Hey everyone, I just downloaded the Optiwatt app that schedules your charging based on the cheapest charging from my electric company (Com Ed). Is it ok for the Tesla to start and stop charging so frequently? It charging at the cheapest times. But if it’s bad for the battery, I’ll stop using the app. I would love your thoughts and explanations.
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Do short charging sessions damage battery?
- Thread starter PAUL POWELL
- Start date
I'd say, as far as the battery is concerned, it's not any different from when you're driving in stop and go traffic and the vehicle is flipping between discharging to make the vehicle go, and charging to slow down the vehicle (regen).
But it sure seems weird!
But it sure seems weird!
Shallow discharging is better than deep discharging.
The thread title is a statement, but should be a question. That type of false statement spreads misinformation.
Moderator note: The thread title has been updated to be unequivocally a question.
The thread title is a statement, but should be a question. That type of false statement spreads misinformation.
Moderator note: The thread title has been updated to be unequivocally a question.
Last edited by a moderator:
zoomer0056
Active Member
It shouldn't be bad for the battery, but I'd be more concerned about overall efficiency.
Having the car start and stop charging a lot could mean it's sleeping less so using more energy.
But as long as the savings are significant over normal scheduling then you'd still save money.
Having the car start and stop charging a lot could mean it's sleeping less so using more energy.
But as long as the savings are significant over normal scheduling then you'd still save money.
Does ComEd really have a live minute-by-minute rate structure (spot pricing) available to consumers?
ATPMSD
Active Member
It is not bad for the battery. There are literally thousands of posts on the HV battery, many with charts and graphs. Concerns like yours are not really worth worrying about. If you really want to dig in just search the forums. My advice? Just enjoy the car.
At least hourly.
Live Prices - ComEd’s Hourly Pricing
Check Prices. Shift Usage. Reduce Your Bill. Take control of how and when you use energy with our live hourly prices dashboard.
hourlypricing.comed.com
Hourly pricing based on an average of real-time 5-minute pricing, and is calculated at the end of the hour.
But if you're using that it would make sense to respond to target the cheapest periods in order to help the real-time price be low.
The main issue with Optiwatt that I have seen here, is that people forget they set it up, then wonder why their car will or wont start charging when they plug it in, in various places. I have seen a few different threads about this exact thing.
They install optiwatt, decide they dont want to use it, delete the app, then think that deleting the app removes any interaction with their car (it doesnt) then wonder why their car doesnt charge or does charge, or doesnt appear to work on Tesla scheduled charging, etc, contact Tesla, complain that Tesla doesnt help them, post here, etc.
Then, when we suggest they change their password to invalidate the token of any third party app (which finally disables the interaction from optiwatt) it works.
Anyway, as far as the question at hand, it wont be bad for the battery, but opening and closing the battery contactors a ton like that cant be good for the contactors (battery contactors are basically the device that allows power to flow or not flow from the battery to the car, think like what happens in a light switch on your wall when you turn it on and off).
I wouldnt use optiwatt for that reason.
This definitely doesnt look deliberate at all, but lack of punctuation makes it look like a statement instead of a question. I am going to report the thread to recommend a mod for this subforum add a question mark to the thread title, which should help alleviate this issue.
They go by 5 minute increments. You can just google "com ed hourly pricing" and you can see the 5 minute price.
That's very interesting. I haven't looked at the numbers to see the pricing variation, but one concern I would have would be that in cold climates, it takes energy to warm the battery up for charging.
Seems like charging on and off in small doses all day might cost as much in wasted heat energy as it saves in electricity pricing... then you have to add wear and tear on the contactors into the equation.
Personally, I'd pass on this scheme.
zoomer0056
Active Member
Thank you. I wasn't trying to clickbait anybody. I was just typing quickly and didn't review the title for punctuation.
Paul
My concern would be about additional wear on your vehicle systems. To function, this program needs to communicate with the vehicle on a regular basis. This keeps the computer awake, the cooling pumps on, and results in a 200 watt consumption any time the car is awake.
A post above mentioned high voltage contactors. These close any time the car wakes up and open any time the car goes to sleep. You’re putting an additional cycle on these components every time the Optiwatt app polls the car for information. I don’t know how this particular app functions in terms of polls per hour, but I would make a wager a guess that it’s at least two dozen times per day.
One would have to weigh the cost savings with the additional system wear. I don’t know how much it costs to replace the main pack contactors, but the DC fast charging contractors are just over $600 installed.
A post above mentioned high voltage contactors. These close any time the car wakes up and open any time the car goes to sleep. You’re putting an additional cycle on these components every time the Optiwatt app polls the car for information. I don’t know how this particular app functions in terms of polls per hour, but I would make a wager a guess that it’s at least two dozen times per day.
One would have to weigh the cost savings with the additional system wear. I don’t know how much it costs to replace the main pack contactors, but the DC fast charging contractors are just over $600 installed.
I do not know how many times the optiwatt starts / stops for a single charge (or rather, per day).
If the car falls asleep in between this behaviour will excercise the contactors to open/close many more times per day than a single charging session.
The contactors are built in the battery and worn out contactors would mean replacing the battery.
The contactors might be built for 100K cycles or so (I think I did read about someone staring 140K).
Having 10 cycles a day or someting like that gives 36500 after ten years.
If the optiwatt adds 20 cycles each day for this type of charging we are closing to the wear out limit of the contactors. I would be careful, at least check how many cycles a regular day gives.
The battery cells themself is probably not affected by this kind of charging.
Thank you very much for this information. Makes a lot of sense. It’s spending dollars to save fractions of a penny! I stopped using the app after 2 days.
