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How i can use a 12 V 7 Ah battery to power up a 3w led light box

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arecssor

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Hi,
i want to take power from a 12v 7 ah battery to 3 watt led board (the led board contains 50 units of 2 led connected in series linked in parallel led board.png along with a 56 ohm (please ignore the 470 ohm ) in series as in the image .when i use 7805 to reduce the voltage the ic is getting very hot , how can i powerup the led box without heating the 7805 ic and with high running time .
 

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alexxx

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There is a big power dissipation on the regulator. Better use a step down LED driver for the LEDs. For the MCU you can still use the 7805.
 

KlausST

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Hi,

You need to know voltage and current of LED panel.

Klaus
 

arecssor

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hi my led panel is using 6v 100 mA in this case how we can power the led panel from the 12v 7Ah battery

- - - Updated - - -

is that ok to use a dc to dc down converter, in this case what will be the running hours
 

KlausST

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Hi,

6V 100mA LED panel gives 0.6W. But you talk about 3W.

you said you connected the panel to a 7805 which gives only 5V, so I doubt there will be high enough current to heat up the 7805.
Please review all your given values.

Klaus
 

arecssor

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Hi,

6V 100mA LED panel gives 0.6W. But you talk about 3W.

you said you connected the panel to a 7805 which gives only 5V, so I doubt there will be high enough current to heat up the 7805.
Please review all your given values.

Klaus

sorry for the mistake the led panel is 3w (6v ,500mA) in this case 7805 will heat up right? so ow can i avoid that if i use a dc to dc step down converter module is that ok is there any other stable and reliable way to take 5-6v 500mA from the 12V 7Ah battery
 

KlausST

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Hi,

is there any other stable and reliable way to take 5-6v 500mA from the 12V 7Ah battery
No. Switching regulator, step down = buck.

Klaus
 

arecssor

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Hi,


No. Switching regulator, step down = buck.

Klaus

in that case what will be the running hours in both load case
1. if am using 7w led pannel load (12v ,600 mA)
2. if am using 3W led panel (6v,500mA)

in the above case as per your opinion which option is best using the 7w led panel structure or 3w led panel structure by considering
1. total running hours that can achieve with the 12v 7 Ah battery
 

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Hi,

You can do the simple calculation in your own. For this you don't need us.
Just follow the example calculation I gave you in your parallel thread.

Klaus
 

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