# Powering LED strips with batteries

I am sort of a beginner at electrical engineering, could someone help me figure out how I can power an LED strip with batteries?

The led strips that I am looking at using are these. They takes 12Volts input, and use about 3Amps. I want to know how I can power these lights at full capacity with batteries / which batteries should I choose?

I'm thinking maybe one of these and a boost converter to go along with it? Or is there a cheaper way? I just want to make this LED strip portable with a battery pack so I don't have to plug it into the wall. Also, how long will these batteries usually last if the strip uses about 3 Amps?

Sorry if these questions seem basic, but any help is appreciated!

• "Which X should I choose?" can be a very open question and depends on your goals and constraints, which you didn't specify. Do you need them to last 10 hours? Do you need them to fit inside a 2x3x3cm box? Do you need them to be rechargeable? Do you need them to weigh less than 50 grams? Consider "Which car should I choose?" and think about how you would answer that if a stranger asked you.
– Bort
May 27 '20 at 22:20
• Your links get blocked by my ad-blocker btw. Not sure if that's just me? Better to include the details in your post as those links won't live forever.
– RJR
May 28 '20 at 7:33

That battery pack is advertised to supply 25800 mAh @ 5V. Even though I am skeptical of those claims, let's use those numbers.

25800 mAh is 25.8 Ah. That means it can supply an amp for 25.8 hours, or 25.8 amps for one hour (of course you can't really draw that much current).

A boost converter will step this up to 12 V, but consume current to do so. let's use the ratio 12/5 to estimate our current needs.

$$3\ A * (12\div5) = 7.2\ A$$

What this means is that to draw 3 A @ 12 V, the 5 V side of the converter needs to draw at least 7.2 A (it will be more due to inefficiencies).

This is more current than a pack like that can supply.

If it could it would run for: $$25.8\ Ah\div7.2\ A=3.58\ h$$

Lead-acid batteries are more suited to these levels. Unfortunately they are often large and heavy, but they do make smaller ones. Look into UPS batteries and evaluate their capacity the way I have shown here.

Example UPS battery

They do make rechargeable lithium packs in 12 V that might work for up to an hour. Search for "12V rechargeable lithium".

Example lithium pack

• Thanks for the info, really helpful! For the Example lithium pack, how do I know if it will produce 3Amps? Because it shows the Voltage and mAh specs, but not the Amps May 27 '20 at 22:12
• google milliamp May 28 '20 at 4:13
• $$1\ mA=0.001\ A$$ $$1\ mAh=0.001\ Ah$$ For the max current draw, you need to find that for each battery. The battery pack you linked shows a 3.1 A max output (although in the reviews some people's measurements showed it can't even supply that much). Lead acid batteries can usually supply much more current than other battery types. May 28 '20 at 16:57
• Just checked the example lithium pack I linked in my answer, if you scroll down you will see it supports "output current: 1 - 2.4A" which is not enough for your strips if they really draw 3A. May 28 '20 at 17:03