Living offgrid with small solar system(s)

[Naam]

goodness gracious gentlemen!

for starters some good ideas/theories but then going overboard, enthusiastically mentioning specific parts which are absoeffingluteless useless plus the icing on the cake when the lame jumps in to carry the blind, respectively the blind starts leading the lame.

where you are now i was decades ago. not only in theory but also by experimenting. so if you want some input from me please start from the scratch, specify your demands, hit the enter button to create paragraphs instead of creating a chaos.

if not, i will just lurk and perhaps make some sarcastic comments once in a while.

[Jing Joe]

goodness gracious gentlemen!

for starters some good ideas/theories but then going overboard, enthusiastically mentioning specific parts which are absoeffingluteless useless plus the icing on the cake when the lame jumps in to carry the blind, respectively the blind starts leading the lame.

where you are now i was decades ago. not only in theory but also by experimenting. so if you want some input from me please start from the scratch, specify your demands, hit the enter button to create paragraphs instead of creating a chaos.

if not, i will just lurk and perhaps make some sarcastic comments once in a while.

Thank you Naam for your gentlemanly guidance to date and that you also recognize we others who have contributed as being "gentlemen" as above. It really has been a respectful and gentlemanly six-page sharing so far.

No smiles in your offer of more guidance above so we can sadly and surprisingly assume you were serious about our "chaos".

We all have to start somewhere so please forgive us; the blind and the lame, and maybe you could graciously allow us to catch up to your experience "in theory and experimenting".

"Those (of us) who have never made a mistake have never made anything" comes to mind.

There is an acceptance in "brain storming" exercises that all inputs are welcome and no one is ridiculed or treated sarcastically.

Could you instead patiently "lurk" but with a smile, and if so inclined offer the positive encouragement that we have so-far felt the benefit of please?

Peace

[Muhendis]

Jing Joe. Dropping a coil of plastic pipe down a bore hole is not possible since the hole is likely only 100mm diameter and there are already some pipes taking up space. The pipe for this task would need to be heat conductive (so plastic is not the best choice) and small enough in diameter to get into the bore hole and back without getting in the way of the existing water pipes. Stainless is the best choice.

Lurkio. Wouldn't want you to change the habit of a life time so keep up the good work..........

[George Harmony]

Muhendis wrote:

A better way is to use the cold water as it naturally is from your underground source. It would need some plumbing skills and a lot of enthusiasm.

This was my simple idea in another subject. If one think logic,why not using what nature offers. @jingjoe gave also valueable tips but @naam seems to be septical about this.

Underground is colder and undeground water is cool(er). Must be a way to cool a space above the ground, not like what an aircon can offer but few degrees cooler and then using fans is and feels cooler.

If can reach 25-26 inside when its very hot at noon, im very happy. Now already the case that during the day its cooler than outside but stil not enough. I even can sprinkle my roof.

Thanks for the tips. I will try to work out something soon.

Edited February 29, 2016 by George Harmony

[Naam]

Muhendis wrote:

A better way is to use the cold water as it naturally is from your underground source. It would need some plumbing skills and a lot of enthusiasm.

This was my simple idea in another subject. If one think logic,why not using what nature offers. @jingjoe gave also valueable tips but @naam seems to be septical about this.

Underground is colder and undeground water is cool(er). Must be a way to cool a space above the ground, not like what an aircon can offer but few degrees cooler and then using fans is and feels cooler.

If can reach 25-26 inside when its very hot at noon, im very happy. Now already the case that during the day its cooler than outside but stil not enough. I even can sprinkle my roof.

Thanks for the tips. I will try to work out something soon.

groundwater is the best choice, i was not skeptical concerning the principle but about "how to use", e.g. the parts used to act as heat exchanger have to be highly conductive. forget PVC or any other plastic material!

i have an 18-22ºC water source that would be temperature wise perfect but useless because of a highly corrosive low pH between 4.8 and 5.2.

[Naam]

lurk... lurk..., smile... smile...

[George Harmony]

Permit me to ask again about batteries. Ive read about a desulfator, only about 900bht. According to the supplier you can connect it also continiously. Will it work?

FUNCTION

The High-frequency Peak Pulse delivers an electronically controlled pulse to the battery causing crystalline sulfates to dissolve back into the electrolyte and so restoring battery function and electrolyte strength regaining the batteries ability to receive charging current and deliver discharge current.

ADVANCED TECHNOLOGY

Many desulfator products use an old technology inductor design to generate the pulse to desulfate a battery. This old technology creates a harsh inductor peak that can be damaging to the battery plates.

NEW CYCLIC PULSING FUNCTION

In a similar manner to a Pulse battery charger (charge rest charge rest etc) a cyclic desulfating pulse function (pulse rest pulse rest etc) optimizes a batteries recovery process. This method of desulfation has been implemented in the new Auto Pulse Desulfator

AUTO PULSE DESULFATOR BENEFITS:

1 Increases Battery Power

2 Extends Battery Life

3 Battery Charge Faster

4 Longer Discharge

5 Prevents Sulfate Build-up

6 Reduces Evaporation

COMPETITIVE ADVANTAGES

1. Fully Automatic voltage selection. 12V 24V 36V and 48V

2 New Cyclic pulse generation method for improved capacity recovery

3 Soft Peak Pulsing

4 Auto cutoff function to prevent over discharge of battery

5. User Configurable override for manual voltage selection:

CUTOFF VOLTAGE

Display. Cutoff voltage

12V battery C12. 11.0V

24V battery. C24. 22.0V

36V battery. C36. 33.0V

48V battery. C48. 44.0V

[Muhendis]

Short answer to your question George is "I don't know". Maybe someone else is using one?

If this method of desulfation works, and there are plenty that believe it does, Then the only thing to look out for is the maximum size of battery which the device is claimed to desulfate. In the case of the CLEN that size is 200 Ahr. Looking at some of the information on line it seems that the CLEN needs to be connected for 30 days continuously to an isolated battery to produce results. This device is manufactured in China so I would not anticipate any degree of quality control. Its' price seem suspiciously cheap so I would suspect a very simple circuit inside the box.

Go for it and let us know the results

[George Harmony]

Thanks @muhendis...i will order it online and will give it a try.

Will update on this subject.

[George Harmony]

Ive just watch this video of a solar powered cabin. A modest guy who shows what he can do with a relatively small solar system. Very nice cabin. If i later can run all the appliances he runs i will be very happy.

Edited February 29, 2016 by George Harmony

[Crossy]

Those not fully off-grid but with flaky / unreliable mains may want to consider a hybrid inverter like these http://www.voltronicpower.com/oCart2/index.php?route=product/product&product_id=73

Highly configurable as to exactly where your solar goes (into batteries, to the load, or back into the mains as grid tie), the manual is available from the linked page.

The 3kW unit is about US $1000, I'm trying to find a Thai supplier, the 5kW "Plus" unit would do us very well.

[Muhendis]

I am using a hybrid system for precisely the reasons Crossy lists. I got mine direct from MPP Inc. Taiwan http://www.mppsolar.com/v3/

I have three PIP-MS 4Kw units paralleled up (stacked) which came to a total of US$2275 and that included the parallel kit and UPS carriage.

After sales service is excellent. Best location for the inverters is outside the house because with three units the fan noise can be a bit distracting (I think that would apply to all inverter/chargers). I did have one problem with a unit which turned out to be caused by a lizard getting into the thing, but the support I got from MPP was very good and fast.

[Jing Joe]

Jing Joe. Dropping a coil of plastic pipe down a bore hole is not possible since the hole is likely only 100mm diameter and there are already some pipes taking up space. The pipe for this task would need to be heat conductive (so plastic is not the best choice) and small enough in diameter to get into the bore hole and back without getting in the way of the existing water pipes. Stainless is the best choice.

Oh dear, I didn't realise it was your your "hole in the ground" that was a bore. Yes agree on a stainless absorber (probably marine grade?) . Good luck with sufficient surface area and limited thermal mass of the limited volume of water down there, unless lucky to tap directly into a moving U/G pure stream like avail here in Oz. E.G. Just 6m down. How about the non-corrosive feature of low pressure poly pipe to interconnect / transfer? Regular stainless hose clamps? could practically test the corrosiveness of the water, well in advance?

The "well" I was thinking of is manually dug, 4 feet in diameter, lined and many many feet deep with possibly 2-3 metres of nice cool water.

Absolutely agree that Black poly pipe has less conductivity, but low pressure pipe being thin is practical enough, is corrosion proof, cheap and great to drop into a well. My suggestion of 50m compensating for the lower conductivity.

Experiences with black 50mm poly pipe filled with water on a slope in the sun;- Great H/W collector in its crudest form, but most relevant to this topic is the considerable conductivity in that it is too hot to touch. Whichever way you look at it; the suns insolation sure heated the water, and conversely the poly pipe didn't insulate the water temperature from the hand. If the pipe were shaded for say 10 minutes I'm sure regardless of its R factor it would still be too hot to touch. Not top engineering but practical. An old definition adapted ;- "Solar experimenter; Is a fool with no Uni degree, (but is humble, positive and practical and Q.B.E.. Qualified By Experience.) Engineer; well he does have a Uni degree".

BTW re solar generally, Seems like Thailand has slightly less Insolation than Australia's 1000 watts max per square metre.

[Jing Joe]

Ive just watch this video of a solar powered cabin. A modest guy who shows what he can do with a relatively small solar system. Very nice cabin. If i later can run all the appliances he runs i will be very happy.

Great George. K.I.S. like this and you will be "very happy".

[Naam]

Q.B.E. Qualified By Experience

[Naam]

[Crossy]

Georges Power Cabin.JPG

I want!!

[George Harmony]

@naam, no need a big system for my 52m house

Very soon i think ill be happy with this 300wp+300Ah bat bank system

Edited March 1, 2016 by George Harmony

[George Harmony]

This guy claims that he can run many (old models) gadgets with only 185wp panels. Im wondering if his system is not too small for all this...??????

11 mei 2009·short video describing a small solar power system that i set up at my house. it consists of twelve 1 amp solar panels (15 watts each for a total of 180 watts of power - per hour). i use it to run all lights (CFL's), fans, tv's, and stereos in the house. also the microwave, coffee maker, blender, can opener, sandwich grill, toaster, vacuum, computer and anything else i can think of. run time for lights/fans only is approx 8 hours. add in vacuuming, microwaving or toaster along with lights, tv and the fans and the run time is reduced to 4-5 hours a day. i bought solar panels, inverter (1000 watt) and killowatt meter at Harbor Freight tools, the batteries (deep cycle) from walmart and the battery cables from checker auto. total cost was about $1200 to $1300

[Muhendis]

George. Looking at that setup, those batteries are maybe 75Ahr each. So the combination of solar panels plus batteries will give him a total available power of just over 2885 watts/hour but if he used all that available power that then there would be nothing left to charge the batteries so it is quite possible to run all those gadgets but I'll bet he's not using all of them all day and every day.

[George Harmony]

@muhendis, ok....i understand.

Coming back to the favorite subject of @naam ..hehehehe...and that 260watt ac, a question.

If all my efforts fail, is it possible to run that ac with only solar panels(300wp) and an inverter. Thus, not connected to a chargrcontroller and battery bank. If possible it means that the ac will turn on auyomaticly during top peak hours, this can mean that is rather hot outside. In the evening i dont need anything, not even a fan.

Edited March 1, 2016 by George Harmony

[IMHO]

Permit me to ask again about batteries. Ive read about a desulfator, only about 900bht. According to the supplier you can connect it also continiously. Will it work?

FUNCTION

The High-frequency Peak Pulse delivers an electronically controlled pulse to the battery causing crystalline sulfates to dissolve back into the electrolyte and so restoring battery function and electrolyte strength regaining the batteries ability to receive charging current and deliver discharge current.

ADVANCED TECHNOLOGY

Many desulfator products use an old technology inductor design to generate the pulse to desulfate a battery. This old technology creates a harsh inductor peak that can be damaging to the battery plates.

NEW CYCLIC PULSING FUNCTION

In a similar manner to a Pulse battery charger (charge rest charge rest etc) a cyclic desulfating pulse function (pulse rest pulse rest etc) optimizes a batteries recovery process. This method of desulfation has been implemented in the new Auto Pulse Desulfator

AUTO PULSE DESULFATOR BENEFITS:

1 Increases Battery Power

2 Extends Battery Life

3 Battery Charge Faster

4 Longer Discharge

5 Prevents Sulfate Build-up

6 Reduces Evaporation

COMPETITIVE ADVANTAGES

1. Fully Automatic voltage selection. 12V 24V 36V and 48V

2 New Cyclic pulse generation method for improved capacity recovery

3 Soft Peak Pulsing

4 Auto cutoff function to prevent over discharge of battery

5. User Configurable override for manual voltage selection:

CUTOFF VOLTAGE

Display. Cutoff voltage

12V battery C12. 11.0V

24V battery. C24. 22.0V

36V battery. C36. 33.0V

48V battery. C48. 44.0V

God quality solar chargers have this type of feature built in.... they will even work out the optimum time to do it, based on bank usage. The principle of it is pretty simple: just over-volt the cells by about 20% and you boil the junk off the plates. The only trick is when to do it, and how long to maintain the extra voltage. Like I say, good quality solar chargers manage this all for you.

Edited March 1, 2016 by IMHO

[IMHO]

This guy claims that he can run many (old models) gadgets with only 185wp panels. Im wondering if his system is not too small for all this...??????

11 mei 2009·short video describing a small solar power system that i set up at my house. it consists of twelve 1 amp solar panels (15 watts each for a total of 180 watts of power - per hour). i use it to run all lights (CFL's), fans, tv's, and stereos in the house. also the microwave, coffee maker, blender, can opener, sandwich grill, toaster, vacuum, computer and anything else i can think of. run time for lights/fans only is approx 8 hours. add in vacuuming, microwaving or toaster along with lights, tv and the fans and the run time is reduced to 4-5 hours a day. i bought solar panels, inverter (1000 watt) and killowatt meter at Harbor Freight tools, the batteries (deep cycle) from walmart and the battery cables from checker auto. total cost was about $1200 to $1300

He has 12x 15w panels, which means 180Wh max. In Thailand, assuming optimium orientation, that will produce an average of 810W per day (+/- 90W), except for cloudy days of course, and lower if the panel are dirty, non-optimal angle, and about 1% less per year as they age.

Factor in 20% charging loss, and that's 648W of charge actually getting in the batteries.

Factor in 10-15% inverter loss, and you're now down to 550 - 582W per day of useful mains power.

As for his batteries, he has 4x 115Ah @ 12V, which is 5520wh - that means he's only running them to a maximum of 12% discharge, assuming he only uses what his PV can top back up. When he uses his bigger wattage loads, he's probably "borrowing" a lot of Ah from the batteries, which then takes him several days to recover the charge. That explains how he's able to "run" his seemingly too big loads for the PV output.

Edited March 1, 2016 by IMHO

[George Harmony]

@muhendis, ok...i understand.

Coming back to the favorite subject of @naam and the 260watt aircon, a question.

If all my alternative efforts to cool down during the day fail, is it possible to run that ac directly from the panels (300wp) via an inverter, thus not connecting to a controller and battery bank???

If possible, it means that the ac will run automaTicly during (hot) top peak hours and ive achived my goals. In the evening i dont need to run that ac, not even a fan is needed.

Added: Sorry double posted

Edited March 1, 2016 by George Harmony

[IMHO]

@muhendis, ok...i understand.

Coming back to the favorite subject of @naam and the 260watt aircon, a question.

If all my alternative efforts to cool down during the day fail, is it possible to run that ac directly from the panels (300wp) via an inverter, thus not connecting to a controller and battery bank???

If possible, it means that the ac will run automaTicly during (hot) top peak hours and ive achived my goals. In the evening i dont need to run that ac, not even a fan is needed.

Added: Sorry double posted

I have never heard of an inverter that operates direct from PV, but is not also designed for grid-tie (i.e. they all require the grid to be connected/functioning for it to produce output).

And there's a good reason why... generally speaking it's fair to assume an electric motor draws about 4x-8x it's nominal wattage at initial startup time. So in the scenario of the "magic inverter" above, it would need to be smart enough to only switch on the output when there's sufficient excess power for startup to be successful, which also means you need to over-spec your PV 4x-8x too...

What you want can be achieved though using a conventional grid-tie inverter - but you won't get auto start/stop - it will be up to you (or a timer) to cycle the AC on/off. In this scenario, the initial startup current is supplemented by the grid so you don't need to over-spec your PV, but if you run the AC for too long it's going to draw from the grid - there's just no way to guarantee the AC runs off PV only. Also if the grid is down, so is your PV, due to anti-islanding feature all such inverters have.

Another theoretical "magic inverter" would be one that uses (small) batteries to supplement motor startup demand only. I've never seen such a device though. All off-grid inverters I know of are going to suck your battery bank dry as PV output falls each day - so there's nothing left in the batteries the next day.. That said, a timer is a potential solution to this... but again, not really automated. You'd need to monitor PV output and adjust runtime duration pretty regularly.

Edited March 1, 2016 by IMHO

[George Harmony]

Here are some examples of pv panels directly connected to an inverter. I have no grid connection. Till now my house is 12volt house.

https://m.youtube.com/results?q=solar+panel+dirext+to+inverter+no+battery

[George Harmony]

This guy said:

Inverter directly connected with solar panels without battery?

I am using a 200w 12volt inverter directly with my 100watt solar panel connected via charge controller.

Solar panel 100w(9to 22volt) + charge controler(12volt 6amp=72watt) + (12v 200w) inverter = load

Okay charge controller is a device that we use to charge a battery directly of the solar pane

so I connected my inverter in the place of a battery it works fine bec the charge controller is a rated for 78 watts and inverter uses some power in conversion my inverter can sustain loads upto 65 watts if the panel is producing enough current.

and charges controller controls the voltage and amps and saves inverter from burning out.

I have read a lot of the internet that u can not use inverter directly with solar panel without batteries unless your inverter is a grid tie inverter I think its crap ppl dont really know what are they talking about.

However if solar panel stops producing enough current inverter might overload other then that u can run inverter directly with solar panel according to my understanding.

https://answers.yahoo.com/question/index?qid=20140608055523AAiuwlk

Lets assume he is right, how many wp solar panels must be used to run that 260watt ac and is a 500watt inverter enough?? Edited March 1, 2016 by George Harmony

[IMHO]

Lets assume he is right, how many wp solar panels must be used to run that 260watt ac and is a 500watt inverter enough??

What you need to start a 260w AC isn't easy to calculate without understanding it's start-up requirements. AC's have three main motors: 1) the inside fan motor, 2) the compressor, 3) the outside fan. The fans are usually only a small % of the overall power draw. For a 260w unit, I'd assume maybe 40-60W a piece for the fans.

Usually, the inside fan blower start before the compressor, which might start before the outside fan, or they might start in unison - so we have 2-3 startup stages to consider.

Assuming startup current draw is 4x nominal:

1. Inside fan: 40-60W with a startup current of 160-240w

2. Compressor: 140-180w, with a startup current of 520-720w

3. Outdoor fan: 40-60W with a startup current of 160-240w

or:

1. Inside fan: 40-60W with a startup current of 160-240w

2. Compressor and outdoor fan: 200w-220w with a startup current of 800-880w

Double these numbers for worst case (8x) startup current if you can't get actual real specs.

So that means, you need an inverter with a peak ability of either 900w (4x) or 1800w (8x) otherwise it just won't start. The same capacity is needed for the PV.

Most inverters can support around 2x their rated current for short-term peaks.

It seems a terrible waste of PV to provision 4x to 8x of what you actually need, just because you want to start electric motors without a supplementary power source!

Short version:

Don't start electric motors directly off PV only - work out a system using supplementary mains or batteries to assist with startup.

Edited March 1, 2016 by IMHO

[IMHO]

Here are some examples of pv panels directly connected to an inverter. I have no grid connection. Till now my house is 12volt house.

https://m.youtube.com/results?q=solar+panel+dirext+to+inverter+no+battery

I only watched the first one, where a guy was using a 50W PV with 20VDC open circuit voltage.

This only works because under this exact load, the panel outputs a voltage within range of what the inverter actually wants - any more or less PV voltage and it just doesn't work anymore. On top of that, this inverter will not exhibit an ideal load on the panel, so he's never getting the full 50w out of it, no matter what he does. His 20w CFL load is probably about all it's good to run.

The thing about PV is, the actual range of voltage it outputs varies wildly based on solar energy it's exposed to, the the load that's placed on it. it's not like a battery where the voltage range is minimal.

Edited March 1, 2016 by IMHO

[Crossy]

You could probably use the hybrid inverter I linked to earlier with a minimal battery to provide the extra oomph to start the A/C.