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Deep Adaptation - Prof. Jem Bendell
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kenneal - lagger
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PostPosted: Mon Apr 01, 2019 12:52 pm    Post subject: Reply with quote

It's not that difficult to rewire the panels into parallel connections to give the 12, 24 or 48 volts but yes a controller that would take a very high input would be a good thing.
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mikepepler
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PostPosted: Mon Apr 01, 2019 3:42 pm    Post subject: Reply with quote

adam2 wrote:
What is needed IMO, is a battery charging controller that will charge a 12 volt or 24 volt battery efficiently from a solar array intended for grid tie operation.

Grid tie arrays are almost always series connected to give several hundred volts.
MPPT charge controllers are available that take an input of several times the battery voltage, but AFAIK are not available for hundreds of volts input.

This one's good for 600V:
https://www.morningstarcorp.com/products/tristar-mppt-600v/

I've got the standard TristarMPPT at home, it's OK for up to 150Voc, though I'm only using at at up to 40V.
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clv101
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PostPosted: Mon Apr 01, 2019 8:49 pm    Post subject: Reply with quote

I don't know much about grid tie PV systems but presumably the box on the wall contains an MPPT controller and an inverter to produce 230V AC. But it doesn't work without a mains supply? Surely the answer is to disconnect and then 'fake' the mains supply (with a small battery powered signal generator) then everything should work fine?
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Potemkin Villager



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PostPosted: Tue Apr 02, 2019 4:06 pm    Post subject: Reply with quote

clv101 wrote:
I don't know much about grid tie PV systems but presumably the box on the wall contains an MPPT controller and an inverter to produce 230V AC. But it doesn't work without a mains supply? Surely the answer is to disconnect and then 'fake' the mains supply (with a small battery powered signal generator) then everything should work fine?


Go on be brave, why don't you try it and see what happens. Smile

The tristar inverters seem to have a huge number of complex features and functions, knobs, bells and whistles and I am sure it all comes at a price. Many of these features would be rather redundant when the thing was called upon to used in time of need.

In the long run I think we are in for a largely electricity free future sooner or later.
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clv101
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PostPosted: Tue Apr 02, 2019 4:52 pm    Post subject: Reply with quote

I don't have a grid tie PV system, or even the grid at my place. All my solar is off-grid.
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mikepepler
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PostPosted: Tue Apr 09, 2019 9:34 am    Post subject: Reply with quote

clv101 wrote:
I don't know much about grid tie PV systems but presumably the box on the wall contains an MPPT controller and an inverter to produce 230V AC. But it doesn't work without a mains supply? Surely the answer is to disconnect and then 'fake' the mains supply (with a small battery powered signal generator) then everything should work fine?

This is exactly what some systems that can automatically fall back to off-grid operation do. They use a fairly large battery and an inverter-charger. When demand is higher than PV output, energy comes from the battery, and vice versa when demand is lower than output. If the battery can't accept any more charge, the controller instructs the PV to shut off temporarily - though I suppose this might happen by default if the mains voltage rises out of spec.
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kenneal - lagger
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PostPosted: Thu May 09, 2019 5:14 pm    Post subject: Reply with quote

This article in the Ecologist by Jonathan Neale, Social Collapse and Climate Breakdown, is written in support of Jem Bendell's thinking. The author claims to have got his head around the idea of collapse but I think he has a way to go yet.

He goes on about fascists telling people in the future that immigrants and refugees are the enemy and that they are coming to take our food but he seems not to realise that when those people are migrating because they lack food we will also be very short of food ourselves. We in the UK will be starving and some of us will be dying because we will not be able to import the 50% of our current food supply that we now import. Yes we will be able to mitigate that loss to an extent by not wasting what we now waste but with climate change and sea level rise we do not know what proportion of the food that we now grow we will be able to grow in the future.

His socialist ideals seem to blind him to the dangers of continuing to import hundreds of thousands of people every year into an island that already has one of the densest populations in the world. It has blinded him to the fact that we will lose land area and have millions of internal migrants of our own to deal with.

His take on previous social collapses as written about by Jared Diamond also seems to be skewed by his politics. Saying that previous collapses were driven by a desire to lead a more simple and egalitarian life is putting a very socialist gloss on how most people might see the events of the time. Diamond says that those collapses were due to the over exploitation of local resources resulting in societal collapse and the overthrow of the local rulers. It may have resulted in the desired simpler and moe egalitarian life but Neale's take on it is rather simplistic and driven by his socialist politics.

Yes, he has a long way to go yet in his disaster thinking.
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