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a battery charging question [as in 'why won't it?']


Wittenham

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32 minutes ago, Wittenham said:

I am no expert but is on a separate meter with a separate electricity company supplying it. [and separate bills].  I think that means it is separate?

 

Not necessarily. All the electricity companies supply the same electricity from the same grid supply. The product is identical. The only difference between them is the tariffs they charge and their administrative efficiency (or otherwise).

 

I'd say it is possible (though unlikely) that both meters get disconnected and supplied by your Tesla system if the billing address is the same. 

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19 minutes ago, MtB said:

 

 

My suspicion is that while the solar panels are producing, the Tesla system disconnects from the grid and becomes free to do it's own thing, so would be free to drift off frequency whilst disconnected if it so wished. It only needs to sync with grid frequency before starting to export or import. 

 

I think it's time to take the charger and a battery to a neighbour's or friend's house known to be on a grid supply and try it there. 

I am only guessing but I would have thought it would be more like a Combi on a boat whereby the inverter section tracks the phase and frequency of the mains even when it is neither drawing nor supplying power from/to the grid, so that if there is a sudden demand on the inverter that exceeds its rating it can seamlessly start to use some mains power to supplement the inverter. (In the case of the boat it’s slightly the other way round, inverter tracks mains when on mains power so it can supplement the mains or take over seamlessly when mains is disconnected).

You obviously can’t mix inverter power and mains power if the phase and frequency aren’t matched, and equally you really don’t want the frequency and especially the phase of the inverter to suddenly jump to that of the mains if mains power supplement is needed.

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13 minutes ago, nicknorman said:

I am only guessing but I would have thought it would be more like a Combi on a boat whereby the inverter section tracks the phase and frequency of the mains even when it is neither drawing nor supplying power from/to the grid, so that if there is a sudden demand on the inverter that exceeds its rating it can seamlessly start to use some mains power to supplement the inverter. (In the case of the boat it’s slightly the other way round, inverter tracks mains when on mains power so it can supplement the mains or take over seamlessly when mains is disconnected).

You obviously can’t mix inverter power and mains power if the phase and frequency aren’t matched, and equally you really don’t want the frequency and especially the phase of the inverter to suddenly jump to that of the mains if mains power supplement is needed.

 

Yes I agree with all that but we are clutching at straws here looking for a reason for the charger rejecting the mains supply it is getting in. one place, whilst accepting it in another, so we are trying to find the unlikely.

 

I rather doubt a Powerwall installation would ever draw on the grid to supplement a dwindling supply, I think it would switch over completely to either one or the other but I'm only guessing. It would seem trivially easy to sync the frequency all the time though as you say, so seamless switchover can happen at any time necessary.

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I switched on a few electric things to push the system past what solar is giving right now and the max 5kw the Powerwall will give/take at any one point.  This is what it looks like.

 

Thanks all, I really value the combination of expertise and willingness to help in this forum.  Where we are now is:

- charger works outside the home [in at least one place]

- charger does not work in either power supply at home [one solar related, one not]

..........but need to confirm they are actually separate power supplies.  We built all this, so I am reasonably confident that they are separate, but i note the point above about being entirely confident.

- I have switched off the power to the van, and put the fridge on high to run the batteries down a bit.  Will power up the charger later and see what happens.

- if i am still looking at a gloomy red light, I will ask the neighbour if i can borrow their supply

 

I will update if any of the above changes/changes anything.

IMG_0684.PNG

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Ok so it looks as though your Powerwall is sharing the 8.6kW load with the grid, so we now know it is accurately synced with the grid phase and frequency.

 

Is that screenshot taken with the charger showing the red light? It could be that the charger only rejects your home mains supply under certain conditions, e.g. when 100% is being supplied by the batteries/inverter.

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4 hours ago, MtB said:

 

 

 

Not necessarily. All the electricity companies supply the same electricity from the same grid supply. The product is identical. The only difference between them is the tariffs they charge and their administrative efficiency (or otherwise).

 

Not only that, but what they provide is AC, so they are selling you electrons, then taking them back, then selling you the same electrons again fifty times a second. People don't take the trouble to examine their electrons closely, so never notice they are being resold the same increasingly worn out electrons they already own. The electricity companies have been getting away with this swindle for years. This is why they are so worried about the rise in electric car use. They would have to make some fresh electricity to cope with the demand and they have long forgotten how to do it. Watch out for them doubling the reselling frequency to 100Hz to get round having to make some more. 😃

Edited by Jen-in-Wellies
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57 minutes ago, Jen-in-Wellies said:

Not only that, but what they provide is AC, so they are selling you electrons, then taking them back, then selling you the same electrons again fifty times a second. People don't take the trouble to examine their electrons closely, so never notice they are being resold the same increasingly worn out electrons they already own. The electricity companies have been getting away with this swindle for years. This is why they are so worried about the rise in electric car use. They would have to make some fresh electricity to cope with the demand and they have long forgotten how to do it. Watch out for them doubling the reselling frequency to 100Hz to get round having to make some more. 😃

I think the point is that with cars running on DC electricity, there is going to be a massive global shortage of electrons. The politicians pushing electric cars are just too stupid to realise it.
 

And will soon be pushing their electric cars.

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30 minutes ago, nicknorman said:

I think the point is that with cars running on DC electricity, there is going to be a massive global shortage of electrons. The politicians pushing electric cars are just too stupid to realise it.
 

And will soon be pushing their electric cars.

We risk being accused of having a negative bias, but everyone is so worried about the supply of Lithium for batteries and various rare earth elements for motor magnets and they have forgotten about the planets finite supply of electrons. People seem so positive about depriving future generations of them. Make electric cars AC instead. We must start recycling our electrons.

Edited by Jen-in-Wellies
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24 minutes ago, Jen-in-Wellies said:

We risk being accused of having a negative bias, but everyone is so worried about the supply of Lithium for batteries and various rare earth elements for motor magnets and they have forgotten about the planets finite supply of electrons. People seem so positive about depriving future generations of them. Make electric cars AC instead. We must start recycling our electrons.

I already recycle my electrons. They come into the house and they go back out of the house but the electric company still want to charge me

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The statutory voltage limits for the UK grid is 230 volts -6% and +10%.  The statutory frequency limit is 50 Hz +/- 1%.

 

As @nicknorman says, the frequency everywhere on the connected grid is the same.

 

Any attempt to connect another supply that is not synchronised results in anything from magic smoke being emitted to a large explosion, depending upon how far out of sync the supplies are and the relative power of them. It is always the customers supply that gets damaged, because the grid has a huge generating capacity compared to anything connected to it. To prevent damage to customers equipment the ele tricity companiex now demand ROCOF (rate of change of frequency) relays between their supply and yours, to disconnect your generating equipment before it gets damaged by the mains, should your equipment fail.

 

The OP should check that the voltage at his property is within limits, as it is not unusual for local supplies to be outside statutory limits, especially if the local substation is approaching or at full load.

 

If his supplies are within limits, I would check the charger at another site and if it still shows a red light, assume that the charger is faulty.

Edited by cuthound
Spillung and clarification
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8 hours ago, Wittenham said:

I switched on a few electric things to push the system past what solar is giving right now and the max 5kw the Powerwall will give/take at any one point.  This is what it looks like.

 

Thanks all, I really value the combination of expertise and willingness to help in this forum.  Where we are now is:

- charger works outside the home [in at least one place]

- charger does not work in either power supply at home [one solar related, one not]

..........but need to confirm they are actually separate power supplies.  We built all this, so I am reasonably confident that they are separate, but i note the point above about being entirely confident.

(snip)

Are the two supplies coming from different step down transformers? I suspect that would be unlikely.

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6 hours ago, Jen-in-Wellies said:

Not only that, but what they provide is AC, so they are selling you electrons, then taking them back, then selling you the same electrons again fifty times a second.

 

I don't buy that. 

 

Electricity travels at the speed of light (IIRC from skool) so an electron arriving in your house at the peak of a cycle will travel 176,000 miles divided by 100 = 1,760 miles by the time it gets to the other peak of the cycle. So the chances of it being sold back to you are vanishingly small. It will get sold to someone else I reckon. 

 

So there. 

 

;) 

 

P.S. there is an obvious counter-argument! 

 

 

Edited by MtB
Get rid of repeat quote
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20 minutes ago, MtB said:

 

I don't buy that. 

 

Electricity travels at the speed of light (IIRC from skool) so an electron arriving in your house at the peak of a cycle will travel 176,000 miles divided by 100 = 1,760 miles by the time it gets to the other peak of the cycle. So the chances of it being sold back to you are vanishingly small. It will get sold to someone else I reckon. 

 

So there. 

 

;) 

 

P.S. there is an obvious counter-argument! 

 

 

 

So you're getting someone else's used electrons. That is really unsanitary and not a bit ickky. I hope they are cleaned properly before being sold again.

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30 minutes ago, Quattrodave said:

Check your socket at home is wired the right way round (live is live & neutral is neutral), a few years ago my charger refused to work at a friend's place I plugged into (he lives next to the river), his socket was wired backwards...

 

This is a good point. I occasionally encounter boilers where the only fault is reversed polarity. They seem capable of working for years like this then suddenly  stop. Other times I encounter a whole house with reversed polarity when a supposed electrician has just 'upgraded' the consumer unit and got the supply cables back to front. Duh... 

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2 hours ago, MtB said:

 

I don't buy that. 

 

Electricity travels at the speed of light (IIRC from skool) so an electron arriving in your house at the peak of a cycle will travel 176,000 miles divided by 100 = 1,760 miles by the time it gets to the other peak of the cycle. So the chances of it being sold back to you are vanishingly small. It will get sold to someone else I reckon. 

 

So there. 

 

;) 

 

P.S. there is an obvious counter-argument! 

 

No sorry, major misconception there! Electrons most certainly do not travel at the speed of light. They may go quite fast in some sort of experimental accelerator but in wiring they travel very slowly. What travels potentially near the speed of light is the propagation effect that an electron moving has on the next electron. So it’s a bit like a Newton’s cradle (executive toy with dangling ball bearings). When the ball at one end hits the group of near stationary other balls, the ball at the far end pings off the pack after a delay corresponding to the “speed of light” (ish) whilst the balls are all moving quite slowly.

 

Or to put it another way, when an electron is set in motion by a potential gradient, the initiation of movement spreads along at the speed of light whilst the actual speed of all the electrons is quite slow.

 

Edit: just checked with mr Google, who says that the electrons in a wire typically move at a few mm per second, which is “quite slow” compared to the speed of light!

Edited by nicknorman
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3 minutes ago, Loddon said:

As has been said either the socket is L-N reversed or the 13-16 adapter is.

Both need checking.😷

 

OR...

 

(Given there are TWO sockets where the charger does not work, and only one where it does) perhaps the socket where it works is reversed, and so is the adaptor. 

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14 hours ago, MtB said:

 

 

 

Electricity travels at the speed of light (IIRC from skool)....

Electricity is something that people think they understand, but  things are not always what they seem. You can describe and predict electrical behaviour mathematically, but sometimes I think no-one understands what it actually is, which is why early theorists came up with the concept of the ether as a mysterious, undetectable,  medium capable of supporting wave motion. Electricity can be considered as a form of wave motion, like waves in water, and you can consider electrical  energy to be  transferred as kinetic energy in the same way that a wave in water transfers energy without the actual water molecules moving laterally , other than oscillating to and fro.  

 

The speed of transmission of electricity in a cable is the speed of the wave of energy, not the speed of the electrons. This wave speed is only the speed of light when the wave flow is in in free space. When a dielectric is involved, the speed will be somewhat lower depending on the relative dielectric constant of the material surrounding the conductor. This is because a flow of electricity in a conductor is accompanied by an electric and magnetic field in its surrounding  medium, and the interaction between the fields and the medium affect the speed of propagation of electricity in the conductor. The velocity factor of the signal in the coax cable for your TV is typically about 0.7 of light speed. In fact, depending on how you arrange Maxwell's equations, you can consider that the flow of electricity in a conductor results from the passage of the electric and magnetic field around the conductor, which is effectvely what happens in the transmission lines known as waveguides, hollow metal tubes that are used at microwave frequencies. 

 

But this is all rather irrelevant to the original query so I will say no more. 

 

14 hours ago, MtB said:

 

 

Edited by Ronaldo47
typos
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My guess (just a guess) is that the issue is with an elementary wiring problem (they are all elementary after you have found them) rather than the electrons being over-tired due to a lengthy journey from the power station.

 

Someone I know employed a less-than-competent farm hand.  When the tractor mower stopped cutting the grass (oddly coinciding with the cessation of the usual whirring-of-blades noise) the farm hand commenced the process of elimination by trying another field.

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12 hours ago, nicknorman said:

No sorry, major misconception there! Electrons most certainly do not travel at the speed of light. They may go quite fast in some sort of experimental accelerator but in wiring they travel very slowly. What travels potentially near the speed of light is the propagation effect that an electron moving has on the next electron. So it’s a bit like a Newton’s cradle (executive toy with dangling ball bearings). When the ball at one end hits the group of near stationary other balls, the ball at the far end pings off the pack after a delay corresponding to the “speed of light” (ish) whilst the balls are all moving quite slowly.

 

Or to put it another way, when an electron is set in motion by a potential gradient, the initiation of movement spreads along at the speed of light whilst the actual speed of all the electrons is quite slow.

 

Edit: just checked with mr Google, who says that the electrons in a wire typically move at a few mm per second, which is “quite slow” compared to the speed of light!

 

IIRC electricity is actually the flow of holes left by the electrons moving in the opposite direction.

 

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UPDATE:   I still have the grumpy red standby light, no happy green charging light.

 

I bypassed the van's internal panel and the original cable, by plugging the charger directly into a different [working] extension cord.  I plugged that into the two separate supplies [at least i believe they are separate...] at my property, and also into the neighbour's house.  No change.

 

So, the only difference between when it worked and when it did not is

- the dongle that converts the standard domestic plug into one that works at the caravan site.  It looks like this.

- a Northumberland electric supply, rather than Oxfordshire

 

Are there any other suggestions on what might be the issue here?

 

 

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5 minutes ago, Wittenham said:

Are there any other suggestions on what might be the issue here?

 

 

I'm  not sure there's much point until you address the suggestions about polarity-checking, made previously.

 

Or maybe you have and I missed it, in which case I apologise.  

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