12V to HUB Industries LED's

[DrunkHalfWit]

Good day everyone!

I have a project in mind and I will need some help or direction to where to go to find some answers.

Here it goes;

I have 6 LED Puck lights from HAB Industries. They all use 3 AA Batteries. I would like to wire them all (series or parallel, not sure which one would be best) and have them connected to a 12v (car) battery, which would be charged everyday with a solar panel. The solar part to the battery, I can take care of that. Now my question is, how can I connect them using a 12v battery?

All I know is that I will need resistors. But there is nothing on the website or the light itself that indicates the mA. I don't even know how to find the mA on the device itself. I do have a meter.

Some help would be greatly appreciated.

The DrunkHalfWit

 

[D.A.(Tony)Stewart]

These devices are unspecified but 3AA's will be 4.5 to 5V with fresh batteries. THe LED's look like low current devices anywhere from 20 to 60mA each at 3V. SO there must be some DC-DC regulator.

Power Networking these will be more reliable in parallel as the load will vary in series and cause interaction when dimmed.

THus you need a 12V to 5V regulator such as those used for USB.

 

[DrunkHalfWit]

Awesome! Thanks for such a prompt response!

Now, I do understand the reliability of the parallel wiring. It does make sense and if one fail, the others will still work. So Parallel it will be.

Now, I understand that I will need some sort of regulator or resistors to bring down the voltage. Although, my question at this point is if each unit needs at least 3v to operate, how is the last (of 6) in the parallel line will get that 3v if I have reduced the voltage from 12 to 5? And also, I am not very literate in this field, but is one single 12v (car) battery will provide enough power to keep these lights (3v x6= 18v) on for a few hours?

Cheers!

 

[Audioguru]

You cannot calculate how long a battery will power the LEDs because you do not know how much current they use. Post the datasheet for the LED puck.

 

[kam1787]

..... will be more reliable in parallel as the load will vary in series and cause interaction when dimmed.

To my mind the same is true for parallel.

Series is usually more efficient and wastes less power. Granted IF [a big if] one LED fails then all the LEDs will be off but in a properly designed circuit with good quality LEDs that is quite unlikely.

I'd suggest putting 2 pucks in series. Measure the current and calculate your resistor (12V-9V)/current

The 2 pucks and resistor form a set. Put 3 sets in parallel.

Now the trouble is that [lead-acid] battery voltage does vary considerably from [about] 10.5V to [about] 14V. A fully charged battery [assuming you will not be using the LEDs while charging] could over-tax the pucks.

How important is light being constant? If very important then use a LDO regulator, or constant-current regulator. Otherwise use a resistor. Check the battery voltage, when fully charged, and use that voltage in calculating the resistor [ (fully charged voltage-9V)/current ]

- - - Updated - - -

........... is one single 12v (car) battery will provide enough power to keep these lights ... on for a few hours?
!

Putting all the 'pucks' in parallel will waste power, and decrease the time the LEDs will be on.

[BTW putting all the 'pucks' in parallel, and having one voltage regulator does mean that if the regulator fails, then all the LEDs will be off - so much for reliability]

You need to take some measurements. Measure how much current a puck draws.

Is it a standard automobile battery you are using? If not you need to find out the AH of the battery [although AH does vary amongst car batteries]

IF the battery AH is say 30, and IF you wire the 'pucks' as I previously suggested and the battery is fully charged, then I would GUESS that they could last for 50 to 100 hours.

 

[kam1787]

Are these your 'pucks'? **broken link removed**

The data-sheet is useless here **broken link removed**

 

[Audioguru]

If the pucks have 6 LEDs (not 5 as in the photo) and are fairly bright at 20mA for each LED then a puck's current is 120mA and the three AA alkaline cells will last for about 15 hours, slowly dimming the entire time.
A car battery will light 6 pucks for "years". Use AA Ni-MH cells in the pucks instead.

 

[D.A.(Tony)Stewart]

To my mind the same is true for parallel.

Series is usually more efficient and wastes less power.

This design requires voltage between 3-5 V like 3 series cells. There is no way to predict how the current will change from the lack of specs.

I would imagine two pucks inseries off 12V, with one off and the other on bright would result in failure to share the voltage evenly. A parallel regulator is essential for each puck.