Charging problem with 2020 S

RamiB

Just received delivery of my performance S 2020. This would be my 3rd model S - and the “raven” is a HUGE improvement in all aspects. However, I have a problem charging at home with my level 2 charger (Juice Box), which has been working fine with my 2015 P85D. After plugging in the car displays “maximum AC charge rate reduced” message and then “AC charging interrupted” message - and the car stops charging. Tesla tech isn’t aware of firmware changes that would interrupt such simple charging operation. I tested the charger again today with the older S and it worked flawlessly. Anyone with similar experiences? Suggestions? Thanks much!

Bighorn

What was the rate?

RedShift

I’ve had my 2013 Model S’s mobile charger (I use a NEMA 14-50 at home) give me trouble when using recently with both my 2018 Model 3 and my 2013 Model S. Same issue as yours. ( “Charging interrupted” )

I switched the mobile charger to the new one I got with my Model 3 and the issues went away. Never figured out why though.

RamiB

30A

Bighorn

The current UMC gives the S 32 amps. I don’t know the implications of a third party charger. Also, a 40A charge gets dropped to 75% if the car sees any instability. Nothing wrong with 30A charging though, for most.

RamiB

Tried it at a neighbor house with a 3rd party charger - same problem. I’m concerned it is the Apple playbook...create incompatibilities with aftermarket products to force you to buy their own...hope I’m wrong.

RamiB

Tried it at a neighbor house with a 3rd party charger - same problem. I’m concerned it is the Apple playbook...create incompatibilities with aftermarket products to force you to buy their own...hope I’m wrong.

Bighorn

32 vs 30 doesn’t sound like much of a conspiracy. Also a charging sweet spot.

RamiB

The charger is actually 40. Car drops it down to 30A

Bighorn

This guy gets 40A from a Juice Box on his 3 which has similar charging parameters to a Raven (start at 5:00). Does your charging screen show 30/40 or 30/30? If the latter, you may have a geofenced limit that can be upped to 40. 30/40 implicates the 75% reduction of unclean power.

RamiB

It shows 30/40, thank you for posting. I contacted Tesla service to schedule an appointment, just to receive a text stating “we don’t support 3rd party chargers” which is a pretty upsetting copout given that the issue is clearly with the car vs. the charger. Again, hopeful it’s not an Apple-like strategy to force their chargers on customers

Bighorn

You should be able to watch it ramp up to 40A before it gets limited to 30. Screen shows both voltage and current, Anderson you might be able to see a significant voltage sag which might be the culprit. Sometimes it’s just a voltage surge from another device on the circuit like a heater or appliance starting. Have never heard that current is limited by design because of the source. 30A is the better charging choice for most. I’ve happily charged at 24 A for almost 7 years.

Bighorn

and, not Anderson

murphyS90D

I have a Leviton 40 amp EVSE connected to a 50 amp breaker in my main panel with 75 feet of 6 gauge wire. My model S happily charges at 40 amps. 6 gauge wire is normally stranded wire. There should be copper ferrules crimped on the end of each wire to guarantee good contact with all of the strands. Missing just one strand will cause heating which results in unwanted voltage drop.

akikiki

murphyS90D. I don't understand. If you have a 50 amp breaker, that means you can draw 40 amp from it to charge your car. What's the benefit of the Leviton EVSE. Why not move that thing out of the way and just plug you MC in and charge the car? There's got to be some sort of electrical overhead that results in heat and leading to waste for hooking it up and using it.

murphyS90D

@akikiki, The UMC stays in the trunk of my car. The Leviton is mounted on the wall of my garage and has a cable long enough to reach my other car which is not a Tesla. When not in use the power is off. The EVSE that came with the other car also stays in its trunk. The Leviton is wired with its own power meter so I can track how much power is used for charging, just like I used to track gasoline usage before I had an electric car.

GoldAK47

If the problem always follows the car, you could have cells going bad in battery, onboard charger, or bad bms. It could be seeing way too high voltage and trying to stop a meltdown. Try tesla charger. Theres no conspiracy, they literally give you the adapter to use non tesla chargers.....

TeslaTap.com

@Gold - I disagree about bad cells or bad BMS - nether should cause any issue like this. The onboard charger could be at fault, but since the mobile connector works fine, it points more to some interfacing issue between the car and the EVSE.

Since the old MS works fine, that would seem to rule out power sag, but perhaps the Raven is more sensitive. The Charger in the Raven is entirely different than the one in a 2015 S, and the Raven can handle up to 48 amps, vs 40 amps, if a single charger, in the 2015 S.

@RamiB - One tiny possibility to check is if the EVSE you are using has a firmware update. I'm not saying it's at fault, but perhaps there is newer firmware that is more flexible. You might also contact the EVSE vendor to see if they have any ideas. It may be a common complaint - but unclear who is at fault. They might have a solution or just blame Tesla.

TeslaTap.com

Another idea is to dial the Tesla down to 20 amps. If that works, it mostly eliminates any signaling faults. You could try increasing the amperage to see where it faults. As BH suggests, watch the voltage in your car to see if it sags. I maybe the Raven is more sensitive than your 2015 S.

GoldAK47

@teslatap - It can absolutely cause it. Already went through it. Over air said it was bad BMS, and ended up being bad cells in one module. As soon as the cells show wacky info, you get that error. When they get bad enough, then it wont even charge. Rare? Possibly.

But did the mobile connector work? I didnt see that anywhere, if so....ignore the above and I agree.

I do like the idea of charging at lower rate to test.

RamiB

Thanks again all for chiming in. Tesla has been very inconsistent in terms of addressing the issue. Initially they told me that they don't handle 3rd party charger problems (which is lame response - this is a generic EV capability IMO), and then - here's an email I received today from Palo Alto service center: "The technicians here had mentioned that the issue you are experiencing should go away once you have near depleted the charge on your Model S. In other words, the issue should go away after going from a 5-10% state of charge to 90%+ a few times." More of a brute force approach...

TeslaTap.com

@Gold - thanks, never heard of that happening before. Did you get the bad BMS error message on-screen, or was it Tesla service that detected the bad BMS? I couldn't quite tell from your description.

TeslaTap.com

@RamiB - Ok, that seems like a weird solution. If you try it, I hope you'll report back the results. I can't think of why that would work, but stranger things have been known to solve problems!

RamiB

In the interim here’s a solution that seems to work: dialed down the Voltage to 20V per suggestion here, and reset the charger - and then the car charged. Slowly, but it does seem to work. Not a long term solution but it’s something for now ;-)

Bighorn

20 amps/240 Volts, which is plenty for most, plus you can dial it up further, the Amps that is.

maxmike_98695203

I just got my 2020 Model 3 and I cannot charge it at 20A level 2 if I lock the car. Looks like the car goes to sleep and disconnects the charger. Works fine if I leave the car open. Great balls of fire - now I have to leave the car with the door open for overnight charging.