Energy Matters Forums

[stevecrout]

I'm hoping to take advantage of the ample sun in Timor Leste and set up a proper solar system. I think I will need to purchase another 2 - 4 80W panels, a pair of controllers and 2 X true sine wave inverters with 24 or 48 v input and 220 volt output capable of 3000w and 1500w respectively, using 2 banks of 4 X 12 volt 105 AH and 2 X 12 volt 105 AH batteries.

I'm learning as I go but I think I have the numbers right. I'd like to run a dual or parallel system so I can keep the refridgerator going for 2 days on its own and allow the second system to run a few small fans and lights in the house so we don't bake! I need to ensure the refridgerator takes priority so I thought the second system might work best.

Does this sound like a feasible project? Do you have any of the list of necessary items for sale? Do you have any suggestions for me? All feedback would be appreciated. I will probably ship any purchased items to Perkins in Darwin and send across to us on their barge.

Steve - stevecrout@hotmail.com or Tracey - tracey_morgan@yahoo.com

[franks]

Alternative Technology Association http://www.ata.org.au
have done work in east Timor to install small PV systems for villages.
If your a private person seek the advice of OZ remote PV equipment suppliers, get a price FOB Darwin then ship to Dili, seek the help of a local sparky to do safety check on your install.
Shame im no longer working in Darwin (was there 2004-2006)..pay my airfare to Dili I can help you out

[Tracker]

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there are a great many threads discussing "Remote PV Power".
They all start with NEED or DEMAND.. We can easily assume the sun shines up there, so full-help needs a full-story.

What do you need to power ? Shack Lighting or a Hospital ?

Whatever you consider, understand that the greater the voltage of the battery bank, the more efficient the system is going to be. No one will agrue against the suggestion that 48V is the best place to start.
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[stevecrout]

We are starting the process of moving to solar power for private housing at this time. Nothing commercial, just a concerned individual who believes there's a better way to provide power and not have to rely on the power company for supply.

What we would like to develop is a package that suits the average small house and keeps the refridgerator running for a maximum 2 days and has a second system to supply some lights and small fans. I wanted to explore using 2 systems so I could drain the fan system without jeopardizing the fridge system and when the fans were off it was only a matter of waiting until the power was restored or the system recharged.

I used the calculator from - http://www.freesunpower.com/system_sizing.php#startGrn

I think the big item here is the Converter and making sure we get the right one(s) is the key to having the system work properly.

our usable solar power times run from 07:00hrs to 18:00 hrs almost every day, giving us plenty of charge time. We have some panels available here but I suspect there are differences in quality depending on manufacturer and I'd rather not take a chance on low quality.

Is there any issue with mounting the panels on tin roofs as far as heat goes? These roofs do produce a lot of heat and I don't know how sensitive the panels would be. I suppose a person could/should attach a solar water heater in the same proximity and place a holding tank under the light panels.

Thanks again for any suggestions.

[Gordon-Loomberah]

I would be inclined to go with a single battery and inverter system- There are some low wattage fans available, and LED lighting that wont be too much of a drain on the batteries. Going for 2 separate systems increases the complexity of the wiring, and greatly increases the cost beyond using a slightly larger single battery bank. You would need an extra charge controller, as well as the extra batteries, 2 independent wiring systems from panels to controller to battery to inverter to house (only one rather than 2 inverters if one system is DC only), as well as wiring the house twice.

Using panels on the roof with sufficient air space for convective cooling will significantly reduce the roof temperature due to the shade provided by the panels.

If the fridge has external coils at the back, then you can add a thick layer of insulation to the sides, door and top, which will significantly reduce the power requirements of the fridge. Most of the power consumed by fridges is due to heat gain through the walls, especially in hot climates, rather than brief door openings.
"Modern" fridges often have the condenser coils built into the walls, meaning adding insulation to the outside will make them less efficient... that's not progress IMHO

[Tracker]

"Modern" fridges often have the condenser coils built into the walls, meaning adding insulation to the outside will make them less efficient... that's not progress IMHO

There are SOME refrigerators on the market that still have the black wire grill.
The stupidity of the heat coils inside the walls is that it is amplifying the problem of heat transmission into the refrigerator.
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[SUNSPOT]

Steve,

How did you go with your RAPS gear for East Timor?

I saw your thread today and may be able to offer you a solution excluding batteries and battery charger.

I am a private individual who with my wife have been generating our own off grid/ stand alone electricity since 1992. We started with 4 x 75w BP mono panels on a wooden frame made from packing pallets and a Trace modified square wave inverter. Like with all good things our sys grew over time.

Upgraded our sys two yrs back, have sold some of the equipment thru the EM forum and have some remaining gear that you may be interested in purchasing:

Inverter _ Selectronics SA41_3KW continuous, True sinewave 48volt DC / 240 volt AC(with remote Key Pad, current shunt kit and spare control board).

PV panelsQty 4 x BP275 (75W monocrystalline) with BP PV mounting / tilt angle frame (mounts up to 6 panels). Frame can be placed on the ground or roof if one prefers. The frame could be a bit expensive to frieght, as a suggestion, could throw in the plastic U-Clamp fasteners/screws used to secure the panels to the frame (frame is made from 1 inch Gal pipe).

MPPT AERL Maximizer _600B. The AERL DC_DC maximizer 600B is able to take O/C input voltages of 18 to165 volts DC (so connect panels in a series string) and can take up to qty 8 x BP275 panels in series (higher the voltage less the voltage drop). Also, it has a user selectable output voltage control so to connect up to various battery banks (12, 24, 36, 48 etc up to 132 volts)

Siemens Battery Isolator Switch

The equipment is of good quality and is in good condition.

Irrespective of your decision of the way ahead, I recommend installing one system only (battery bank and inverter) to provide for your requirement.

Worthwhile comments to consider:

The Maximisers are older technology but do perform very well and can be paralleled up (I did run four of them in parallel)_options can be discussed further if you so desire.

Four panels may be stretching it a bit especially when considering battery bank internal resistance / charging requirements and wanting to run a fridge say 24/7. But like a lot of others you can freeze plastic bottles of water and put in the fridge door over night, we still do this some times even with 6kW PV array (noise is the issue for us).

Check out the sys on the EM forum and you will see how the equip above formed part of the sys prior to upgrade 2 yrs back.
http://forums.energymatters.com.au/used-wind-solar/topic2207.html

John