3 Pin Charger Dropping to 5a

[Ryder35]

Hi All,

Got my model 3 on Thursday and am noticing that the 3 pin charger normally shows 10/10a but frequently drops to 5/5A. The manual says that if it detects a wiring problem it will drop by 25% but not 50% also I would have thought it would then show 7.5/10A not /5A

Anyone got any ideas. Also I have the 3 pin charger from my i3, would that work with the Tesla? I am thinking I could try that to eliminate a fault in the charger itself?

I do plan to get a wall charger at some point but for not I have to use the 3 pin.

Thanks for any help

 

[WannabeOwner]

I would try a 13 AMP socket close to the distribution board (e.g. park the car nearby and run the UMC in through a window), and also check that the plug doesn't get warm.

You may have to manually increase the AMPs (on dashboard) if car has "remembered" that GPS location as a low-AMP setting (IDK if that actually happens though)

 

[Roy W.]

And certainly give the i3 charger a try and see what you get.

 

[NorfolkMustard]

Any flashing red lights on the front of the UMC? The manual has a page at the back to decode the flashes.

 

[Ryder35]

Any flashing red lights on the front of the UMC? The manual has a page at the back to decode the flashes.

All looks good on UMC and charge port (flashing green lights) I have plugged in the BMW charger to see how that goes. The plug on the UMC is quite warm.

 

[Ryder35]

Interestingly every time I have monitored the charging on the app with the BMW charger it has been pegged at 10A. Could it be a fault with the Tesla UMC?

 

[Roy W.]

Interestingly every time I have monitored the charging on the app with the BMW charger it has been pegged at 10A. Could it be a fault with the Tesla UMC?

It sounds like it. Have you tried the UMC in an alternative 13A socket?

 

[Ryder35]

It sounds like it. Have you tried the UMC in an alternative 13A socket?

Only have a single socket in the garage so not an option

 

[WannabeOwner]

The plug on the UMC is quite warm.

That may be an indicator that the wiring to your garage is not up to sustained full-power draw. UMC may be engineered to be more conservative than your i3 cable (not that BMW are likely to stint on that, just maybe the UMC has more "gubbins" built in to detect etc.

Only have a single socket in the garage so not an option

If you cannot reach a different socket - e.g. through a window, near the consumer unit, then I would try a 13 AMP socket at a different location - neighbour maybe? if the plug doesn't get warm in that scenario, and car stays at full AMPs, then if it were me I'd get the garage wiring checked anyway ... either way, I would use the UMC short term, at lower AMPs, rather than risk that i3 cable is safe, with plug getting warm (as in: if plug is "nearer to hot than tepid")

 

[arg]

frequently drops to 5/5A

If it's definitely saying 5/5A rather than 5/10A, then it's the UMC making the decision rather than the car. The back-off on voltage that you mention from the manual is a car feature, so it would be saying 5/10A or 7/10A . The first number is how much current the car is actually drawing, the second one the amount being offered by the chargepoint (UMC in this case).

OTOH, 5A is a strange value for the second number, since the signalling protocol only goes down as far as 6A, so I suspect you have mis-read the display or typed it here

 

[Fly.guy]

My understanding is that the UMC 13a Plug includes a thermal sensor to detect issues such as this. Maybe it’s registering the heat and derating itself to keep the show on the road.

Either way, a good socket shouldn’t be getting hot (a little warm maybe but not hot) even with a continuous 10a draw. You might want to replace your single garage socket with a decent quality new double socket.

Maybe get a sparky in to do it if your not confident tackling it yourself....

 

[Ryder35]

If it's definitely saying 5/5A rather than 5/10A, then it's the UMC making the decision rather than the car. The back-off on voltage that you mention from the manual is a car feature, so it would be saying 5/10A or 7/10A . The first number is how much current the car is actually drawing, the second one the amount being offered by the chargepoint (UMC in this case).

OTOH, 5A is a strange value for the second number, since the signalling protocol only goes down as far as 6A, so I suspect you have mis-read the display or typed it here

It is 100% saying 5/5A

 

[Ryder35]

My understanding is that the UMC 13a Plug includes a thermal sensor to detect issues such as this. Maybe it’s registering the heat and derating itself to keep the show on the road.

Either way, a good socket shouldn’t be getting hot (a little warm maybe but not hot) even with a continuous 10a draw. You might want to replace your single garage socket with a decent quality new double socket.

Maybe get a sparky in to do it if your not confident tackling it yourself....

When I say hot, we are not talking uncomfortable to touch or anything like that. Maybe I should have described it as warm. I think the obvious solution is to get a wall charger fitted but would like to know if there is a problem with the UMC. I will try it at my parents house next time I am there though.

 

[Ryder35]

OTOH, 5A is a strange value for the second number, since the signalling protocol only goes down as far as 6A, so I suspect you have mis-read the display or typed it here

 

[davidmc]

Just wondering if you are using an extension cable with the UMC? Or is it directly plugged into a wall socket?

Is the wall socket your plugged into on a ring circuit with a small fuse (RCD) at the main board?

 

[Ryder35]

Just wondering if you are using an extension cable with the UMC? Or is it directly plugged into a wall socket?

Is the wall socket your plugged into on a ring circuit with a small fuse (RCD) at the main board?

No extension cable. It is a dual socket that has a trip switch built in (for use with lawnmowers etc.) Garage door plugged into one socket UMC direct into the other.

There is an old Electromotive charger at our office car park that uses a 3 pin socket so will try that this week to see if I get the same issue.

 

[zap fizzle]

If the plug is AT ALL warm at just 5 amps, either the plug or socket is seriously defective. Focus on that.

 

[Ryder35]

If the plug is AT ALL warm at just 5 amps, either the plug or socket is seriously defective. Focus on that.

Agreed though I suspect it is getting warm when it is running at 10A amd maybe dropping down to 5A because of that?

 

[pjuk]

Define warm? If it's too hot to touch say for more than 5 seconds then it's likely to be above 50°C which is bad. If it's warm like a someone's hand it's likely to be between 30-40°C which is fine for something drawing 5-10A.

I routinely have equipment at work drawing 13A continuous for hours on end from a 3-pin socket and it rarely goes above 40°C unless the ambient temperature of the room is high. The real problem is if you have something that is immediately too hot to touch.

As you said, test it out on another socket at work or try a heavy duty extension cable from another socket in the house.

 

[WannabeOwner]

The real problem is if you have something that is immediately too hot to touch.

Presumably? that doesn't happen with UMC 'coz it would detect the heat and reduce the AMPs? In which case should we infer that if the UMC reduces AMPs then there is a problem that needs Sparky to investigate? (Perhaps after trying the UMC at another location to make sure it is happy at full-chat and plug does not get above slightly-warm, and thus ruling out a fault in that UMC)