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Discussion Starter #1
I would like to make some PVC candles for my graveyard using the tea light candles but need help with powering them. I set my display up the first of October and it is up until the first week of November. The batteries that come with the tea lights would never last and the hack with 4AA batteries wouldn't work for me either. I have all of my tombstones lit with LED spotlights from MiniSpotlight.com and they are powered with their power supply, which outputs 12 Volts. I run low voltage wiring between each row of tombstones with a LED Spot shining on each stone. All of the LEDS go to the one power supply mentioned above. I have about 30 Spots and would like to be able to use the PVC Candles in front of the tombstones and just connect to the wiring I am already using. Is there an easy way to add a resistor somewhere to drop from the 12v to 5v so I can still use my existing set up? If so how do I figure out what resistor to use? I remember reading someones post that the tea lights can handle 4.5 - 5 Volts only before blowing the circuit board and LED. I know just enough about wiring to be dangerous so I am looking for the simplest way of doing this, I don't want to have to make a flicker circuit or run additional wiring through my graveyard. Any help will be greatly appreciated.
 

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Going bump in the night..
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Here's a wizard to help you figure out a resistor to use for the voltage.
LED series parallel array wizard

is your low voltage power supply a "traditional" yard lighting transformer? (ala Malibu lights)
Make certain you have one strong enough to provide juice to all the added units - just LED's add only a little, but the flicker tealights might draw more.
 

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Discussion Starter #4
Homestead Haunt: I had thought about that but after seeing everyone's candles flickering I was hoping to get that effect. I might just have to end up going that route.

Ugly Joe: I'm not sure about the transformer, I met the guy that owns the company I bought the lights from at HauntCon a few years ago. He said the transformer I bought would run 100 LED's. I'm not worried about the transformer being able to handle the load as much as the tea lights being able to handle the volts. I'd hate to make up a couple of dozen and fry them after 2 nights use.

Thanks to both of you for the suggestions. Anyone know if I can just add a resistor to the wiring going into the bottom of the candles to drop the volts? Any ideas on a SIMPLE way to get the PVC candles to flicker using my existing low voltage wiring?
 

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The Evil Apparitionist
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Homestead Haunt: I had thought about that but after seeing everyone's candles flickering I was hoping to get that effect. I might just have to end up going that route.

Ugly Joe: I'm not sure about the transformer, I met the guy that owns the company I bought the lights from at HauntCon a few years ago. He said the transformer I bought would run 100 LED's. I'm not worried about the transformer being able to handle the load as much as the tea lights being able to handle the volts. I'd hate to make up a couple of dozen and fry them after 2 nights use.

Thanks to both of you for the suggestions. Anyone know if I can just add a resistor to the wiring going into the bottom of the candles to drop the volts? Any ideas on a SIMPLE way to get the PVC candles to flicker using my existing low voltage wiring?
I would use one of these on each tea light :

78L05 Positive Voltage Regulator-The Electronic Goldmine


The tea lights only draw a few milliamps at most and this 5 volt regulator is good up to 100 max, 50 or so nominal. It will keep the voltage at 5 volts. A simple resistor will not work since the current is always fluctuating up and down on tea lights.

Regulators like this have three terminals and are easy to hookup (you could solder it inside the tea light). There is a Vin (voltage in - your 12 volt supply positive, a Vout (5 volts for the tea light), and a ground (connects to both the negative lead on the 12 volt supply and the tea light).

 

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Discussion Starter #6
I would use one of these on each tea light :

78L05 Positive Voltage Regulator-The Electronic Goldmine


The tea lights only draw a few milliamps at most and this 5 volt regulator is good up to 100 max, 50 or so nominal. It will keep the voltage at 5 volts. A simple resistor will not work since the current is always fluctuating up and down on tea lights.

Regulators like this have three terminals and are easy to hookup (you could solder it inside the tea light). There is a Vin (voltage in - your 12 volt supply positive, a Vout (5 volts for the tea light), and a ground (connects to both the negative lead on the 12 volt supply and the tea light).


Yes! That is exactly what I needed to know. Thanks HomeyDaClown! I appreciate everyone's help with this. I've been making props for years but am just starting to get my feet wet with electronics, that's the reason I want to use the circuit already built into the tea lights instead of making my own. If someone has a different approach to the PVC candle/flicker/all off of same low voltage wiring I'm using for regular 12v LED'S (whew!) I'd love to hear it but if not I think I will be ordering some Voltage Regulators.
 

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The Evil Apparitionist
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Yes! That is exactly what I needed to know. Thanks HomeyDaClown! I appreciate everyone's help with this. I've been making props for years but am just starting to get my feet wet with electronics, that's the reason I want to use the circuit already built into the tea lights instead of making my own. If someone has a different approach to the PVC candle/flicker/all off of same low voltage wiring I'm using for regular 12v LED'S (whew!) I'd love to hear it but if not I think I will be ordering some Voltage Regulators.
With the regulators pretty small and cheap you will be creating 12 volt flicker lamps to match your LED spots. The nice thing is that regulators don't care if the current draw changes (as long as you stay away from the max rating) the voltage output will be a constant 5 volts on the output. The regulator should fit right inside the tea light's battery compartment, no need to open the case, just solder it to the battery terminals and cut or drill small holes for the two power wires to exit the lid. Just make sure you tie both negatives (flicker light and 12 volt supply) to the same ground pin on the regulator.
 
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