# Having issues finding the correct Boost Step Up Regulator

So, I'm working on building a LED hula hoop for my wife, and am having issues with choosing the proper Step Up / Boost Regulator.

What I'm working with:
3.7v 900mAh Li-Ion batteries (looking to run 4 maybe 5 in paralell)
ws2821b LED Strip, 30 LEDs, 2.7meters of LEDs, which will draw 4.05A.
Arduino Pro Mini, 5v board.

What I want to do is power the LEDs as well as the Arduino board with my batteries in paralell
If I use 4 batteries I'm looking at 3600mAh, if I use 5 batteries, I'm looking at 4500mAh.

Very rarely will I be running all three RGB LED's at full brightness, as I'm looking to make use of the multiple colors or patterns.

This is the latest step up i'm looking at:

The ID of the tubing I'm using is 7/8ths, however lets set that part aside for now.

After discussing this with a handful of people, I was told that the product I linked will likely burn out quickly if I'm drawing 4.05A.

Can anybody explain where my math is wrong, and why this is not a good choice?
Even better, maybe somebody can suggest a product that fits my needs. If you can't find one that fits my size requirements, that's fine. It will at the very least let me know what kind of specs I'm looking for.

Any help is appreciated!

If your circuit draws 4A at 5v, that is 20W. The board is capable of handling 5A input. At 20W and 3.7v. The input is above the rating of the board.

You need one with input of at least 6A plus a safety factor.

Weedpharma

weedpharma:
If your circuit draws 4A at 5v, that is 20W. The board is capable of handling 5A input. At 20W and 3.7v. The input is above the rating of the board.

You need one with input of at least 6A plus a safety factor.

Weedpharma

Weedpharma,

The issue I'm having is that I can't seem to find a 5v step up with an input above 5V and output above 5A.
Any suggestions?

Maybe you can utilise the track resistance of the LED strip, and feed it with two converters. One at each end.
Leo..

Wawa:
Maybe you can utilise the track resistance of the LED strip, and feed it with two converters. One at each end.
Leo..

Wawa, can you explain further? I'm fairly new to this, and don't quite have the terminology correct.

Thank you!

I think you're building a Hula Hoop with a 2.7meter LED strip.
If you supply it with 5volt on one end, and when many LEDs are lit, you will have less than 5volt at the other end. Because of the resistance of the wiring in the strip there is a volt drop.
A second identical boost converter could feed 5volt into the other end of the strip.

Normally you don't connect converters in parallel, because one will do the work while the other one just sits there.
But because of the strip resistance in between, they both have to do some of the work.
Currents might not be divided equally. Maybe 40/60. But at least it's better then one overheating.

Another way to get 50/50 power distribution is to cut the positive wire (not ground and data) in the middle of the strip. So each converter only has to power ~1.35meters.
One of the converters could also power the Arduino.
Leo..

Wawa:
I think you're building a Hula Hoop with a 2.7meter LED strip.
If you supply it with 5volt on one end, and when many LEDs are lit, you will have less than 5volt at the other end. Because of the resistance of the wiring in the strip there is a volt drop.
A second identical boost converter could feed 5volt into the other end of the strip.

Normally you don't connect converters in parallel, because one will do the work while the other one just sits there.
But because of the strip resistance in between, they both have to do some of the work.
Currents might not be divided equally. Maybe 40/60. But at least it's better then one overheating.

Another way to get 50/50 power distribution is to cut the positive wire (not ground and data) in the middle of the strip. So each converter only has to power ~1.35meters.
One of the converters could also power the Arduino.
Leo..

Wawa,

So, if I were to use do strips of 1.35meter strip, which would draw 2.025A, would the below regulator suffice?

Or would I be safer using regulator rated at 5A output, such as the one I linked to previously?

Within reason, a higher rated regulator is better. The components are less stressed.

Weedpharma

gFFto:
So, if I were to use do strips of 1.35meter strip, which would draw 2.025A, would the below regulator suffice?

http://www.amazon.com/product/dp/B00C92Y1G6

Or would I be safer using regulator rated at 5A output, such as the one I linked to previously?

They have used a bad sample to take a picture from.
Part of the coil is shorted with blobs of solder. Wouldn’t trust that one.
The efficiency of the Pololu converters, due to a higher switching frequency (small inductor), might also be better.
I think the 5Amp one will be fine for ~2Amp. 2A won’t be continiously drawn anyway.
I hope you understand you don’t have to cut the 2.7meter strip.
Just the positive track, roughly halfway.
Data can still be fed into the strip on one side only.
Grounds at oppisite ends of the strip can be joined.
Leo…