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School me on LED voltage

Old 10-25-2020, 06:19 PM
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Default School me on LED voltage

https://www.amazon.com/gp/aw/d/B07P396KTC/ref=ox_sc_act_image_1?smid=A3TZHQ5NMUI6C3&psc=1 https://www.amazon.com/gp/aw/d/B07P396KTC/ref=ox_sc_act_image_1?smid=A3TZHQ5NMUI6C3&psc=1

9-30 volts, 24000 lumens, I have a $20 12v 5ah battery, what is the expectation?
Old 10-25-2020, 06:35 PM
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240 watts at 12 volts should be 20 amps, so a 5 amp hour battery will not last very long if you try to pull 20 amps out of it ,if it even tries to work
Old 10-25-2020, 06:46 PM
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Originally Posted by CoolerFull View Post
https://www.amazon.com/gp/aw/d/B07P3...5NMUI6C3&psc=1

9-30 volts, 24000 lumens, I have a $20 12v 5ah battery, what is the expectation?
Their numbers are very optimistic. But if true that 24 amps of draw. That rating is usually at 14.4 so at 12 it will be more. What is your batt rating 5ah at 20amp hour?
Old 10-25-2020, 07:09 PM
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If those LED lights do draw 20 amps, you are looking at maybe 3 minutes of run time before your battery is completely discharged. Those batteries can typically handle a max discharge of 75amp for 5 seconds.
Old 10-25-2020, 08:36 PM
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Well, the bottom line is that's not a very big battery.

But, I have some personal experience that can - wait for it - shed some light on the subject. (Sorry).

It is true that volts x amps = watts for a DC device. However, I bought some lights that were supposedly 18W lights (unspecified lumens) and when I connected them I found them to be fairly dim. So I connected my meter and measured a current draw of 0.5 amps. I got to reading the papers that came with them and they claim to have an input voltage of 9-36 volts. LEDs don't run directly on battery power. There is circuitry that regulates the voltage and limits the current to each LED. (Trying not to get too complicated here.) What happens is, the power supply/circuitry draws a constant current across the voltage range. So, the manufacturer claimed they were 18 watt lights because they use 0.5 amps at 36 volts. (36 x 0.5 = 18) BUT, they will also use 0.5 amps at 9 volts and even 12 volts. The point is they use a constant current.

Now back to the OP. Those 240 watt light probably draw 8 amps (240/30 = 8). If the battery is in good shape and fully charged, you might get 30 minutes (5/8 hours). At best.
Old 10-26-2020, 01:59 AM
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What sort of LEDS will draw 20 amps at any voltage?
Old 10-26-2020, 04:09 AM
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Originally Posted by 23_WA_Proline;[url=tel:14166608
14166608[/url]]Well, the bottom line is that's not a very big battery.

But, I have some personal experience that can - wait for it - shed some light on the subject. (Sorry).

It is true that volts x amps = watts for a DC device. However, I bought some lights that were supposedly 18W lights (unspecified lumens) and when I connected them I found them to be fairly dim. So I connected my meter and measured a current draw of 0.5 amps. I got to reading the papers that came with them and they claim to have an input voltage of 9-36 volts. LEDs don't run directly on battery power. There is circuitry that regulates the voltage and limits the current to each LED. (Trying not to get too complicated here.) What happens is, the power supply/circuitry draws a constant current across the voltage range. So, the manufacturer claimed they were 18 watt lights because they use 0.5 amps at 36 volts. (36 x 0.5 = 18) BUT, they will also use 0.5 amps at 9 volts and even 12 volts. The point is they use a constant current.

Now back to the OP. Those 240 watt light probably draw 8 amps (240/30 = 8). If the battery is in good shape and fully charged, you might get 30 minutes (5/8 hours). At best.
Some alternative facts right there.
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Old 10-26-2020, 04:28 PM
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Originally Posted by 23_WA_Proline View Post
Well, the bottom line is that's not a very big battery.

But, I have some personal experience that can - wait for it - shed some light on the subject. (Sorry).

It is true that volts x amps = watts for a DC device. However, I bought some lights that were supposedly 18W lights (unspecified lumens) and when I connected them I found them to be fairly dim. So I connected my meter and measured a current draw of 0.5 amps. I got to reading the papers that came with them and they claim to have an input voltage of 9-36 volts. LEDs don't run directly on battery power. There is circuitry that regulates the voltage and limits the current to each LED. (Trying not to get too complicated here.) What happens is, the power supply/circuitry draws a constant current across the voltage range. So, the manufacturer claimed they were 18 watt lights because they use 0.5 amps at 36 volts. (36 x 0.5 = 18) BUT, they will also use 0.5 amps at 9 volts and even 12 volts. The point is they use a constant current.

Now back to the OP. Those 240 watt light probably draw 8 amps (240/30 = 8). If the battery is in good shape and fully charged, you might get 30 minutes (5/8 hours). At best.
Thats not how it works. What is Vf of load? Buck or boost? If your CC output required 500mA you would not have Iin of 500mA regardless of supply voltage.
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Old 10-26-2020, 04:36 PM
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Reading some of the comments that 240 watts sounds incorrect. One of them says "Definitely not 240w. Tested at 26.2w each" and another one says they draw about 3.2 Amps each, so somewhere between 2 and 3.2 Amps might be the real answer. On a 5AH battery, that's net you a bit over an hour or maybe up to two for one light on one battery.
Old 10-27-2020, 12:51 AM
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I doubt those little lights are that bright. The 50” light bars are around 30,000 lumum.
Old 10-27-2020, 04:14 AM
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Light: Watts / Volts = Amps: 240W / 12V = 20 A. These lights draw 20 Amps.
Battery: Amp Hrs / Amps = Hrs: 5Ah / 20 A = .1/4Hr. = The battery will las15 minutes.

But, you'll never get 100% of the rated Ah from a battery. As they get closer to discharge, the voltage drops. I'm assuming your battery is lead acid. If that's right, figure about 70% - 75% of the rating. You'll get the full 5Ah but the last part of that will be at too low a voltage to be useful.

I think you can run these lights for 10 minutes.
Old 10-27-2020, 09:11 AM
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Read more of the comments on the Amazon site. These lights have to be closer to 2A each at 12VDC. Lots of folks are using 16 GA wire which wouldn't work well if they were really drawing 20A.

I think the 240W is an "incandescent equivalent" rating, not an actual power rating for the LEDs.
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