Earth leakage Zoe with Tesla DC charger

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doggy
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Real Name: David Kerr
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Earth leakage Zoe with Tesla DC charger

Post by doggy » Fri, 16 Aug 2019, 14:22

I did some tests on a Tesla DC today. It has two cables (left and right). The right EVSE always works with my Zoe. The left one only works about 20% of the time with a charging impossible or check charging post error. My theory is earth leakage is the problem. I got to test the right hand (working ) one.
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Screenshot_20190816-151647.jpg (273.74 KiB) Viewed 226 times
I think the limit for leakage is about 200mA for each category, so one of them is getting close.

I did not have a chance to check the other one and see what the figures were. Presumably a little more marginal.

The reported ground to neutral resistance was 0.0 ohms.

Incidentally, the AC input power was 15,169watts and DC to the traction battery was 14,356watts (95%) and 42watts to the 12V battery (0.3%). All AC phases were identical current so no neutral current.

Regds,
Dave

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jonescg
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Re: Earth leakage Zoe with Tesla DC charger

Post by jonescg » Fri, 16 Aug 2019, 15:02

Where is it measuring these currents? Also, is it referring to leakage from the AC imput to the charger, or leakage from the traction pack?
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doggy
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Re: Earth leakage Zoe with Tesla DC charger

Post by doggy » Fri, 16 Aug 2019, 15:17

Hi Chris,
Leakage currents all relate to the three phase AC input to the charger.
DC is apparently measured there also but would most likely come from the traction battery or rectified AC.
So it's a bit like having a very comprehensive RCD.
Incidentally, in Europe they have specs for the curve of RCDs/CBs feeding EVs which are rather different from the common house types. They include DC as well as AC leakage.
I tried ordering one to protect my 32A single phase outlet at home but changed my mind when informed the Australian price would be close to $900! My electrician agreed with me that it was a total ripoff and he installed a fairly common (type A from memory) unit. I have had no problems with that- so far.
Cheers,
Dave

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