Somewhat odd situation compared to all of you long distance drivers! I do fine with 110V charging for my M3 SR+ because my commute is ~6 miles/day RT. My question is whether I should plug in every day to keep it at 80% or let it drain to 10-20% and then bring it back to 80%. I realize that the general advice is to keep it plugged in and then run it through a deep drain and recharge every once in a while to keep the battery chemistry and calibration ok. BUT, at 6 miles/day, it might take me 3 or more weeks to get down to 10-20%. So, what's more important? Keep it at 80%? TG
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110 V charging and driving only a few miles/day...
- Thread starter tg27
- Start date
Sandollars
I bleed Cardinal
Leave it plugged in. If you're really only driving 5-6mi/day, just drop the charge max to 70%. It doesn't really hurt the battery to not give it cycles, you just end up with the range guess-o-meter not being as accurate. You don't lose range.
In fact, it's more damaging to the battery to leave it topped at 80% than it is to leave it at 70%, even if the charge controller becomes less accurate over time. There's no reason to do a full top/deep discharge cycle unless you really need to have the range be 'accurate'. Everyone should just turn off the guess-o-meter and leave it on %.
If you have a good reason for leaving it at 80%, then sure, do that, but if it's just excess for no reason, you're not really getting anything.
In fact, it's more damaging to the battery to leave it topped at 80% than it is to leave it at 70%, even if the charge controller becomes less accurate over time. There's no reason to do a full top/deep discharge cycle unless you really need to have the range be 'accurate'. Everyone should just turn off the guess-o-meter and leave it on %.
If you have a good reason for leaving it at 80%, then sure, do that, but if it's just excess for no reason, you're not really getting anything.
If it takes you weeks to drain 10-20%, i'd say plug it in once a week or so and charge to ~80%. But its probably not a big deal either way.
It sounds like you don't yet have the car though, since at 6 mi/day you'd probably be down around 55% charging to 80 after a week. If the car is primarily used for short trips and parked in the sun most the day, cut the range estimates in half.
It sounds like you don't yet have the car though, since at 6 mi/day you'd probably be down around 55% charging to 80 after a week. If the car is primarily used for short trips and parked in the sun most the day, cut the range estimates in half.
If he's on 120V charging, I personally would never want to only plug it in once or twice a week. With 120V charging, you're only going to add ~70mi of charge overnight assuming you use a 120V/20A charger. Less on 120V/15A.
I used to charge on 120V/20A, and I can tell you range anxiety is real if you forget to charge a couple of day in a row and need to take a trip that ends up being 40-60mi round trip. Better to get in the habit of charging daily, since again, it won't hurt the battery and it's what Tesla recommends.
Tam
Well-Known Member
If you read the link that @Zoomit pointed out, it says:
"Many shallow charge cycles are better for lithium batteries than fewer deep ones..." @jdw
If you don't believe that then just observe your Model 3 charging habit: Take if off from the timer and keep it plugged and see once it has reached your setting of 80%, would it let the vampire drain down to 77%, 75%, 70%...? If you keep track of it, it would frequently charge your battery back to 80% in a very tight range like 79% to 80% and 80% to 80%.
You can see the logging record from the other post:
Charging the battery in AZ Heat/middle of the day?
So, if I have a choice, I would rather charge from 75% to 80% every day than choosing 10% to 80% every few weeks.
However, Tesla's battery is quite good so don't worry about it:
Elon Musk on Twitter
"Not worth going below 80% imo. Even 90% is still fine. Also, no issue going to 5% or lower SoC.
9:57 PM - 30 Nov 2018"
Try reading the post, the poster uses about 70 miles PER WEEK. So a single night will give a complete charge!!!
Let's get real here. We're not talking 90%-10% every day. We're not ever talking 80%-20% over a week, we're talking something like 80%-50% that's a relatively short cycle. I believe that the recharge cycle is about 3%, although it seems to change. 6 miles (plus some idle drain) is slightly more than 3%.
My point exactly "However, Tesla's battery is quite good so don't worry about it:"
darth_vad3r
Well-Known Sith
Someone quoted you in another thread so I just wanted to point out a minor correction here at the source. I didn’t reply earlier on this because I agree with all your points. Now that someone else noticed and used it as a source ... I just wanted to correct the use of the term “guess-o-meter” (as most people understand that term to mean).
On other EVs the gauge is a “guess-o-meter” that changes based on past driving and “guesses” your available range based on that and the estimated state of the battery.
In the Tesla the only “guess” part is the estimate of kWh in the pack, and yes it can recalibrate and change, but it’s not a “guess-o-meter” in the traditional EV sense. If the calibration is not off and you drive at a precise car-specific Wh/mi, you will see the energy gauge tick down predictably.
In a guess-o-meter EV, this would only happen if you drive at an unknown “previous X miles” Wh/mi efficiency. Otherwise the guess is off. You don’t know how much to expect it to be off by because you don’t know what the guessed Wh/mi is. With the Tesla it’s consistent.
evM3Sekar
Member
My RT is 30mi/day. I charge using the standard 120v outlet. I always leave it plugged in when not driving. My battery max needle is set to 65%, and charging starts at 10p. Almost 4 months and 4300mi later, everything is fine and dandy.
Only once did I take it up to 100% (for a long trip) over a couple of days - you guessed it, just using the 120v outlet.
OP here. Thanks for all the help, guys/gals. I have had the car for 3 months and I am careful with using the app (updating drain) and my phantom drain is only ~1% each nite and yes, I only use about 3% for my daily 'commute' - so it really will take me 3 weeks or so to go from 80% down to 20%. I have been reading these battery charging posts for a few months now and learned that everyone has an opinion but no one is really wrong - the battery is great and I should stop worrying about it! But I am a science guy, so I like the degradation charts the most. I just think my situation is different than I've seen posted or from the charts I've checked.
You're right, it isn't a true 'guess-o-meter' like on other EVs that do it based on instantaneous usage and some fixed kWh metric. That being said, the estimate on kWh of the pack is still an estimate; just because you haven't done a calibration (through low SoC->high SoC), doesn't mean it's actually lost capacity though. There's no harm to the battery to just leave it's calibration off, as far as I can tell. You're just going to have a slightly wrong representation of your actual charge, though, no?
darth_vad3r
Well-Known Sith
Yes, we're on the same page. I tried to say, it's just an estimate, and it can be off ... I wouldn't quite call it a guesstimate because it's pretty darn good. Repeated shallow discharges does shift its accuracy though, for sure. I think we should just reserve the range "guess-o-meter", "G-O-M", "GOM" phrasing for the other usage to not confuse people.
I was using ~10% twice a day and charging back for a few weeks/month and my 90% level was dropping. After a more recent run down to <20% and eventual recoup back to 90% (over the course of a few days) my 90% level has come back to what it was when I first got the car.
For some people that calibration being 'off' will really bother them, but if you can get over that hangup OP, I would say just keep using the shallowest depth of discharge you can ... charge it up 3% every day, leave it plugged in, stay at a nice low 70% SoC every night and your battery will be happy.
Don't listen to people who tell you to stop worrying about it ... read my sig... some people like the science and all the details. Enjoy those aspects of your car just as much as you enjoy driving it!
All the charts I've seen show the shallowest depth of discharge cycles is healthiest for the battery... I'd say it's fair to extrapolate that down to 3% ... even the car itself does this if you leave it plugged in and it stops charging, loses some charge to 'vampire' drain, and then starts charging again.
When you get home, plug it in and charge it right away (unless you've got some other time of use concerns). Without a schedule set, it will also start charging again during the night if it drops down too low for any reason. If you plan ahead at least one night for a trip, you can top up from 67% Friday night to 92% Sat. morning in 12 hours of L1 charging... and that's what the Model S's used to charge to on a regular basis IIRC ... and sounds about just right for me to start a trip at.
Even if you don't plan ahead, starting an unexpected trip at 70% should get you to a Supercharger no problem and that "extra" 20% you need to charge because you started at 70% instead of 92% will cost you maybe 5-10 minutes
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I have the same commute. And the same 120v charging. SR+.
I find that sentry mode actually uses more power than my commute. Ish.. they’re both about 10% a day.
I could get by plugging in once a week strictly for commuting, but sentry has already caught one porch pirate and one guy trying to open my car door in the first month of ownership! So I’m leaving it on and accepting the ridiculous extra amount of power it consumes. 120v sucks and I wish I had L2 but so far even I’m getting by. That reminds me I should go plug in..
Without sentry on your commute rather than worrying about plugging in ALWAYS vs plugging in weekly.. just plug in when it works for you and as long as that’s at least 3 nights a week you are going to be just fine. Don’t worry about optimizing the charging that much. Optimize your life!
Sometimes set your target at 70%, sometimes at 90%, or anywhere in between, your battery will be fine.
I find that sentry mode actually uses more power than my commute. Ish.. they’re both about 10% a day.
I could get by plugging in once a week strictly for commuting, but sentry has already caught one porch pirate and one guy trying to open my car door in the first month of ownership! So I’m leaving it on and accepting the ridiculous extra amount of power it consumes. 120v sucks and I wish I had L2 but so far even I’m getting by. That reminds me I should go plug in..
Without sentry on your commute rather than worrying about plugging in ALWAYS vs plugging in weekly.. just plug in when it works for you and as long as that’s at least 3 nights a week you are going to be just fine. Don’t worry about optimizing the charging that much. Optimize your life!
Sometimes set your target at 70%, sometimes at 90%, or anywhere in between, your battery will be fine.
ralph142
Member
If you go find the battery degradation thread, you’ll see the research on li. Fundamentally, high or low voltage in the cells for extended times is bad for long life. So, avoid charging above 90% and discharging below 10, unless you must. An 80-20 or 70-30 cycle is best for long range trips, but for a short commute charge as low as youre comfortable, 50-60-70-80 ish? But go ahead and do it every day. Tesla says the batteries are good for 1500 cycles 0-100, before they degrade to 80% of rated capacity. The warranty is 8 years to 80%. If you went 0-100 every week, 1500 cycles is 30 years. Of course those are models, and no one actually knows in real use and time. That said, model s packs have been around since 2012, and there is no enormous problem requiring mass replacement with them yet, afaik. I’m pretty sure we would hear about it endlessly if there were.
For what it’s worth my weekly use is close to 100 miles, and I recharge to 80% daily on a 120 v 15 amp outlet. For trips I charge up higher as necessary to minimize stops.
For what it’s worth my weekly use is close to 100 miles, and I recharge to 80% daily on a 120 v 15 amp outlet. For trips I charge up higher as necessary to minimize stops.
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