# 12v LED Strip with 12v battery, 300 SMD LED

#### Nathanzieber

Joined Nov 2, 2015
3
Hey folks,

Pretty new to all of this.

I'm building a lightsaber with a friend and we're using a 300 SMD LED strip that's 5 meters long. We'd also like to add a small motor. They would be (preferably) powered together and toggled on/off with a switch.

The problem is, we'll need to fit the power supply into the handle.

Is 12v batteries the best option?
Could I wire multiple ones together to provide enough power for the small motor too?

Sorry for the lack of details, I'll post the product link below to hopefully provide the necessary details.

Led's: http://www.amazon.ca/dp/B00VUDUKPG/ref=pe_386430_126088100_TE_item

12v batteries:
http://www.amazon.ca/gp/aw/d/B00891...2v+battery&dpPl=1&dpID=41IPmpfGp5L&ref=plSrch

#### blocco a spirale

Joined Jun 18, 2008
1,546
You will struggle to power the device with those tiny batteries, they are not suitable for this application.

Ideally, you need to know the voltage and current consumption and expected running time of the LEDs and motor, then you can select the correct batteries.

But, for intermittent use, 8x AA cells (in holders as 2x sets of 4) should be sufficient and can be fitted within a tube of suitable diameter.

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#### Nathanzieber

Joined Nov 2, 2015
3
You will struggle to power the device with those tiny batteries, they are not suitable for this application.

Ideally, you need to know the voltage and current consumption and expected running time of the LEDs and motor, then you can select the correct batteries.

But, for intermittent use, 8x AA cells (in holders as 2x sets of 4) should be sufficient and can be fitted within a tube of suitable diameter.
The handle would need to contain the motor on top of the power source though.
Would using multiple 9V batteries be worth it?
Changing out the batteries every few hours of use is not a problem for me.
It's more of a novelty item for us.

#### blocco a spirale

Joined Jun 18, 2008
1,546
Neither the 12V batteries you linked to nor 9V pp3 batteries are suitable for applications that can draw large currents ,i.e. motors and large LED arrays, they are also expensive compared to batteries comprising AA or AAA cells. 8xAA cells wouldn't be any larger than "multiple 9V batteries" and, of course, 9V isn't 12V which is what the LEDs require and it would rapidly drop to 7V under load.

#### #12

Joined Nov 30, 2010
18,222
I figure about 2 amps for 100 groups of (3) LEDs. Confirmed by the recommended power adapter which is rated for 12 volts, (2) amps. This puts you in the range of alkaline "D" cells for three hours. "C" cells only calculate to 9 minutes. Then you need more power for the motor.

This makes me think about NiMH cells because of their low internal resistance and more energy per cubic inch. Here is a one hour option for $20: http://www.all-battery.com/12v2000mahnimhbatterypack11606.aspx and here is the vendors page: http://www.all-battery.com/12vnimhnicdbatterypackseries.aspx Here are the raw AA cells to last one hour at 10 for$19 if that configuration makes it convenient to assemble the right shape for the handle:
http://www.all-battery.com/10pcsaa2300mahnimhrechargeablebatteryflattopformakingpacks-90481.aspx

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#### Nathanzieber

Joined Nov 2, 2015
3
Okay. That's something to work with.

I'm rethinking the power source.
Ideally, if you figured correctly, what would be the longest lasting battery alternative? If I did want to make it last longer than a few hours?

I can also cut the strip down significantly. To 8 feet.

#### #12

Joined Nov 30, 2010
18,222
what would be the longest lasting battery alternative?
The longest lasting battery alternative is to plug it into the wall with the recommended power adapter.
The longest lasting battery alternative that I have met is a forklift battery, but I hear submarines have larger batteries.
Apparently I am failing to understand your question.

Eight feet of LEDs is 48 strings @0.02 amps each for a total of .96 amps. Half the length requires half the current, give or take the difference between a yard and a meter.

Here is 5 hours of "C" cells at $48: http://www.all-battery.com/12pcsofcsize5000mahhighcapacityhighratenimhrechargeablebattery90420.aspx Here are 10 hours of "D" cells for$96:
http://www.all-battery.com/12pcsofP...cityhighratenimhrechargeablebatteries904.aspx

All these prices seem to amount to \$10 per amp hour. It seems to me that, by now, you should be able to look at the battery sellers and figure out that 5000 ma hours is 5 amp hours, and you could get an amp for 5 hours out of that.