Only 71kwh usable in X90D

[ekhozindar]

I posted this in another thread but decided to start a new one instead.

Just took a trip with my family in our X90D to go on a cruise and I can say I'm more than a little unhappy with the amount of kilowatt-hours I was able to get from my battery with a full charge. We barely made it to the supercharger. Girlfriend was in a panic the last 50 miles thinking it we were going to be stranded on the side of the road with our 2 year old.

71kwh total. That's ridiculously low. Even from the expected 82kwh, that's a 12% reduction in capacity. If that's the norm, how is that acceptable? And at what point is battery degradation beyond expectations?

And this is coming from a guy who likes to keep their car longer than a couple years. If this was an ICE car I would easily be able to get 300 to 400 thousand miles on it because I took good care of it. But this leads me to believe that no matter what I do, this car will end up being undrivable for me before I hit 200k.

 

[McManX]

Where does the expected 82 come from?

 

[ekhozindar]

That figures been around for quite a while. I believe wk07 found that number out a couple years ago.

 

[kingjamez]

Time to take it into the service center.

 

[McManX]

That figures been around for quite a while. I believe wk07 found that number out a couple years ago.

Ahh yes I remember now

 

[AnxietyRanger]

Well, FWIW, the 90 kWh has anecdotally arguably had most issues with degradation, power limiters, DC charge throttling etc., suggesting that it is possible a somehow vulnerable design.

 

[apacheguy]

My guess would be that this pack has seen the permanent imbalance issues that @wk057 has recently alluded to. The brick that is at the lowest voltage will dictate the capacity reported by the BMS.

 

[brkaus]

You didn't actually say what you started at.

Run it to near empty. Charge it fully and measure the power that it accepts. Figure in about 10% overhead in charging.

Your wh/mi also looks high, but I drive an S.

 

[ekhozindar]

My guess would be that this pack has seen the permanent imbalance issues that @wk057 has recently alluded to. The brick that is at the lowest voltage will dictate the capacity reported by the BMS.

Hmmm.. if what you say is the case, Would that mean actual charge is higher than stated charge?

 

[ekhozindar]

You didn't actually say what you started at.

It says full charge.

 

[brkaus]

It says full charge.

Doh. Long day, my reading skills are on the decline I fear. Thanks. I see it now.

 

[tslaEbay]

@ekhozindar...so in the early days you were getting 82kwh.
But after 50k miles...nowadays you only see 71kwh?

 

[tslaEbay]

BTW..how many rated miles you see if you do full charge these days?

 

[jelloslug]

Take it in. It's still under warranty.

 

[ekhozindar]

BTW..how many rated miles you see if you do full charge these days?

I haven't done rated miles in a long time, I'll have to check when I get back to shore.

 

[jelloslug]

I haven't done rated miles in a long time, I'll have to check when I get back to shore.

Yea, something is up. Have you ever had the battery check or replaced?

 

[brkaus]

I haven't done rated miles in a long time, I'll have to check when I get back to shore.

Hopefully you are someplace warm!!!

 

[apacheguy]

Hmmm.. if what you say is the case, Would that mean actual charge is higher than stated charge?

In a battery you are limited by the weakest link. That is why balancing is so important. However, if one cell group has irreversible damage and cannot be balanced then this will weight down the whole pack since the BMS will not allow over or under voltage for this cell group.

 

[animorph]

There are lots of threads here trying to reconcile the trip kWh number with the battery capacity and rated miles. As far as I know, the trip kWh number does not include some of the ancillary power usage. It always seems low.

I doubt there's anything wrong with your battery. And that's probably all Tesla will tell you. As long as your rated miles look good, this is just one of Tesla's mysteries.

 

[Lancew]

My X90D has 45,000 miles and was built 4/16. The 2 times I have charged to full and let it go to zero have shown about 71kwh used as well. One was early on (10,000 miles) and one was recent.