Setting Charge Timer: Missing Something?

[Jack Tripper]

Since I’m renting my current place, I can’t install a 14-50 and I’ve been relying on a nearby supercharger. I’m on pace to supercharge about 60 to 70 times this year.

Coming up on my one year anniversary, my battery capacity is already down 5% (90% is 217 miles, down from 249 when I got the car). So now I’m looking to start trickle charging in hopes of preventing further battery degradation.

I’ve noticed that V9 42.2 is missing schedule timing flexibility. For example, I can only schedule a start time but not a stop time. Even on Nissan’s Leaf, there are settings for charging such as start and end times that can be customized for different days the week. This is great based on your electricity rate plan that can vary between weekdays and weekends.

I sometimes will drive more than 30 miles in a day, which is what I anticipate I can get over a 10 hour overnight trickle charge. This will result in charge continuing into the morning hours, which is more expensive.

Summary: Is there any way to set charge start and end times for different days of the week?

 

[BluestarE3]

You might be able to do this with third-party apps like Teslafi?

 

[KArnold]

Or Dashboard for Android.

 

[bmah]

This has been a long requested feature for the in-car software, but the only way to do this for now is with a third-party solution.

Bruce.

 

[jgs]

I was going to post this tongue-in-cheek but actually, I don’t see any obvious reason for it not to work: a heavy-duty appliance timer (“lamp timer”) to enforce the end time? A kludge, yes, but a cheap and simple one.

 

[TexasEV]

“Trickle charging” does not prevent battery degradation. It does increase your electric cost though as it’s less efficient than at higher kW and makes the charging circuit run longer, potentially increasing wear on other parts. Also this version of firmware is no different than any other version with regard to scheduled charging. You set the start time you want it to start charging if you don’t want it to charge right away. For 30 miles, how much different could it be?

You may be overthinking this. Just enjoy the car?

 

[dusdev]

This has been a long requested feature for the in-car software, but the only way to do this for now is with a third-party solution.

Bruce.

I'm sure Tesla engineering has a lot of different priorities... but it seems to me like adding some more options on the charge timers is a relatively easy "low hanging fruit". I'd love to be able to say charge anytime on the weekend (since we have low time-of-use on weekend) and limit charge times during weekdays, for instance.

 

[Jack Tripper]

I thought trickle charging was supposed to be easier on the battery than Supercharging and result in less degradation. Is this a mistake notion?

“Trickle charging” does not prevent battery degradation. It does increase your electric cost though as it’s less efficient than at higher kW and makes the charging circuit run longer, potentially increasing wear on other parts. Also this version of firmware is no different than any other version with regard to scheduled charging. You set the start time you want it to start charging if you don’t want it to charge right away. For 30 miles, how much different could it be?

You may be overthinking this. Just enjoy the car?

 

[jgs]

I thought trickle charging was supposed to be easier on the battery than Supercharging and result in less degradation. Is this a mistake notion?

I think it’s widely agreed that lower-speed charging is easier on the battery than repeated Supercharging, but there are people who carry it to an extreme and figure that if slow is good, slower must be better, and either dial down their amps when charging at 220v or even eschew 220v for 110v. That would be “overthinking”. It looks to me as though perhaps @TexasEV missed the part in your original post where you said you couldn’t install a NEMA 14-50, and assumed you were such a person? (I mean, I could be wrong, please correct as needed, @TexasEV.)

Anyway, considering your choices are either a household outlet at your home (which I guess is what you mean by “trickle charging”) or habitual Supercharging, I’d absolutely go with the household outlet. Even if there was no difference at all in battery longevity, it’s more convenient to charge at home, even if it’s low-speed charging. This is especially so since it sounds as though it will normally be able to keep up with your driving needs.

I do agree that unless you commonly expect to spill over into the higher rate tier, or unless your higher rate tier is obscene, it might be best to just not sweat it. I used to fret about the higher tier when preconditioning my car, for example, until I worked out that all the preconditioning I’d done the previous month worked out to maybe a buck or two on my bill.

 

[TMeister]

Old school solution...

Use a heavy duty timer where you set the start time well before you will tell the car to start charging and the end time when your reduced rate stops. Since you will be using 120v, these are readily available like this one for $10
https://www.lowes.com/pd/PRIME-15-A...tial-Plug-in-Countdown-Lighting-Timer/4740882

You will get a notice that charging has been interrupted when the timer turns the circuit off.

 

[David99]

I've been using 'Dashboard for Tesla' (Andorid app) for a while now. Definitely the best tool for charging the car based on start or end time, 'off peak' charging all while obeying a schedule. It also helps with degradation as it delays the charge process as long as possible to finish just in time you need the car again. So the average state of charge is lower.

 

[ckoval7]

Old school solution...

Use a heavy duty timer where you set the start time well before you will tell the car to start charging and the end time when your reduced rate stops. Since you will be using 120v, these are readily available like this one for $10
https://www.lowes.com/pd/PRIME-15-A...tial-Plug-in-Countdown-Lighting-Timer/4740882

You will get a notice that charging has been interrupted when the timer turns the circuit off.

Be very careful with these! I had one running a heat lamp for a bearded dragon, which I'm pretty sure doesn't draw anywhere near what the car does, and the damn thing burnt my house down. Now I don't trust them for anything more than Christmas lights.

 

[Eevee]

Yes, electricity will be more expensive if you charge in the morning, BUT on a trickle charge it's not consuming a ton of electricity. You might not even notice the difference in your bill. And it's not like this energy would ever go to waste, unlike Christmas lights or something else that makes more sense to set on a strict schedule. The scheduling for charging is mostly for higher energy use from a NEMA 14-50 or some such.

 

[tga]

BUT on a trickle charge it's not consuming a ton of electricity.

WIthout demand charges, 10kWh is 10kWh. It doesn't matter if you used 12A@120V or 40A@240V. The kWh used is the same. (Well, not really, since 120V charging is less efficient.)

 

[SSedan]

My water heater has a timer that is a 7day wheel with pins, someone makes something heavy duty.

You could also dial back the charge limit as the week progresses if you think it would spill into the morning tier.

Far as trickle charging, stop and think about it for a second. If you had a 18650 cell charger on the desk at home and it took 4 whole days to charge that single cell would you call that a trickle charger?
I would call it way slower than trickle, and that is what we are talking about.
I say that to try and shoot down the "trickle charging is better" crowd.
15amp 120volt is a lot better than nothing but to argue it for battery health is silly. A NEME14-30 at 17mph is more like a trickle charge That is still 18hours to charge a 100kwh battery based on rudementry 315miles divided by 17mph.

Also with the battery cooling system I really don't think the 10-11hours it takes on a 14-50 outlet is anything remotely like quick charging, IF any heat built up the coolant till transmit it away quickly.

 

[Eevee]

WIthout demand charges, 10kWh is 10kWh. It doesn't matter if you used 12A@120V or 40A@240V. The kWh used is the same. (Well, not really, since 120V charging is less efficient.)

I was referring only to the portion of trickle charging that occurs during the more expensive electric rate, the few mornings where 2-3 of those 10 hours is during the morning , after the lower evening rate has passed. These 2-3 hours at the higher rate would not occur if he charged more quickly from a 240V outlet, it simply wouldn't spill over into the morning because the charging would be complete within a few evening hours. The OP's specific issue is that some times he drives so much that trickle charging would not stop before peak electric rates start. The fact that it's not everyday and it's only a few hours on the days that it occurs is why I suggest the cost difference might not be noticeable. And if he's motivated by energy conservation, well I said that the power doesn't go to waste the way Christmas lights set to ON during daylight do.

Since I’m renting my current place, I can’t install a 14-50 and I’ve been relying on a nearby supercharger. I’m on pace to supercharge about 60 to 70 times this year.

Depending on how long you plan to rent, you might want to just ask your landlord if it would be ok to install a new outlet. Many will be fine with it so long as you pay for it.

I’ve noticed that V9 42.2 is missing schedule timing flexibility. For example, I can only schedule a start time but not a stop time. Even on Nissan’s Leaf, there are settings for charging such as start and end times that can be customized for different days the week. This is great based on your electricity rate plan that can vary between weekdays and weekends.

I sometimes will drive more than 30 miles in a day, which is what I anticipate I can get over a 10 hour overnight trickle charge. This will result in charge continuing into the morning hours, which is more expensive.

Another workaround if you don't want to involve a 3rd party app is simply lower the charging capacity on the days when you've driven more than average, when you fear it will keep charging through morning hours. That should cause it to stop charging by morning time.

So, you'd just have to do a bit of math. Say you get home with it charged to 130 miles and you plan to plug it in 8 hours and your get about 4 miles per hour on trickle charge (that's what I got when I did it) then it's just 8x4 = 32 then 130+32=162, and you said your car gets 217 miles when it's at 90% charged ... so you want to just slide the charge capacity slider thingy to about 65%. That would let it charge up to 162 and no further so that it would likely be 'done' charging before the morning electric rate kicks in. Of course you have to keep adjusting it each night, which is probably a huge PITA but it's one option that's probably very safe (no risk of starting a fire or getting hacked etc).

 

[jgs]

Depending on how long you plan to rent, you might want to just ask your landlord if it would be ok to install a new outlet. Many will be fine with it so long as you pay for it.

This is a good point. In fact I'm currently renting during a home renovation, and did exactly that. The landlord was quite happy to have me pay to make capital improvements to his property .

 

[sorka]

Since I’m renting my current place, I can’t install a 14-50 and I’ve been relying on a nearby supercharger. I’m on pace to supercharge about 60 to 70 times this year.

Coming up on my one year anniversary, my battery capacity is already down 5% (90% is 217 miles, down from 249 when I got the car). So now I’m looking to start trickle charging in hopes of preventing further battery degradation.

I’ve noticed that V9 42.2 is missing schedule timing flexibility. For example, I can only schedule a start time but not a stop time. Even on Nissan’s Leaf, there are settings for charging such as start and end times that can be customized for different days the week. This is great based on your electricity rate plan that can vary between weekdays and weekends.

I sometimes will drive more than 30 miles in a day, which is what I anticipate I can get over a 10 hour overnight trickle charge. This will result in charge continuing into the morning hours, which is more expensive.

Summary: Is there any way to set charge start and end times for different days of the week?

This has been requested for years. Stop time is far more useful than start time as it allows you to charge your battery closer to when you leave and have it start based on how long it will take to reach your stop time. I really really would like to set my stop time a minute or two before I exit off peak TOE in the morning.

It's also better for the batteries because we'd all have lower average SOCs over the life of the battery.

 

[David99]

I really really would like to set my stop time a minute or two before I exit off peak TOE in the morning.

It's the major and main reason I use Dashboard for Tesla. Even if you don't have an Android phone, get a cheap used one or a cheap Android tablet that you keep at home just to manage charging your car. It works very reliable.

 

[sorka]

I thought trickle charging was supposed to be easier on the battery than Supercharging and result in less degradation. Is this a mistake notion?

It's not the speed that you charge it but the time that the battery sits warm AND the amount of time it sits at higher SOCs. Storing at higher SOCs, like 90% is not good for the battery. If you trickle charge your car to 90% with 110v volt, it will spend hours near 90% before it actually gets there vs charging at 80 amps right before you're about to leave. Driving is already going to warm up the battery. If you can charge it and heat it by charging right before you leave, it's more efficient for the battery and you don't spend that much time at higher temperatures, but you DO spend much more time at lower SOCs before you start charging if you wait until a few hours before you leave and then charge quickly.

It turns out that taken to an extreme, supercharging is not any worse than slow charging and MIGHT even be better for it. For the convoluted explanation as to why:

Does Repeated Supercharging Shorten Life of Battery Even at 90%?