How to connect LED strip to batteries?

Hello everybody,

I am trying to make a small lamp powered by sections (3 leds each) of a LED strip wired together.
I tried attaching a section of the strip to a 9V battery and it works great. however, I heard that it will only last a few hours.

I am looking for something that perhaps will last a few days? More if possible? I am trying to make this as simple as possible, with an ON and OFF switch. Will I need resistors or anything extra for such a build?

Thanks for any help !!

if you want a LED strip to run for a few days on battery, you will need a much larger battery, or a lot of smaller batteries. you could try 2 of those large 6V heavy duty batteries run together to give you a 12v output. google the Eveready 1209 battery, something like that

mds82 said:

if you want a LED strip to run for a few days on battery, you will need a much larger battery, or a lot of smaller batteries. you could try 2 of those large 6V heavy duty batteries run together to give you a 12v output. google the Eveready 1209 battery, something like that

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Thank you you for your reply.

I am only trying to wire/solder to the battery like 3 led lights though, NOT the whole 5 meter strip. Will I still need a huge battery ?

Also, how long should it run on a 9V battery ??

thanks

it depends on the led strip, give it a shot and see. maybe a few hours

No way anyone can tell you how long without knowing what the LEDs are. Or what the battery is for that matter. Probably less than a day, maybe an awful lot less. Since LEDs are so sensitive to voltage changes (tiny voltage change, huge brightness change), they nearly always require some sort of current control. The crudest form is to run in series with a resistor, so for example 3 LEDs and a resistor could be run from 12V. Otherwise as soon as the battery shows the slightest voltage drop the LEDs get too dim to be useful. Or alternatively if the voltage is slightly too high, like while charging, then the LEDs blow up

A good 9V battery is going to hit 8V at about 200-250mA.

With a typical 12V strip, where each LED grouping is about 20mA (they can be 10-50mA), at 9V, you are likely going to be about 3-6mA. It could be less, probably will not be much more. I would estimate with a good alkaline 9V battery, one group of 3 LEDs from a 12V strip (with the resistor of course embedded in the strip), will probably run about 40 hours. Is that enough light for what you need? ... only you know that.