I3 vampire loads when parked off the grid

I travel frequently and will be parking the I3 at the airport. There will be times when I will have the I3 sitting at the airport for up to 7 days off the grid with only a 40% state of charge (SOC). What impact on the SOC do the vampire loads have when the I3 is parked in the off state for an extended period of time. I am assuming the connecteddrive subsystem is either on 24x7 or wakes up periodically which will eventually wear the battery down.

Does anyone have any experience in this area? Thanks in advance.

Todd

+1. I would like to know about the parasitic loss as well.

On a somewhat related subject, lot of airports now have EV charging available. JFK has a few in terminal 5. It is not ideal if you are flying out of a different terminal. Also, not sure if you can leave your car on the charger for multiple days.

I don't have specific i3 data but I have been in BMW e-mobility program for the past five years now driving the MINI-E and ActiveE and they haven't had any significant vampire load issues. My ActiveE for example will only lose about 1% to 2% state of charge if it's parked for a week without use. I expect the i3 to be similar.

carbonblackcab said:

+1. I would like to know about the parasitic loss as well.

On a somewhat related subject, lot of airports now have EV charging available. JFK has a few in terminal 5. It is not ideal if you are flying out of a different terminal. Also, not sure if you can leave your car on the charger for multiple days.

Click to expand...

For what it's worth, I fly regularly out of SFO (San Francisco airport). There are EV charging stations at several points throughout the short term garage -- but the problem is, I have NEVER ONCE seen an open space at those stations. I.e., there are clearly way more EV cars trying to park there than there are chargers. So if you show up at SFO (unless you've got a REx) you better know in advance that you will have enough charge left to get home after your return flight.

TomMoloughney said:

My ActiveE for example will only lose about 1% to 2% state of charge if it's parked for a week without use. I expect the i3 to be similar.

Click to expand...

For perspective, "standby" losses have the potential to be a very serious issue for an electric car, and they are not alway insignificant. For instance, when it first came out, a Tesla Model S lost battery charge at a rate of 42% to 53% per week of its measured 200 mile range, as observed by Consumer Reports (http://consumerreports.org/cro/magazine/2013/07/tesla-model-s-review/index.htm):

When it’s left unplugged, we noted a parasitic loss of energy that amounts to 12 to 15 miles of range per day.

Click to expand...

During my test drive, the Tesla salesman assured me that the problem has since been fixed, and parasitic loss is now "only" 4 miles of range per day, which works out to a rate of 14% per week.

The seriousness of the potential to be stuck with inadequate range to get to a charging station after a prolonged parking period pales in comparison to the consequences of allowing the battery to completely discharge. Put simply, it will destroy a lithium ion battery pack, and require very expensive replacement.

Ironically, REx owners in the US are more at risk of a total discharge in this scenario than are BEV owners. A BEV owner will be more likely to arrive at the airport with greater than 50% useable state of charge (~57% total SOC), whereas a REx owner driving to an airport that exceeds his electric range will be down to roughly 17% total SOC (assuming BMW allocates the full 13% reserve to the bottom end, plus 4% total SOC [which is the ~5% useable SOC the REx is targeted to maintain]).

What I most want to know is if BMW built in the capability for the car to disconnect the drive battery completely at an emergency level of SOC. If so, the good news is that the self discharge rate is typically less than 2% per month, making battery damage far less likely.

ultraturtle said:

TomMoloughney said:

My ActiveE for example will only lose about 1% to 2% state of charge if it's parked for a week without use. I expect the i3 to be similar.

Click to expand...

For perspective, "standby" losses have the potential to be a very serious issue for an electric car, and they are not alway insignificant. For instance, when it first came out, a Tesla Model S lost battery charge at a rate of 42% to 53% per week of its measured 200 mile range, as observed by Consumer Reports (http://consumerreports.org/cro/magazine/2013/07/tesla-model-s-review/index.htm):

When it’s left unplugged, we noted a parasitic loss of energy that amounts to 12 to 15 miles of range per day.

Click to expand...

During my test drive, the Tesla salesman assured me that the problem has since been fixed, and parasitic loss is now "only" 4 miles of range per day, which works out to a rate of 14% per week.
...

Click to expand...

Ultraturtle,

I don't have as much experience as Tom on BMWi vehicles, but have one of the highest miles in the country for the Active E and own both a Roadster and Model S. Those of us with the Active E were testing the same battery chemistry as well as drivetrain as the i3. I have observed that leaving the Active E unplugged for a significant time (a week or longer) the vampire loss IS insignificant.

As for the Tesla vehicles, they are both rather inefficient in being left unplugged. One of the latest version of Model S firmware v5.8.4 (1.49.57) is loaded in my vehicle and I have left the Model S at the airport for about three days and have lost between to five or nine miles (I don't remember exactly, but it was less than ten).

All drivers adjust to how their particular vehicle behave and make allowances for it. EV or ICE they all have their idiosyncracies. In my 2000 3 Series, the guessometer was so bad that when it estimated that I had fifty miles left in the tank, it was a mad scramble to fill up as I've run out of gas around 45 miles left in the past.

TomMoloughney said:

I don't have specific i3 data but I have been in BMW e-mobility program for the past five years now driving the MINI-E and ActiveE and they haven't had any significant vampire load issues. My ActiveE for example will only lose about 1% to 2% state of charge if it's parked for a week without use. I expect the i3 to be similar.

Click to expand...

The 3rd week of January I left my i3 parked in the garage (at home, unheated), unplugged, with 84% of charge.
When I came back 8 days later I checked the SOC on the iRemote app and it was: 84%!

Tom, you might call this similar, I call it excellent!

i3me said:

The 3rd week of January I left my i3 parked in the garage (at home, unheated), unplugged, with 84% of charge.
When I came back 8 days later I checked the SOC on the iRemote app and it was: 84%!

Click to expand...

It's an interesting observation...but it doesn't prove there isn't vampire loss. It may be that the i3 (like the ActiveE) doesn't seem to update the SOC meter unless the car is charging or moving.

In the ActiveE, the SOC meter won't change with the car just sitting there, but once the car is moving it will recalculate and drop quite rapidly. For me, the first mile takes 2-5% off the SOC. Subsequent miles use less %. (in the ActiveE 1 mile uses nominally 1% SOC sans heat) I attribute this to instrumentation, not that the first mile really uses extra charge. It's just how the software works out SOC.

So it "appears" there is no loss in the ActiveE, but there is...it's just hidden by the instrumentation. The i3 may be the same way. Time will tell.