My Mini came with a larger battery

[Adam Berti]

I got a good chuckle this morning when I saw my car charged up with 32 kWh last night Figured my car must have a larger battery!

I drove the mini hard yesterday in -20C and pulled into the garage with about 4km remaining at the end of the day. I did about 100km, with 80 around 100km/h.

It did have precondition on this morning, but I'm not sure if that counts?

This leads to a more serious question, can the mini pull power out of the extra bottom 20%? If it wasn't minus 20 I was going to drive around the block until it stopped and see what happens (hoping that I Could push it back to the garage if need be!)

 

[Carsten Haase]

The power reported by the app is the power from the wall (what the utility will charge you for) not what goes into the battery. The charger has an efficiency of roughly 80-85% so rough 25-27kWh into the battery.

As far as I'm aware you can't use the buffer capacity. The car will say zero percent and stop with some real capacity left to prevent damage to the cells.

 

[Adam Berti]

Interesting, thanks for sharing that @Carsten Haase. Do you know if the precondition gets counted in the measurement?

I'm actually building my own battery for my sailboat from Chinese EVE cells so have gotten very intimate with lithium battery technology, benefits, limitations etc.

 

[teslarati97]

Preconditioning always runs off the battery but the MINI can also be simultaneously charged via the EVSE. If you keep track of your SoC, you might be able to see the state of charge cycle between 99% and 100% on a Level 2 charger.

The total charge will also include ongoing parasitic losses for heating/cooling of the battery (up to 300 watts) and battery balancing. This hurts Level 1 charging the most due to the long charging times.

 

[ogler15]

This leads to a more serious question, can the mini pull power out of the extra bottom 20%?

It can technically, if the voltage sensors inside battery pack overestimate pack voltage. Very unlikely though, multiple failures have to happen to get there

 

[GetOffYourGas]

I'm actually building my own battery for my sailboat from Chinese EVE cells so have gotten very intimate with lithium battery technology, benefits, limitations etc.

I'd love to hear more about this project. I use a Torqeedo Travel (with 500Wh integrated battery) as a kicker on my sailboat. I've been toying with the idea of a larger house bank to support longer runs.