Thread: solar power for home?

Hi all.
What a lovely chat ..Been useing sola for 10 years in our motor home and loved it ..12 volt fridge all that stuff.. Now we have a sola caravan with two 2 faced 190 watt panals"from sola panel xpress " Qld. 2 agm batts "no lead"140amp each.. and a 400 watt wind gen for a longer than a 2 week stop..the batt are charged from the landy as we drive..the fridge is two a door 170 lt 12 volt.. tv is lcd 48cm 12volt..have a 300 watt invert for the sat settop box..water pump also 12volt.. hot water and stove are gas..but we can heat the shower water on the open fire and pump it in to the van..The only part of this i hate is there are not many places now where one can camp out and not be TOLD you carnt camp here mate!!!
And qld being the worst..we do carry a 1k invert. gen just in case...life can be so good when your geared up to use it wisely...If only bio desiel wasnt to complicated to make ..one more thing the outboard is 4 stroke honda..
Traveling would be a breezzz..IF i could fit a sail to the landy...robert42..

Just out of curiosity, has anyone got a comparison of how much power it takes to make a conventional incandescent globe and a low power fluros globe.

The reason I ask is that so far I found these low power globes are not lasting as long as conventional globes.

For the last 8 or so years I have been putting the date on each new globe as I replace a blown one.

I’m not very impressed with the results.

Cheers

We found a HUGE difference in how long the "cheap" fluro globes last compared to the brand ones (even with the much higher cost the name ones are better value)

Just a thought for those installing 12v systems at home. Waeco (and no doubt others) make large fridges now that are 12v. Are these more efficient than your domestic 240V running through your solar system? (Obviously if you already have the domestic one you'd run that until you update/replace it)

Of course this makes the wiring around the home a little more complicated because you would then need a 12v supply to the fridge area.

Then of course you could add a 12V microwave etc etc.

Just wondering if anyone has looked in to it. (And of course these are dearer to buy)

Hi cookiesa, if you are connected to the grid, 240 volt version in almost every type of device will be more efficient than 12v.

Furthermore gas fridges are not as efficient as 240vac but are more efficient than 12v.

If your not connected to the grid then there are different approaches available for some appliances.

BTW, microwave ovens can actually use huge amounts of power.

I asked someone about those heat pump hot water systems today. Apparently they use 1/4 the power of a similar conventional system. They cost around 2500 (after all rebates) and a normal system is about 1000.

Apparently they really give solar a run on total energy used, and don't cost anywhere near the same to install (if you have a existing conventional system).

Anyway, here is a question for the fridgies. We have a westinghouse fridge that's 10 years old. It still goes alright, but uses 900kw PA. Most equivalent fridges use about 500-600 now. Is it likely that it's using more as it gets older?

Originally Posted by cookiesa

We found a HUGE difference in how long the "cheap" fluro globes last compared to the brand ones (even with the much higher cost the name ones are better value)

Just a thought for those installing 12v systems at home. Waeco (and no doubt others) make large fridges now that are 12v. Are these more efficient than your domestic 240V running through your solar system? (Obviously if you already have the domestic one you'd run that until you update/replace it)

Of course this makes the wiring around the home a little more complicated because you would then need a 12v supply to the fridge area.

Then of course you could add a 12V microwave etc etc.

Just wondering if anyone has looked in to it. (And of course these are dearer to buy)

My experience, dating bulbs as they are installed, is that price is no indicator of durability - some cheap CF ones are still in use after fifteen years, some expensive ones lasted less than a year. None have been replaced because of low output, all have been sudden failures, one explosively.

Twelve volt appliances will automatically be more efficient by the efficiency of the inverter, which is probably from 80 - 95% (look at the detailed specifications - efficiency will vary quite a bit according to the power being drawn. But as well as this, 12v appliances tend to be designed to be more efficient as the market they are sold into is more efficiency conscious.
12v wiring is not as big a problem as you may think, partly because there is no requirement for it to be done by a licenced electrician. But if the cable run is any distance, the cost gets quite high, as the wiring will have to be very heavy compared to the similar circuits for example in a caravan where distances are a few metres, not tens of metres. The current for a microwave will be of the order of a hundred amps at 12v, and will require wiring heavier than welding cable, unless the battery bank is right next to the kitchen.

My assessment when designing our house was that the extra cost of 12v equipment would be better spent on increasing the size of the solar installation, so that there was a better choice of gear. But the answer may well be different for others.

John

Interesting post. That was my thought is that if you are planning a new house with the intention of solar etc then you may be better off by purchasing 12v appliances were practicle in the begining.

Most 12v appliances are very well insulated and efficient, as you mentioned.

My experience with sailing is that wind generators are good only if you have a reasonable storage capacity as the wind seems to be less consistent than the sun for charging. They are reasonable at putting a decent charge in when conditions are good though. Solar is probably easier to estimate and model to work out your useage/storage/charging needs for this sort of application but the wind would make a good additional source. (Obviously there would be modelling on this for most areas, local building codes can generally give some idea of local wind conditions seasonally)

Late last year I installed a wind generator as a trial to supplement the solar. This is sufficiently successful that I am planning a second one. What made it practical is the availability of cheap Chinese wind generators. It is rated at 200w, but it has given up to 20A at 28v, or almost three times its rated power.

In this area at least, it is complementary to the solar, as overcast often coincides with the passage of a front with strong winds.

John