Diy The Best Sunjar in www.instructables.com :-)

It is very easy and cheap to diy a sunjar !My circuit can test the sunshine and the leds turn on only at night and turn off while the sun rise again:)

Step 1 The circuit programme

The units can easilly got by electronic pcb junks!

Comments

[dasimpson1981]

your doing it again efan over complacating when this will do the same job

[dasimpson1981]

my panels give out 2.5 to 3 volt at 20ma
what i have just found is 2 in series wont run this circuit with the components i am using diffent pnp transitor and 1k res insted of 5k

but if i get another to cells wire them up in series and parallel so i get 5-6volts but 40ma the unit works correctly

[dasimpson1981]

the silver things between the batterys are neo magnets they are easy for snapping togeather batterys

[dasimpson1981]

just to prove i wasent lieing about the amount of leds i run from this unit the breadboard bit of a mess the part i am using for jt winding is somthing i found in an old pc psu same for the transistors resistors and other bits
the first is the light the camera isent showing how bright it really is
the next is the bread board with the above circuit
and the last one is the unit i found in the psu i use for the jt windings

[efanfengshun]

FINE WORK.
How long are the leds on lasting with one suuny day charging?

[dasimpson1981]

it is winter here at the moment so they isent alot of sun.
the batterys are fully charged at moment the unit is at present running the batterys flat.
once they are flat i will take the cover of the panels to find out.
need to get a clock and a realy to make a light sensing circuit so i can tell exactly how many hors they run for

[efanfengshun]

What is it at each point of the battery in your second photo,Is it magnet?

[dasimpson1981]

yeah neo magnets they hold the batterys together.
and dead leds as magnetic posts to connect it to the breadbored

[efanfengshun]

Is big coil or bigger diameter copper wire can improve the jt output current?

[dasimpson1981]

to improve current erm if you raped a 3rd coil the fewer the winds the more current the more wind they are the higher the voltage but less current
jt are not ment for current step up but voltage step up hence they work well with lighting but thats about it

[dasimpson1981]

less winds on the base and more on collector can get higher voltage.
but wont some really fun facts wind a 3rd coil run that thru a diode to a cap see what you get and watch the running current you will be seprised

[efanfengshun]

delicious!:-)

[dasimpson1981]

got to tell you tho if you build this unit do not and i mean do not look at the led i am still seeing purple dots

[efanfengshun]

:)

[dasimpson1981]

just been messing with this circuit more and well seems any npn and pnp transistor will work the 5k resistor can be swoped for a pot to allow ajustment for the level of darkness it turns on at

[efanfengshun]

Yes.But i made it before.

[dasimpson1981]

you know it might be worth compareing them both see which one is more effecient

[efanfengshun]

I preffer yours.

[dasimpson1981]

yeah it is a little simpler just messing with the jt side seeing how many leds i can get working

[efanfengshun]

Yes. very clever design but i still want a simple anti-over-charge circuit.

[dasimpson1981]

a Zener diode would also stop the over charge

[efanfengshun]

How about this one? but i think it could more simpler.

[dasimpson1981]

i myself would find out what the trickle charge limit is and have a wind turbine run at that and maybe solar to charge it faster during the day as long as these dont go above what you use they wont be any problems

[efanfengshun]

The li -ion cell it self has a protecting circuit in it.

[dasimpson1981]

then you have nothing to worry about if the battery is 3.6 volts you need to feed it 5-6volts to charge it you need to work out at what ampage to charge it at and for how long

[efanfengshun]

:)From my observation two solar cell series connection are lower than two solar cell parallel connection then jt to li-ion.
the solar cell :2*2.4v/65vma

[dasimpson1981]

if one solar panel is 2.4volt and 65ma
in series that would be 2.8 volt at 65ma
in parallel that would be 2.4 volt but 130ma

but that are when they are running at 100% that ant oftern some days i get 1ma other i get the full 20ma of my panels

[efanfengshun]

I puzzled if one solar panel is 2.4volt and 65ma in series that should be 4.8 volt at 65ma .

[dasimpson1981]

you would need 3 solar cells to charge the 3.6 volt battery tho i work it ut for every 1.2 volt battery you need 1 2 volt cell

[efanfengshun]

yes. So i used two solar cell then jt to abuot10v-15v low current to li-ion it charged well.:)

[dasimpson1981]

yes but for the length of time you ran it with the jt you could of got way more of a charge into just using the solar panels

basicly it will charge faster from the panel then the jt

[dasimpson1981]

yes you are correct i hit the wrong number

[dasimpson1981]

in series the voltage is higher but ampage (current) is the same
in parallel the voltage is the same but ampage is higher
a 3.6 volt battery needs 5 to 6 volts to fully charge same as a 1.2 to 1.5 volt battery needs 2 to 2.5 volts to charge

[efanfengshun]

From my observation two solar cell series connection to 1.2v battery are still lower than two solar cell parallel connection then jt to li-ion.
the solar cell :2*2.4v/65vma
Maybe i should use two solar cell parallel connection to 1.2v battery ,:)

[dasimpson1981]

dont forget the diode to stop the battery discharging thru the solar panel

[efanfengshun]

Does the high volt but lowe current by jt can improve the charging efficiecy to battery?

[dasimpson1981]

it will charg but take a very very long time to charge
i have found if you run a dead bettery that wont take a charge on a joule thief it will then after take a charge

[efanfengshun]

i have found if you run a dead bettery that wont take a charge on a joule thief it will then after take a charge
What is it meaning?

[dasimpson1981]

ok you have a battery that reads 0.00 volts or 0.10 volts put that in a wall charger and it will not charge
but charge it with a jt for an hour then put it in the wall charger it will then charge

[efanfengshun]

This shows that high volts but low current provides active tpositive hing to the battery .Maybe the long time worth.:)