In 2014, Elon Musk tweeted in response to a question about the best charging range for battery longevity – is 90%-40% better or 80%to30%? Elon responded “80% to 30%”
Recently, Like Tesla Kim posted a video explaining how she had limited her overnight charging to around 50% as she had heard that is best for lithium batteries. However, when she went to charge up to 100%, her 310-mile Tesla Model 3 showed only 260 miles of range available.
After visiting the service center and receiving a ‘hard reset’, the GOM is displaying correctly again. The Tesla Service Center recommendation is that if you suspect a range miscalculation, you should:
- Charge to 90% nightly, and leave it plugged in after reaching 90%. Range should increase within several weeks.
- If unsuccessful, charge to 100% and leave plugged in until charging stops.
- Drive down to under 10% and repeat 100% charge 2-3 times until full recalibration occurs.
Range affected by charging?
This all leads to an unanswered question about whether Like Tesla Kim’s actual battery pack capacity and thus her range was affected, or if it simply affected the estimated range on the Tesla GOM.
Like Tesla Kim decided to tweet Elon herself to ask about charging. His response is that it isn’t worth bothering limiting charging below 80%, and even 90% SoC is still ok.
Some Tesla Model 3 owners suggested that it could be the capacity was actually affected, and not because of battery degradation, but because of unbalanced battery cells.
A battery pack’s capacity is limited to the capacity of the weakest module. If cells become unbalanced, then one or more modules will have less capacity.
Tesla rebalances battery modules at high states of charge, so any EV should be fully charged on a regular basis to ensure the pack stays balanced.