Pipemajor said:
planet4ever said:
No EV manufacturer in his right mind would let you charge a lithium battery to 100% of its total capacity. The choice we are being given is to charge to (about) 90% or to charge to (about) 75%. What's so hard to understand about that?
Yes, you can charge a lithium battery to 100% but you have to sneak up to it.
that is SOP in the charging world and experience HAS PROVEN that does not work. it is apparently too difficult to hit 100% without going over. and it only takes a very little bit of going over to reduce pack capacity. problems is, that charging is something that will be done 300-400 times a year.
so lets say we charge to 100.01% all those times. in a year, we may have lost 3% MORE capacity than normal. now dont quote me on this because i have not a clue as to the EXACT damage overcharging does. but basically EVERYTIME u overcharge, you WILL lose some capacity. granted, it makes sense that just having the ability to charge to 100% seems unlikely.
problem is, we have a moving target to hit. changes in temperature will change pack capacity. theis something that the system cant away judge. its the reason why weather is temperate on the west coast. we have an onshore flow about 97% of the time. that pretty much prevents us from getting snow (we get a LOT of fog). the only time we get snow is when we have a major arctic flow that overcomes the warming of the oceans, or we get an off shore flow which happens 1-2 days a month around here.
all in all, the REAL differential between EV manufacturers is how well they do charge management. so i would have to assume that Nissan's 100% is probably only 95% or some safe range that will overcome a high percentage of thermal situations.
so this begs the question; if Nissan has charge management down so well, then why do we need the 80% setting??
1) mostly because over 75% of us can COMFORTABLY use the reduced range without issues
2)there is ALWAYS a better way. its funny that the 80% figure is selected but we have seen that before. the current battery management king; the Prius runs its SOC from 40-80%. they already have cars in the wild whose traction batteries should have lost capacity 150,000 miles ago. that fact is hard to ignore.
so this brings up another thought; what is the warranty based on? 100% or 80% charging?. well we can all read what we want (if a warranty exists) but i have to say that the 80% setting should take us waaaay beyond the warranty claims and the 100% should take us comfortably beyond the warranty claims.
now lithium charge management has dramatically improved over the past few years. we probably have not noticed it because the things we charge; cellphones, laptops, MP3's etc have "appeared" to loose battery capacity which actually is not true.
our newer devices have 3 times the capabilities of previous devices so having half the battery life still means a 50% improvement in performance.
so things like charging your cellphone for no more than one hour with a car charger and only if absolutely necessary is something you should heed carefully.
