Solar Charging Night Light not working...

default · Jul 25, 2020

On Sun, 7 Jun 2020 07:30:42 -0700 (PDT), alberto.m.scattolo@gmail.com
wrote:

Ok guys, I tried!
If I directly connect the PNP base to battery negative the LED lights up as bright as possible but it never turns off, even if I put everything in the sun.
If I add a 5k resistor between PNP base and battery negative it works as expected, so it automatically turn on and off according to the amount of light on the solar panel, but the led brightness is not much even when I cover the panel or if I disconnect it.
Ideas?

Thanks a lot!

Have you tried looking for a happy medium resistance? You want to
turn on the PNP and drive it into saturation (ideally) and have it
turn off when the panel is making electricity.

It is never good practice to connect the base of a bipolar transistor
to forward bias it without some current limiting resistor. If your
transistor survived, it is only because the battery wasn\'t powerful
enough to fry it.

The ideal size resistor depends on the current gain of the transistor.
Gain is specified at a particular collector current in the datasheet
and there may be a graph too.

Small signal transistors usually have gains of ~100. So with 1
milliamp flowing in the base you should get 100 in the collector
circuit. (more or less... gains can be specified as some minimum and
the maximum, for a production run of parts, can be several times
higher)

Jasen Betts · Jul 25, 2020

On 2020-05-30, default <default@defaulter.net> wrote:

On Sat, 30 May 2020 05:32:30 -0000 (UTC), Jasen Betts
jasen@xnet.co.nz> wrote:

On 2020-05-29, default <default@defaulter.net> wrote:
On Fri, 29 May 2020 06:02:32 -0000 (UTC), Jasen Betts
jasen@xnet.co.nz> wrote:

So you have... nothing. Post a schematic.

No, asshole, I have built it and it works. I am not wasting any
further time responding to your clueless taunts with useful
information.

ROFLMAO

sure you built it

Yet another demostration of your stupidity.

--
Jasen.

Jasen Betts · Jul 25, 2020

On 2020-05-30, default <default@defaulter.net> wrote:

On Sat, 30 May 2020 05:32:30 -0000 (UTC), Jasen Betts
jasen@xnet.co.nz> wrote:

On 2020-05-29, default <default@defaulter.net> wrote:
On Fri, 29 May 2020 06:02:32 -0000 (UTC), Jasen Betts
jasen@xnet.co.nz> wrote:

So you have... nothing. Post a schematic.

No, asshole, I have built it and it works. I am not wasting any
further time responding to your clueless taunts with useful
information.

ROFLMAO

sure you built it

Yet another demostration of your stupidity.

--
Jasen.

Jasen Betts · Jul 25, 2020

On 2020-05-30, default <default@defaulter.net> wrote:

On Sat, 30 May 2020 05:32:30 -0000 (UTC), Jasen Betts
jasen@xnet.co.nz> wrote:

On 2020-05-29, default <default@defaulter.net> wrote:
On Fri, 29 May 2020 06:02:32 -0000 (UTC), Jasen Betts
jasen@xnet.co.nz> wrote:

So you have... nothing. Post a schematic.

No, asshole, I have built it and it works. I am not wasting any
further time responding to your clueless taunts with useful
information.

ROFLMAO

sure you built it

Yet another demostration of your stupidity.

--
Jasen.

default · Jul 25, 2020

On Sat, 30 May 2020 03:53:45 -0700 (PDT), alberto.m.scattolo@gmail.com
wrote:

Oh guys, come on.
Unfortunately I still cannot try your suggestions as I am not at home, but please, let\'s try to be pragmatic.
If any of you have ideas, schematics or whatever, post it. I have limited components at home and some are just scavengered but I would give a try to any good idea that would allow me to keep 4 bright led on all night long.

BTW, is replacing the battery with a capacitor an idea worth trying/meaningful?

Thank you all

That would depend on how many hours of light you expect to get out of
one charge. Some guy had posted a series of fountain lights he was
running from a cap. Farad size caps aren\'t cheap as a rule.

I think Jasen has the glimmering of an idea, bias the oscillator
itself to stop during daylight rather than have the voltage drop of
the PNP transistor, to contend with when it\'s on. I suspect it may be
trickier than he suggests though. The circuit works because when the
oscillator transistor switches off abruptly, it causes a high voltage
spike in the inductor. Diddling the bias may have other consequences
in addition to shutting it down during daylight. But, I have my own
projects to play with.

BTW there are Chinese IC\'s that do exactly what you want, using a
single inductor. see: https://tinyurl.com/yag3y9g9

The YX8182 IC does the same thing without an inductor.

I built several circuits of that type to illuminate a buoy, so I could
kayak before the sun came up. A flashing light attracts attention
faster and uses less power.

default · Jul 25, 2020

On Sat, 30 May 2020 03:53:45 -0700 (PDT), alberto.m.scattolo@gmail.com
wrote:

Oh guys, come on.
Unfortunately I still cannot try your suggestions as I am not at home, but please, let\'s try to be pragmatic.
If any of you have ideas, schematics or whatever, post it. I have limited components at home and some are just scavengered but I would give a try to any good idea that would allow me to keep 4 bright led on all night long.

BTW, is replacing the battery with a capacitor an idea worth trying/meaningful?

Thank you all

That would depend on how many hours of light you expect to get out of
one charge. Some guy had posted a series of fountain lights he was
running from a cap. Farad size caps aren\'t cheap as a rule.

I think Jasen has the glimmering of an idea, bias the oscillator
itself to stop during daylight rather than have the voltage drop of
the PNP transistor, to contend with when it\'s on. I suspect it may be
trickier than he suggests though. The circuit works because when the
oscillator transistor switches off abruptly, it causes a high voltage
spike in the inductor. Diddling the bias may have other consequences
in addition to shutting it down during daylight. But, I have my own
projects to play with.

BTW there are Chinese IC\'s that do exactly what you want, using a
single inductor. see: https://tinyurl.com/yag3y9g9

The YX8182 IC does the same thing without an inductor.

I built several circuits of that type to illuminate a buoy, so I could
kayak before the sun came up. A flashing light attracts attention
faster and uses less power.

server · Jul 25, 2020

On Saturday, May 30, 2020 at 3:48:49 PM UTC+2, default wrote:

I think Jasen has the glimmering of an idea, bias the oscillator
itself to stop during daylight rather than have the voltage drop of
the PNP transistor, to contend with when it\'s on. I suspect it may be
trickier than he suggests though. The circuit works because when the
oscillator transistor switches off abruptly, it causes a high voltage
spike in the inductor.

Ok, how would be the schematic?

BTW there are Chinese IC\'s that do exactly what you want, using a
single inductor. see: https://tinyurl.com/yag3y9g9
The YX8182 IC does the same thing without an inductor.

Any specific schematic to suggest?

I would like a steady light effect (high frequency on/off is also fine as far as it seems constant at human eye).

Thanks

server · Jul 25, 2020

On Saturday, May 30, 2020 at 3:48:49 PM UTC+2, default wrote:

I think Jasen has the glimmering of an idea, bias the oscillator
itself to stop during daylight rather than have the voltage drop of
the PNP transistor, to contend with when it\'s on. I suspect it may be
trickier than he suggests though. The circuit works because when the
oscillator transistor switches off abruptly, it causes a high voltage
spike in the inductor.

Ok, how would be the schematic?

BTW there are Chinese IC\'s that do exactly what you want, using a
single inductor. see: https://tinyurl.com/yag3y9g9
The YX8182 IC does the same thing without an inductor.

Any specific schematic to suggest?

I would like a steady light effect (high frequency on/off is also fine as far as it seems constant at human eye).

Thanks

default · Jul 25, 2020