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Does anybody adjust their charging amps using app?
- Thread starter edulinka
- Start date
DirtyT3sla
Member
Most of the time you don't need it.
One reason I personally would use it, would be to keep the car charging amount less than the amount of power my solar is providing. Say my solar system is only giving 4kW and I don't want to use 7.2kW to charge my car because then I'd have to pull from the grid. So I'd reduce amps so my car only pulls 3kW or something.
I've also reduced amps in the car before when I was at a random house charging and wasn't sure how reliable their wiring was (house was super old) so I just lowered the amps a bit to not stress the outlet/wiring too much.
One reason I personally would use it, would be to keep the car charging amount less than the amount of power my solar is providing. Say my solar system is only giving 4kW and I don't want to use 7.2kW to charge my car because then I'd have to pull from the grid. So I'd reduce amps so my car only pulls 3kW or something.
I've also reduced amps in the car before when I was at a random house charging and wasn't sure how reliable their wiring was (house was super old) so I just lowered the amps a bit to not stress the outlet/wiring too much.
I generally use reduced amps when charging overnight or at home. Doing so avoids the phantom drain that happens and keeps the battery happy. That is the legacy of the old, JB Straubel comment in ~2013 ‘a plugged in Tesla is a happy Tesla’.
I didn't know you could reduce the charging amps from the app. How do you do that?
I have done it from the car's touch screen when charging off of a V3 wall charger fed from our whole house generator. Charging at the full 48 amps caused some voltage fluctuations so I dropped it to 20 amps (I was in no hurry).
OxBrew
Active Member
I charge at 32A, just to keep any heat buildup in all the components well below their rating limit. Just a wild guess, but working with battery engineers, I know how they decide on maximum ratings. If there's a built in safety factor that allows for a very very low rate of failure over the design lifetime, and I'm only using 3/4 of that rating, then I'm lowering the chances of failure even more, maybe so low it can't be reliably calculated.
Heat cycling is the enemy. Expansion/contraction of different materials in contact with each other eventually degrades that contact.
But I have no problem charging at full amps if I am ever in a hurry and really need it. Has not happened yet.
Another anecdotal observation: the heat pump seems to kick up into a higher setting at 48A compared to 32A. So there might be something going on with excess heat that they are needing to remove.
I might be totally wrong, and getting no benefit from lowering the amps, but what does it hurt? I still only need a few hours at most, most nights, to get back to 75%, so there's no reason to push it.
Heat cycling is the enemy. Expansion/contraction of different materials in contact with each other eventually degrades that contact.
But I have no problem charging at full amps if I am ever in a hurry and really need it. Has not happened yet.
Another anecdotal observation: the heat pump seems to kick up into a higher setting at 48A compared to 32A. So there might be something going on with excess heat that they are needing to remove.
I might be totally wrong, and getting no benefit from lowering the amps, but what does it hurt? I still only need a few hours at most, most nights, to get back to 75%, so there's no reason to push it.
boulder.dude
Member
I was under the impression (from a thread on this site somewhere) that lower AC amps was actually less efficient than higher?
When charging at lower power (lower voltage and or amperage) charging is less efficient. Charging involves overhead losses; heat losses in the wiring, battery and charging components. The faster you can complete charging the lower the cumulative overhead charging losses. For an individual charging session the difference in cost amounts to pennies but it adds up over time. Also, your time is worth something so unless you are charging while you are doing other things there is an opportunity cost associated with the down time while charging.
JerseyShoreMY
Member
Would it be safe to say that leaving the wall charger energized 24/7 wastes more power than pennies on a lower charge rate?
I always charge at home, twice a week at 30 amps max. Battery very happy.
When on the road, of course use the Supercharger to travel. But when arriving at the destination, we also put on the trickle charger... seems to keep the batter more happy as well.
Any thoughts?
The power used by the Wall Connector when not charging is just a few watts as with other electronics. The built-in WiFi circuitry uses some power. There is no practical way to turn off the Wall Connector. The circuit breaker is not designed for that type of usage and would not last long if you continually flip the breaker on and off. You could, at some expense, have an electrician install a service disconnect switch close to the Wall Connector. (In some areas the local electrical code requires a service disconnect switch for any hard wired circuit/equipment rated for more than XX amps.)
It could save a few pennies if you flipped off the circuit breaker for the Wall Connector if you are going to be away for many days or weeks.
I use the ability to adjust the max charging amps in the Tesla app on a daily basis. Even multiple times a day to better match the output from the solar panels on my RV which I use to charge my Model S which you can see more information about in this video.
This function used to not be in the Tesla app and in that case I used a WiFi connected charger (Juicebox Pro 40) to adjust the amps which worked fine until Juicebox changed their software and totally screwed it up to be unusable. Luckily I upgraded to MCU2 around the same time and gained this functionality and I use it regularly. One of these days I need to figure out how to write an API app to automatically reference the Victron VRM monitoring portal and automatically adjust the Tesla charging amps based on the incoming solar, and the current state of charge of the RV battery. The reality is while automating it would be useful, I'd need a manual override function because life is too irregular to be able to perfectly automate it. Specifically since the car is our only family car it gets used by either me or my wife randomly any day and depending on the solar yield and how long the Tesla is away from home I charge the Tesla at varying rates depending on how quickly I need to discharge the RV battery. My primarily goal is simply to use the RV electricity when we're not camping, the secondary goal is to ensure the RV battery never completely fills up because if that happens the solar charge controllers completely shut down power production and I'm missing out on potential energy and I also want to know how much energy my RV solar panels are capable of producing each year.
This function used to not be in the Tesla app and in that case I used a WiFi connected charger (Juicebox Pro 40) to adjust the amps which worked fine until Juicebox changed their software and totally screwed it up to be unusable. Luckily I upgraded to MCU2 around the same time and gained this functionality and I use it regularly. One of these days I need to figure out how to write an API app to automatically reference the Victron VRM monitoring portal and automatically adjust the Tesla charging amps based on the incoming solar, and the current state of charge of the RV battery. The reality is while automating it would be useful, I'd need a manual override function because life is too irregular to be able to perfectly automate it. Specifically since the car is our only family car it gets used by either me or my wife randomly any day and depending on the solar yield and how long the Tesla is away from home I charge the Tesla at varying rates depending on how quickly I need to discharge the RV battery. My primarily goal is simply to use the RV electricity when we're not camping, the secondary goal is to ensure the RV battery never completely fills up because if that happens the solar charge controllers completely shut down power production and I'm missing out on potential energy and I also want to know how much energy my RV solar panels are capable of producing each year.
LetsGoElectric
Member
To prevent idle fees.
When using an outlet that (for whatever reason) can't provide the full amperage.
I do because I’m on 110 and need to share the circuit with other things in the garage.
When charging to 100% before a trip, I adjust the charge rate to finish just before the time of my departure.
i limit my charging at home to 15A as that is plenty to charge up over night, and it puts less strain on house's wires and fuses
Maybe it is time to upgrade your electrical service and install a new panel. My home (built in 1963) had a 150 amp fuse panel. I was down with replacing fuses as needed. Then the neutral connection snapped off at the back plane of the panel, held only by the wires pressing against the neutral wire. This happened while I was away. There had been a storm and the power was interrupted for time. When I arrived home I found that half the house had low (really low) voltage, i.e. ~80V when measured at the receptacle and half of the outlets measured higher than 130V It took weeks to troubleshoot and in the meantime I lost a surge protector. Lesson learned; old service panels (my panel was 50 years old) should be replaced. I replaced the service panel shortly afterwards with 200 amp service and a new breaker panel. This happened about 4 years before I purchased my first plug-in vehicle.
Charging at 15 amps when you could be charging at a higher amperage is less efficient.
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