24 kWh charging strategy

[rkilby]

Hi all, new to the forum recently purchased a 2015 jap import 24 kWh Leaf with 10 bars of battery health and 30k kms on the clock car is in beautiful condition and drives like new. Running leaf spy light and charging Hx indicates it’s first few years involved a lot of fast charging sessions. I use about 1 percent of charge per km so getting around 70 km usable range with city driving.
My question, is battery longevity best served by running battery between  ? Battery chemistry happy points or is it purely cycles and I should just fully cycle the battery to reduce charging cycles ? I currently have the BMS set at 80% max for charging and running battery down to around 20% to 30% prior to home charging using granny cable takes about 3 hours to recharge back to 80% which is fine. This seemed to be the accepted wisdom from my research for these older batteries with no active thermal management. 
your thoughts and experience appreciated.
How about the practice of a quick DC charge every couple of months to keep the chemistry lively 🤔
Cheer Rohan 

[EVangelist]

Jul 13, 2021 10:46:39 GMT 11 rkilby said:

My question, is battery longevity best served by running battery between  ? Battery chemistry happy points or is it purely cycles and I should just fully cycle the battery to reduce charging cycles ? I currently have the BMS set at 80% max for charging and running battery down to around 20% to 30% prior to home charging using granny cable takes about 3 hours to recharge back to 80% which is fine. This seemed to be the accepted wisdom from my research for these older batteries with no active thermal management. 
your thoughts and experience appreciated.
How about the practice of a quick DC charge every couple of months to keep the chemistry lively 🤔
Cheer Rohan 

Welcome to the forum Rohan, although it doesn’t get a huge amount of traffic these days 

Re charging, I suggest not charging above 80% regularly unless you need to go to 100% for a specific trip.   And if you do charge to 100%, plan it so that you start driving soon afterwards (within say 12 hours).  Don’t leave it at 100% for days.  Equally, don’t leave the battery close to empty for days on end.

Re “charging cycles” an advantage of Li-Ion batteries is that a “cycle” is charging 0%-100% and discharging 100%-0%, but it doesn’t matter whether that is done in 1 step up and 1 step down, or multiple steps. e.g. charging 30%-80% then discharging 80%-30% and doing that twice is still one “charge cycle”.  Translation: just charge to 80% daily regardless of how much or little you have driven.  It doesn’t matter.

I don’t subscribe to the “quick DC charge” to “keep the chemistry lively” theory.  If you don’t need to fast charge, then don’t.  But I wouldn’t sweat it if you need to do it.