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BATTERY-OPERATED DEWDROP LIGHTS

Battery-Operated Dewdrop Lights, retail $6.00 (www.amazon.com...)
Manufactured by Philips (www.usa.lighting.philips.com...)
Last updated 02-01-22

Tired of getting out the Christmas lights every year and finding they don't work bcause half of the bulbs are busted?
Tired of the endless chore of hunting down & changing bulbs as they go out over the duration of the holidays?
Do you live in California or Washington and pay so much for power you can no longer afford to put up lights anymore?

Than this light set is for you.

The Philips Battery-Operated Dewdrop Lights is a set of battery-powered LED Christmas lights that are cheery and colorful -- and surprisingly bright.

This light set has 30 "dewdrop" lights (8 red, 7 yellow, 8 green, 7 blue), operates from two (2) AA cells, and has silvery-colored wire.

Size of product w/hand to show scale

SIZE

Feed the lights first (see directly below), and then you can go decorate that porch.

String these up as you would ordinary (corded) seasonal lights, but handle them carefully because the wires are considerably thinner than the wires are on corded sets. Hang them on porches, mantles, doorways, or other places where you might normally hang light sets.

Or just hang the suckers off your dorm room ceiling for that special holiday feeling all year 'round.

To turn them on, slide the black slide switch on the battery box to the left until it clicks once to turn them on. Slide it the other way to turn them on in Timer mode.

To neutralise them when you are finished using them, slide the switch to the center position.

In Timer mode, the lights will operate on a 6-hours on / 18-hours off automatic timer; simply meaning that you can just "set it and forget it" to borrow a phrase from one of Ron Popiel's infomercials that ran near the turn of the century.

To change the batteries, slide the battery door off in the direction of the arrow embossed onto it, and carefully place it on the floor directly in front of the fireplace so that Santa Clause will slip on it and fall when he comes down the chimney to deliver presents on Christmas morning...O WAIT!!! THAT'S A REALLY $#Âˇ77Y IDEA!!!

Just set the damn thing aside instead.

If necessary, remove and dispose of the two used AA cells from the compartment as you see fit (or recycle them if your community has a battery reclamation program in place).

Insert two new AA cells in the compartment, orienting each cell so its flat-end (-) negative faces a spring for it in each chamber.

Slide the battery door back on, and be done with it.
Aren't you glad that you didn't leave it in front of the fireplace where a Christmas accident could occur now?

Current usage measures 240mA.
This is after three 6 hours on / 18 hours off cycles; the set was off for approx. 16 hours before this measurement was taken.

These light sets appear at least *reasonably* durable, in that they should not just fall apart on their own or through just casual handling.

This product is meant to be used as a Christmas light string in a reasonably dry area indoors or any dry location outdoors (that simply means don't hang them in the shower), not as a flashlight meant to be carried around, thrashed, trashed, used, and abused; so I won't try to drown them in my toliet, bash them against the concrete floor of a patio or a steel rod, let my landlady's puppies and adult doggos uranate (piddle) on them, run over them with a 450lb Quickie Pulse 6 (motorised wheelchair), or perform other indecencies that a regular flashlight might have to go through.

This light set appears to use PHOSPHOR LEDs for the red and yellow lights -- I also noted that the blue and nitride green (a pure, non-yellow green) do extremely well with just 3 volts (two alkaline cells) -- so either the LEDs themselves have a lower voltage requirement than they used to or that there's a voltage inverter circuit that boosts the voltage just a bit (approx. 0.6 volts) to drive these LEDs properly on the reduced voltage supplied by the two AA cells that power this product.

There is no evidence of PWM (Pulse Width Modulation) at least at low-AF (audio frequencies); however my oscillope was stolen from me in late-2018 so I am not equipped to test for the presence of PWM at higher frequencies.

Photograph of the set, "illuminurinated" of course.
Outdoors at midday; overcast sky.

Photograph of the set, "illuminurinated" of course.
Indoors, very subdued lighting.

Spectrographic analysis of one of the phosphor red LEDs in this light set; spectrometer's range extended to 820nm in the NIR to capture the unexpected NIR emission.

Spectrographic analysis of one of the phosphor red LEDs in this light set; spectrometer's response narrowed to a band between 440nm and 460nm to pinpoint native emission peak wavelength, which is 447.650nm.

Spectrographic analysis of one of the phosphor red LEDs in this light set; spectrometer's response narrowed to a band between 630nm and 660nm to pinpoint the phosphor peak wavelength, which is 643.230nm.

The raw spectrometer data (tab-delimited that can be loaded into Excel) is at p2r.txt

Spectrographic analysis of one of the phosphor yellow LEDs in this light set.

Spectrographic analysis of one of the phosphor yellow LEDs in this light set; spectrometer's response narrowed to a band between 440nm and 460nm to pinpoint native emission peak wavelength, which is 447.650nm.

Spectrographic analysis of one of the phosphor yellow LEDs in this light set; spectrometer's response narrowed to a band between 560nm and 590nm to pinpoint the phosphor peak wavelength, which is 566.200nm.

The raw spectrometer data (tab-delimited that can be loaded into Excel) is at p2y.txt

Spectrographic analysis of one of the green LEDs in this light set.

Spectrographic analysis of one of the green LEDs in this light set; spectrometer's response narrowed to a band between 505nm and 525nm to pinpoint emission peak wavelength, which is 515.800nm.

The raw spectrometer data (tab-delimited that can be loaded into Excel) is at p2g.txt

Spectrographic analysis of one of the blue LEDs in this light set.

Spectrographic analysis of one of the blue LEDs in this light set; spectrometer's response narrowed to a band between 455nm and 475nm to pinpoint emission peak wavelength, which is 463.150nm.

The raw spectrometer data (tab-delimited that can be loaded into Excel) is at p2b.txt

USB2000 Spectrometer graciously donated by P.L.

TEST NOTES:
Test unit was purchased on Ebay on 11-30-21 and was received at 11:12am PST on 12-04-21.

UPDATE: 01-18-22
Late-afternoon yesterday, I just so happened to be looking directly at the lights when the 6-on/18-off timer automatically turned them on.
Instead of just immediately blazing to full power, these lights turned on slowly -- looked like a ~75ms to ~100ms (milliseconds) "soft start" rather than just instantly turning on at full power.
Nice touch there, Philips!!! :-)

I also happened to note that when the batteries are going to pot, the green LEDs maintain high intensity when all of the others have pretty much extinguished (down to less than 1% of their original intensity or even completely out).
I'm currently at a total loss to explain this behaviour.

The next time that the batteries peter out and only the green LEDs remain lighted, I'll take loaded (lights turned on) voltage and current measurements.

Spectrographically, they look like InGaN (indium gallium nitride) pure green LEDs, but when they're subject to low voltage, they behave like GaAlP (gallium aluminum phosphide) high efficiency yellow-green LEDs.

UPDATE: 01-21-22
I took some Vf measurements both with new batteries and with older batteries where some the LEDs were operating at just a few percent of their original intensity yet the green LEDs were still happily blazing away.
To wit:

Vf with new batteries: +3.13 volts
All LEDs at 100% intensity.

Vf with older batteries: +2.60 volts
Blue LEDs: 10%
Green LEDs: 80%
Yellow LEDs: 2%
Red LEDs: 1%

UPDATE: 01-23-22
I took another Vf measurement; this time, the red & yellow LEDs were completely extinguished and the blue LEDs were down to ~1% of their original intensity -- the green LEDs were still at 50%+ of their original intensity and were still easily visible in broad daylight.
The "under load" (light set was turned on) Vf was 2.49 volts.

UPDATE: 01-25-22
I figured it out!
I figured out what's going on with the low Vf and the InGaN LEDs still going!!
I figured out Blue Clues!!!

As you can see by the photograph directly below, there *IS* a DC-DC inverter in this set that allows those GaN and InGaN LEDs to function on just two AA cells!

UPDATE: 02-01-22
I measured the Vf while the green LEDs were below 1% intensity.

Vf of the set was 2.13 volts.

After I replaced the batteries, I immediately noted a very intermittent connection somewhere in the primary power system; it took a rather concerted effort to get the lights to come on and STAY on.
I will be investigating this some more tomorrow when there's ample daylight.

PROS:
Brighter than expected
Uses just two AA cells, not the usual three

NEUTRAL:
Set has some degree of water-resistance but is NOT submersible

CONS:
Battery life ~~*MAY BE*~~ ***IS*** on the short side.
(this is what nocked that last star off its rating!!!)

Philips

Battery-operated Christmas light set

"Dewdrop" LED

30 (8 red, 7 yellow, 8 green, 7 blue)

N/A

Slide on/off/timer on battery box

Plastic and silvery-colored insulated wire

N/A

2x AA cells

240mA

Light splatter-resistant at best

SANTA KLAUZULE VYPRAZDNOVÁNÍ JEHO JEŠTERKA SE KOMÍN, NE!!!

None

Lighted length 9.6 feet (2.9M)

79.4g (2.80 oz.) incl. batteries

China

Unknown/not stated

Battery-Operated Dewdrop Lights * www.amazon.com...

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