Living offgrid with small solar system(s)

[George Harmony]

You can use 5watt led bulb.

Can a 10wp panel produce 50-60watt per day?? If so,put in paralel extra batteries for the longer life of the batteries. Or use 2x 7ah. Such batteries are not so expensive.

Edited February 26, 2016 by George Harmony

[Naam]

in 2015 i used up 39,000 kWh. 5 months peak consumption was ~4,000 kWh

a question for the learned offgrid, free energy, free distilled water solar eggsburts experts:

how many m² of photovoltaic panels do i need to go offgrid even during peak consumption months and what would be the total estimated cost including all accessory parts?

[IMHO]

You can use 5watt led bulb.

Can a 10wp panel produce 50-60watt per day?? If so,put in paralel extra batteries for the longer life of the batteries. Or use 2x 7ah. Such batteries are not so expensive.

How much charge you'll get into batteries from a 10Wh panel depends on several factors - weather, mounting location, wire length, cell quality, even the charger type (PWM or MPPT). It would be reasonable to assume 4-5 useful harvesting hours/day, and 20% losses - so 32Wh to 40Wh of actual battery charge on a sunny, cloudless day.

[IMHO]

in 2015 i used up 39,000 kWh. 5 months peak consumption was ~4,000 kWh

a question for the learned offgrid, free energy, free distilled water solar eggsburts experts:

how many m² of photovoltaic panels do i need to go offgrid even during peak consumption months and what would be the total estimated cost including all accessory parts?

Here's some simple ballpark math for on-grid:

Assumptions:

4.5 hours harvesting/day

10% losses for grid tie

50 Baht/Wh installed price

Math:

In order to make 4,000 kWh in 30 days, you need to make 133kWh/day, which in 4.5 hours of sun means 30kW/hr. Add 10% to cover inefficiency and that's 33kW/hr

33,000 x 50 Baht = 1.65M Baht.

Note: that's an awful lot of panels (110 units of 300w PV, which are roughly 2M x 1M in size each).

For off-grid batteries, use the following assumptions:

Depth of discharge: 20%

Days of Autonomy: 2

Cost for lead acid: 3 Baht/Wh

133KwH x 5 (for DOD) is 665kWh x2 (for 2 days autonomy) = 1,330,000 Wh x 3 Baht = 4M Baht.

You'll need 10% more panels to charge them than the on-grid numbers above, plus you'll need multiple chargers, big DC wiring, and several banks of parallel inverters.

Gut feel, about 6.5M Baht.

Edited February 26, 2016 by IMHO

[Muhendis]

in 2015 i used up 39,000 kWh. 5 months peak consumption was ~4,000 kWh

a question for the learned offgrid, free energy, free distilled water solar eggsburts experts:

how many m² of photovoltaic panels do i need to go offgrid even during peak consumption months and what would be the total estimated cost including all accessory parts?

Here's some simple ballpark math for on-grid:

Assumptions:

4.5 hours harvesting/day

10% losses for grid tie

50 Baht/Wh installed price

Math:

In order to make 4,000 kWh in 30 days, you need to make 133kWh/day, which in 4.5 hours of sun means 30kW/hr. Add 10% to cover inefficiency and that's 33kW/hr

33,000 x 50 Baht = 1.65M Baht.

Note: that's an awful lot of panels (110 units of 300w PV, which are roughly 2M x 1M in size each).

For off-grid batteries, use the following assumptions:

Depth of discharge: 20%

Days of Autonomy: 2

Cost for lead acid: 3 Baht/Wh

133KwH x 5 (for DOD) is 665kWh x2 (for 2 days autonomy) = 1,330,000 Wh x 3 Baht = 4M Baht.

You'll need 10% more panels to charge them than the on-grid numbers above, plus you'll need multiple chargers, big DC wiring, and several banks of parallel inverters.

Gut feel, about 6.5M Baht.

Hey IMHO come and see me. I can do it for 2/3 of your price..........

Edited February 26, 2016 by Muhendis

[Lantern]

Lived off grid between 1985 and 2005.

Lots of good info here

rpc.com.au

[BKKdreaming]

Question:

can you make a 220v refrigerator or window air conditioner run on 12 volt by changing the motor that drives the compressor to a 12v motor and the fan to a 12v fan ?

Yeah maybe have to change some relays and small stuff , but use the basic "box" that holds the lines , coolent , evaporator etc

Just wondering if we are trying to re-invent the wheel ?

[IMHO]

in 2015 i used up 39,000 kWh. 5 months peak consumption was ~4,000 kWh

a question for the learned offgrid, free energy, free distilled water solar eggsburts experts:

how many m² of photovoltaic panels do i need to go offgrid even during peak consumption months and what would be the total estimated cost including all accessory parts?

Here's some simple ballpark math for on-grid:

Assumptions:

4.5 hours harvesting/day

10% losses for grid tie

50 Baht/Wh installed price

Math:

In order to make 4,000 kWh in 30 days, you need to make 133kWh/day, which in 4.5 hours of sun means 30kW/hr. Add 10% to cover inefficiency and that's 33kW/hr

33,000 x 50 Baht = 1.65M Baht.

Note: that's an awful lot of panels (110 units of 300w PV, which are roughly 2M x 1M in size each).

For off-grid batteries, use the following assumptions:

Depth of discharge: 20%

Days of Autonomy: 2

Cost for lead acid: 3 Baht/Wh

133KwH x 5 (for DOD) is 665kWh x2 (for 2 days autonomy) = 1,330,000 Wh x 3 Baht = 4M Baht.

You'll need 10% more panels to charge them than the on-grid numbers above, plus you'll need multiple chargers, big DC wiring, and several banks of parallel inverters.

Gut feel, about 6.5M Baht.

Hey IMHO come and see me. I can do it for 2/3 of your price..........

2/3rd of this price is just the batteries - the only way you're doing it cheaper is with less days of autonomy (i.e. your system won't still power the house after a few cloudy days) or you're pushing up the DOD and costing the client a new bank of batteries more regularly

Anyone can do it cheaper... but it will be a false economy if you're changing batteries more regularly.

Seeing as you've got this system figured out though, I'm curious how you'd configure the battery bank(s) The most I can get into one bank is 96x 2V/400Ah - so it would take 9 or 10 separate banks - which also means 9-10 sets of inverters and 9-10 solar chargers. Wow.

In short, it's just a hypothetical system anyway... it's not workable.

Edited February 27, 2016 by IMHO

[IMHO]

Question:

can you make a 220v refrigerator or window air conditioner run on 12 volt by changing the motor that drives the compressor to a 12v motor and the fan to a 12v fan ?

Yeah maybe have to change some relays and small stuff , but use the basic "box" that holds the lines , coolent , evaporator etc

Just wondering if we are trying to re-invent the wheel ?

It's possible, yes, but you're probably just better off buying a more energy efficient fridge, and taking the 10-15% inverter hit. Most fridges use induction motors - you're not improving upon the energy usage of that by going DC, even if using $$$$ brushless motors.

Edited February 27, 2016 by IMHO

[Muhendis]

Getting back to the FLA batteries. There was an earlier question raised about the validity of some desulfation gadgets which I am a bit skeptical about. I've had another look at a few web sites and found this one

http://www.reuk.co.uk/Battery-Desulfation.htm

which seems to be full of really good information and is quite convincing. I feel tempted to take the plunge. Do any of you other guys have any experiences with this pulse desulfation technique?

[George Harmony]

My opinion is that if one decides to go offgrid one perhaps have to adjust the loads. For example replacing desktop to laptop. Using low consumption appliances like fridge/freezer of 30watt.

It seems that there are coffeemakers of 600watts+ but also from 150-300watt.

Using led lamps etc..etc..

Attached pict is a 3watt ledtube on my terrace. Its outside it looks not so bright. Inside though its enough for one small room.

Added:

Forgot to mention, 2nd pict taken when there was power outage in the area.

Edited February 27, 2016 by George Harmony

[Jing Joe]

1. it would be interesting to see a 12v Air conditioning set-up with auto parts for a room ,

2. again has anyone done it ?

3. how much temperature drop do you get

4. and does it cut the humidity too

1. the principle and the required parts are the same like a conventional split unit except that the compressor is belt driven by an electric motor,

2. yes i did many rainy seasons ago in the African bush,

3. depending on compressor size and power supply the same like a conventional unit,

4. of course!

When you guys get an A/C going, don't dismiss the potential to use the condensate derived from the humidity in bold above.

I've measured the TDS Total Dissolved solids as near zero and its drinkable in that respect.

No hormones or pesticides from rivers or dams that aren't filtered out with reverse osmosis filters as with in-home or vending machines.

It's the same principle as natures dew and just need to keep the A/C clean and free from dust.

No mozzie fogging nearby lately?

Cover the bucket with a lid with a hole for the tube for extra cleanliness.

At the very least is good for car battery water and car radiators.

Here in Oz they were selling machines to produce pure drinking water using exactly the same refrigerant principle.

Not real good in dry climate.

Is there cheap water-quality lab testing for bacteria near you? Probably not applicable anyway.

Free solar power, free hot water, free pure water. Good luck.

I think I'd probably want to give it a very big dose of UV irradiation before I drank it

Hi to IMHO, Yes some thoughts could go to this if one is really not trusting, BUT a small Ozone producer with a fish tank bubbler is often used as an alternative in the industry.

Good part of this is that within hours, two molecules of O3 break down into three molecules of O2, so the water becomes quite oxygenated.

In the pure water industry its a reality that when shining UV through/into water, any pollutant particles that might happen to be in it, can shield some water molecules from UV exposure.

If you weigh up the possible impurity of BKK home filtered water Vs air condensate from A/C, I would go for the latter any time.

And as suggested before;- a lab test would satisfy any lingering doubts.

BTW the question is often raised; why not drink the minerals in water? You need to drink incredible amounts to get much calcium from any calcium-carbonate compound in that water just as one example.

They are not so bio available to humans as believed yet irrigate veges with it and they DO produce the pure minerals from the compounded minerals in that water.

Edited February 27, 2016 by Jing Joe

[Jing Joe]

Hi folks.

There's a general consensus that minimum of two horsepower is needed for auto A/con.

That's 2hp x 746 watts and is designed for the interior size of the vehicle and surely a bit in reserve.

So any good imagination of using an electric motor to run one needs a rethink?

So again we need to do the sums.

And even with the smallest domestic Air-con; do the sums.

It's hot right now and I'm using just a fan and getting bye.

[Naam]

comparing automotive and conventional airconditioning requires to observe several huge differences:

1. the heat load/transfer per size of a car from ambient temperature and radiation is a multiple of a room in a home.

2. conventional compressors are either on or off (if not an inverter) drawing heavy amps at start.

3. a belt driven automotive compressor renders a variable cooling capacity depending on rpm. the starting amps are

negligible and based on the selection of an optimal transmission (pulleys) and electric motor.

[Jing Joe]

My opinion is that if one decides to go offgrid one perhaps have to adjust the loads. For example replacing desktop to laptop. Using low consumption appliances like fridge/freezer of 30watt.

It seems that there are coffeemakers of 600watts+ but also from 150-300watt.

Using led lamps etc..etc..

Attached pict is a 3watt ledtube on my terrace. Its outside it looks not so bright. Inside though its enough for one small room.

Added:

Forgot to mention, 2nd pict taken when there was power outage in the area.

Well done enthusiastic George.

I lived for many years with DC incandescent bulbs but now almost exclusively LED's.

Their low power and brightness allows a better coverage distribution with more of them in the home.

Comparing the few old lamps Vs new LED now is astounding, just with the flick of two switches.

Those LED in strips are a little power hungry in the whole roll, but at least can be cut to shorter lengths and then are economical.

Great for concealed lighting, The double sided tape on the back is not great so rip it off and silicon it wherever?

They are not all that robust so be careful or else some sectors will die.

Terminate 12v to them by cutting the silicon top side carefully, then carefully scraping clean down to the copper cct. and carefully soldering small speaker wire, noting the correct polarity. They wont damage if incorrect. A short bit of heat shrink tube stops twisting and possibly shorting.

Edited February 27, 2016 by Jing Joe

[Naam]

in 2015 i used up 39,000 kWh. 5 months peak consumption was ~4,000 kWh

a question for the learned offgrid, free energy, free distilled water solar eggsburts experts:

how many m² of photovoltaic panels do i need to go offgrid even during peak consumption months and what would be the total estimated cost including all accessory parts?

Here's some simple ballpark math for on-grid:

Assumptions:

4.5 hours harvesting/day

10% losses for grid tie

50 Baht/Wh installed price

Math:

In order to make 4,000 kWh in 30 days, you need to make 133kWh/day, which in 4.5 hours of sun means 30kW/hr. Add 10% to cover inefficiency and that's 33kW/hr

33,000 x 50 Baht = 1.65M Baht.

Note: that's an awful lot of panels (110 units of 300w PV, which are roughly 2M x 1M in size each).

For off-grid batteries, use the following assumptions:

Depth of discharge: 20%

Days of Autonomy: 2

Cost for lead acid: 3 Baht/Wh

133KwH x 5 (for DOD) is 665kWh x2 (for 2 days autonomy) = 1,330,000 Wh x 3 Baht = 4M Baht.

You'll need 10% more panels to charge them than the on-grid numbers above, plus you'll need multiple chargers, big DC wiring, and several banks of parallel inverters.

Gut feel, about 6.5M Baht.

Hey IMHO come and see me. I can do it for 2/3 of your price..........

three years ago i calculated ~8.8 million Baht which would have saved me 200,000 Baht p.a., i.e. return on investment 2.27% assuming a stable electricity price.

even in the present economic environment i claim to achieve this 2.27% yield p.a. relying exclusively on the investment advice of my two dogs

addendum: 2/3 of 6.5mm Baht = 4.333mm, yield 4.62% = not satisfactory.

[Naam]

Getting back to the FLA batteries. There was an earlier question raised about the validity of some desulfation gadgets which I am a bit skeptical about. I've had another look at a few web sites and found this one

http://www.reuk.co.uk/Battery-Desulfation.htm

which seems to be full of really good information and is quite convincing. I feel tempted to take the plunge. Do any of you other guys have any experiences with this pulse desulfation technique?

i read about it but have no experience.

[George Harmony]

If possible its perhaps interesting to hear others who are offgrid. Not the technical part of their system but "what do you load out of the system?"

How big if your system and what can you do with it.

How many lamps are burning on an average evening and the type of lamps?

Do you use a solar powered waterpump?

Do you use a fridge?

Etc. Etc..

Many youtubes vid shows the incoming voltages/amps/current and how they connect the system. Not so much shows the actual loads of an offgrid house.

Edited February 27, 2016 by George Harmony

[Naam]

Do you use a fridge?

[George Harmony]

With my current system of 80wp no, not yet a fridge. Fruits and vegetables in a sort of evaporate fridge.

@naam,

If i ran that 260watt ac for lets say 2hours, how can i also cool a kind of a coolbox with that ac?? Or do i have another rubbish idea....

[Naam]

With my current system of 80wp no, not yet a fridge. Fruits and vegetables in a sort of evaporate fridge.

@naam,

If i ran that 260watt ac for lets say 2hours, how can i also cool a kind of a coolbox with that ac?? Or do i have another rubbish idea....

yes you can, your idea is not rubbish! it takes of course a little additional "engineering" such as a few meters of 50mm flexhose to and from the a/c unit. but estimated temp in coolbox not lower than 10-12ºC.

[Jing Joe]

Hi folks and Naam especially if you are contemplating setting up?,

Don't know if anyone noticed my comment to watch the angle of panels in relation to summer sun angle?

If set too high thinking to "harvest" (like that word) winter sun if you have such in LOS, watch out for the sun falling on the back of the panels from sun up to about 9am and 3pm to sundown. You may be loosing out when you think it should be super.

Of course it depends on latitude.

Just make sure the brackets are an easily adjustable design.

[Naam]

Naam especially if you are contemplating setting up?

going photovoltaic solar? no way, and that for a number of reasons. i use solar to produce hot water for my pool but i missed the chance to generate centrally hot water for bathrooms and kitchens because the panels i am using were not available. i also use 4 systems (grid charged batteries > inverter) to provide uninterrupted power supply for house water supply, TVs, computers and a microwave when one or more phases are low voltage or off completely.

and should grid power supply become very unreliable, my plans are ready to install a genset that can handle at least two thirds of my average load.

[George Harmony]

With my current system of 80wp no, not yet a fridge. Fruits and vegetables in a sort of evaporate fridge.

@naam,

If i ran that 260watt ac for lets say 2hours, how can i also cool a kind of a coolbox with that ac?? Or do i have another rubbish idea....

yes you can, your idea is not rubbish! it takes of course a little additional "engineering" such as a few meters of 50mm flexhose to and from the a/c unit. but estimated temp in coolbox not lower than 10-12ºC.

Thanks for your reply. For for example meat ive heard you need continiously 4c inside your fridge or coolbox. Perhaps i will try later this setup with no power

[Naam]

With my current system of 80wp no, not yet a fridge. Fruits and vegetables in a sort of evaporate fridge.

@naam,

If i ran that 260watt ac for lets say 2hours, how can i also cool a kind of a coolbox with that ac?? Or do i have another rubbish idea....

yes you can, your idea is not rubbish! it takes of course a little additional "engineering" such as a few meters of 50mm flexhose to and from the a/c unit. but estimated temp in coolbox not lower than 10-12ºC.

Thanks for your reply. For for example meat ive heard you need continiously 4c inside your fridge or coolbox. Perhaps i will try later this setup with no power

calling this idea rubbish would mean insulting honest rubbish.

[George Harmony]

Don't know if anyone noticed my comment to watch the angle of panels in relation to summer sun angle?

If set too high thinking to "harvest" (like that word) winter smile.pngsun if you have such in LOS, watch out for the sun falling on the back of the panels from sun up to about 9am and 3pm to sundown. You may be loosing out when you think it should be super.

Of course it depends on latitude.

Just make sure the brackets are an easily adjustable design.

@jingjoe

About charging with solar panels

This is perhaps also a good idea to connect a step-up-down module betweeen a solar panel and the chargecontroller. As i understand well a battery will only be charged when the incoming voltage is around 2 volt higher than the battery voltage. A step-up-down module with constant output of e.g. 14volt will charge the battery even when the incoming voltage is below the battery voltage. I tried the lm2577 module with a small panel and it works ok

Edited February 27, 2016 by George Harmony

[Jing Joe]

Don't know if anyone noticed my comment to watch the angle of panels in relation to summer sun angle?

If set too high thinking to "harvest" (like that word) winter (smile), if you have winter in LOS, watch out for the sun falling on the back of the panels from sun up to about 9am and 3pm to sundown. You may be loosing out when you think it should be super.

Of course it depends on latitude.

Just make sure the brackets are an easily adjustable design.

@jingjoe

About charging with solar panels

This is perhaps also a good idea to connect a step-up-down module between a solar panel and the charge controller. As i understand well a battery will only be charged when the incoming voltage is around 2 volt higher than the battery voltage. A step-up-down module with constant output of e.g. 14volt will charge the battery even when the incoming voltage is below the battery voltage. I tried the lm2577 module with a small panel and it works ok

I had forgotten to mention my regulator is just that; an electronic voltage "tracking" design which is pretty much how you described it George.

The tech at that company reminded me about all the power I had been missing out on for years before using their model.

It had previously been a PL30 I think, which was small but did have great readout capabilities, but not tracking.

I had also suggested checking out for the panels that have more than usual number of cells and therefore produce higher open circuit voltages. You need to read their design specs and compare but they are around.

My two latest generation 24 v cells in series have just this and under some weather conditions produce 25% of the power of the other 24 cells.

They even produce some power in cloudy conditions and in light rain when the older gen are beyond/below the benefit of the tracking regulator..

Edited February 27, 2016 by Jing Joe

[George Harmony]

@naam wrote about my fridge idea

[qoute]calling this idea rubbish would mean insulting honest rubbish.

Last try about fridge and cooling. If im able to produce ice its sure that i can use coolbox as a fridge.

How about cooling a room. Just blow with a fan from inside another coolbox with ice into the room. Will my small living room be colder or can i lower the temp of a 4x4m room?

[Naam]

@naam wrote about my fridge idea

[qoute]calling this idea rubbish would mean insulting honest rubbish.

Last try about fridge and cooling. If im able to produce ice its sure that i can use coolbox as a fridge.

How about cooling a room. Just blow with a fan from inside another coolbox with ice into the room. Will my small living room be colder or can i lower the temp of a 4x4m room?

it is a no-brainer to cool your living room to an even uncomfortable low temperature. all what you need is a BIG coolbox (2x2x2m), a few tons of ice cubes and several industrial grade big fans.

but make sure that the water of the melting ice can drain.

[George Harmony]

Hahahaha....understand.