Solar Power Thread

E

empirex

Banned
Joined
May 7, 2009
Messages
2,518
Reaction score
0
Location
Cape Town
Maybe mods can see fit to sticky this thread.

When I say solar I don't mean solar geyser, rather a solar electricity system that requires deep-cycle batteries, inverters, etc.


Anyway, is there anyone else that has attempted this before?
There are so many brands of batteries and products out there that it's a little hard to know where to start.

Popped into Builders Warehouse and they had a kit by Ellies that included all the components, but didn't spend too much time looking at the time.

So any one been down this road before, I will be looking into this further but if anyone has and tips or advice that would be great!
 
have looked into solar lighting, but due to the vast selections & combo's and of course the "fly by night" rip off's - have left it alone.
would like to replace my existing eskum lighting with solar power aswell as my 1.1kw pool pump.
would like a system that has a small diesel generator for backup and to fast charge batteries if needed.
 
I'm on a phone so replies brief.

I've recently gone off the grid with an 8kW PV array. 40 x 210W panels back to 230VAC 50Hz via MLT Drives PowerStar II bi-directional grid-tied inverter.

For now, I export about 20-25kWh during daylight, and reimport it at night, using the grid as a battery, so my nett consumption is pretty much zero. This is possible only because my local municipality has agreed to a pilot project and installed a four-quadrant meter to measure imports, exports and nett usage.

I have a small 1260 Ah 48V DC battery bank, which at 20% discharge is good for about 3kWh.
 
Arthur said:
I'm on a phone so replies brief.

I've recently gone off the grid with an 8kW PV array. 40 x 210W panels back to 230VAC 50Hz via MLT Drives PowerStar II bi-directional grid-tied inverter.

For now, I export about 20-25kWh during daylight, and reimport it at night, using the grid as a battery, so my nett consumption is pretty much zero. This is possible only because my local municipality has agreed to a pilot project and installed a four-quadrant meter to measure imports, exports and nett usage.

I have a small 1260 Ah 48V DC battery bank, which at 20% discharge is good for about 3kWh.
Click to expand...

Quick question on this,

The fact that you can "export" does this lessen the need for large banks of batteries?

I ask this because this (from my research) has been one of the largest cost factors...
 
Yes, it's a major factor in saving on batteries since the grid is used as an energy store, rather than (very) expensive batteries. This was a critical factor in my own installation as it saved me over R250K. The only downside now is that I rely on the grid for non-daylight power. But power during the day is no longer an issue - my wife again runs the washing machine on heated cycles, the irrigation system runs during the day, and we no longer run the dishwasher at night.
 
I must get hold of my municipality and see if they're amenable to the idea...

Because I calculated all in, I'd have to spend R300k+ to get off the grid, but if I can spend considerably less than that and get mostly off the grid, or at least have to pay minimal for my electricity, then I would be very interested in the idea.

How much did your whole install cost btw, if you don't mind me asking?
 
If you have the money and space to do it, go for it!!!
I had a look at a solar system for my pool pump.
Payback period for a 1.65kw (1.1kw pump x 1.5 safety factor) system was around 6 years without any battries.
This was working on R1.4 per kwh.
Total cost for just the solar panels around R25,000 at current pricing of around R12/watt.

Problem is to find enough roof space to mount 7 x 250W panels facing the correct way and angle.

If you start installing battries, it can get very sticky extremely fast.
Battries is expencive, needs replacing between 3 to 5 years.
You get glass battries which lasts up to 15 years, but the cost is prohibitive!!!
Then cabling and safety around the battries, especially gas build-up and ventilation.

I find http://www.gwstore.co.za/ a good place to start.
There is loads more out there so just google a bit...
 
exsolar.co.za are also a great place to get panels, etc.

From my previous employer we learn't alot about going solar, very expensive and ROI is unlikely. The only real advantage is where you need to compliment your existing feed, your running a business where uninterrupted electricity supply is crucial or its economically not viable to lay down electricity to a point like a shed or our garage (I installed one of those units from Builders, worked great for a few weeks but died on us).
 
cbrunsdonza said:
From my previous employer we learn't alot about going solar, very expensive and ROI is unlikely.
Click to expand...

I did some quick calculations and the electricity prices will need to at least triple before solar PV becomes feasible (i.e. reach ROI before the batteries need to be replaced).
Alternatively the equipment costs will need to drop drastically.
 
Just remember that the biggest power user in the house is your heating (hot water + heat).
So a solar geyser is the first thing you should look at.
I'm looking into doing something with the Arduino, LED's and movement sensors. Do a low power light (5v/9v/12v) that, for now, can be charged from 220v and later maybe solar.
 
spiderz said:
Just remember that the biggest power user in the house is your heating (hot water + heat).
Click to expand...

Agreed, solar heating water is the first step.
However it's a lot harder moving away from heating appliances.

Like my wife's 2000W hair dryer, 1000W microwave oven, 2000W kettle, etc.
There are some things that just work better on electricity than solar heating or gas.
 
I bought a 4l insulated hot pot urn thing. It only has a 1kw element, but it keeps water near boiling all day. Saves having to reboil the kettle each time you want some hot water. I fill it with hot water from the solar geyser for added savings ;)

I looked at putting the pool pump offgrid. The 50k initial cost was just too much.
 
Arthur said:
I'm on a phone so replies brief.

I've recently gone off the grid with an 8kW PV array. 40 x 210W panels back to 230VAC 50Hz via MLT Drives PowerStar II bi-directional grid-tied inverter.

For now, I export about 20-25kWh during daylight, and reimport it at night, using the grid as a battery, so my nett consumption is pretty much zero. This is possible only because my local municipality has agreed to a pilot project and installed a four-quadrant meter to measure imports, exports and nett usage.

I have a small 1260 Ah 48V DC battery bank, which at 20% discharge is good for about 3kWh.
Click to expand...

+1 on this setup , the batteries price and life span is what deters most from a solar setup. Using the grid is the best way to go atm until battery technology has improved and price has decreased.
 
When going off the grid the first step is to significantly reduce power consumption.

Replace the fridge with a well insulated high efficiency version.
Replace lights with LED bulbs from builders warehouse.
Replace old oven with a convection oven, these cook more quickly so save power.
Replace geyser with solar geyser. Insulate roof.
Make sure windows don't bleed air thereby trapping in warm air in summer.
Upgrade PC to newer model and only buy what you need, do you really need 2 gtx 580 in sli.
Replace shower rose with low flow shower head.

Once this is done you may find electricity is such a negligible cost you don't have to go off grid.
 
Last edited:
Sinbad said:
I bought a 4l insulated hot pot urn thing. It only has a 1kw element, but it keeps water near boiling all day. Saves having to reboil the kettle each time you want some hot water. I fill it with hot water from the solar geyser for added savings ;)

I looked at putting the pool pump offgrid. The 50k initial cost was just too much.
Click to expand...

Unless you need a few litres of hot water you could use a flask instead.
 
Singularity1 said:
Unless you need a few litres of hot water you could use a flask instead.
Click to expand...

We had a flask, it got dropped and broke - so i replaced flask and kettle with this :) It functions like a flask, except it also has a thermostatically controlled heating element.
 
Sinbad said:
Less than 2 years.
Click to expand...

Errr well my colleagues and i did a bunch of tests and studies on renewable energy in the household a few years back and there is no exact answer to this question. Its greatly influenced by things such as quality of solar geyser, size of geyser, location , water usage plus other smaller variables. Conclusion is you will start getting money back but in some cases that can be up to 10 years :wtf: . From our study however average was about 4-5 years.
 
Last edited:
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X