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Old 31st May 2020, 1:53 pm   #61
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Location: Melbourne Australia
Posts: 426
Default Re: How much DC on your mains ?

Transformerless inverters (ie. many of the PV inverters) are speced to have a very low DC level. But it could be likely that on average all the PV inverters do not additively contribute a net DC current flow.

Battery inverters are typically transformer coupled (but I don't have first hand info on Tesla products).
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Old 31st May 2020, 2:50 pm   #62
Join Date: Mar 2020
Location: Sydney, New South Wales, Australia.
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Default Re: How much DC on your mains ?

I highly doubt a decent commercial grade battery unit like a Tesla wall would be feeding DC to the mains.
I was thinking more along the lines of home built units.
Every man and his dog has a Youtube video up these days showing how they made their own Tesla wall from reclaimed laptop batteries.
Im sure there would be home experimenters out there that have not correctly isolated their battery pack from the mains.
At the very least the might be causing a spike in DC on the negative rail if connected wrong.
Speaking of negative RAIL. I remember a house we lived in once got a DC voltage up through the old copper drain pipes from the electric trains from a fault at the station near our house.
Having a shower was sometimes a shocking experience.
If only he could have used his evil genius for niceness instead of evil. Max Smart 18 Sept 1965
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Old 31st May 2020, 3:05 pm   #63
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Location: Grantham, Lincolnshire, UK.
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Default Re: How much DC on your mains ?

Found that reference. don't they get buried quickly?
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Old 1st Jun 2020, 1:48 am   #64
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Location: Worksop, Nottinghamshire, UK.
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Default Re: How much DC on your mains ?

Solar panels in large fields, mostly the early ones sound like a 405 TV set with mains ripple on the line output stage.
They chop the DC to make a set of half sine waves and then switch them to make a set of three sine waves to apply to the 11/33KV three phase drop cable on the closest pole.
They do about 1/4MW per acre on a clear sunny day.
If the stock in the warehouse turns over a couple of times before the go ahead to erect the panels comes up the technology can sometimes improve so much that things can get a bit "toasty" if the drop cable is only rated at 100A.
It was toasted copper with melted vinyl over it at this location.
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Last edited by Refugee; 1st Jun 2020 at 1:53 am. Reason: grammer
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