Full charge shows only 64 miles is this normal?

[alpine788]

I just bought a used 2015 i3 rex with 29900 miles on it from a local BMW dealer. I just fully charged it last night and thought it would show 72-74 miles but only shows 64. Is this correct? Should I check my battery life integrity?

 

[EvanstonI3]

The Guess-O-Meter is essentially based on the last 18 miles of DRIVING and updates constantly as the car is driven. It takes into account additional loads like the Heater or A/C being used as well as how cold the battery pack is. Sounds about right for 2015 though. What is the temperature like where you are?

 

[eNate]

In addition to what Evanston wrote, it's normal to have some battery degradation. 10% of 70 miles reduces down to 63 miles, and that would be "not unexpected" for an 8 year old EV.

BMW warrants the battery if it falls before 70% capacity. Based on your numbers, I'm guessing you're well above that.

There's an easy way to check estimated battery capacity via the "hidden menu."

https://youtu.be/ELT5b2YWL58

 

[alpine788]

In sunny SO Cal.. so mornings rt now are around 39-47. Car has only 29,900 miles on it... and dealer serviced its entire life.. very well kept..

 

[alpine788]

Thanks for responses.. I was told by service writer at the BMW place I bought it (BMW of Monrovia ) that it was 75% or lower that they'd replace entire battery pack. Is he wrong/?

 

[alpine788]

Additionally, I had watched the video you attached (thank you) and will perform that today.. but on the video it was 18.8 as I recall. What is good and what is bad? In other words.. what number would it have to be for me to be worried and bring it for replace (although since it is still under factory warranty for a few more months I guess that would be ultimately a good thing!)?

 

[EvanstonI3]

18.8 is about the max for a 2015. 12.9 would be "bad" but not a definitive "bad" until the proper test procedure is done by a BMW Dealer. They don't replace based on BATT.KAPPA. Also you PAY for the test and if it passes, they send you on your way. Only if it actually Fails and falls below 70% value will they consider replacement. Your car does not appear to be anywhere near that threshold at this time.

The BATT.KAPPA apparently represents the data based on the cell/module with the LOWEST value. So if just ONE Cell/Module is bad or low for some reason it will affect the reading for the entire pack.

Also- 39-47 ambient temp WILL affect the Battery a bit and cause lower range. When Pre-conditioning the Battery in advance (and plugged in), the car will pre-heat the battery to a max of 10C/50F. If you did that and then drove the car you would notice a slight increase in range based on temperature alone.

 

[alpine788]

Thanks again Evanston. How do I precondition?

 

[EvanstonI3]

Since you have a 2015 and you are in the USA, you can't use the MYBMW app to do this but you can do it via the iDrive interface in the car.
Go to SETTINGS, then PRECONDITION (at the top of the Setting Menu)

You MUST set a "Departure Time". It MUST be at least 3 hours away. There is no "Precondition" button that instantly starts the Precondition cycle. The car must also be plugged in to either L1 or L2 charger.

For example, if you set a Departure Time of 9am and choose "Precondition", the car will measure the ambient air temp for awhile and keep track of the temperature of the battery pack. If the pack falls below 50F, the car will come on 3 hours in advance (in this case, 6am) and will circulate warmed coolant around the battery pack until it reaches 50F. Then it will shut off until about 8:30am when the interior cabin climatize cycle occurs. This brings the cabin to whatever temp you had previously set at.

In your case the actual Precondition cycle will only run for maybe 30 minutes, but if the temp is really cold (like 0F or colder) it can run for a couple hours.

Also note that you can only run the Precondition/Cabin Climatize cycles TWICE in a row without moving the car. You must turn the car on and move it at least a foot or so in order to reset the cycle. So you can't just leave it sit for a week and have it come on every day to keep the car's batteries up to temp if you don't drive it.

 

[eNate]

In sunny SO Cal.. so mornings rt now are around 39-47. Car has only 29,900 miles on it... and dealer serviced its entire life.. very well kept..

Consider that batteries degrade just by being batteries. They're like kids: they can be coddled, but that won't stop them from aging. Even if they've been perfectly cared for...

 

[Neil]

I'm hoping this is a reasonable topic to bring this up on since my full charge is much less than 64 miles. I've been sporadically tracking kappa on my 2014 i3 Rex (with ~76000 miles) since December 2021, as I'm considering the optimal time to bring my car in for a battery check. In California, we have 10 years to do this, and I'm waiting as long as I can to give me the best chance of the battery failing the test. Here's the data I've collected. Please excuse the formatting.

Date Kappa % of 18.8 % charge when measured
12/16/2021 12.1 64.4%
1/11/2022 12.5 66.5%
1/15/2022 12.5 66.5% 14%
1/18/2022 12.1 64.4% 100%
1/25/2022 12.0 63.8% 49%
1/27/2022 12.0 63.8% 12%
2/3/2022 12.3 65.4% 62%
3/2/2022 12.2 64.9% 100%
3/8/2022 12.1 64.4% 58%
3/23/2022 12.9 68.6% 40%
4/5/2022 12.9 68.6% 25%
4/12/2022 13.1 69.7% 100%
4/27/2022 13.0 69.1% 24%
5/19/2022 13.0 69.1% 26%
7/11/2022 12.3 65.4% 100%
8/20/2022 13.8 73.4% 12%
9/2/2022 12.5 66.5% 20%
10/27/2022 12.6 67.0% 19%
11/20/2022 12.1 64.4% 14%
12/19/2022 12.0 63.8% 27%

Basically I'm going to wait until about 6 months before the 10 years are up and then get serious about bringing it in.

I'm looking for comments, questions etc. regarding a good strategy to follow up with as what's the best way to give me better odds of having a module or battery replaced.

TIA

 

[alohart]

Consider that batteries degrade just by being batteries. They're like kids: they can be coddled, but that won't stop them from aging. Even if they've been perfectly cared for...

Amen! The battery pack in our very coddled 2014 BEV lost ~25% of its capacity despite having been driven only ~13k miles over 7.5 years. Meanwhile, many other 60 Ah battery packs don't seem to be degrading nearly as rapidly. Maybe the quality control of 60 Ah battery cells wasn't as good as that of 94 Ah and 120 Ah battery cells. Seems a little bit like the luck of the draw with 60 Ah battery packs.

 

[alohart]

For example, if you set a Departure Time of 9am and choose "Precondition", the car will measure the ambient air temp for awhile and keep track of the temperature of the battery pack. If the pack falls below 50F, the car will come on 3 hours in advance (in this case, 6am) and will circulate warmed coolant around the battery pack until it reaches 50F.

Our 2014 BEV didn't have the heated seat and battery pack option (not needed in our tropical climate), but it did have a heat pump. Supposedly, I would not have been able to precondition (warm) the battery cells because there were no electrical resistance heater wires below the them. However, the heat pump would have allowed me to precondition (cool) the battery cells. So I think that preconditioning (warming) the battery cells is done with resistance heating and not with the refrigerant that cools the battery cells. The refrigerant plumbing schematic doesn't indicate an obvious way to precondition (warm) both the battery pack and cabin simultaneously, and BMW's TIS Website doesn't describe preconditioning (warming) the battery cells with refrigerant, only with electrical resistance wires.

That said, a Norwegian i3 BEV owner swears that the A/C compressor turns on during preconditioning (warming) his battery pack. One explanation could be that the compressor is running so the heat pump can precondition (warm) the passenger cabin while the electric resistance wires are warming the battery cells.

 

[alpine788]

TRUE DAT E NATE!

 

[partialteen]

For example, if you set a Departure Time of 9am and choose "Precondition", the car will measure the ambient air temp for awhile and keep track of the temperature of the battery pack. If the pack falls below 50F, the car will come on 3 hours in advance (in this case, 6am) and will circulate warmed coolant around the battery pack until it reaches 50F.

Our 2014 BEV didn't have the heated seat and battery pack option (not needed in our tropical climate), but it did have a heat pump. Supposedly, I would not have been able to precondition (warm) the battery cells because there were no electrical resistance heater wires below the them. However, the heat pump would have allowed me to precondition (cool) the battery cells. So I think that preconditioning (warming) the battery cells is done with resistance heating and not with the refrigerant that cools the battery cells. The refrigerant plumbing schematic doesn't indicate an obvious way to precondition (warm) both the battery pack and cabin simultaneously, and BMW's TIS Website doesn't describe preconditioning (warming) the battery cells with refrigerant, only with electrical resistance wires.

That said, a Norwegian i3 BEV owner swears that the A/C compressor turns on during preconditioning (warming) his battery pack. One explanation could be that the compressor is running so the heat pump can precondition (warm) the passenger cabin while the electric resistance wires are warming the battery cells.

Thank you for sharing your understanding. It is really helpful for me.
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