Battery charging arguments

[twalace]

*Moderator Note: This is an off topic argument pulled from another thread. Enough snippiness here that I nearly put the whole thing into the snippiness thread. Stay on topic and no more snarky stuff.

You mean BMS failed to protect the battery?

And, if I may request, before you disagree please read up fully on why we have BMS to start with.

No, not what I mean. I use to race electric RC cars professionally so I'm very versed in the charging of batteries and what happens to them over the long haul. What I'm advising is a lot of people could save themselves some headaches by Googling some basic knowledge on the charging of batteries and what happens over time. And I also have a home solar system I built with it's own BMS so I do understand how they operate...

 

[DJP31]

I note some bad charging habits in your statement above, if this is typical of your charging scenarios I'm really not surprised you finally had an issue.

What bad charging habits do you see?

 

[Ferrycraigs]

I note some bad charging habits in your statement above, if this is typical of your charging scenarios I'm really not surprised you finally had an issue.

Are you able to expand on what the ‘bad charging habits’ are?

 

[twalace]

What bad charging habits do you see?

charged it up with a 22kW AC to 90% and parked it (indoors) for the remainder of the week.

 

[twalace]

Are you able to expand on what the ‘bad charging habits’ are?

Usually I take 6 or 7 supercharger stops

 

[Geek190]

Lol.....
I thought that was what Tesla recommended. Keep it plugged in. 90% is just fine according to Elon.

 

[twalace]

Lol.....
I thought that was what Tesla recommended. Keep it plugged in. 90% is just fine according to Elon.

Do some research on leaving lithium based batteries charged at maximum does to them and get back to us...

 

[Geek190]

I'm not really disputing you.

I'm simply pointing out that....

Tesla has repeatedly said keep the car plugged in.

Elon said:
Not worth going below 80% imo. Even 90% is still fine. Also, no issue going to 5% or lower SoC.

— Elon Musk (@elonmusk) December 1, 2018

 

[Geek190]

Directly from Tesla's website

 

[Ferrycraigs]

Do some research on leaving lithium based batteries charged at maximum does to them and get back to us...

We are regularly advised that it isn’t the charging to 100% that is bad, it’s the leaving it at that level for some time. It is perhaps one of the most frequently posted bits of advice on EV ownership. However trying to track down how bad is it to do so, ie what damage actually happens, is a very difficult thing to establish. I now take the view it’s about as damaging as driving a piston engined car to the red line. Not good to do it regularly, but not actually that bad to do so occasionally. Yes it causes damage, in that the engine as not likely to last as long as an engine that isn't regularly driven to that speed. But quantifying the actual damage is difficult. Probably minimal, but better not to do it.

For me, I am more concerned about the damage frequent charge cycles above 80% (or 90%) have, rather than the occasional charge to 90%, which Elon has said, is perfectly fine to do.

 

[twalace]

Directly from Tesla's website


View attachment 511444

Yes, charging up to those percentages are fine if you are going to use the car. Leaving the batteries at that SOC for a week or two is not...

 

[twalace]

We are regularly advised that it isn’t the charging to 100% that is bad, it’s the leaving it at that level for some time. It is perhaps one of the most frequently posted bits of advice on EV ownership. However trying to track down how bad is it to do so, ie what damage actually happens, is a very difficult thing to establish. I now take the view it’s about as damaging as driving a piston engined car to the red line. Not good to do it regularly, but not actually that bad to do so occasionally. Yes it causes damage, in that the engine as not likely to last as long as an engine that isn't regularly driven to that speed. But quantifying the actual damage is difficult. Probably minimal, but better not to do it.

For me, I am more concerned about the damage frequent charge cycles above 80% (or 90%) have, rather than the occasional charge to 90%, which Elon has said, is perfectly fine to do.

Exactly my point!

 

[Ferrycraigs]

Yes, charging up to those percentages are fine if you are going to use the car. Leaving the batteries at that SOC for a week or two is not...

I agree that is the commonly accepted dogma. But Tesla recommend keeping the car plugged in, and that charging to 90% is fine. Ergo Tesla recommendation could see an owner having their car plugged in every night, with a charge setting of 90%. After a month, the battery may have been at 90% for days at a time, possibly even longer. I’m struggling a bit to see the difference. In the instance earlier, it seems @RobPet's charging the car to 90% and leaving it for the week is a pretty rare occurrence, ie probably annual.

Usually I take 6 or 7 supercharger stops

I’m guessing you are not talking about Rob's Netherlands to Alps journey, but for journeys in general.
Thanks for explaining. But if your concern is the car holding a high charge for a protracted period, surely on a journey there is no advantage in charging to a lower level, but more frequently. If on a journey, a high SoC will deplete as soon as the next leg starts. Or do you stop more frequently because of a different advantage? Personally I never drive as far as I can go on each leg. I much prefer to drive for a couple of hours, the a Supercharger top up takes about the same time as a comfort break and a coffee (ie 40 mins). But I get the sense this is not what you mean.

 

[Ferrycraigs]

Interesting enough, I've received the same message twice now.

I might be encouraged by that. The next message may say your battery is toast, and that you get a replacement battery out of it.

 

[twalace]

I agree that is the commonly accepted dogma. But Tesla recommend keeping the car plugged in, and that charging to 90% is fine. Ergo Tesla recommendation could see an owner having their car plugged in every night, with a charge setting of 90%. After a month, the battery may have been at 90% for days at a time, possibly even longer. I’m struggling a bit to see the difference. In the instance earlier, it seems @RobPet's charging the car to 90% and leaving it for the week is a pretty rare occurrence, ie probably annual.


I’m guessing you are not talking about Rob's Netherlands to Alps journey, but for journeys in general.
Thanks for explaining. But if your concern is the car holding a high charge for a protracted period, surely on a journey there is no advantage in charging to a lower level, but more frequently. If on a journey, a high SoC will deplete as soon as the next leg starts. Or do you stop more frequently because of a different advantage? Personally I never drive as far as I can go on each leg. I much prefer to drive for a couple of hours, the a Supercharger top up takes about the same time as a comfort break and a coffee (ie 40 mins). But I get the sense this is not what you mean.

Again, charging up to a high SOC is fine if your going to use the car, even if this is your daily routine as the battery will be used thus drawing off some of the stored energy. If you use only Supercharging for the entire life of your battery you will incur a little more battery degradation than mixing in some home charging.

 

[faughtz]

If you use only Supercharging for the entire life of your battery you will incur a little more battery degradation than mixing in some home charging.

Please provide data substantiating your claim.

I saw less degradation than typical in this case, until tesla capped my cells.

 

[DJP31]

Usually I take 6 or 7 supercharger stops

That was in order to cover his 1000kms journey. I would have thought that’s exactly what the car and Superchargers are for.

 

[johnman10]

I note some bad charging habits in your statement above, if this is typical of your charging scenarios I'm really not surprised you finally had an issue.

I think you have misunderstood. We paid a 6 figure for a car. If we wanted inferior cars that can only work at certain temperatures and could hold only a certain amount of DC after just a few years, we would have bought a Leaf.

 

[First EV]

I note some bad charging habits in your statement above, if this is typical of your charging scenarios I'm really not surprised you finally had an issue.

Lol typical blame the fellow tesla owner since this hasn't affected you personally. So it must be their fault since to state otherwise would be to admit your car could have this problem in the future. Head in the sand after finishing the koolaid.

 

[twalace]

I think you have misunderstood. We paid a 6 figure for a car. If we wanted inferior cars that can only work at certain temperatures and could hold only a certain amount of DC after just a few years, we would have bought a Leaf.

ALL EV's suffer range limitations in extreme temperatures regardless of cost!