Living offgrid with small solar system(s)

[George Harmony]

So, if i buy a very small one and turn it on in a room or space with 20c, i can make ice??

If this is the case then a coolbox based on the "sure chill" idea is an effective way to cool drinks and meat for lets say 10 days. Every 10 days making ice and put it in the "sure chill" coolbox. So, not wasting energy. Only to produce i trun on the peltier. In the evening hours i think im able to reach 19-20c in my small cellar ... So i can make ice with a small peltier fridge with power cons 35watt only.

[Jing Joe]

About fridges.

Ive been told that gasfridges absobs a lot of gas.

It would be a challenge to make my own fridge.

More info 1st pict: https://m.youtube.com/watch?v=u2C9XbAVz5U

Anyone have exp with peltier fridges? They coo down 20-22c below ambient temp. Does this mean that i can make ice if my room temp is 20c????

If i can make ice its not so difficult to make a cooler box based on pict 2

Yes, gas fridges are energy in-efficient but could get you bye if it is a 3 way fridge front door caravan type in another post. 12v Gas 240v

Compressor devices have a C.O.P. coefficient of performance of about 2.4.

that is 2.4 times the transfer of heat/cold energy comparable with straight resistive heating for example because of the evaporative nature of the beast.

Reverse cycle aircons in cold weather is a better way to explain COP. i.e. comparing resistive heating to heat transfer pumps such as rev cycle aircon.

The refrigerant hot water systems here in Aus are claiming a COP of about 4 if one can believe it.

One guy had to pay the minimum qtly. bill of about $13 when in fact he only used $9.

Yes peltier (thermo electric) fridges will drop 20 -22 below ambient BUT you can stack two elements and get more like 40 below ambient.

They do this in Science labs.

There are different size wattage devices. Best start with two new ones of same model.

Don't skimp on getting the heat away from the hot side of the assembly.

Likewise have large enough cold surface and even a fan inside too.

Make a larger hot surface with 1/8 inch (at least) aluminium plate 500 x 500 ? and rivet many 10mm x10mm aluminium U channel heat sink type fins.

Zinc heat sink paste helps.

But even then peltier are only about 50% efficient.

N.B. most peltier "cool boxes" have fans with brush motors and usually thought of as picnic or more temporary uses. Again refer to the Alibaba sites for fans re brush-less fans. Some even have magnetic levitation bearings. Wow.

GEORGE:- UPDATE TYPED IN ABOVE

Edited February 23, 2016 by Jing Joe

[BKKdreaming]

Lots of 12v - 24v cooking stuff made for truckers and RVs

but anything heating food will take a lot of wattage , so solar is probably the way to go with reflective panels etc

[Jing Joe]

Sorry George.

Bum steer.

I forgot that the 3 way caravan fridges use the absorption principle (and BTW also need to be dead plum vertical/horizontal.)

The gas mixtures are heated by one of 3 means, 12v 240 v or L P Gas.

Not a compressor type. Sorry.

Compressor fridges are surely the way to go if you can spare the intermittent 60watt approx power consumption.

Duty cycle? I've timed an ordinary domestic fridge to be about 60% on, 40% off in say 24 degree C weather and not being opened.

How about design your own "Esky" compressor box with ingenious shelving and really up the insulation wall thickness to say 75 mm?

I made my camper trailer thermo electric device cold box 400x400x400 outside and 300x300x300 inside.

White polystyrene foam 50mm, siliconed together and painted white ready for fibreglass. Next step, but not really needed.

Not enough airspace behind it (YET) to make the best hot plate heat sink with fan but that will be the next step.

So I temporarily sealed the square hole for the body of the device and made a tallish vertical shaped crushed ice holder from punched zinc sheet grille.

It locates at the rear of the cold food goods and the air doesn't stratify the cold too much to just the bottom because it is a vertical stack holding one bag of garage ice. Too much food blocks the circulation/flow of the air and in may confine the cold to the bottom.

The temp probe goes down one front corner in a PVC tube siliconed to the foam, and the readout is just outside usually showing 5 degrees min.

A drain hole with 6mm PVC tube siliconed in place takes the melt water away to a hole in the van floor.

It last about 2 to 3 days.

BTW my reference to using two slabs together to achieve 40degree differential means of course a 2 x 12 volt parallel power drain not one.

About 4 to 5 amps each from memory of my single one.

Depending on the curve of the performance graph, wouldn't it be interesting if the two slabs when in series electrically could optimistically get even a 30 degree differential? Probably not.

.

Edited February 23, 2016 by Jing Joe

[George Harmony]

Thanks JingJoe.

This guy on youtube claims that he can make small gallon of ice with a fridge-freezer,power consumption of only 30watts after startup.

https://m.youtube.com/watch?v=YrHN6iTMtvM

I realise that for the kickup you need perhaps 10x more power for a few seconds only.

Is it true that there are freezers available which draws only 30watt after startup?????

If true,

Why does he not make a 10 days coolbox and every 10 days turn on his freezer for 1-2 hours only to make ice???? Wasting energy if you use the fridge all the time.

[George Harmony]

Again about batteries as batteries are relatively expensive.

QUESTIONS:

What is wisdom for small systems? Connect 3 batteries in paralel or install seperate systems. If for whatever reason you drain your batteries more than 50% frequently it will damage faster for sure. In pararel you have to replace them all or not???

Seperate systems you replace one by one and for gadgets whereby the load is minimum perhaps it has longer life. Or am i talking nonsense??

For what i call "on and off spaces" like toilet, bathroom and hall ive installed dc sensor switches. So i cant forget to turn it off. The load of these spaces is total max only 18watt hours on an average day. I intend to use a seperate system for this and 7ah is more than enough. Wise or not??

[Crossy]

Why does he not make a 10 days coolbox and every 10 days turn on his freezer for 1-2 hours only to make ice???? Wasting energy if you use the fridge all the time.

Latent heat of fusion for water is 334,000 J / kg (to turn water at 0C to ice at 0C)

1 US gallon is about 4 litres or 4kg of water.

So to freeze that gallon you need to extract 334,000 x 4 Joules of energy = 1,336,000 Joules.

A compressor type heat pump can pump about 3 times the energy with which it is supplied, so 30W consumption can pump about 100W.

100W is 100 Joules per second, so to extract 1,336,000 joules will take 13,360 seconds or about 4 hours.

You do the maths.

[George Harmony]

@crossy,

From practical point of view if im offgrid or run that fridge freezer on solar like in the video id rather make ice 4 hours every 10 days then turn it off and put it in 10days coolbox rather than day and night running that fridge. In the vid you cleary see that the freezer compartment is much more smaller than the fridge.

[Jing Joe]

Again about batteries as batteries are relatively expensive.

QUESTIONS:

What is wisdom for small systems? Connect 3 batteries in paralel or install seperate systems. If for whatever reason you drain your batteries more than 50% frequently it will damage faster for sure. In pararel you have to replace them all or not???

Seperate systems you replace one by one and for gadgets whereby the load is minimum perhaps it has longer life. Or am i talking nonsense??

For what i call "on and off spaces" like toilet, bathroom and hall ive installed dc sensor switches. So i cant forget to turn it off. The load of these spaces is total max only 18watt hours on an average day. I intend to use a seperate system for this and 7ah is more than enough. Wise or not??

Probably like this;- your batteries in parallel would be better because with a given amount of amp/hours having been used, the state of discharge would be consistently less so battery life would be prolonged. Generally the less the discharge each cycle, the longer the life.

Factors such as equal age, equal capacity, same brand etc could vary this I guess.

Routine checking of individual batteries out of circuit would answer one of your Q above.

Sulphation as someone mentioned, is an enemy but then comes the pulsating charge possibilities to desulphate.

yet another story. I made a big one for 1000AH but wasn't big enough.

[Muhendis]

Again about batteries as batteries are relatively expensive.

QUESTIONS:

What is wisdom for small systems? Connect 3 batteries in paralel or install seperate systems. If for whatever reason you drain your batteries more than 50% frequently it will damage faster for sure. In pararel you have to replace them all or not???

Seperate systems you replace one by one and for gadgets whereby the load is minimum perhaps it has longer life. Or am i talking nonsense??

For what i call "on and off spaces" like toilet, bathroom and hall ive installed dc sensor switches. So i cant forget to turn it off. The load of these spaces is total max only 18watt hours on an average day. I intend to use a seperate system for this and 7ah is more than enough. Wise or not??

Having three batteries in parallel will ensure that they are all balanced. In other words the weaker battery of the three will be maintained by its parallel partners. This is good news and bad news. Simply stated and without going into the battery physics. the good news is that the battery bank will always have the optimum charge. The bad news is that a weaker battery will take power from the other two. This is not normally an issue because unless something goes seriously wrong with one of the batteries the difference in life expectancy is minimal. What may happen is that one battery will decay quicker than the other two and the overall capacity will be reduced. In this scenario it is a simple matter of disconnecting each of the batteries in turn, identifying the low capacity battery and replacing it with a new one. So there is no need to have separate systems.

Please bare in mind that the more batteries you have in parallel, the greater the amp/hr capacity. As you increase the battery capacity so you must make sure the charger and solar panels can supply enough current to charge them in the required time.

Having all your gadgets running off the same battery bank will be cheaper in terms of installation costs and complexity, but you're right about the minimum loads giving the batteries a longer life. Whether it is a wise thing to do or not is really something for you to decide but you might like to consider what you will need to do when you decide in the future to increase the consumption on your various circuits.

[Crossy]

@crossy,

From practical point of view if im offgrid or run that fridge freezer on solar like in the video id rather make ice 4 hours every 10 days then turn it off and put it in 10days coolbox rather than day and night running that fridge. In the vid you cleary see that the freezer compartment is much more smaller than the fridge.

It may be easier to add insulation to a regular chest freezer and just run it when needed to freeze the water or when you have spare power.

So long as all the ice doesn't melt / all the water freeze it will maintain about 0C, you will get back almost all the energy you extract so you only lose what leaks via the insulation once the contents is down to temperature.

[George Harmony]

@muhendis,

Thanks for your reply. I think for the "on and off spaces" i will use a very small system and for the other loads another system with batteries in pararel with ofcourse higher amp for my near future def setup.

For a simple security system with nightsensor, sirene and buzzers and 2 stand alone cameras with memory card i can use a used car battery cause the alarm goes off and recording starts only when the sensor has been activated. The car battery in normal situation remains always full when i continiously connect to a small solar panel and the load is minim.

[George Harmony]

@crossy,

I appreciate your advices. Thanks.

[Jing Joe]

Muhendis rightly mentioned battery sulphation.

I searched google for the desulphating liquid that can be added to flooded batteries because a friend got 8 years from his car battery. That's 4 more than usual here and he added it right from the start. Couldn't find that particular brand but there are some big name products out there.

There are also some wacky individuals with home-brew recipes. "Let George beware".

Was very excited to find new and supposedly powerful and versatile new electronic pulsing desulphating devices on the market now.

There were about 8 years ago only small ones for 12v and I unsuccessfully made a too-small unit for my 1000 AH 48 V setup. They failed after 10+ years and I replaced with 800AH.

Didn't look much past the range available nor other brands nor reviews but here is one website and wow has it got me interested>>

http://recovermybatteries.com/?gclid=CKXFzqmjj8sCFdgmvQodcA4MpA

Small bikkies but these devices could put out a bit of RFI into digital TV reception either directly into the aerial or via the common 12v supply. But only when watching. BTW I assume you told us your TV is 12v.

George- you seem to have some caring friends out there eh.

Good luck or more-so; good management.

Edited February 24, 2016 by Jing Joe

[George Harmony]

Cooking with solar panels:

As decribed by JingJoe best way of cooking food is using gas.

But,

Have you ever ordered a chinese dish? Within few minutes the fresh made dish is on your table. They prepare it with a wok. 99% of all their dishes they make it with a wok. If i cook myself i also use a wok and have been using electrical wok.

Electrical wok consumes 900-1500 watt. Lets say you use it for 10-20 minutes. Its not so much watt hour. To cook with such a wok you dont need panels up to 1500wp if you have enough battery capacity. Since there is no 12volt electrical wok you need an inverter of lets say 2000watt.

Warming up food you can use 12v microwave, also not consuming a lot of watt hours since you use it only 1-3 minutes.

Slowly i expand my solar systems and will try to cook with an electrical wok if i have enough capacity Cooking during the day and during watt peak hours if ofcourse more efficient.

[Jing Joe]

@muhendis,

Thanks for your reply. I think for the "on and off spaces" i will use a very small system and for the other loads another system with batteries in pararel with ofcourse higher amp for my near future def setup.

For a simple security system with nightsensor, sirene and buzzers and 2 stand alone cameras with memory card i can use a used car battery cause the alarm goes off and recording starts only when the sensor has been activated. The car battery in normal situation remains always full when i continiously connect to a small solar panel and the load is minim.

Clever.

What brand/model + a picture of your "2 x standalone cameras", how much and where did you buy it pls George?

My Wife will be there soon for a holiday and could bring one back.

I suppose you have a warning sign in Thai well positioned?

Do such warning deterrents have an effect there still?

Any regulator needed on the small solar panel?

[Muhendis]

Muhendis rightly mentioned battery sulphation.

I searched google for the desulphating liquid that can be added to flooded batteries because a friend got 8 years from his car battery. That's 4 more than usual here and he added it right from the start. Couldn't find that particular brand but there are some big name products out there.

There are also some wacky individuals with home-brew recipes. "Let George beware".

Was very excited to find new and supposedly powerful and versatile new electronic pulsing desulphating devices on the market now.

There were about 8 years ago only small ones for 12v and I unsuccessfully made a too-small unit for my 1000 AH 48 V setup. They failed after 10+ years and I replaced with 800AH.

Didn't look much past the range available nor other brands nor reviews but here is one website and wow has it got me interested>>

http://recovermybatteries.com/?gclid=CKXFzqmjj8sCFdgmvQodcA4MpA

Small bikkies but these devices could put out a bit of RFI into digital TV reception either directly into the aerial or via the common 12v supply. But only when watching. BTW I assume you told us your TV is 12v.

George- you seem to have some caring friends out there eh.

Good luck or more-so; good management.

With regard to these various desulfation devices. I am a bit sceptical about the validity of some of the claims. There has been some research on them but the batteries used for this research were quite specific in terms of the type and construction of the plates. I have seen several reports about the high frequency desulfators all of which are quite scathing in their condemnation of the devices but once again there is no documented evidence produced to say that they don't work.

Jing Joe can you please buy one of the UK one's from the web site and let us know what sort of results you get? I don't have an open enough mind about it yet to put my money down........

[Jing Joe]

Cooking with solar panels:

As decribed by JingJoe best way of cooking food is using gas.

But,

Have you ever ordered a chinese dish? Within few minutes the fresh made dish is on your table. They prepare it with a wok. 99% of all their dishes they make it with a wok. If i cook myself i also use a wok and have been using electrical wok.

Electrical wok consumes 900-1500 watt. Lets say you use it for 10-20 minutes. Its not so much watt hour. To cook with such a wok you dont need panels up to 1500wp if you have enough battery capacity. Since there is no 12volt electrical wok you need an inverter of lets say 2000watt.

Warming up food you can use 12v microwave, also not consuming a lot of watt hours since you use it only 1-3 minutes.

Slowly i expand my solar systems and will try to cook with an electrical wok if i have enough capacity Cooking during the day and during watt peak hours if of course more efficient.

Yes we eat Thai nearly every meal but we use gas wok and saucepans but could use the electric wok with the 3kw inverter on 48V. Tall gas bottle lasts 15 months.

BUT you could convert a 240 wok to 12v??? BUT then 900 watts (min) at 12 volts equals 75 amps.

Naaaa-- either buy an inverter of simply cook on gas. but surely you would use your gen set you mentioned for the short cooking time? Remember the battery life syndrome? its very real. and you would need to buy a 1500 watt inverter.

BTW for lower power heating devices generally, remember;- you can use specially insulated resistance wire, and cartridge silicon has an extremely high temperature tolerance to hold it against whatever you are heating. Flat toaster wire is usable. Anodized aluminium is insulating.

Must google the 12v microwave you mentioned just out of curiosity. The only reason for 400W inverter in our camper trailer is for 70 watt electric blanket to pre-warm bed for cold-frog Thai wife on cold nights when not at powered sites. Have made low voltage electric blankets before but didn't bother this time for camper. At powered sites we use 240v batt charger in shade, a small 240 v microwave, jug, toaster, hot plate etc. elsewhere its all 12v & cook on gas. Solar power 2 x 80W new generation panels + nice charger

The ventilation fan is the smaller of the two fans from car radiator and speed control is a switchable modified old fashioned jug element that only gets warm so very slightly power wasteful, but no motor noise like a switch-mode speed controller. Very slow for all-night fresh, medium for cooking and soon will have high for a hurricane.

What did you think of the inverted bilge float switch upside down in the top of the header tank and the brush-less pumps?

Good pics of yours. Any more George?

George; Have you entered a new phase of maybe crossing from 12v DC to inverter power? Just thinking, just watching.

Next phase could start find yourself you expensively thinking;- 24 V 400A/H battery & 1500W inverter and then all your cute ingenious 12v satisfaction might become obsolete? Just thinking just watching. All because of that "cooking-on-12v" subject?

[Jing Joe]

Muhendis rightly mentioned battery sulphation.

I searched google for the desulphating liquid that can be added to flooded batteries because a friend got 8 years from his car battery. That's 4 more than usual here and he added it right from the start. Couldn't find that particular brand but there are some big name products out there.

There are also some wacky individuals with home-brew recipes. "Let George beware".

Was very excited to find new and supposedly powerful and versatile new electronic pulsing desulphating devices on the market now.

There were about 8 years ago only small ones for 12v and I unsuccessfully made a too-small unit for my 1000 AH 48 V setup. They failed after 10+ years and I replaced with 800AH.

Didn't look much past the range available nor other brands nor reviews but here is one website and wow has it got me interested>>

http://recovermybatteries.com/?gclid=CKXFzqmjj8sCFdgmvQodcA4MpA

Small bikkies but these devices could put out a bit of RFI into digital TV reception either directly into the aerial or via the common 12v supply. But only when watching. BTW I assume you told us your TV is 12v.

George- you seem to have some caring friends out there eh.

Good luck or more-so; good management.

With regard to these various desulfation devices. I am a bit sceptical about the validity of some of the claims. There has been some research on them but the batteries used for this research were quite specific in terms of the type and construction of the plates. I have seen several reports about the high frequency desulfators all of which are quite scathing in their condemnation of the devices but once again there is no documented evidence produced to say that they don't work.

Jing Joe can you please buy one of the UK one's from the web site and let us know what sort of results you get? I don't have an open enough mind about it yet to put my money down........

Too easy Muhendis and would gladly let you know. But I'm also sceptical ( note my comment- "supposedly powerful" ) and I will first follow up on research and comments like you did. e.g. Documentation about if they do or dont work and even then it would take months to validate either way. Yes risky, but maybe they figure that those who have a AUD$8000 bank of batteries at stake would gladly take the risk to buy their questionable product.

Re various battery constructions, its probably got a lot to do with the ability to shock/shake/drop the white sulphate deposits out of the plates?

Mine are currently the AGM type construction and are about 6 years old.

[George Harmony]

@JingJoe,

For your info , im building my house in Indonesia at the moment NOT in Thailand. Here cctv stand alone camera is easy to get online. I many things order online.

For an outdoor and indoor version its only between 700-1000 baht.

If you can not get these products where ever you are now, inbox me your email. Perhaps I can send it to you by JNE or other courier service.

About the cooking with an electric Wok. Its just an idea for the future. Perhaps@Muhendis can predict the lifetime of the battery if I draw daily 200-400 watt hour using for example 125Ah battery. Also an inverter of lets say 2000 watt will not last forever. Financially speaking, is it then worth to cook like this.

Added:

With a memory card of 8GB for example you can record about 2 days continuously and it will delete automatically and starts from beginning again. So it something happens connect it to your laptop and watch it ...the bigger the memory card you use the longer you can record. Plug and play products.

(About the cooking. If i have total of 1500-2000 Wp panels it will ofcourse be no problem at all if I cook during peak hours or am I wrong? )

Edited February 24, 2016 by George Harmony

[Muhendis]

About the cooking with an electric Wok. Its just an idea for the future. Perhaps@Muhendis can predict the lifetime of the battery if I draw daily 200-400 watt hour using for example 125Ah battery. Also an inverter of lets say 2000 watt will not last forever. Financially speaking, is it then worth to cook like this.

Ok George I'm going to start with the basics. Please humour with me if you already know this.

125Ahr........ What this means is that you can take 125 Amps from the battery for 1 hr. At the end of that time the battery would be discharged and close to death. It would ideally need to be fully recharged to minimise sulfation before you use it again. That is a cycle. Deep cycle batteries are good at this type of cycling due to the construction of the plates etc. You may be able to get up to 500 cycles like this but 300 is more likely. Generally it is preferred to keep the depth of discharge to somewhere between 20% to 50% This will extend the life of the battery but at the cost of only using part of its capacity.

Your 125Ahr 12v battery according to Ohms Law will drive a 1.5KW load for one hour (12v x 125Ahr) so by reducing the maximum discharge to 50% you would reduce either the time for a 1.5KW load to 1/2 hour or drive a 750 watt load for one hour. this will add many useful cycles to the life of your battery but unfortunately it is not a proportional relationship. As time goes by the plates will degenerate, internal resistance will increase and the dreaded sulfation will occur. This can be minimised by regular maintenance. If the battery is FLA (That's the one with screw caps to allow topping up of the acid with distilled water and to allow readings of the SG to be made) then you can keep an eye on the acid level and apply a desulfation cycle ever so often.

If you draw 500 Watt/hr per day then that would be the same as 41.7 Amps/hr (500W/12V). Using your 125 Ahr battery and limiting yourself to 50% capacity then you would be able to use the battery for 1.5 hrs before recharging. I'm sure you can now work out a few other scenarios from this.

Your idea that a 2KW inverter not lasting for ever is possibly true but if it is designed and built to a reasonable standard then the likelihood is that it will be replaced due to better things becoming available rather than old age or component failure.

If you are interested in further reading about batteries you might like to google "Battery University".

[George Harmony]

Thanks for your reply @muhendis.

You wrote:

If the battery is FLA (That's the one with screw caps to allow topping up of the acid with distilled water and to allow readings of the SG to be made) then you can keep an eye on the acid level and apply a desulfation cycle ever so often.

If i manage to store the FLA battery outside there is no healty risk. If i understood well a fla battery can have a longer life if you regularely service the battery.

If i plan to buy later the following only for using the electric wok:

1x100wp panel, gives me on a normal day min. 450watt

1x125ah fla deep cycle battery

1xinverter 2000watt

So after using the wok 450watt the battery will be full again.

Is it possible then than the battery last at least 5 years??

Look how handy such a wok is. Cooking where ever you want, even on the dining table or at your terrace.

[Muhendis]

Locating the battery outside is fine so long as you can protect it from the elephants elements. It will last longer out of the sunlight. Presumably you will only use the wok for 20 minutes or so every day. If that is the case then five years will be no problem at all. The level of discharge during 20 minutes use would be 0.2 x 450 = 90 watts = 7.5 Ahr = 0.06 of the battery capacity.

[George Harmony]

Then its very interesting for me to plan for this setup. Only max 30min per day using an inverter which i initially not want is perhaps worth the try. Thanks again @muhendis.

What i can do with 12v appliances is:

Pumping water

Burning lamps

Fans and exhaust fans

Using a fridge

Watching tv

Using a laptop

Making coffee

Boiling a bit water

Using a dc micro wave

Simple security system

Using a dc razer

Etc....

And EVEN with the ac wok cooking the total system is still relatively small. 250-300wp is in fact enough with 200-250ah battery bank.

Is it not wonderful.

I read many examples of grid-tie and offgrid systems. Too many too expensive setup in my opinion. There are also solar systems for whole house ac if use ac and want to invest in new products. Just youtube for examples.

My humble opininion is: If you want to use alternative energy and still have the same comfort as you were ongrid perhaps you have to adjust a little bit of your lifestyle but then go totally off grid or use grid only as backup. Here in indonesia you can apply for grid connection on prepaid basis and topup your credit in for example 7-11. The meter gives a warning when your prepaid balance is low. My backup is a small genset also with ac and dc plugs

Offgrid you can even make your own ice cubes with 90wp panel hehehehe

Look:

Edited February 24, 2016 by George Harmony

[George Harmony]

Locating the battery outside is fine so long as you can protect it from the elephants elements. It will last longer out of the sunlight. Presumably you will only use the wok for 20 minutes or so every day. If that is the case then five years will be no problem at all. The level of discharge during 20 minutes use would be 0.2 x 450 = 90 watts = 7.5 Ahr = 0.06 of the battery capacity.

Sorry,forgot to ask.

Is it not 0.20 x 1200 (or 1500 watt depending on the specs of the wok ofcourse.)

Cooking fast with wok its wise to use full power. Since its electric the heat of the wok will slow go down enabling you to let it cook further.

[Jing Joe]

Muhendis gives you wise advice George. How do I know its wise? because I agree with him. Forgive me.

Just a quick thought. How does this logic sound>>

If you "make hay while the sun shines" that is; cook when you have full sun AND IF your panels were to equal the cooker, then in theory NO power will come from the battery. Any deficit of power from the panels less than this will be made up by the batteries so all is not that bad, depending on panel capacity Vs cooking power.

Conversely to your your power setting comment; cooking with LOWER power will enhance the calculation above.

Except for the quality of their Electrolytic Capacitors, inverters should just about last for ever. Commonly used temperature ratings of only 105 degrees used to be a design weak point. I think 115 Celsius is the next grade up.

Yes; "M's" wisdom suggests the inevitability of an inverter upgrade before an existing one giving up the ghost.

Standing back I see how much more complicated/expensive your alternative power has become just from contemplating cooking with batteries despite the panel size notes above. You would know the "KISS" principle. Keeping it simple. I once contemplated making Brown's gas (hydrogen/oxygen combined) for cooking and welding but our gas usage is so cheap,and standard, and safe, and simple. Less to go wrong.
Gas fired steel wok is quick, and simpler to wash than electric for me, and I am avoiding Teflon like the plague, now the truth is really out there.

I'll think more about the CCTV soon and thanks for suggestions/offers.

"M" suggests wisely keep batteries out of of the sun, and cold weather isn't their friend either. None of that there in Indo?

P.S. both your dishes pictures so far look great & healthy but that looks a very different wok? Have you been caught out boasting with cut and paste from glossy cookbooks George?

Edited February 24, 2016 by Jing Joe

[Muhendis]

Locating the battery outside is fine so long as you can protect it from the elephants elements. It will last longer out of the sunlight. Presumably you will only use the wok for 20 minutes or so every day. If that is the case then five years will be no problem at all. The level of discharge during 20 minutes use would be 0.2 x 450 = 90 watts = 7.5 Ahr = 0.06 of the battery capacity.

Sorry,forgot to ask.

Is it not 0.20 x 1200 (or 1500 watt depending on the specs of the wok ofcourse.)

Cooking fast with wok its wise to use full power. Since its electric the heat of the wok will slow go down enabling you to let it cook further.

Yep! You are paying attention after all. I didn't use the right figure for the wok power.

[Muhendis]

Muhendis gives you wise advice George. How do I know its wise? because I agree with him. Forgive me.

Just a quick thought. How does this logic sound>>

If you "make hay while the sun shines" that is; cook when you have full sun AND IF your panels were to equal the cooker, then in theory NO power will come from the battery. Any deficit of power from the panels less than this will be made up by the batteries so all is not that bad, depending on panel capacity Vs cooking power.

Conversely to your your power setting comment; cooking with LOWER power will enhance the calculation above.

Except for the quality of their Electrolytic Capacitors, inverters should just about last for ever. Commonly used temperature ratings of only 105 degrees used to be a design weak point. I think 115 Celsius is the next grade up.

Yes; "M's" wisdom suggests the inevitability of an inverter upgrade before an existing one giving up the ghost.

Standing back I see how much more complicated/expensive your alternative power has become just from contemplating cooking with batteries despite the panel size notes above. You would know the "KISS" principle. Keeping it simple. I once contemplated making Brown's gas (hydrogen/oxygen combined) for cooking and welding but our gas usage is so cheap,and standard, and safe, and simple. Less to go wrong.

Gas fired steel wok is quick, and simpler to wash than electric for me, and I am avoiding Teflon like the plague, now the truth is really out there.

I'll think more about the CCTV soon and thanks for suggestions/offers.

"M" suggests wisely keep batteries out of of the sun, and cold weather isn't their friend either. None of that there in Indo?

P.S. both your dishes pictures so far look great & healthy but that looks a very different wok? Have you been caught out boasting with cut and paste from glossy cookbooks George?

Spot on Jing Jon. If you use electricity only in the sunny times then the life of the battery becomes time dependent rather then cycle dependent. However for this situation to exist the power from the solar panel must be at least equal to the power requirements of the appliance plus losses. If the battery and the panel are both supplying power at the same time then battery use will be reduced.

I would also like to mention for Georges benefit the need for a decent charge controller to ensure that the battery gets its required 100% charge. Don't forget, the power from the panel needs to be sufficient to recharge the battery in only a few hours. This doesn't look like it will be a problem but it needs some consideration.

[Crossy]

Some good stuff here

It's amazing how little power you can get away with, it's when there is no power at all that it hurts.

During the flooding we went for 6 months with no mains (in a condo) but Wifey obtained a little 1.5kVA Honda generator. Combined with an inverter to drive a fan, my PC (the ADSL amazingly kept working) and the telly at night run from the car battery we survived just fine, even had xmas lights on at night

Charge the battery and run the freezer during the day off the generator, battery usually lasted until about lunch time. Ran the genny until 10pm. Even shared the genset with the next door lady (light / fan /TV).

Cooking and water heating was gas, delivered by boat and lugged up to the 10th floor by the gas man.

The locals thought we were batty to stay when others had evacuated, we were significantly more comfortable than those who moved to the university sports hall (and then Don Mueang airport when the uni flooded)

[Muhendis]

Some good stuff here

It's amazing how little power you can get away with, it's when there is no power at all that it hurts.

During the flooding we went for 6 months with no mains (in a condo) but Wifey obtained a little 1.5kVA Honda generator. Combined with an inverter to drive a fan, my PC (the ADSL amazingly kept working) and the telly at night run from the car battery we survived just fine, even had xmas lights on at night

Charge the battery and run the freezer during the day off the generator, battery usually lasted until about lunch time. Ran the genny until 10pm. Even shared the genset with the next door lady (light / fan /TV).

Cooking and water heating was gas, delivered by boat and lugged up to the 10th floor by the gas man.

The locals thought we were batty to stay when others had evacuated, we were significantly more comfortable than those who moved to the university sports hall (and then Don Mueang airport when the uni flooded)

My imagination is trying very hard to picture living in a condo on the tenth floor with a Honda generator running. I guess the neighbours didn't object to the noise and you probably had it on the balcony to deal with the fumes? But well done for the improvisation. As you say, it's surprising how little power you need to live a reasonable life.