Leaving MS for 3 weeks. UMC vs. HPWC?

[Al Sherman]

We're beating the slider setting to death in the other thread. I'm going with 50% when leaving for 3 weeks. Assuming I get 4.5 by departure date.

Can anyone see a reason to prefer the HPWC or the UMC for plugging in the whole time I'm gone? How about charge rate? 60 (HPWC)? 40 (UMC)? Or something lower with either/or?

Your thoughts please?

 

[widodh]

If it's not going to do anything and just sitting at 50% I don't think it doesn't matter much. There won't be a very high charge rate for a long time, it will just top-off once every 24 hours.

 

[NigelM]

You can adjust your charge rate using the center screen; makes no difference whether you use the HPWC or the UMC.

 

[Al Sherman]

You can adjust your charge rate using the center screen; makes no difference whether you use the HPWC or the UMC.

Yes but can anyone see a reason to adjust the charge rate? ie: set it lower than 60 amps for the HPWC, or less than 40 amps for the UMC?

 

[islandbayy]

Yes but can anyone see a reason to adjust the charge rate? ie: set it lower than 60 amps for the HPWC, or less than 40 amps for the UMC?

I would just set it at the minimum 5 amps and plug it into a 110/120 outlet. It "Might' be done charging by the time you come back.

 

[dsm363]

I would just set it at 50% and charge at 40A with your HPWC although UMC vs. HPWC wouldn't matter.

 

[NigelM]

I would just set it at 50% and charge at 40A with your HPWC although UMC vs. HPWC wouldn't matter.

+1.

 

[caddieo]

Assuming you leave with the battery at 50% SOC, will it make any difference if you trickle charge at 110 versus 250 with the 14-50 outlet? And suppose you leave for 6-8 weeks, will that change your thinking? Thanks in advance for any and all replies.

 

[Crispix]

It seems that Tesla Motors and its CEO really want us to get in the habit of not worrying about such things. I have a feeling the battery management hardware and software are sophisticated enough that it probably doesn't really matter whether we set it to keep a 50% or 90% charge while away and it probably doesn't really matter whether we charge with a 14-50, HPWC, or just plug it in to a 110 outlet (yuck). We're probably talking about negligible differences in battery health.

That said, I love obsessing about this stuff, too. I'd probably set it to 50% and a slower charge rate because it somehow feels "better" for the battery. But deep down, I doubt it makes a difference.

 

[dave]

It seems that Tesla Motors and its CEO really want us to get in the habit of not worrying about such things. I have a feeling the battery management hardware and software are sophisticated enough that it probably doesn't really matter whether we set it to keep a 50% or 90% charge while away and it probably doesn't really matter whether we charge with a 14-50, HPWC, or just plug it in to a 110 outlet (yuck). We're probably talking about negligible differences in battery health.

That said, I love obsessing about this stuff, too. I'd probably set it to 50% and a slower charge rate because it somehow feels "better" for the battery. But deep down, I doubt it makes a difference.

The problem I have is that Tesla hasn't given us any guidance on battery health maintenance when it comes to charge levels and rates of charging. Everything I read on the forum is a bunch of educated guesses, with some people saying that specific charges are better, and other people saying that Tesla has it all figured out and it doesn't matter. There is a lot of basis for people'e comments but it would be nice to get some guidance from Tesla instead of relying on the guesses of people on a forum.

 

[ZBB]

We're heading out on vacation in a little less than two weeks and will be gone for 2 weeks.

Since I'm in AZ, I'e been paying attention to the slider thread and the non-Tesla studies that indicated better battery life at lower SOC, especially in hot weather. Its not uncommon for the temps in our garage to be anywhere between 100-108 -- and the temp gauge in the can be over 100 when I leave for work in the morning (even though the temps outside are below 90 -- insulation works both ways...). So I've settled on normally charging to 75%, which gives me plenty of range to commute and go out to dinner or other evening errands. I also have timed charging set to start at 2am to take advantage of our TOU plan.

For the vacation, I'm planning on setting the slider to 50% and leaving the UMC at its normal setting (40A). I'm curious to measure the vampire loss -- so I'll do my regular charge to 75% the night before we leave, then drop it to 50% before heading out. I'll then check status via the mobile app once every day or two to monitor the vampire losses and see how many days it takes before it starts topping itself off. This will be good to know for doing airport parking in the future (at least until Tesla comes up with a silver bullet update that can slay the vampires).

 

[andrewket]

I was recently gone for two weeks. I set the charge limit to 50%, scheduled charge time of 1am (TOU plan) plugged into a HPWC set at 60A (my normal rate). Every other day the car charged for ~8 minutes to regain SOC from vampire losses.

A

 

[wycolo]

> I was recently gone for two weeks. I set the charge limit to 50%, scheduled charge time of 1am (TOU plan) plugged into a HPWC set at 60A (my normal rate). Every other day the car charged for ~8 minutes to regain SOC from vampire losses. [andrewket]

Or dial down the charge screen to just 10A which would do the same job in about an hour but with less stress overall. And HPWC or any other large unit (Clipper Creek) would be preferred over the UMC for long term unsupervised usage due to bigger contactor, cooler running circuit boards and better connections.
--

 

[Lloyd]

I left mine while on a trip several months ago for 10 days. I plugged it into a friends garage 120v plug with 10 miles remaining on the meter. It charged at ~2.5 mph and took 3 + days to get to a full standard charge. Then it charged about daily for 1.5 hours or so to keep it there. I needed a range charge to get home, so when getting on the plane to return, I hit range charge, and it was just finishing the range charge by the time I returned. Really slick!!

 

[Doug_G]

Plug it in with whatever, set the slider to 50%, and don't worry about it!

 

[gregincal]

> I was recently gone for two weeks. I set the charge limit to 50%, scheduled charge time of 1am (TOU plan) plugged into a HPWC set at 60A (my normal rate). Every other day the car charged for ~8 minutes to regain SOC from vampire losses. [andrewket]

Or dial down the charge screen to just 10A which would do the same job in about an hour but with less stress overall. And HPWC or any other large unit (Clipper Creek) would be preferred over the UMC for long term unsupervised usage due to bigger contactor, cooler running circuit boards and better connections.
--

I really find it hard to believe that setting the charging to 10A is going to make any difference except make the charging less efficient. For a battery a large as the Model S has, 40A or even 60A charging is already considered slow, and 8 minutes a day isn't going to overheat any UMC.