Lighting

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Re: Lighting

Postby Gordon-Loomberah » Wed Aug 21, 2013 4:07 pm

davidg wrote:SP-Pro - SPMC 482AU (7.5kw continous)
Peak efficiency @
20% load 95%


Very good indeed, but keep in mind that 20% load is 1.5kW! No one is likely to be running that much lighting in their house overnight... or any other time really ;)

FarmerJohn wrote:...running background loads most of the time of around 180-200w


What is the efficiency at 2 and 3% load, which is more like the loads we are talking about here?
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Re: Lighting

Postby davidg » Wed Aug 21, 2013 6:00 pm

Gordon-Loomberah wrote:
FarmerJohn wrote:...running background loads most of the time of around 180-200w

Also put the "Euro" ones down as well, which are more conservative and they say 93% for 5% load so would expect that to be about right.

Gordon-Loomberah wrote:What is the efficiency at 2 and 3% load, which is more like the loads we are talking about here?

From my own system with an SPMC-482 inverter for about 180-200w background loads it does appear to be right. It may even be ahead of the quoted "euro 93%" down that low, certainly when the weather is like it is the varible speed cooling fan nevers runs at all. The inverter actually has to be hot for that to run that has not happened for sometime. :D
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Re: Lighting

Postby Windy » Thu Aug 22, 2013 6:04 pm

I had been considering going the dc route for lighting, but the extra cost of wiring and light switches and LED drivers plus a 48 volt to 24 volt DC converter didn't really add up. I might still run DC for lighting in my shed.
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Re: Lighting

Postby davidg » Thu Aug 22, 2013 6:45 pm

Windy wrote:I had been considering going the dc route for lighting,

Problem is the rate of loss gets very high very quickly with distance or the costs rise rapidly (cable size) with distance, then there is the cost of the lights that are useful for say 12volts typically cost more than 240Vac products, the currents involved rise rapidly and losses rise with the current just as quickly, in 12V systems these kill the potential savings, and make it a pain to get replacement "lights " overtime. :(
SPS Standalone Power System/Hybrid specialist - Store the Sun!
SELECTRONIC SPMC482-AU, 8.2kW's of Arrays
Selectronic Certified AC-Coupled Fronius 8.2kW Inverter
1900Ah 48V Bank

An OTT Genset for a house.
PVOutput Stats

Sparkys light up your life :)
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Re: Lighting

Postby Gordon-Loomberah » Thu Aug 22, 2013 7:02 pm

davidg wrote:the currents involved rise rapidly and losses rise with the current just as quickly, in 12V systems


It's even worse than that, the power loss rises as the square of the current increase!
I^2R - twice the current, 4 times the loss.
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Re: Lighting

Postby davidg » Thu Aug 22, 2013 7:56 pm

Gordon-Loomberah wrote:I^2R - twice the current, 4 times the loss.

:lol: Was working on simple but OK :lol:
SPS Standalone Power System/Hybrid specialist - Store the Sun!
SELECTRONIC SPMC482-AU, 8.2kW's of Arrays
Selectronic Certified AC-Coupled Fronius 8.2kW Inverter
1900Ah 48V Bank

An OTT Genset for a house.
PVOutput Stats

Sparkys light up your life :)
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