Planning your own Solar Power System

spiff said:
Just a question before I go spend money on a manual change over switch and since I've practically got a ups, do these automatic change over switches work fast enough to prevent the dstv decoder rebooting?
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Auto changeover is quick. I don't even notice that mains have come back on once eskom is back up.

On the subject of manual changeover switches, I have a Hager so when I change over from UPS to eskom it doesn't disconnect either if I am quick to switch it back.

Not sure if they are made that way but I changed it back to eskom the other day and nothing was effected.
 
I saw a very interesting system yesterday where one guy was almost completely off the grid and of the water supply. He has a solar panel that drives the borehole pump, which pumps into the dojo tanks, therefore generating enough pressure for the water during the day. His stove runs on gas and he now plans on getting the batteries setup. The invertor is already installed.

I'm currently convinced that anything with an element can really be sustained on solar pannels.
 
jcheek said:
UPS output panel.jpg
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johnjm said:
Very nice! Where is the best place to get that monitor display from? Plugs would be great too.
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The "UPS monitor" in the pic is a Lovato model DME D120 T1 energy (kWh) meter.
Technically it's "just" a single-phase DIN-rail-mount energy (kWh) meter, and Lovato make a range of them, but that particular model (the DME D120 T1) can measure up to 63A directly and also has some very useful auxiliary monitoring functions apart from just energy, eg voltage, current, power, power factor.

You can buy the DME D120 T1 (and others like it) from Electrahertz and you can have a look at the relevant Lovato catalogue page on the Electrahertz website here.

The DME D120 T1 costs about R1500 and it's probably overkill for many applications, but if - like me - you like to know exactly what's going on in a system, it provides a wealth of information in a small package and a lot of bang for the buck. That's if your UPS/solar inverter/whatever doesn't already have that kind of monitoring built-in already, of course.

Oh, the 2- and 3-pin DIN-rail-mount sockets also come from Electrahertz - they are made by a company called "Scame", if I recall correctly.
 
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spiff said:
Just a question before I go spend money on a manual change over switch and since I've practically got a ups, do these automatic change over switches work fast enough to prevent the dstv decoder rebooting?
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It depends on :
  • the device(s) used for switching, ie mechanical switches or semiconductor switches. The latter can obviously operate much faster than the former.
  • how the secondary power source (inverter fed from battery or solar) is controlled relative to the primary (mains) power supply.
Referring to the second point : On self-contained systems, where the automatic changeover device is closely associated with the inverter, the inverter's output can be kept in phase with the primary (mains) supply, both before the mains supply fails, and just before switching back to it after it has been restored following a power failure. That minimises the chance of discontinuities and makes the changeover very quick and seamless, especially if the changeover switch uses semiconductor switches.

johnjm said:
Auto changeover is quick. I don't even notice that mains have come back on once eskom is back up.
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Is that on a self-contained system with auto-changeover, using semiconductor switches ? Or with the changeover switch separate from the inverter ?


johnjm said:
On the subject of manual changeover switches, I have a Hager so when I change over from UPS to eskom it doesn't disconnect either if I am quick to switch it back.
Not sure if they are made that way but I changed it back to eskom the other day and nothing was effected.
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Because the Hager's switch stroke is so short, you can flick the switch from one side to the other and achieve a pretty rapid switchover, yes!
If you are fortunate with the relative phasing at the switching instant, and the downstream device(s) have some ride-through capability, you can be lucky, yes. I have managed to do the same on mine now and then :D
 
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Thanks man. Regarding my auto changeover I have no idea as its built into the UPS.
 
johnjm said:
Thanks man. Regarding my auto changeover I have no idea as its built into the UPS.
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Self-contained, in my lingo .. lol.
In your case, the inverter can be pre-synchronised to mains before switchover and probably uses semiconductor switches, which is a great recipe for a no-break switchover. Enjoy!
 
thanks for the replies guys,

so basically I can hack a UPS.

just replace the UPS's batteries with my 12v deep cycle.

I'll just have to find a separate source for the charger - don't want that running off the UPS when the mains goes off.
 
Finally taking the plunge for a home UPS:

1x Axpert MKS 5KVA Inverter
4x Deltec Betta BC-6CNFJ-100 12V 100 Ah Lead Crystal Battery

Will get an electrician to wire it all up via a secondary DB.


This will be used to power a few lights, TV, amp, alarm, and garage door.
 
Anyone with experience regarding shipping via normal post from Hong Kong? I purchased an inverter on Ebay and the estimated delivery date has come and gone.

I have sent a message to the seller to hopefully get some kind of tracking information, I really want the darn inverter as it is the last part of my solar setup I need.
 
Naks said:
Finally taking the plunge for a home UPS:

1x Axpert MKS 5KVA Inverter
4x Deltec Betta BC-6CNFJ-100 12V 100 Ah Lead Crystal Battery

Will get an electrician to wire it all up via a secondary DB.


This will be used to power a few lights, TV, amp, alarm, and garage door.
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Please let us know how it works. I am looking at getting something similar and then adding solar panels later. Where did you get the Axpert from? Any idea how much the electrician will charge?
 
The Axpert I don't have yet, most sites are out of stock - Weable, etc.

I know this works since a colleague of mine has built the same DIY.

Not sure about the electrician's costs, since this will require thick cables, a new db, fuses, etc.
 
Naks said:
The Axpert I don't have yet, most sites are out of stock - Weable, etc.

I know this works since a colleague of mine has built the same DIY.

Not sure about the electrician's costs, since this will require thick cables, a new db, fuses, etc.
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Thanks :)
 
Naks said:
Finally taking the plunge for a home UPS:

1x Axpert MKS 5KVA Inverter
4x Deltec Betta BC-6CNFJ-100 12V 100 Ah Lead Crystal Battery

Will get an electrician to wire it all up via a secondary DB.


This will be used to power a few lights, TV, amp, alarm, and garage door.
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5Kva is overkill for that. A 2.4kva is more than enough.
 
johnjm said:
5Kva is overkill for that. A 2.4kva is more than enough.
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future-proofing it, with the intention of adding solar panels within the year. Then the pool can also run off it if need be, and if we have guests the second heat-pump needs to come on.

I worked out power consumption on a typical evening is around 1500W: around 12 downlights, TV, DSTV, AMP, PC, router, garage door, alarm, etc.
 
Naks said:
future-proofing it, with the intention of adding solar panels within the year. Then the pool can also run off it if need be, and if we have guests the second heat-pump needs to come on.

I worked out power consumption on a typical evening is around 1500W: around 12 downlights, TV, DSTV, AMP, PC, router, garage door, alarm, etc.
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How did you measure that?

600w for lights (why not make that 60w by adding LED?)
TV 150w
Dstv and amp prob 100w
Garage door is 200w but only when in use
PC between 50 and 400

In order to future proof you will need to change to LED.

You only want to add solar if you are planning to go off grid.
 
johnjm said:
You only want to add solar if you are planning to go off grid.
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Given where the price of electricity is going to... I would not necessarily agree with that statement.

If you have enough battery capacity, or have enough load during the day to justify the cost of PV, solar makes sense. Getting 40% odd (let's presume) of your energy usage basically free of charge every month, can be substantial.
 
savage said:
Given where the price of electricity is going to... I would not necessarily agree with that statement.

If you have enough battery capacity, or have enough load during the day to justify the cost of PV, solar makes sense. Getting 40% odd (let's presume) of your energy usage basically free of charge every month, can be substantial.
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Do your sums dude, it will take 15 years to make back the investment.
 
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