100w led check

DIWdiver said:

1. No, you shouldn't need a separate driver. Any reg with a good current limit should be enough. That's all an LED driver is. Whether that one qualifies as 'good' might not be a certainty, but I think there's a good chance it will.

2. Suitability of that battery depends on what you are expecting. That battery is 12V, 7 Ah, at a 20 hour rate (meaning 1/20th of the capacity for 20 hours, in this case 7/20 = 0.35A). That gives you 84 Wh. If you are going to push the LED to 100W, the efficiency of the reg is going to drop, probably to 80% or so, meaning you'd be pulling 125W from the battery. That's over 10A. At such a high rate the capacity will suffer notably and the voltage will drop some too, so you'll probably get around 30 minutes plus or minus a few. If you're happy with that, then the battery is suitable. Yuasa is a decent brand, but beware that you might get an old battery from fleabay (look to see if the datestamp has been tampered with). That battery is designed for lighter loads. A battery designed for heavy loads would suffer less ill effects, but you would pay for it.

3. You can connect a 12V fan directly to the 12V battery. They are designed to work that way.

4. No question the way to control brightness is to adjust the current limit on the supply. If you want something more user-friendly than the trimpot on the board, then remove the pot on the board and wire in a larger single turn pot. I could help you figure out how to make sure the top end of the pot is only 3A or so. That way, you won't be able to turn it up to 5-10A and fry the LED.

5. 100W is pushing that reg pretty hard. I would expect the efficiency to suffer, as I mentioned above. Of course I'm just guessing based on a few decades of experience with switching power supplies, including LED drivers. It could be a little better or much worse than I estimated. I would also expect it would want to be cooled. I'd blow some of that air in the direction of the reg.

6. To take some strain off both the reg and the battery, I'd use two of those batteries in series. That would more than double your battery life, and (probably) keep the reg cooler and more efficient.

7. I'm anxious to hear about some experiences with those cheap fleabay regs. They look quite promising, and might be a real boon to the DIY community. Please post results, and don't hesitate to ask if you need more help.

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