Living offgrid with small solar system(s)

[George Harmony]

Here is an example of someone who uses simple youle thief + simple aluminium air battery.

Edited June 5, 2016 by George Harmony

[George Harmony]

Another way of emmergency lighting for remote village:

Charge by hand some supercapacitors and you can have few hours or whole night lighting

As i understood well supercapacitors last very very long time ccomparing with normal batterie and:

The energy in a capacitor is:

E = C * V2 / 2

When C is in Farads, V in Volts, then E is in Joules.

150F * (2.7V)2 / 2 = 547 J

The switching power supply will need some minimum voltage to work with. Let's say it can operate down to 1 V. That represents some energy left in the cap the circuit can't extract:

150F * (1.0V)2 / 2 = 75 J

The total available to the switching power suppy is therefore 547 J - 75 J = 470 J. Due to the low voltages, the losses in the switching power supply will be quite high. Let's say that in the end only 1/2 the available energy gets delivered to the LED. That leaves us with 236 J to light the LED.

Now we need to see how much power the LED needs. Let's go back to your original white LED and pick some numbers. Let's say it needs 3.5 V at 20 mA to shine nicely. That's 3.5V * 20 mA = 70 mW. (236 J)/(70 mW) = 3370 seconds, or 56 minutes. At the end of that, the light would go dead rather quickly, but you will have fairly steady brightness up until then.

Five or six in series and with efficient joule thief ... :)

[George Harmony]

Here is handy charge and discharge online capacitor's calculator:

http://mustcalculate.com/electronics/capacitorchargeanddischarge.php

[Muhendis]

I have been enjoying your comments about low voltage LED lighting but I find myself asking questions about the power to lumens comparison. For the sake of myself and our valued readers I came up with this useful site http://eartheasy.com/live_led_bulbs_comparison.html Yes I know there is no 12v information but the important bit (for me at least) is the relationship between watts and lumens. I hope you find it useful.

[George Harmony]

12 volt led lamps:

https://www.ledlight.com/12-volt-led-spot-flood-lights.aspx

[George Harmony]

Just an update of my saltwater experiment.

It works really great for few days. This morning the same battery i "back wash it" just under a crane, not yet 1 minute. Then i soak it in saltwater again and its still working.

I made one also with graphit. Burn the pencil, took the graphit out and it works alao great

Added:

If someone is interested to experiment this also and is lazy to do some diy just use carbon brush (for electric motor) :)

Edited June 6, 2016 by George Harmony

[Crossy]

Volts? Amps?

Is that one cell driving a white LED directly without a joule-thief?

Electrodes? Electrolyte?

[George Harmony]

Volts? Amps?

Is that one cell driving a white LED directly without a joule-thief?

Electrodes? Electrolyte?

Its driving that tiny dc motor you see on the pict. Ive ordered the components for making joule thief. Hope to receive it today. Just doing some experiments myself for learning. I later ofcourse try to make some lamps myself with serial and/or paralell connected saltwater cells.

What i just did is half burned pencil touching a copper wire and as cathode alumium foil. Works also. So you dont have to take out all the graphite from the pencil

Will keep you updated.

[George Harmony]

Here are some examples of home made battery with measurements of volts and amps.

http://sci-toys.com/scitoys/scitoys/echem/batteries/batteries.html

[Crossy]

Ah, it's a motor (and fan?), it looked like an LED which is what made me ask the question.

[Crossy]

Here are some examples of home made battery with measurements of volts and amps.

http://sci-toys.com/scitoys/scitoys/echem/batteries/batteries.html

Don't see any Amps being measured here, only DC Volts.

That LCD calendar thingy probably draws less than 1mA even with the beeper sounding.

That these home made devices will power anything at all is testament to the low power technology in the loads being used. Which is of course why we can re-visit these simple power sources.

If you can light, say 5 or 6 white LEDs that's a fantastic amount of light when compared with none, but it's still only about 0.5W.

[George Harmony]

I think why (salt) water wett cell batteries are not popular is because the expensive replacement of the anode. Thats why i try to figure out the cheapest way to make diy anodes.

Here is the housing of a commercial version of such a battery with 40ah 12v. The trick for me is to try to make the anodes myself so i can run some of my 5 and 7wats usb lamps at 4-5 volt. Think i need to design 3 cells only and if the bigger anode results in higher amp.....lets try to make it

[Crossy]

Yup G ^^^.

Any primary (non-rechargeable) battery is going to use up one or other of the electrodes, invariably the more expensive metallic one (of course).

It's the materials cost of the consumable electrode, not the "free" salt water that will be the killer

If you can get the materials free (beer cans, scrap copper wire), or at least very cheap then all is well and good. otherwise you may end up better off buying Duracells

EDIT You seen this one? (another Al / air cell) http://www.instructables.com/id/Aluminum-Can-Saltwater-and-Charcoal-Battery/

[George Harmony]

Yeah @crossy, ive seen that already.

I have this "silly idea" to use carbon water filter(s) as cells and refresh/clean/backwash it automaticly during the day. These carbon filters are here not so expensive and is much more bigger comparing to the commercial anodes. Ofcourse you must do some diy but i think i can achieve reasonable amps and the lifetime is hopefully long if i wash it daily during the day cause i dont load during te day :)

What do you think of this idea @crossy?

[Muhendis]

A word about these so called joule thief circuits. As Crossy has said you can't get out more than you put in (Thee casn't get awt fer nowt). The trick is to switch a high voltage/current device on and off with a mark space ratio of (say) 1:10. The average power used is very low but the on time power is high enough to make things work. Now. Let us say that the "on" time is 1mS and the off time is 10mS and that this is repeated cyclically. The electronics can react to this time scale well enough but the human eye cannot. So, in the case of an LED lamp, what we perceive is a continuous bright light and our test meter tells us that the current consumption is quite low. In The case if the crap circuit of Georges that he got somewhere on the internet, The high voltage spikes generated by the transformer may be enough to cause the fluorescent lamp to start. Once again we are looking at the time domain of the power cycle so the lamp might keep starting every cycle and will remain on for as long as the voltage of that cycle is high enough. My personal comment on the circuit is that I seem to recall seeing it before. About 50 years ago..............

Yes M this circuit might very well have been the topic of this forum 50 years ago but now, as has been raised; LEDs are the reason why some old and simple battery designs can be revisited. Especially for village life as is George's wonderful passion.

It's a case of NOT QUITE "everything old is new again" because compact flouro lights were great, way back.

So George; keep your focus on LEDs till something better comes along.

Reckon the principle of the "joule thief" was the sole reason history was revisited.

P.S. Reading your note again M re the M/S ratio reminded me of my discovery of the dimming circuitry in one or two of the 30 LED torches I have.

The lesser brightness is as hoped not simply resistive dimming but a M/S ratio of about 0.6 to 1 as accidentally discovered noticing a small stream of water in stroboscopic action of an interrupted pattern. Any more would too much information.

More easily seen but different; was not quite looking directly into the beam whilst oscillating it rather like a windscreen wiper motion. The M/S ratio was more discernible.

JJ I just ran a simulation of the "joule thief" circuit and of course it works just as good today as ever. My dislike for it is that 20% of the energy from the battery goes into the base-emitter junction of the transistor. So I had a think for a few seconds and came to the conclusion that with a supply of only 1.5v you're not going to get much better with such a simple handful of components. So old = good............I'm old too.

[Crossy]

Now there's an idea, I hadn't thought of using carbon filter elements as electrodes.

[Muhendis]

Now there's an idea, I hadn't thought of using carbon filter elements as electrodes.

Me too. Isn't George the ingenious one. However I wonder about the purity requirements. No. Not George. The carbon and the salt water. The better the quality the better the flow of electrons.

[IMHO]

Volts? Amps?

Is that one cell driving a white LED directly without a joule-thief?

Electrodes? Electrolyte?

Its driving that tiny dc motor you see on the pict. Ive ordered the components for making joule thief. Hope to receive it today. Just doing some experiments myself for learning. I later ofcourse try to make some lamps myself with serial and/or paralell connected saltwater cells.

What i just did is half burned pencil touching a copper wire and as cathode alumium foil. Works also. So you dont have to take out all the graphite from the pencil

Will keep you updated.

That tiny little motor could probably be powered by a lemon or potato battery - can't get more eco than than that

[George Harmony]

1st is the waterfilter from which i took out a litte bit of act carbon for my experiments. Really a little bit cause it looks like its stil full.

3rd pict i put more carbon in and made a spiral with thick copper cable till the bottom. So its surrounded by the carbon. Can you imagine that you do the same inside the whole carbon filter

2nd pict i solder a joule thief and it works

[Muhendis]

Volts? Amps?

Is that one cell driving a white LED directly without a joule-thief?

Electrodes? Electrolyte?

Its driving that tiny dc motor you see on the pict. Ive ordered the components for making joule thief. Hope to receive it today. Just doing some experiments myself for learning. I later ofcourse try to make some lamps myself with serial and/or paralell connected saltwater cells.

What i just did is half burned pencil touching a copper wire and as cathode alumium foil. Works also. So you dont have to take out all the graphite from the pencil

Will keep you updated.

That tiny little motor could probably be powered by a lemon or potato battery - can't get more eco than than that

Many years ago I helped a guy change from bourdon tube load cell metering to electronic metering. I used a very small motor which was around 25mm diameter and 19mm thick. This was the meter movement and was integrated into the proportional feedback loop. The motor, when running free without load, took no more than 5mA at 2v. George. Although you are making great strides with your exciting experiments you need to record your battery load in Amps and the voltage measured across that load so that your captivated readers can appreciate all the more, your achievements and maybe add to your expanding knowledge.

[George Harmony]

I know @muhendis. Someone borrowed my multimeter and did not bring it back ???? .... (will i ever get it back ?? )

Tomorrow i must buy another one.

Here is another example of pencil aluminium air battery with joule thief. Mine with act carbon is bigger. I think the bigger the more amps and with thick copper cable perhaps more current.

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

[George Harmony]

Ordered also some supercapacitors with more farads than this example.

Intention is to charge two with very small panel, connect some diodes and you dont have to worry about overcharging

Lets see how long my usb lamp(s) can burn....keep you updated after i received it.

And just for fun i ordered also a hp hand charger ...

[George Harmony]

Here is another example of solar lighting with super capacitors. This Dutchman made a complete report of one of his outdoor lighting.

[Crossy]

Read and understand this article on supercaps http://batteryuniversity.com/learn/article/whats_the_role_of_the_supercapacitor

Then answer this:- "Currently rechargeable batteries are better than supercaps in low-power energy storage applications - discuss".

HINT Look at energy storage density, discharge curve, cost.

[Jing Joe]

Hi guys. Just a quickie;

The carbon filters would surely be too dear to use brand new but recycled would be great??

Put the word out in the built-up areas where they use them and use the carbon in the village.

How about George's research for village life in Hawaii?

Main reason this post; How about the carbon (probably crushed coal) in the BBQ fuel beads. ???

Slightly larger than golf balls.

George; I have old lead acid batteries with good containers and lead plates pos and neg plates hanging down.

The tops of the cells can be cut to remove/access/use just one set of plates as a possible cathode but what kind of anode would be needed for a salt water primary battery..

Indeed I dont know the chemistry enough to know even if lead would be suitable??

No laughing please guys.

[Muhendis]

Some years ago there was a company in America that was developing a type of supercapacitor for the electric car. The plates inside were nano coated with billions of tiny pillars. This was to increase the surface area of the plates and hence capacitance of the device. It worked very well as a supercapacitor but the company quietly disappeared from the electric vehicle scene. Supercapacitors just do not have the V/I characteristics required for that sort of application. With a capacitor the voltage starts to decay the moment you begin to take current from it. The smaller the load and/or the larger the capacitor the less noticeable this decay is, but it is always going to be there. It is possible to use a voltage regulator connected between the capacitor and the load which will give a constant voltage for some time until the capacitor voltage has decayed to the minimum working voltage of the regulator then the regulator's output voltage will start to decay. The time taken for this is dependant, once again, on the size of the capacitor and the amount of current drawn from it. Also there will be losses within the voltage regulator which will hasten the capacitors discharge.

[Jing Joe]

To Muhendis. Remember the posts about wind generators? I opened my spare single phase noisy Hummer 1kw hub and counted the poles at 56. Supermagnets too.

Yours has 7 phases and I am interested the brand please? Are you 100% happy with it especially the noise and over-speed protection?

My reason to revisit the spare hub is to use on petrol motor when no wind and no sun.

[Crossy]

Indeed Muhendis ^^^, our Dutch friend fails in this, he's wasting probably 75% of the energy stored in his (expensive) capacitors.

Also since it "charges in an hour" he's also wasting at least 80% of the energy his panel is producing (assume a 5 hour charging day).

Supercaps do have a long useful life, but need some not-so-simple electronics in order to get the best from them.

[Jing Joe]

A word about these so called joule thief circuits. As Crossy has said you can't get out more than you put in (Thee casn't get awt fer nowt). The trick is to switch a high voltage/current device on and off with a mark space ratio of (say) 1:10. The average power used is very low but the on time power is high enough to make things work. Now. Let us say that the "on" time is 1mS and the off time is 10mS and that this is repeated cyclically. The electronics can react to this time scale well enough but the human eye cannot. So, in the case of an LED lamp, what we perceive is a continuous bright light and our test meter tells us that the current consumption is quite low. In The case if the crap circuit of Georges that he got somewhere on the internet, The high voltage spikes generated by the transformer may be enough to cause the fluorescent lamp to start. Once again we are looking at the time domain of the power cycle so the lamp might keep starting every cycle and will remain on for as long as the voltage of that cycle is high enough. My personal comment on the circuit is that I seem to recall seeing it before. About 50 years ago..............

Yes M this circuit might very well have been the topic of this forum 50 years ago but now, as has been raised; LEDs are the reason why some old and simple battery designs can be revisited. Especially for village life as is George's wonderful passion.

It's a case of NOT QUITE "everything old is new again" because compact flouro lights were great, way back.

So George; keep your focus on LEDs till something better comes along.

Reckon the principle of the "joule thief" was the sole reason history was revisited.

P.S. Reading your note again M re the M/S ratio reminded me of my discovery of the dimming circuitry in one or two of the 30 LED torches I have.

The lesser brightness is as hoped not simply resistive dimming but a M/S ratio of about 0.6 to 1 as accidentally discovered noticing a small stream of water in stroboscopic action of an interrupted pattern. Any more would too much information.

More easily seen but different; was not quite looking directly into the beam whilst oscillating it rather like a windscreen wiper motion. The M/S ratio was more discernible.

JJ I just ran a simulation of the "joule thief" circuit and of course it works just as good today as ever. My dislike for it is that 20% of the energy from the battery goes into the base-emitter junction of the transistor. So I had a think for a few seconds and came to the conclusion that with a supply of only 1.5v you're not going to get much better with such a simple handful of components. So old = good............I'm old too.

Yes I too wondered about about the wasted power just for switching the 2N3055. The 555 timer (even less-than-50years- way-back) would surely have been used into a Mosfet switcher, given appropriate voltages available.

George; have you discovered even more modern switching techniques? That will keep you really engrossed and busier than you are now.

Keep up the good work. You have some appreciated onlookers.

[Crossy]

There are some very clever energy-harvesting devices available such as this http://www.ti.com/product/BQ25504 fairly low external component count, high efficiency, input as low as 330mV.

Negative is that it's in a tiny surface mount package so you'll need someone with the specialist tools to knock up a board and mount the beast.

Google "simple low power boost converter"

EDIT This is more DIY-able http://www.instructables.com/id/Adjustable-Voltage-Step-up-07-55V-to-27-55V/

Or buy a kit to modify https://www.adafruit.com/product/14