Charging Amp drop from 40 amps to 24 amps

Charging Amp drop from 40 amps to 24 amps

Until a few weeks ago, my Model X (and Model S beforehand) always charged at 40 amps. Now, it seems to only charge at 24 amps. Have not made any changes to our home electrical system. Have Solar City/Tesla solar, with 2 Powerwalls, so all power is fed from solar or Powerwall, with almost no grid usage. Anyone have similar issue? Any idea on why this happened? Have tried to get answer from Tesla, but no response. Thanks!

Vawlkus | August 27, 2019

Did you try charging the amps setting on the charging screen?

Passion2Fly | August 27, 2019

Yes, Tesla changed some settings with their latest updates. This is mostly for the Gen1 portable chargers with the higher 40A charge limit. It might have to do with the battery fires in China... my Model X now defaults to 30A and I need to manually move the charge current up to 40A... funny thing is that my Model 3 defaults to 40A with the same charger!

volefen | August 27, 2019

my car is in service right now and I asked my Tesla service advisor about upgrades. He said that they don't have any plans how and when it will be done as of yet. He has told me he heard that some small group of AP2 were invited for trial upgrades. Supposedly emails are being sent randomly to small group of AP2 asking to set up upgrades. I asked if he can put me down on the list but he said that he has no access...

ebender888 | August 29, 2019

i always make sure it is set to 40 amp when i'm getting ready to charge. Once connected, it drops to 24 amps and no way to increase. Spoke with Tesla service and they're researching my MX history to see if they can determine the cause. Will update if they ever get back to me.

Vawlkus | August 30, 2019

No messages on your dash when the drop occurs? Mine did something similar with certain local chargers that aren’t grounded properly.

Pungoteague_Dave | August 30, 2019

"so all power is fed from solar or Powerwall, with almost no grid usage."

All power on such systems is grid-regulated. You do not receive power directly from your panels or batteries unless off-grid entirely. With a grid-connected system you supply power with your panels and battery, but all power usage effectively comes from the grid

Vawlkus | August 31, 2019

Not always the case Dave.

I’ve seen a couple of the installation videos, and the grid is always upstream from the panels and powerwall.
The Teslanomics video lays it out the best, with the panels feeding the powerwalls, and the powerwalls supplying the house. Only if the powerwall can’t supply the house, does it draw from the grid.
Once the powerwall is fully charged, the powerwall starts to feed the grid power from the solar cells.

Pungoteague_Dave | September 1, 2019

Incorrect Vawlkus - I have a 32kwh solar array (124 panels). Yes, the solar production is inboard from the meter, and hence the electrical grid. However, all balancing and control of NET metering occurs using grid-supplied electricity. The powerwall and solar panels are "dumb" systems that simply feed power in as available. This is why it is silly for folks to state that their car drives using solar electricity. Our system is supporting an oyster aquaculture operation with large pumps running 24/7, and it easily handles the rest of our property's systems, netting us over $30k annually in net meter reimbursements and SREC payments. My Tesla's tags read "SUN NRG". But it is all a lie. Even though we produce about twice our actual usage via solar, the fact remains that every single kwh of power used on our property is generated by an offsite power plant, most likely 75%+ coal. Because net metering is just that - when you add a new load to your existing powerwall or solar panel array, such as plugging in your car, a power plant somewhere suddenly works just that much harder, producing carbon outputs. We all charge using mostly carbon-based fuels. | September 1, 2019

@PD - Unless you live in the west. Most power is hydro, nuclear (which is slowly going away), geothermal, wind and solar. Zero coal or diesel now in our state, and occasional gas peaker plants, which are being replaced with solar/battery systems (also slowly). In my specific area, I'm 100% renewables 24/7, beyond my home solar array.

Really cool that you get payments from the utility for your home power generation. Ours will not pay anything if you generate more than you use, which sort of sucks.

mcdonalk | September 2, 2019

Our Model S sometimes changes from 40A to 32A. I think that this happens during the summer since the AC system is switching on and off when the car is charging, and the resultant induced electrical noise may be detected by the car as an impairment. During other times of year when the AC does not run at night, the car charges at 40A.

Vawlkus | September 3, 2019

Just because YOUR system is configured that way doesn’t mean all others are.

ebender888 | September 11, 2019

In service today. They state that the new cables/adapters are capped at only 32 amps; previous cables were capped at 40 amps. Which is odd, as the charging screen indicates it can charge up to 48 amps, but that only applies if you buy the Tesla wall charger. Regardless, they could only get it to charge on their wall charger to 24 amps, so there is a problem with the vehicle. My problem is it will take them several days and they do not provide loaner cars anymore (without much discussion and dispute), but they provided an Uber credit (which should cover me for 2 day only). Wish service was like it was a few years ago when i had my MS85!