SOLAR LIGHT BATTERY ELIMINATOR QUESTIONS

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Hi, I am planning to use a power supply instead of the batteries in my
solar landscape lights because of a shade problem and the uniqueness of
the lights. With the two re-chargeable batteries installed I am
measuring 3vdc @ 500 micro amps. I am wondering if this measurement is
correct. My experience is that most leds require 10 milliamps. Did they
find a way to operate them so efficiently? There are two low intensity
leds in each lamp and one flickers. I figure at 500 microamps, apiece,
hooking 11 of these lamps in parallel I would need a power supply
capable of an output of 3 volts at 55 microamps? Since the ultra low
current I figure a plug in xfmr like a phone charger would work and I
would have to use a resistor to limit the current since most of these
are in the 100 ma and up range? What about a battery impedance problem,
by leaving the batteries out and hooking the power suppy directly to the
battery terminals? Will this be a problem?
Many thanks in advance.
Dale

 

[linnix]

Hi, I am planning to use a power supply instead of the batteries in my
solar landscape lights because of a shade problem and the uniqueness of
the lights. With the two re-chargeable batteries installed I am
measuring 3vdc @ 500 micro amps.

The measurement is probably as good as your math.

I am wondering if this measurement is
correct. My experience is that most leds require 10 milliamps. Did they
find a way to operate them so efficiently? There are two low intensity
leds in each lamp and one flickers. I figure at 500 microamps, apiece,
hooking 11 of these lamps in parallel I would need a power supply
capable of an output of 3 volts at 55 microamps?

This doesn't make sense at all.

Since the ultra low
current I figure a plug in xfmr like a phone charger would work and I
would have to use a resistor to limit the current since most of these
are in the 100 ma and up range?

Most likely, not enough current, after you work out the measurement and
math.

What about a battery impedance problem,
by leaving the batteries out and hooking the power suppy directly to the
battery terminals? Will this be a problem?

Yes, you need to avoid overcharging as well.

 

[Luhan]

Hi, I am planning to use a power supply instead of the batteries in my
solar landscape lights because of a shade problem and the uniqueness of
the lights.

I solved the problem by removing the stakes and hanging those solar
powered yard lights in the trees here. They get more sun that way and
look really nice at night.

Luhan

 

[Ken Taylor]

Hi, I am planning to use a power supply instead of the batteries in my
solar landscape lights because of a shade problem and the uniqueness of
the lights. With the two re-chargeable batteries installed I am
measuring 3vdc @ 500 micro amps. I am wondering if this measurement is
correct.

Was that with the light operating? It sounds like standby current draw.
Or are you measuring the battery voltage and reading the current rating
off the battery (which would likely be 500 milli-amp, not micro-amp).

My experience is that most leds require 10 milliamps. Did they
find a way to operate them so efficiently? There are two low intensity
leds in each lamp and one flickers. I figure at 500 microamps, apiece,
hooking 11 of these lamps in parallel I would need a power supply
capable of an output of 3 volts at 55 microamps?

How do you figure this? 500 x 11 = 5500uA (or 5.5mA). Assuming the 500uA
is right.....

Since the ultra low
current I figure a plug in xfmr like a phone charger would work and I
would have to use a resistor to limit the current since most of these
are in the 100 ma and up range? What about a battery impedance problem,
by leaving the batteries out and hooking the power suppy directly to the
battery terminals? Will this be a problem?
Many thanks in advance.
Dale

You'd want a resistor in for sure - measure the current draw when a
light is on and apply Ohm's Law to figure out a resistor for the number
of lights you want to hook up. Assuming the LED's are really 10mA each
and there are two each light, that gives you 220mA total. If you use a
9VDC plug-pack/wallwart you'd want a resistor about 15 Ohms. There's
probably an intensity control built into the lights so you may want to
play with just one light to start with in case you fry it.

Cheers.

Ken

 

[Ken Taylor]

I solved the problem by removing the stakes and hanging those solar
powered yard lights in the trees here. They get more sun that way and
look really nice at night.

Luhan

There's an idea! I'm surprised by how long mine actually last into
the night, they're pretty good.

Cheers.

Ken

 

[Noone]

There's an idea! I'm surprised by how long mine actually last into
the night, they're pretty good.

Cheers.

Ken

I use a couple on the end of my dock in the summertime. It is super dark on the lake late at night . A small LED is useful as a hazard marker, but not bright enough to bother people. Very low maintenance. I take them in during the winter. The biggest problem is the opaqueing of the clear plastic over the solar cells due to UV and bird guano. They can attract a bug or two and some birds will roost on them waiting for their evening meals to arrive.

Blakely

 

[JeffM]

I use a couple on the end of my dock in the summertime. It is super dark on the lake late at night . A small LED is useful as a hazard marker, but not bright enough to bother people. Very low maintenance. I take them in during the winter. The biggest problem is the opaqueing of the clear plastic over the solar cells due to UV and bird guano. They can attract a bug or two and some birds will roost on them waiting for their evening meals to arrive.
Blakely

Most people set their newsreaders for a line break at ~ 74.
It would be considerate of you to do likewise.

 

[Noone]

Most people set their newsreaders for a line break at ~ 74.
It would be considerate of you to do likewise.

Jeff:

I use Netscraper for both mail and news and I think my
settings got pushed out and never reset back.

Thanks for the tip!