Do you charge your i3 everyday?

[Blue20]

Just wondering is it good for the battery life-span to have it charge every day? Or better to let it drain and then top up?

 

[mindmachine]

You don't want to charge everyday unless you run the battery down to near empty everyday. The batteries prefer to be about 60 to 70% full. Full is not as good and empty is not as good , half full as a rule of thumb is excellent.

 

[Jeremy]

My problem is, I'm retired now and don't have many regular scheduled journeys - but my wife an I often like to take off on the spur of the moment, sometimes for 100 mile plus journeys.

I've therefore got the choice of leaving it 1/2 charged and having to "REx" home on a 100 mile trip - or keeping it fully charged with a of risk battery degradation.

I think I'm going to do the latter - and hope that BMW have designed in enough spare capacity "headroom" to avoid the problem.

 

[uktechie]

No rules on charging for me, I want to leave home with full charge as don't know how far I might go each day.

 

[ultraturtle]

BMW keeps roughly 13% of the total battery capacity unusable in order to protect against accelerated capacity degradation caused by approaching full or zero charge. The battery system is also protected by warranty to retain at least 70% "state of health" to 8 years or 100,000 miles, so BMW is quite confident that their design and engineering will keep you out of trouble. This is not the case for all EVs, with one prominent manufacturer allowing owners to tap the full capacity of their battery system, while specifically refusing to offer any capacity guarantee.

You should be fine regularly "topping off", since you will only be bringing SOC up to maximum useable, not maximum total. There is a difference. You would be wise to time your charging to complete just before you need it when you can. Lithium ion batteries don't really like sitting around for long periods of time near fully charged.

 

[Voltage1]

If this helps - My Volt is two years old - 22k miles - I drive 18 miles to work - and I charge it (240 volt)- drive 18 miles home and charge it (240 volt). On a longer run I can still get 50 + miles on a charge, I have not seen any degradation of the battery at all. On my last long run two months ago I went 54 miles beforeit switched to the engine. Please understand this is a 2012 Volt rated at 35 miles on battery, so to get 54 after two years of topping off twice a day when only usng 1/3 capacity should be a good indication that the batteries are much hardier than we have been told.