Would repetitive nearly full cycle charging impact range?

I am 2 weeks into my commute. 63-66 miles each way. > 1500 miles. Always start at 100% charge - usually reach destination with 1-2 bars left. Indicated remaining range has been dropping after climbing the first few days. My driving style and speed is pretty consistent - freeway for all but 3 miles. It rose to combined 85 miles for a few days. Then 82, 78 and today it is at 75. There has been a few days at each level. Miles per KWh initially rose to 5 and today is down to 3.9. Weather has been pretty consistent during this time.

I am using Level 2 charging at both ends of my commute.

An electrician friend said that although lithium batteries should not exhibit memory, he thinks I may be setting an artificial capacity floor by charging without variation in usage. He suggested I actually run it into turtle mode and recharge to full, then look at where I end after a commute cycle to see if this is the case.

Naturally, you should try what he is suggesting. However, has ambient temperature changed during your data collection ? It may be responsible for some difference.

Good info ... keep us updated

TaylorSFGuy said:

I am 2 weeks into my commute. 63-66 miles each way. > 1500 miles. Always start at 100% charge - usually reach destination with 1-2 bars left. Indicated remaining range has been dropping after climbing the first few days. My driving style and speed is pretty consistent - freeway for all but 3 miles. It rose to combined 85 miles for a few days. Then 82, 78 and today it is at 75. There has been a few days at each level. Miles per KWh initially rose to 5 and today is down to 3.9....

Click to expand...

You don't mention the speed you're driving at, but 3.9mpk and 75 miles of range sounds good for a mostly freeway commute. I find myself wondering how you ever posted a 5mpk over that route. Are you resetting the mpk at the beginning of each drive?

Honestly, I wouldn't worry about the guessometer (mileage prediction), as long as the bars are coming out consistent.

Temperature in Olympia has been pretty much the same with temps ranging between 45 and 52 at 9AM. My speed changes in generally the same areas. Some areas are 57 and then others are 63 but again, my driving is consistent day to day. All meters are reset at the beginning of each day. Except for one which shows my overall at 4.1 since date of purchase.

My initial point of concern is not the mpk, nor is it the 75 miles being a good number (because in the winter it won't be far enough with lights, wipers and heat). My main point is that the total capacity seems to be dropping based on a repetitive usage and charging pattern. Are any others doing this same type of usage (nearly full cycle) with little variation?

Everyone knows lithium-iom batteries have no memory effect, you dont need to cycle them down to 0 to get full capacity next time.. The BMS goes by cell voltage and temperature to determine the low point on the battery.

"My main point is that the total capacity seems to be dropping based on a repetitive usage and charging pattern"

You really dont know if that is true, you cant go by the cars instrumentation. The Guesstimator™ will change depending on your mood and the phase of the moon that day. I would go by the SOC indicator, has it changed?.. do you always get to your destination with 2 bars remaining?

Luckily you still have room to slow down to 55mph so that you dont have to charge the battery to 100% everyday. You probably know your battery will be spent in 4-5 years.