Charging at 100% vs 50% and Battery Life

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jumper

Well-known member
Joined
Oct 27, 2016
Messages
54
Now that I can charge at 240V (US) I have the option to do so at 100% or 50%, presumably about 4.5 hours on 50%. Are there any battery life improvements when using the lower charging level? My neighbor with a Tesla S says he was told by the dealer that their fast charge was useful when traveling, but there is a battery life hit for doing so.

I do wish I could change the Audi's charging level from the Etron App, and as a parameter in the car's charging timers, rather than only from the Bosch charging unit itself. In a perfect world I'd have the charging timer set to 50% on weekdays, and 100% on weekends. Given my utility's EV electric rate, I will only charge up overnight on weekdays, but I'd like to use the 100% charge to top-off on the weekends as we come and go, since the cheapest TOU electric rate applies all weekend. While I may well manually change the charger between 100 and 50% my wife will never do so.
 
The charger in the e-tron is only 2.5kW and the battery is much much smaller than a Tesla at about 9kWh of which only 7 is chargeable at the wall. You won't damage it or reduce the capacity by using 240v. Teslas use a higher voltage DC to directly charge the battery when using a supercharger station, rather than the onboard inverter.
 
srwhitney":3o2uc4rl said:
The charger in the e-tron is only 2.5kW and the battery is much much smaller than a Tesla at about 9kWh of which only 7 is chargeable at the wall. You won't damage it or reduce the capacity by using 240v. Teslas use a higher voltage DC to directly charge the battery when using a supercharger station, rather than the onboard inverter.

Its 3.3kW.. not 2.5
 
have tried both charge rates many times. No difference. Sometimes either one is more or less.
SOC (State of charge) is not an exact science. I do the same trip (46kms) every weekday. Same speed , same temp, same road conditions. Most of the time the EV ends at 36-39kms. Occasionally I am surprised and get an extra 3-4kms.
Remember the battery is well under utilised to preserve its life.

So I just stick with the fast charge that takes about 2hours and 15 mins
 
I've noticed that my charger says 50% as well since I've moved to a 240V outlet. However, it still charges in just over two hours from empty, so I don't know what the difference really is. Maybe it's future-proofing for higher capacity batteries or faster charging rates on future cars?
 
I think the goal would be to get a charge flow of 3.8kw/hr which is the fastest capability of the car itself.

Jumper, in this tread, said he takes 4.5 hours to charge from empty at the 50% 240V industrial socket setting; this makes sense. (Im assuming he has a over 16A/ 240v electrical set up).

Others say using the industrial socket at 50% they can charge in 2.5hours. that doesn't compute in my brain.

At 240V, each amp brings a flow of .24kw/hr. The Audi supplied EVSE is capable of doing 10A and 16A at 240V. At 240V, the resulting flow would therefore be either 2.4 kw/hr at 10A and 3.8 kw/hr at 16A.

When using the industrial socket, maximum flow is 240V/16A, at the 100% setting..it will charge in 2.3 hours ie 3.8kw/hr. .. Why would anyone want to use the industrial socket in a 240V/16A plug at 50%?? This flow would be 1.9kw/hr....slower than even the household socket, 100% at 10A/240V.

Instead of using the industrial socket at the default at 50%, i would suggest you use it at 100%. if you have the electrical to support it.

I guess the debate is battery health. Suggesting slower is better.. I'm no expert but i cant imagine at 3.8kw/hr flow is battery harmful. ..the slowest is 110V/8A, if you subscribe to that theory, shouldn't one just use the slowest 8A/110V household socket?

It sounds like most already have put in upgraded electrical to 240V/16A++ but if you haven't another option, would be to use the household socket in a 240V/10A environment (100% maximum); that would get 2.4kw.hr and 3.8 Hours time to charge from empty.

Why? Its easier and less expensive to set up at 240V /10A 6-15R than it is to do a 240V /16A 6-50R. 10A flow uses 14 gauge wire, that you already have in your walls, and a 15Amp double breaker to the panel. Just need to put in a 240V receptacle where your standard 110V R is and an adapter from 5-15p to 6-15p.
 

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