Could/should the Cree LED light bulb be adapted for 12v use?

ThrowerLover · Jul 23, 2013

The Cree light bulbs available from Home Depot are 6 watts up to 9.5 watts. I put a 6 watt version into a plug-in light socket adapter and plugged it into a 12v-to-120v inverter in my truck. It appeared to be as bright as when I screwed it into a standard socket at home. My question is: Would this make an acceptable light driven by an automobile battery under the two different conditions of 1) the engine idling or 2) driven strictly by the battery? I can see a number of uses for this setup, especially if used with a clamp lamp that has a reflector.

mds82 · Jul 24, 2013

basically you would need a different driver for it.

JohnR66 · Jul 24, 2013

There are already LED bulbs available that run on 12v AC and DC, such as the ones in the GU5.3 socket type. Since they are already the reflector style, there is no need for the big aluminum reflector. Otherwise, It is easiest just to run the Cree bulbs off the inverter.

Here is a 4w Samsung MR16 bulb that I use.

ThrowerLover · Jul 24, 2013

mds82 said:
basically you would need a different driver for it.

I'm gonna pretend for a moment that I know something about electricity, so bear with me.:thinking:

The voltage will have been converted to 120 to drive the bulb. My question is about efficiency. I already own all the stuff: the bulb, the plug-in socket adapter, the clamp lamp with reflector, and the 12v-to-120v inverter. What I'm wondering is if this set-up would drain the battery unnecessarily due to either the wattage of the bulb or because of the possible inefficiency of the inverter.

Maybe some of you technically oriented folks know how to do the math to estimate how long you could run this setup off of an "average" car battery.

brickbat · Jul 24, 2013

ThrowerLover said:
...What I'm wondering is if this set-up would drain the battery unnecessarily due to either the wattage of the bulb or because of the possible inefficiency of the inverter.

Maybe some of you technically oriented folks know how to do the math to estimate how long you could run this setup off of an "average" car battery.

We can't really 'do the math' because we don't know which Cree lamp you're referring to, and we don't know the efficiency of your inverter. We also don't know how severely you want to thrash your car battery. A new car battery in good shape is good for about 50 Ah, but you don't want to pull the full capacity out very often - ideally never, as they're just not designed for that type of service.

idleprocess · Jul 24, 2013

ThrowerLover said:
I'm gonna pretend for a moment that I know something about electricity, so bear with me.:thinking:

The voltage will have been converted to 120 to drive the bulb. My question is about efficiency. I already own all the stuff: the bulb, the plug-in socket adapter, the clamp lamp with reflector, and the 12v-to-120v inverter. What I'm wondering is if this set-up would drain the battery unnecessarily due to either the wattage of the bulb or because of the possible inefficiency of the inverter.

Maybe some of you technically oriented folks know how to do the math to estimate how long you could run this setup off of an "average" car battery.

In a perfect world, your 6W bulb driven by a lossless inverter would draw 500mA (0.5A), which would take about 100 hours to drain a 50 A-H battery. In reality, your inverter is perhaps as low as 80% efficient, meaning 625mA of draw or ~80 hours to drain. If you wanted to run it for an hour or two, probably no harm of running your battery down to the point of being unable to start the vehicle (I've certainly done the same with my own vehicles on occasion powering AC loads with an inverter); probably not so much so if you want to light your remote cabin for a week-long vacation without starting the vehicle occasionally.

Could/should the Cree LED light bulb be adapted for 12v use?

ThrowerLover

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mds82

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JohnR66

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ThrowerLover

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brickbat

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idleprocess

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