Author Topic: Cutting through the BS for alternative power  (Read 12830 times)

Offline chrisc

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Cutting through the BS for alternative power
« on: February 08, 2015, 08:54:33 AM »
A very good friend is a retired marine electrical engineer and has been involved in substitute and alternative power supplies for many years.  He expressed concern at what he has been hearing from shops who purport to offer solutions to electricity blackouts, and ridiculous prices quoted for solar systems, some over R500k

He suggests the following

For the time being, while the load shedding varies between level 1 and 2, a simple inverter/charger/battery combo will be sufficient for your needs.  The size one you buy will depend on what you want to keep running, but on investigation with many households, an 800VA or 1200VA unit is more than adequate

Should the load shedding become more intense, then you can consider attaching solar panels, but the price will increment by a factor of 5 or more

Batteries are about 80% efficient.  In other words, to extract 100 a/h from a battery you have to pump in 120 a/h.  They also last between 4 and 6 years so must be considered a consumable item

A 24 volt or 48 volt battery conversion system is more efficient than a 12 volt system since the upward multiplication is a lot less.  Large power 12 volt transformers have a lot of wastage within the coils compared with a 24 or 48 volt unit.  Many inverters convert the DC straight to AC, then rely on a transformer to convert this to 220 volts.  The wasted energy will manifest itself as heat

Pure sine wave is much more desirable than modified sine wave, which can be a modified square wave or a trapezoidal wave

After much selection and consideration, he suggests components from this supplier in Somerset West

URL:  http://www.exsolar.co.za/products/

Look at Products / Inverter/chargers and True Sine wave inverters.  They have a sophisticated battery charger which will enhance the life of the battery.  One such unit was purchased in 2006 and still uses the original batteries (2 x 12 volt 40 a/h) after 9 years



There are obviously other equally good devices around, but these are recommended as being the correct device to fit the bill if you do not want to go the generator route and offer the most cost-effective way to provide alternative power at the moment






Offline Adagio

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Re: Cutting through the BS for alternative power
« Reply #1 on: February 08, 2015, 09:11:54 AM »

Good info Chris, thanks for the confirmation. :thumbs:

I have visited ExSolar (at the Interchange opposite Somerset Mall) and have often wondered if they are pulling the mickey or not. They really have some impressive state of the art systems, as well as basic kits - thereby catering for all requirement levels.

Offline Tom

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Re: Cutting through the BS for alternative power
« Reply #2 on: February 08, 2015, 09:14:40 AM »
Chris... Thank you or this info.  :thumbs:
Much appreciated
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Offline philipc

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Re: Cutting through the BS for alternative power
« Reply #3 on: February 08, 2015, 09:15:26 AM »
 Thanks chris,
as you state, cutting through the BS, a system as you suggest is the best option.
Gennies are the best 'bang for your buck' and are available at just about any shop, but at best they offer only a temporary, noisy  solution.

A note of warning to genset users: I see there is a tendency to plug the power into a wall outlet, ie a male plug going to another male plug straight into the wall plug. This is not only very dangerous but also illegal. You are bypassing any safety device you would have had on the electricity supply and you run the risk of burning you house to the ground. I dare you to convince the insurance company to pay up after such a disaster.

To add to the system that chris proposes one could use a static switch that will automatically disconnect from the mains and switch to the inverter if the power goes down, and back again when the power comes back on. Obviously you would need the correct size inverter etc.

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Offline kamikazi

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Re: Cutting through the BS for alternative power
« Reply #4 on: February 08, 2015, 09:25:34 AM »
Good info Chris, thanks for sharing. Will visit ExSolar, have driven past there many times before, but thought they'd only do solar installations. I agree that a good UPS unit is more than good enough to cope with load shedding. For longer power outages though you are still out of luck.

Offline Family_Dog

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Re: Cutting through the BS for alternative power
« Reply #5 on: February 08, 2015, 09:38:19 AM »
The practice of using two male plugs on an extension cord is very dangerous. An Electrician mate of mine told me about a local gentleman who has been imprisoned for 22 years after having taught his son how to do just this during load-shedding, Well, the son did exactly what dad told him while his father was at work and successfully electrocuted - and killed - a Municipal electrician who was working on the overhead power lines at the time and hospitalising another.

Definitely not a good idea!


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Offline chrisc

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Re: Cutting through the BS for alternative power
« Reply #6 on: February 08, 2015, 12:33:49 PM »
Neighbour of brother in law in Montagu got a quote for R700k (yes, not R70k) for a 10 kw solar system complete.  Some of these sales people must be smoking something bad...

The Multiplus device is meant to be plugged in to the load and the incoming mains all the time.  The transfer time is 20ms which won't upset a computer and certainly won't upset an audio system or a PVR.  If you use this device in something like a caravan park, where your current load is severely limited, then you can use this to augment the power for short periods to provide more current

Offline Rotten Johnny

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Re: Cutting through the BS for alternative power
« Reply #7 on: February 08, 2015, 12:40:55 PM »
^^^ I know quite a few people that have parted with 100-250k for an inverter coupled to some solar panels and batteries.  By my calculations the markup is over 100%
Audiophile: There is almost no other group that prides themselves more on wasting good money on utterly worthless ****, and then trying to furiously blow smoke up their own ass to justify it.

Free your mind...and your ass will follow.

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Re: Cutting through the BS for alternative power
« Reply #8 on: February 08, 2015, 12:49:28 PM »
The practice of using two male plugs on an extension cord is very dangerous. An Electrician mate of mine told me about a local gentleman who has been imprisoned for 22 years after having taught his son how to do just this during load-shedding, Well, the son did exactly what dad told him while his father was at work and successfully electrocuted - and killed - a Municipal electrician who was working on the overhead power lines at the time and hospitalising another.

Definitely not a good idea!


-F_D

Can someone please explain this no-no which I don't understand? How do you use two male plugs on an extension cord? There are many extended/extension cords/cable drums here with adaptors for plugging in two or more 'male plugs'. Eg in the place where I assemble needles I have an elbow-poised 100W lamp and my soldering station plugged in and both switched on at the same time. Sometimes I even have 3 tools plugged in - eg my rechargeable soldering iron being charged.

In the room where I test cartridges, there are only two wall outlets and I have used very thick 3-core mains cables going almost right around the room to plug in my computer, printer, scanner, 4 amplifiers, a pre-amp, 3 turntables and ancilliaries but at any given time only use 1 turntable, 1 amp or 1 power amp and 1 pre plus my computer which stays on all the time.

All these extension cables are 'over-specced' and their female extender sockets are of good quality. Earthing is carried to all plug extenders.

Is this what the caution above is all about?

Thanks.

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Offline GECO

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Re: Cutting through the BS for alternative power
« Reply #9 on: February 08, 2015, 01:03:54 PM »
The no no is pumping 240v back into the grid. Legal connection method will eliminate that possibility

Online skollie

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Re: Cutting through the BS for alternative power
« Reply #10 on: February 08, 2015, 01:18:49 PM »
Thank you. I don't do that.

skollie
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Offline Skylark

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Re: Cutting through the BS for alternative power
« Reply #11 on: February 08, 2015, 01:29:54 PM »
The male to male ext lead basically means the genset output is fed into the house wiring via making a plug point live and therefore feeding the rest of the wiring system but in doing that nullifying much of the db board protection and making the neighbourhood grid live when most expect it to be offlinr?
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Offline chrisc

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Re: Cutting through the BS for alternative power
« Reply #12 on: February 08, 2015, 02:06:49 PM »
The adage "a little knowledge is a dangerous thing" applies particularly to people who would create a lead with two male plugs on it. 

The only way to properly wire a section of your house to an alternative power device is to do it at the DB board.  You remove (and tape up or make safe) the incoming mains lead from the circuit-breaker and wire the live cable to its input.  The neutral you could share, but if you want to be properly safe, identify and remove this neutral as well and connect both to your alternative supply.  You are then completely isolated from the incoming mains.  In any case, work like this must be done by a licenced electrician.  You don't want your house looking like the pictures of illegal connections which have been displayed

Offline chrisc

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Re: Cutting through the BS for alternative power
« Reply #13 on: February 08, 2015, 04:48:16 PM »
Another good supplier in the southern peninsula - http://www.alternagy.co.za/.  Tel 021-7853183

Offline Shonver

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Re: Cutting through the BS for alternative power
« Reply #14 on: February 08, 2015, 05:13:57 PM »
The other problem with male-male mains leads is that if unplugged on one end you could potentially have exposed live pins (prongs).

Also, the one about pumping power onto a live grid (not exactly the subject of this discussion but...): you must have the phases synchronised, else you could end up loading the grid instead and potentially blowing up something.
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