I have had some interesting battery results in the past 2 1/2 months. I had my battery replaced July 2nd and the battery hit its peak value on July 15th (13 days later) at 100% SoH and 65.92 AHr. Since then the battery has done is gradual decline, averaging ~0.017 AHr per day to the end August. This is pretty spectacular as its the hottest part of the year (note I did NOT get a lizard battery). Unfortunately the stats change starting after August 31st. My AHr degradation increased to ~0.048 per day - a significant difference. I don't quite understand the behavior. The weather is definitely cooler than in July and August (despite it being a more mild summer). So why the increased capacity loss?
The ONLY thing that directly relates to this: multiple charging. I used to charge at work using Blink units everyday. I would only use ~65-70% of my battery to get to work (25 miles) but would charge for 2 hours to fill it back up. Then my car would sit for 7 hours fully charged before I drive it home. From our standard practices, to get the most out of the battery, it suggested to leave it charged @ 100% as little as possible. Now that CarCharging raised the rates ($2 per day now becomes $4.70 per day - so hell no), I don't charge at work anymore (this went into effect at the beginning of September). So far, unless there is something else going on, NOT charging my car twice a day (and leaving at 100% for many hours) is hurting the capacity more. My graphic plot of AHr shows a significant tilt down past August 31st. I would have originally attributed this to just an anomaly, but the trend has been going for over 2 weeks with showing signs of increasing the rate of loss.
Is there any other explanation for the sudden downward increase? Its been extremely consistent. Despite "normal" behaviors for Li-ion batteries, this seems to contradict the rules - it almost feels like Lead Acid - it wants to be charged up and topped off. As always, I will continue to track it daily, but I wanted some other minds thrown against the problem. The only other plausible explanation is that the battery finally "settled" and the original 1.5 months of loss were inflated (less loss) because the battery was settling still (despite it loosing AHr) and this is the true delta in loss that should be occurring, and the date of change, coupled with the change in charging habits was just a coincidence.