on a roadtrip so because of that, the LEAF BMS is allowing more range to be available.
Sound far fetched? Well, I guess that is the advantage of having my own blog; I get to make all the rules!