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How many amps do i need to power two LED Cob 9v bars ? Answered

I was wondering how many amps would these two LED bars need in order to work if connected in series, and would a regular 9V battery be enough to power them ?


What kind of battery should i use if a 9v isnt enough ?



Best Answer 2 years ago

You need a minimum of 18VDC at 1/4Amp.

It could be done with two 9V batteries also in series, But why not run each on its own nine volt battery.

Also you will only have a few minutes time on an alkaline battery and the cost of a Li is prohibitive.

Try 6 AA batteries in series as a minimum and run the lights in parallel.


Because of very limited space, 6 AAA batterys should work but I dont know how long would they last.

A typical alkaline AAA has a 860–1,200 mah rating so at 250ma times two sets is 500 ma.

860ma-hrs/500ma = 1:43 low end to 1200ma-hrs/500ma 2:24 high end..

An AA Battery can deliver 2600ma-hrs/500ma = 5.2hrs => 5:12

Your answer is within your question.
If they are 9V and each has 3W they need at least 660mA to work - far more than what a 9V battery can supply.
Your link is not working, so I can't check the data for the LED's but if they are without the regulating electronics you will need a suitable LED driver board for them.