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Forum Index : Solar : It has begun

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readyakira

Senior Member

Joined: 17/07/2008
Location: United States
Posts: 114
Posted: 11:33pm 07 May 2010
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So, it has been a while since I posted here. I have had a lawnmower that every time I wanted to use my lawn mower I had to jump the battery. Every season I had to buy a new battery and mid season I would have to start jumping the mower. So I had a little extra money and made a few cheesey purchases. I bought this charge controller http://www.harborfreight.com/7-amp-solar-charge-regulator-96 728.html and this panel http://www.northerntool.com/shop/tools/product_200263174_200 263174 I figured this would keep those batteries charged and maybe last longer. So anyways after 1 day in the sun the lawnmower battery had plenty of getupandgo to start the mower(which has always been hard to start) and I was slightly impressed.

So, I have this van I am building as a toy and the battery has been sitting in the back for a year now and half dead at 9.2v so I hooked the setup to it, and left it there a day. At first I figued I would top the battery off and put it back in the van, but something hit me in the head lie a brick. "why not power some lights in the ouse with it." So, I took the battery in the house along with my Power Inverter http://www.cobra.com/products//cpi-1550-1500-watt-power-inve rter And plugged in my CFL lamp and used it all night! Wow! So, now I am hooked. I now It was just a CFL bulb 13w 110v but it was nice to have free light fo a night. So I think I will continue to buy panels when I can afford them.

Now, I have numerous questions. First when a panel is rated at 15w, is that like 15w per hour? And my electric bill says last month I used 41kw per day so that is about 2kw an hour....???? and I would need approx 2.5kw of panels to become off grid? which whould mean I would need what in amp/hour batteries to be off grid?

My long term goal is of course to be off grid. I do not have the cash to dish out 5k for a system so I would have to build it myself for the most part pc by pc. So I fugre to first start collecting panels. So, if my math is correct, if I use 41kw a day I need to be able to charge at the very least 142amps at 12v??? this of course does not take into effect that I can't charge at night so I figure that would be a start. Which also means that i need how much more in battery power to accomodate for high watt useage hours, and how much more for times available for charging.

Which brings me to my next question. Panel wise, what is my best way to start buying panels? Should I get the amorphious type so they charge in cloudy days? or the blue crystaly types? I am new here to this type, but I don't remember anything the really gives a cheap way to start for a guy like me. I can prob come up with about $150 a month to put towards this. And I figure as I go things should get a bit easier.

Also battery wise I guess phone co batteries are te best but how in the states am I gonna aqquire those... anyone in the states worked on this problem?Edited by Gizmo 2010-05-09
Don't you think Free/Renewable energy should be mandatory in new buildings?
 
readyakira

Senior Member

Joined: 17/07/2008
Location: United States
Posts: 114
Posted: 11:47pm 07 May 2010
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well somehow I screwed up the links and cant seem to figure it out. if a mod can fix my post I would appreciate it.
Don't you think Free/Renewable energy should be mandatory in new buildings?
 
Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5019
Posted: 01:27am 08 May 2010
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Fixed the links for you.

Yeah your right about the amps and amp/hour ratings. A 15 watt panel, in full sunlight for one hour, can make 15AH.

Working out how many panels you need depends on how much full sunlight you get. If you use 2kw per hour, then a 2.5kw panel will cover it, while the sun is out. If you only get 8 to 10 hours of full sun per day, then you will need closer to 10kw of panels and a bettery bank to supply your needs for a full 24h day.

That will be expensive. But the trick is to use less electricity, and therefore spend less on solar panels. Simple things like converting to fluro lights, turning off applicances at the wall, not having a 2nd fridge, can save you half your daily power needs.

Glenn


The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ
 
AMUN-RA

Senior Member

Joined: 10/03/2007
Location: Australia
Posts: 144
Posted: 03:29am 08 May 2010
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Gizmo
A 15 watt panel, in full sunlight for one hour, can make 15Wh or .8 AH ???

Every day the sun shines
& gravity sucks= free energy.
 
KarlJ

Guru

Joined: 19/05/2008
Location: Australia
Posts: 1178
Posted: 03:37am 08 May 2010
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Indeed
Buy yourself an energy meter from ebay, I just got one for $50 AUD
they claim you can easily reduce your bill by 20%.

I have used the single outlet types and found some interesting conclusions
-dishwasher uses 1KW even on an "eco" wash, thats alot of juice!
-clothes washer doesnt use much only 100-150W for mine depending on load size.
forget the drier -hang them up on an airer inside or outside if the weather is good.

Throw away all your downlights (50W each starts adding up quickly) replace with LED
3x3W (ie 9W each) CREE's are about $30 each here in Aus, so not disgustingly expensive.
or just get a light that faces up to the ceiling, throw in a 20W CFL and get about the same light as 200W of downlights.

Solar hot water is a BIG energy saver -probably 10KW a day or more being wasted there.

dribs and drabs of different panels here and there is going to be a nightmare with poor to average efficiency at best.

Better to spend your money as Gizmo suggested, getting that power bill down to 16KW/day first. (an allegedly Australian Household)
Luck favours the well prepared
 
VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 03:52am 08 May 2010
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Hi Ready

You are beginning to see the light, and Gizmo,s comment on its easier to save it than generate is a very valid point.
I have a 1000 watt PV cell grid feed unit that reduced my power consumption by $150 a quarter also put a solar hot water system on and that saved 10 kw a day so that is a saving of another $180 on the bill. The old fridge went next as the old one was using to much power, 6kw a day and the new high efficiency one uses less than two kw per day and I use a combination of fluro and led lighting, but that has only reduced the bill by $10 a quarter, by turning off the television and associated things at the wall makes 500 watt per day not much but it all adds up as the 500 watts a day equals the output of a 100 watt panel.

It does work well as long as you are aware of what is happening in the system.
Even the 500 watt a day adds up to 180 kw a year $32 but when all is added together it allows you to fund a bigger and better system that will save more and after a couple of years you can be semi independant of the utilities.

Get yourself one of those little power meters from ebay or an electronic shop and see what each appliance is using so you can prioritize the high usage units.

All the best

Bob
Foolin Around
 
Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5019
Posted: 04:05am 08 May 2010
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Yeah Karls spot on.

From a purely financial point of view, if your already grid connected, the best way to save money is to become more energy efficient around the home.

Its a lot easier than you think, and those energy meters can give you some real usefull data. This page might give you an idea how much can be saved just buy turning applicances off at the wall http://www.thebackshed.com/windmill/articles/EcoSwitch.asp. I swear by the eco-switch idea, and have one on my PC and my entertainment system. When I go to bed or work, the only thing drawing power at my place is my single fridge and the hot water service. My next place will have a solar hot water service.

You should be able to reduce your power bill by half without noticing it in your day to day life, except for the fact you turn switches off more often and maybe wash the dishes by hand now and then. Once you become more energy efficient, have a look at your daily power usage figures again and you'll find a solar power installation a lot more affordable.

Glenn


The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ
 
AMUN-RA

Senior Member

Joined: 10/03/2007
Location: Australia
Posts: 144
Posted: 06:33am 08 May 2010
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Average australian household 2 adults 3 daughters teenage, pool, air cons,-90days &

2kw of solar I just paid our summer electricity bill $964.05

should I get rid of the wife an kids??????? Average over 50kwh per day over summer
Every day the sun shines
& gravity sucks= free energy.
 
AMUN-RA

Senior Member

Joined: 10/03/2007
Location: Australia
Posts: 144
Posted: 06:37am 08 May 2010
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ready in the states try the outback forum lots of good gear and many people off grid or grid connected http://www.outbackpower.com/ mick
Every day the sun shines
& gravity sucks= free energy.
 
KarlJ

Guru

Joined: 19/05/2008
Location: Australia
Posts: 1178
Posted: 10:00am 08 May 2010
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amun-ra.
That bill is BS high, start training them. and helping them
Close doors/ windows hot days, open up at night when cooler outside etc etc

Get down to Bunnings buy an electronic 12 event timer. ($22)
put this on the solar hot water for the pool.

At the moment you have a differential temp controller, few degrees higher on the roof and wham on it goes. NO GOOD wasteful....

Set the timer so that at 11am on 5 mins 11:30am on 5 mins
11:50am on 10 mins 12:15 on 10mins 12:40 on 10 mins.
etc until you have a reasonable spread, obviously more off time outside peak sun hours
to allow the roof and pipe to warm up.

Just saved you 4KW running that pump now less about 1hr from 5hrs.
Best bit -make no difference perhaps even better than before.... and as the temp controller is still there -pump wont turn on unless temp diff still there.

Get an ioniser for the pool cost about $800, drop normal run times from 8 back to 6 hrs
salt chlorinator =300W +pump. gone.....ioniser perhaps 30W and bonus 1/10 the chlorine required to keep the pool safe.

just saved you 1.5KWx 2 hrs run time + 220Wx8 hrs =total 4.6 +4

Just knocked off 8.6 KW / day off your bill -or you could get ANOTHER 1.5KW solar system for what $8K.....bullsh*t! a $22 timer has saved you $4K......

As for the aircon, get evap, run it 5 days run the aircon the other 2 days, keeps the house dryer and when its stinking hot evap just dont cut it.

Cost 5KW/hr Aircon $1+ per hour
cost 300W/hr = less than $0.50 per DAY....
cost about $5K installed to 11 points (big house)

or a handful of ceiling fans -costs almost nothing to run those

mmmm that just saved you another 20KW or so
(or another 4KW of solar panels call it $18K for that kit)

Down to about 21KW day now bro...

Weather sealing rubber -seal up all external doors for about $20, save you a fortune!
could theoretically save that $20 every month!!!!!!!!!

get cracking world is warming while u wait.

Prev owner of my place $750 every 2 months and $1000 every 2 months for the 4 months over Christmas!!!!!!!!!!

I just aint paying for that hence I've either done all of the above or working on it.
Luck favours the well prepared
 
KarlJ

Guru

Joined: 19/05/2008
Location: Australia
Posts: 1178
Posted: 10:24am 08 May 2010
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Oh and in the mean time Aircon set no lower than 25degrees
and Heating set no higher than 17 degrees

both of these are well within comfortable limits.

My mum sets her heating in Melbourne to come on at 12deg
and that is NOT comfortable!!!

Karl
Luck favours the well prepared
 
AMUN-RA

Senior Member

Joined: 10/03/2007
Location: Australia
Posts: 144
Posted: 01:12pm 08 May 2010
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Townsville doesn't get cooler at night, pool is not heated runs for 6 h per night only
air con set for 25 evaps (swampy's) dont work in townsville summer humidity too high already just dont cut it got that part right this is a common type of bill for average townsville home in summer wish there was an easy answer Had my home checked for a green loan they told me my home is the best it can be and told me to buy a new beer fridge as the one I have is too old ????
Every day the sun shines
& gravity sucks= free energy.
 
KarlJ

Guru

Joined: 19/05/2008
Location: Australia
Posts: 1178
Posted: 03:12pm 08 May 2010
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mmmm Townsville
I have lived in Cairns, Mereeba and up on Horn Island real hot up there.

do you live in the dark? I find that helps too..

roof vents, better than good insulation ie batts 200mm thick is about R3.5
mandatory i'd think.

Mate in Darwin runs fans during the day and aircon at nights. saves him a few bob.

I doo see the problem in really hot humid places though.

small high efficiency split system aircons use less than fully ducted jobs but if one is there tough to justify spending the money again.

Looks like less hungry appliances is the go, trade in the plasma heater for an LED tv
at about 1/4 the consumption for same size.

throw away PC's are replace with laptops when they reach end of life.

If there are any halogen downlights get rid of those ASAP, not only inefficient but cant insulate around them either and they get bloody hot. so double whammy when you're trying to aircon the place.

more panels........can be done for about $6K/kw fully installed these days and 1.5 is worth about $8K.


Luck favours the well prepared
 
readyakira

Senior Member

Joined: 17/07/2008
Location: United States
Posts: 114
Posted: 02:55am 11 May 2010
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So, back on my topic. I am trying to do math and I am not sure of the power consumption of these 12v lights but it cant be much as a lawnmower battery is powering these 2 lights for 5hrs now and the voltage with no charge being applied has only dropped from 12.1 (with load) to 11.9 (also still with load). I am hoping to build a system that can at least power a few more lights, a small fan, and a fridge. I would only power the fridge for the time being when the power goes out. and season for that is fast approaching. I believe my fridge draws about (going by exp with others I work with) 2amp running and 15-19amp startup. Most fridges cycle on and off every 15min. problem becomes when the fridge goes into defrost the heater tends to draw abaout 1500w.
Don't you think Free/Renewable energy should be mandatory in new buildings?
 
VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 04:39am 11 May 2010
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Hi Ready

From what you are describing it will take a fairly large system, what power are you on now? I am assuming 110 volts as you are USA and also by the fridge current you mention.

A fridge is one of the biggest power consumers you are using 220 watts to run yours according to those figures,the start current isnt so important in the power consumption calculation as it is only for a couple of seconds but it is hard on the inverter, you would need a 2500 watt inverter to start it reliability. Preferably a 3500 watt unit so you can run a few other small appliances as well.

Battery bank would need to be at least 24 volt 500 amp hour capacity to run that inverter. Solar panels would need to be 400 watt for the fridge. For each other appliance you want to run add another 200 watt solar panel {small lcd TV, toaster, microwave, washing machine, fan. computer) still requires a sensible use approach as in not to much on at the one time and switch off whats not nessesary.

You will need a dump load device to stop your batteries getting overcharged there are several on ebay and that can be put into the hot water system to help heat it up
A good MPPT regulator will help get the best out of your panels as well.

I have found that you can switch of the fridge for six hours overnight as long it isn't opened, Put a couple of water bottles in the freezer section as well. I have used one of those little timers that you can program for time to do it, make sure if you go that way that the timer is rated at 10 amps.

Lights is the easy part, you can purchase led lights on ebay at 10 units for $150 enough for a small house they are 12 volt 5 watt units, so 1 battery 12 volt and 2 80 watt panels will run that including a small pressure pump( 12 volt for water). The battery would need to be at least 100 ah rating.

If you are planning to use the off grid system full time as the price of power increases you may look at replacing the fridge with a more efficient one as the new ones now operate on a lot less power. It could save the cost of a solar panel and that helps pay for the new fridge. My new one uses 1600 watts a day and the old one used 4000 watts a day. That made a panel reduction from 4 to 2 panels required to power it.

If you are in a windy area you could use a wind turbine as a help but always allow for enough solar panels to cover your basic needs. A small generator as battery charger is a good idea and easily made from a few bits and pieces at the local wrecker.

You may consider the use of grid feed inverter if that is practical.

Hope that's been some help

All the best

Bob
Foolin Around
 
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