LED and Batteries

Hi Guys,

I am looking at a project over the next few weeks were I am looking to mount a high output LED source with a battery.

I am stuck on a few bits and bobs (well, sort of the fundaments) and hoped that there are some experts who can help....

Basically, I am looking to replace some current bulbs I have with LED Sources. The bulbs however are 120W and 230V! Essentially Par 38's.

I want to look at a different bulb, with an LED source so am firstly looking for reccomendations on sources. I am looking for the source to be (ideally) low voltage. Along the lines of 6V or 12V. Does anyone know if such things exist that can be within these requirements and give relative brightness to around 120W tungsten (but obviously not tungsten)?

Secondly, I am looking for a battery to run this. The battery life I would like to be in the region of 8-10 hours before a re-charge is required...... and of course the charger. I am looking to make a few of these units so anything that could charge multiple units would be of interest.

In terms of circuits, again not really my expertise in dealing with re-chargable devices. I assume a connector like an XLR would be mounted on my 'box'. This would go into the battery for charging? Also on the 'prongs' of the said battery wired in paralell would be the 'outputs' and these would go via a simple rocker switch to the LED source....

Does this sound fairly plausable? Do I need to add lots of additional circuitry or is the simple (and straightforward) method a reasonable one?

Sorry if any of this is a bit vague, but I am hoping the people here can help me

Cheers
Neil

oh, I like to use Rapid for parts, unless there are other suggestions - I guess it comes down to what the products are.

From what I can understand, you want to run some LEDs on a battery, that will produce the same amount of light compared to a 120 W tungsten. And you want to run them at 6 or 12 V.

What battery do you want to use ? How large can it be ?

Try to be more explicit

Like Calinoaia says, we need a little bit more info on your requirements. If size isn't an issue, you could use a standard 12V car battery which has the capacity to power enough LEDs to put a 120W lightbulb to shame. But then there are the issues of how you are going to set those LEDs up so that they properly illuminate. Are you looking more directional or ambient lighting? If you need a little something a little more svelte, you're probably looking at Lithium Ion, which you can put in series to get the 7.4V or 14.8V you need, but then you need to worry about balanced charging.

Either way it should be fairly simple...

Hi guys

I wrote a reply here with an image.....but I can't see it, can you?

Or do I need to re-post?

Please repost, I can't see it either.

dam, I think its done it again?

I cannot see the pic either, that's a pity. Won't you try it again? You could upload it at tinypic or some similar site and post the link here? I think this would be an option, if you want to try it again? I would recommend a 12V car battery because this is enough power for the lights I guess!

There are many ways to design this type of unit. I would use the following basic design process:

A typical 120W incandescent bulb has a luminous flux (perceived power of light) of about 2100 lumens.

First, let’s choose a high power LED with a forward voltage of 12V so that it can be powered by a typical sealed lead acid battery. Consider the Bridgelux warm white LED BXRA-W0802-00Q00. This LED outputs 930 lumens and draws 1.05A at 12.2V. So putting three of these LEDs in parallel would give us 2790 lumens at the nominal supply voltage.

Next, you said you were looking for 8-10 hours run time. The three LEDs would draw about 3A, so I might select a 12V 30AH sealed lead acid battery such as Powersonic PG12V28FR.

This is a high level approach that would then be followed up by detailed study of all the performance graphs.

Hope this helps.

"StrykerTECH":http://www.stryker-tech.com/ Engineering Staff

That sounds great.