How many RGB strips and dumb strings on MR16

[SteveMaris]

Hey guys,
I read one thread regarding this same topic but there was conflicting answers.
I also read in the wiki that the MR16 can handle 35 amps.
Can someone please clarify how many total watts each 3 channels can handle?

I have dumb strings outlining my roof. It is looking like I will need 2 strings of 100 each. Each string is 0.3 watts per pixel for a total of 30 watts a string. Can I put 200 pixels (60watts) on 3 channels? I also plan on using an additional 4 5m meter 60 led per meter (72watts) on the other 12 Channels.
Am I off base here?
Thanks..Steve

[rm357]

It's 2.5 amps per channel.

If using 12 volt LED strips, that's 30 watts per channel, but if using 5 volt LED strips, it's only 12.5 watts per channel.

If you are going to be pushing it that hard and have room in your case, you might want to consider adding a piece of flat or angle iron to the mosfets that connects to those channels to help them get rid of the excess heat.

[rm357]

I did a little quick research and the limiting factors on current are the traces on the board itself and heat buildup in the mosfets. With a proper heat sink, the MOSFETs are rated for 15amps each, but the traces on the board would probably melt, burn, and release the magic smoke.

[hicksjo]

It's 2.5 amps per channel.

If using 12 volt LED strips, that's 30 watts per channel, but if using 5 volt LED strips, it's only 12.5 watts per channel.

If you are going to be pushing it that hard and have room in your case, you might want to consider adding a piece of flat or angle iron to the mosfets that connects to those channels to help them get rid of the excess heat.

The limitation of 2.5 amps on current, if based on heat in mosfet, is dependent on operating voltage.  Meaning the limit is actually on wattage, not current.  The stated 2.5 amps assumed 12 v operating voltage ... Therefore 30 watts is the recommended limit per channel, and the stated 35 amp limit really equates to 420 watts on entire device.

[zwiller]

Steve,
We share the same confusion.  Maybe I can open this up further.  Isn't the wattage/amperage of a pixel based on it's max rating on white?  So on dumb stuff when split to 3 discrete channels the load is distributed right?  (My pretend EE knowledge)  IE  200 dumb pixels is 60w TOTAL (when white), 20w red, 20w blue, 20w green, a total of 60w white.  Also for the strips assuming the wattage is correct, 72W/3 = 24w = 2A @ 12v.  There is probably a better way to explain this...

I say Steve's OK but I am a newbie to dumb gear.

Starting to educate myself now as I plan to add dumb elements next year. 

[SteveMaris]

Steve,
We share the same confusion.  Maybe I can open this up further.  Isn't the wattage/amperage of a pixel based on it's max rating on white?  So on dumb stuff when split to 3 discrete channels the load is distributed right?  (My pretend EE knowledge)  IE  200 dumb pixels is 60w TOTAL (when white), 20w red, 20w blue, 20w green, a total of 60w white.  Also for the strips assuming the wattage is correct, 72W/3 = 24w = 2A @ 12v.  There is probably a better way to explain this...

I say Steve's OK but I am a newbie to dumb gear.

Starting to educate myself now as I plan to add dumb elements next year.

Yes, this is my line of thinking exactly. And based on the 2.5 per, should be ok......

[chrisatpsu]

35A max limit.
in 12v world...

583 dumb nodes...
dumb strings = 583 nodes
dumb strips = 583 sections of 3 leds (total 1750 leds)

[rm357]

The 35 amp limit is based on the amount of copper in the traces on the board.
Exceeding it puts you at risk of starting a fire.

Please think twice before giving advice that could be dangerous.

The wattage approach is valid only for the MOSFET, but not the maximum current for the board itself.

[rm357]

Assuming 12 volts, the 30 watts per channel would allow you to run 90 watts worth of RGB when each color is on its own channel.

[SteveMaris]

Thanks for the replies.
Crisatpsu,
 Thanks for the fast shipping.