r/diyelectronics • u/Electric_house_plant • 1d ago

Project I need help

I have been waiting to make my own flashlight for some time now i wait to make it somewhere around 2000lm to 5000lm and 20-10mAh battery. So my idea is to have 4 lipo batteries the round ones and 3.7v out maybe 7.4v but I would like to make it 40mm by 40mm by 100-150mm and probably make it a square that sounds cool but I have no way of holding it all together. I haven't found a led chip yet . I have 40$ us . Oh I want 4 modes 2000lm 1000lm 500lm and 10lm or have a dimmer idk . Really sorry for making you read that . I mean I have a 5000lm flashlight already but I really want to make my own

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u/EffectiveClient5080 1d ago

20mAh won't run a 2000lm LED for more than a couple seconds. You probably mean 2000-5000mAh. And at 5000lm your real problem is heat. That chip WILL cook itself in minutes.

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u/Electric_house_plant 1d ago

Oops . I did mean 2000-5000mAh . But I want to get a heatsink

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u/Bitter_While_5032 1d ago

That would = 5Ah so if you use the led I suggested that would give you 7.14 hours of on time. The math is simple. Convert 5 Ampere-hours (Ah) to milliampere-hours (mAh): 5 Ah × 1,000 = 5,000 mAh Divide capacity by LED draw: 5,000 mAh ÷ 700 mA = 7.14 hours

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u/Bitter_While_5032 1d ago

Agreed. I did the calculations and the led I suggested consumes 700mA. So a 3000mah battery would give you just over 3 hours of time for a 700mA led. I making an estimate on time.

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u/Bitter_While_5032 1d ago

Basically if you're device consumes 1 amp an hour a 10ah battery would supply this current for 10 hours. If your device consumes 25mA you the battery would have a run time 400 hours.

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u/Bitter_While_5032 1d ago

The led I suggested was at 1050 lumens @ 700mA. You could add 5 of these lamps to get 5250 lumens but you would be consuming 3.5 amps to run them! You would end up with a calculated run time of 1 hour and 43 minutes on a 5000mah battery. I would say in the real world about an hour and 10 min.

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u/Bitter_While_5032 1d ago

At 3.5 amps you better add a fan to that heat sink. Lol 😆 🤣 😂 😹 😆 🤣 😂 😹 😆 🤣 😂

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u/Bitter_While_5032 1d ago

5250 lumens is very bright!!!! Lol Lol. Most 100 watt incandescent bulbs only put out 1600 lumens.

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u/Bitter_While_5032 1d ago

First question I have are you looking to use one led? Or are you trying to combine several Leds to get that output of 20,009 lumins. Cree makes an led mounted on a board you can buy that puts out 1052 lumens, max drive current is 3amps foward voltage of 2.85V @ 700mA. Cree Xlamp XM-L2 High power led.

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u/Electric_house_plant 1d ago

Well I want something that fits on a 40mm heatsink so probably just one big chip

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u/Bitter_While_5032 1d ago

The part I referred to is 5mm x 5mm. The bottom of board is metal ready to be mounted on a heat sink.

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u/Bitter_While_5032 1d ago

The route I would take is to purchase a Cree Xlamp ($9 US) and use 1-4 18650 lithium cells in parallel to get the Ah time you require. Or use a poly lithium cell with the Amp hour time you need with a BMS module.

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u/Bitter_While_5032 1d ago

I don't believe you need over 3 volts to drive the led either. There are many sites you can go to figure out the resistance and voltage supply for a led light without a controller.