3 Pin Charger Dropping to 5a

[Fly.guy]

What is about odd is that 5a is below the minimum current as set out by the relevant standards/regs that are used to communicate between an EVSE and an EV. Officially the minimum is 6a. This suggests that Tesla have ‘pushed’ the standard somewhat....

Depending on your level of comfort doing such things, maybe (after switching off the relevant breaker at the consumer unit) have a look in the socket to check that everything is tightened down and that there is no scorching visible internally.

 

[Fullerene]

Whilst you're waiting for a chance to try at another location or similar, maybe worth replacing the fuse in the plug on the UMC. I really doubt that's the underlying issue but standard fuses when used at high current will tend to increase in resistance over time. Fundamentally the plug will heat up due to resistance and the associated heat loss

If the plug is warm it may be dissipating something in the order of 5W, by comparison some low power soldering irons are in the region of 15W.

I had an old extension lead with a plug that got a bit 'melty' after laying undisturbed for a very long time, 20 years... The resistance of the 13A fuse had got to the point where it was dissipating a lot of heat but not to the point where the fused ruptured.

I have also got a lovely example of a mint looking glass fuse with the wire clearly intact, however it doesn't conduct electricity. I keep this to demonstrate to people that looking good doesn't necessarily mean is good. Doesn't happen very often but easy to meter the fuse before closing up the plug or electrical enclosure.

I doubt this is causing enough of a voltage drop on the circuit to cause the charge current reduction. So if you can replace the fuse maybe worth a try? Good luck

 

[Ryder35]

Whilst you're waiting for a chance to try at another location or similar, maybe worth replacing the fuse in the plug on the UMC. I really doubt that's the underlying issue but standard fuses when used at high current will tend to increase in resistance over time. Fundamentally the plug will heat up due to resistance and the associated heat loss

If the plug is warm it may be dissipating something in the order of 5W, by comparison some low power soldering irons are in the region of 15W.

I had an old extension lead with a plug that got a bit 'melty' after laying undisturbed for a very long time, 20 years... The resistance of the 13A fuse had got to the point where it was dissipating a lot of heat but not to the point where the fused ruptured.

I have also got a lovely example of a mint looking glass fuse with the wire clearly intact, however it doesn't conduct electricity. I keep this to demonstrate to people that looking good doesn't necessarily mean is good. Doesn't happen very often but easy to meter the fuse before closing up the plug or electrical enclosure.

I doubt this is causing enough of a voltage drop on the circuit to cause the charge current reduction. So if you can replace the fuse maybe worth a try? Good luck

Thanks will try it on my work chargepoint and report back. M guess is it is dodgy wiring in the garage but we will see.

For what it is worth I have put a pic of the socket below...

 

[Ryder35]

So tested with the charger at work and the same thing is happening so I assume it is the UMC that is the issue not the electrics.

Do I just report it via the "Request Help" section of my home page?

 

[zap fizzle]

"Tested with the charger at work" is very ambiguous.

Do you mean "you tried your UMC in another socket and it acted the same"? If so, then agreed, raise a service request in the app. If you're near a service centre, and you just turn up, I'd hope there's a reasonable chance they'd test/swap it on the spot.

If you mean "you tried with a different charger entirely at work, and it acted the same" then the UMC isn't at fault and perhaps the car is?

 

[Ryder35]

"Tested with the charger at work" is very ambiguous.

Do you mean "you tried your UMC in another socket and it acted the same"? If so, then agreed, raise a service request in the app. If you're near a service centre, and you just turn up, I'd hope there's a reasonable chance they'd test/swap it on the spot.

If you mean "you tried with a different charger entirely at work, and it acted the same" then the UMC isn't at fault and perhaps the car is?

Sorry! As mentioned earlier in the thread the charger at work is an old Electromotive one that is basically a 3 pin plug on a post! It charged at 10/10A but still dropped to 5/5A, though not as frequently.

 

[TestPilot]

Certainly don't judge anything on the performance of the i3 cable. My colleague's cable melted and BMW said they'd replace it this time but not again, as it's only supposed to be for "emergency" use not daily charging.

 

[Tony Hoyle]

That's a pretty poor excuse. No electrical device legal to sell in the UK should melt under frequent use.

 

[TestPilot]

That's a pretty poor excuse. No electrical device legal to sell in the UK should melt under frequent use.

Yeah, I thought it was p*ss poor.

 

[zap fizzle]

Sorry! As mentioned earlier in the thread the charger at work is an old Electromotive one that is basically a 3 pin plug on a post! It charged at 10/10A but still dropped to 5/5A, though not as frequently.

Apologies. The UMC is fukt then, that's pretty definitive.

If you had a building full of Tesla owners it might have been interesting to swap the bs1363 tail off your UMC with someone else's as a test, but as it is I think you can just put the whole UMC back to the service centre and say "it's faulty pls fix". They'll probably just swap it.

 

[Leoht]

I just had the same problem. In the U.K. a standard 3 pin plug is fast enough. I just have a dedicated circuit and extension lead for it. Charging dropped to 5/5A as above. No heating at the socket (not even warm). I then noticed the plug wasn’t all the way in pushed it in, now it’s back to 10/10A.