electronchaser
Posts: 79
Joined: Fri Nov 08, 2019 3:14 pm

DC fast charging update after 3500miles

Wed Feb 19, 2020 4:18 pm

Lots of people ask about battery life, degradation, charge times, etc. both on the forums and in real life. Thought I'd keep track of things for a while and provide some info for current/future owners.

Having used 50kW DCFC, for a while, I think its more than enough power and speed for me, and I'm picky.
In fact I find it so adequate that level2 charging has become annoyingly slow. (I ran into a store, was expecting to take 10 minutes, so I was looking to come back with 30 miles added range. Took about 20 minutes, and 63 miles range added. ) A level two would have added max 7-10miles of range.


2019 120ah BEV, 90% DCFC for the last 3500 miles. Battery Kappa still shows 39.2-39.0 kWh, battery temps are consistently 28-30c while fast charging. With my driving style, fast and heavy, I add about 3 miles of range per minute of DCFC.

The 50kW CCS actually ranges from a low of 350Vx120amp to 400Vx120amp. Charge times vary based on how low SOC is when I plug in, since the car ramps up voltage in proportion to batter SOC.

I get the full 400Vx120amps until approx 87% SOC, by 94% its at 400Vx60amps, (usually when I end the session)


I'll add more, including pics when I DCFC and get home. :)
Am I trashing it?, absolutely, but with love, like every other BMW I've owned.
Rondel stands for something, and I fully utilize all the non neutered abilities its got.
Takeaway. This is an amazing piece of engineering. And I'm not impressed with 'stuff'

electronchaser
Posts: 79
Joined: Fri Nov 08, 2019 3:14 pm

Re: DC fast charging update after 3500miles

Wed Feb 19, 2020 10:28 pm

Am I trashing it?, absolutely, but with love, like every other BMW I've owned.
Rondel stands for something, and I fully utilize all the non neutered abilities its got.
Takeaway. This is an amazing piece of engineering. And I'm not impressed with 'stuff'

Obioban
Posts: 80
Joined: Wed May 22, 2019 6:16 am

Re: DC fast charging update after 3500miles

Thu Feb 20, 2020 9:33 am

I don’t think anyone is suggesting that using public level 2 chargers makes any sense—level 2 chargers are for overnight charging at home, where speed doesn’t really matter.

DC fast chargers do wear out batteries faster, but it takes many miles for that to present itself. It just means your battery will get used up in less cycles.

That said, if I couldn’t charge at home for some reason, absolutely DCs are what I’d use. Though, I also wouldn’t own this car, so….

eNate
Posts: 506
Joined: Mon Sep 09, 2019 5:33 pm

Re: DC fast charging update after 3500miles

Thu Feb 20, 2020 10:01 am

Obioban wrote:
Thu Feb 20, 2020 9:33 am

I don’t think anyone is suggesting that using public level 2 chargers makes any sense—level 2 chargers are for overnight charging at home, where speed doesn’t really matter. ..

Totally disagree with that as a blanket statement. Different occasions call for different charging routines.

For going about day-to-day use, public L2 is great for adding modest range to the battery. We plugged in to a free L2 at the mall and I was pleasantly surprised to come out 90 minutes later with 30 extra miles added to the range. On a pay-for L2, we took the kids to a play and lunch, and 2 1/2 hours later we came back to the car with 50 more miles in the tank, and the cost was less than $4.

In both of these examples, I plugged in because I needed the boost, otherwise I would have stuck with home charging. L3 would have been total overkill unless a L2 wasn't available and I was forced to charge with my family in the car. I didn't need a full battery, I didn't need the expense, I didn't want (or wasn't able) to run out and unplug the car if it topped off, and I saved the wear on my battery.

This isn't to argue that L3 isn't needed. I took an unplanned 60 mile detour the other day to take care of my wife's blown tire, and my i3 didn't have enough charge to complete the trip plus the other driving I would need to do later that day. $3 and 15 minutes at a L3 charger bought me the 30 additional miles of range I needed to go about my day.
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alohart
Posts: 2169
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: DC fast charging update after 3500miles

Thu Feb 20, 2020 12:04 pm

DC fast charging a 120 Ah battery pack would be considerably less damaging than doing so with a 60 Ah battery pack. The charging power of a 120 Ah battery pack would be ~1C compared with ~2C on a 60 Ah battery pack, C being the charging power required to charge a battery cell from 0 to 100% in 1 hour. 1C is a pretty mild charging power.
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2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

electronchaser
Posts: 79
Joined: Fri Nov 08, 2019 3:14 pm

Re: DC fast charging update after 3500miles

Thu Feb 20, 2020 4:35 pm

alohart wrote:
Thu Feb 20, 2020 12:04 pm
DC fast charging a 120 Ah battery pack would be considerably less damaging than doing so with a 60 Ah battery pack. The charging power of a 120 Ah battery pack would be ~1C compared with ~2C on a 60 Ah battery pack, C being the charging power required to charge a battery cell from 0 to 100% in 1 hour. 1C is a pretty mild charging power.
Makes sense. Larger pack, same charging power.
L3 makes sense because I normally don't stop somewhere for long enough to appreciate any range from a L2.

I dunno to be honest I can't bring myself to be bothered by degradation or other issues. Or damage. That's on BMW.
Ifffff I can get 3000 full discharge cycles at 120 miles per "tank", I will have gotten 360,000 miles out of he pack. I've got 2940 full cycles left :) Even at that point battery won't be dead.
Am I trashing it?, absolutely, but with love, like every other BMW I've owned.
Rondel stands for something, and I fully utilize all the non neutered abilities its got.
Takeaway. This is an amazing piece of engineering. And I'm not impressed with 'stuff'

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