Big storm and no power in SA

Tombie · 12th January 2018, 12:37 PM

That future is still beyond a political term which is about as far as they look...

**Tins** · 12th January 2018, 01:36 PM

Originally Posted by Mick_Marsh

it is a net user of a lot of power. Add to that, the batteries will need to be replaced in the not too distant future.

You can rest assured that a certain South African born US ~~snake oil salesman~~, sorry, businessman has factored that into his calculations...

DiscoMick · 12th January 2018, 05:27 PM

I have read that Tesla batteries carry a 10-year warranty, but from what I've read there is some dispute over what that warranty actually covers. I guess we'll find out in 10 years.

Tombie · 12th January 2018, 06:11 PM

Originally Posted by DiscoMick

I have read that Tesla batteries carry a 10-year warranty, but from what I've read there is some dispute over what that warranty actually covers. I guess we'll find out in 10 years.

Nope

in 10 years we won’t.

If anything, We will find out what it covers pre-10 years

**Eevo** · 12th January 2018, 09:26 PM

Originally Posted by Mick_Marsh

Yep. Apparently, voltage drop is only a concern when you are charging a second battery in your 4WD. It doesn't enter into it when we're talking about HV transmission lines over vast distances.
.

the higher the voltage, the smaller the drop.

Tombie · 13th January 2018, 10:20 AM

Originally Posted by Eevo

the higher the voltage, the smaller the drop.

And also the reason they went AC

**Tins** · 13th January 2018, 10:36 AM

Originally Posted by Tombie

And also the reason they went AC

I always believed that electrical loss was less in HVDC than HVAC.

**Tins** · 13th January 2018, 10:41 AM

Originally Posted by DiscoMick

I have read that Tesla batteries carry a 10-year warranty, but from what I've read there is some dispute over what that warranty actually covers. I guess we'll find out in 10 years.

If Tesla is still around in 10 years. The subsidies are drying up. The Tesla 3 car is nowhere near where Musk wants it to be in terms of production. And, as Tombie points out, the warranty stuff will be tested well within the 10 year period. You don't honestly think that the warranty will extend even one day past that point, do you?

**Mick_Marsh** · 13th January 2018, 11:46 AM

Originally Posted by johntins

I always believed that electrical loss was less in HVDC than HVAC.

Generally, AC is more efficient (less losses) than DC for power transmission.

In fact, in those HV transmission lines you see all over the country, there is no electricity flowing in those aluminium conductors.Zero. Zip.
Read up on "skin effect". For good measure add "transposition", "bundling" and "voltage gradient" as worthwhile looking up.

Oh, everything has it's place. You use appropriate technologies for the application. Everybody knows Basslink is a DC transmission system. AC would have had far more losses. Think about it. Sea water is an electrolyte and air is an insulator.

**JDNSW** · 13th January 2018, 01:22 PM

The big advantage of AC for power transmission is that it is (relatively) cheap and easy to change the voltage. When transmitting power, the higher the voltage the lower resistive losses, both because the lower current for the same power means means reduced voltage drp, and because the higher the voltage for the same power, the smaller the proportion of power that is lost for that voltage drop.

All good until the voltage gets high enough that further voltage increases mean more loss due to leakage. And higher voltage mean more money spent on insulation.

The main drawback of AC is that if you put it underground or, worse, under water, inductive losses become very high.

On the other hand, DC has the advantage that inductive losses are nil, and for the same nominal voltage less insulation is needed (AC has higher peak voltage than the same nominal voltage DC. But changing voltage is, compared to AC, very expensive.

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