Tesla wall charger rarely charges at 32A

[MaDProFF]

I recently installed a Tesla Wall charger in the garage, on 40A breakers, at first it seemed to charge fine at 32A but most of the time now it only charges at 17/18 Amps, If I disconnect sometimes and reconnect or turn off charging and start it again it goes up to 32A but it slowly drops after a while back to 17 ish Amps, I also noticed the low Volts it charges at as well, never seems to be around 230/240, more like 210.

It gives the recharging time to recharge as if it was charging at 32A, but the time goes way past that which is really annoying, as the whole point of getting a 32A charger was to charge the car back to 90% in my off peak time period.

Anyone else has this, or had this problem is it a fault of the unit, or a way to solve it.

Thanks

Merry Christmas everyone

 

[tsh2]

I'm sure the electricians on the forum will have better ideas, but this sounds potentially unsafe to use. My guess is a poor joint somewhere in the circuit causing a voltage drop, and the charger is regulating the current it takes to limit the drop. The problem is that you risk the faulty joint overheating. Maybe just a loose screw terminal?

 

[Smiddy]

When they installed mine they had to get a certain breaker that cost £140, not sure if that might have something to do with it.

 

[MrBadger]

The low current is due to the low voltage. The reason for low voltage is up for investigation but its out of UK spec. Could be you are getting low voltage because you were marginal on voltage in first place and lots of power being used close by - DNO may need to investigate and rectify. Or it could be a fault. Or something in between.

 

[MaDProFF]

The low current is due to the low voltage. The reason for low voltage is up for investigation but its out of UK spec. Could be you are getting low voltage because you were marginal on voltage in first place and lots of power being used close by - DNO may need to investigate and rectify. Or it could be a fault. Or something in between.

I was suspecting it was due to low voltage, as I notice it is very low sometimes.

I will look into it more thanks

 

[MrBadger]

If you have a long or torturous cable run to charger, then DNO may deem it acceptable. Don’t know if you have a way to measure voltage closer to main fuse when charging but that may tell of DNO or sparky is first port of call - if > 216v then DNO may not want to know.

If it’s an unavoidable long cable run then if not already done then oversizing cable may be enough to tip balance but sounds like you may not get 6v back.

Hopefully it’s just localised marginal voltage which DNO should sort - part of the reason why they want to be notified about EV and other high power installations and conversely Solar PV for over voltage.

https://www.westernpower.co.uk/downloads-view/29134 Other DNO’s will behave similarly.

 

[MaDProFF]

It is quite a long run to the garage, at present it is 14/mi/hr 224v 17/32A I will do some testing of the voltage around the house and in the garage in the next few days but I suspect I may have to run a heavier cable to the garage

 

[ellett]

For 240v @ 40A you need 8 gauge wiring for a typical run, but if the run is long you may need 6 gauge wiring to compensate for the additional per-meter resistance.

 

[MaDProFF]

I need to measure my run, but according to figures, cable should be ok at a guess for under 50 metre run.

Funny thing is if I turn off charging from the app, and wait a few minutes and restart it, it charges at 32A