What size battery

[Rustydiver]

Want to get a separate battery to run my video tx and led lights.
Looking at getting a compact 3s so i can run it from the balance lead.
what mah sould I go for.

[quadfather]

It depends on the power consumption of the VTX and LEDs, then how long you want them to last for and how much weight you can carry.

What is the battery going to power in detail?

[Rustydiver]

It';s powering a ts351 vtx.

A round 16led light which is at the back and is great for orientation.

I';ve got a 2200 3s battery i can stap on but thought it might off been overkill.
But after weighing and looking at 1000 mah battery there is only about 50grams in it.

[quadfather]

If it';s a NeoPixel ring then that will draw 16 x 18mA = 288mA.  Not exactly sure how much the VTX draws, I would estimate it in the region of 200mA.  Both of them can be powered with 6-7V, so a 2S battery should be fine.  You won';t need a high C-rating since the current drawn will be pretty much constant, which in turn means that you will have a fairly stable voltage.

I have a bunch of Zippy Compact 500mAh 2S batteries.  If this was my project that is what I would start with, they';re also dead cheap.  Perhaps go for a little more capacity, but keep a low C-rating, which will also keep the weight down.

[quadfather]

Just to add, the 2200mAh battery you have will work, of course.  If the extra weight is not an issue just use it.  It will keep the stuff lit up for a day and a half.*   



* I may be exaggerating slightly.

[Paul01]

If it';s a NeoPixel ring then that will draw 16 x 18mA = 288mA.

Neopixels use 60mah when white, the quote 18mah is only for a single LED! Which of course Neopixel contain 3 of each Red Green Blue. This would be nearly an amp not 288ma when showing all white.

[quadfather]

Neopixels use 60mah when white, the quote 18mah is only for a single LED! Which of course Neopixel contain 3 of each Red Green Blue. This would be nearly an amp not 288ma when showing all white.

Wow! Why would they not mention this in the description? 

16 ultra bright smart LED NeoPixels.... Each one has ~18mA constant current drive...

Thanks for the clarification.

[Paul01]

Thought it was worth mentioning, if you buy Neopixels from Adafruit (they designed them) you get all this information.

https://learn.adafruit.com/adafruit-neopixel-uberguide/power

Worth a read for anyone using Neopixels

[Rustydiver]

Just to add, the 2200mAh battery you have will work, of course.  If the extra weight is not an issue just use it.  It will keep the stuff lit up for a day and a half.*   



* I may be exaggerating slightly.

Or i could strap another 5000mah battery on it, in parallel with the other battery and take off like a rocket.

Ive got a couple off 2200 ones so will try that

[quadfather]

Thought it was worth mentioning, if you buy Neopixels from Adafruit (they designed them) you get all this information.

https://learn.adafruit.com/adafruit-neopixel-uberguide/power

Worth a read for anyone using Neopixels

Yeah, good call.  I was going with the product description on the page where they sell the stuff and it didn';t mention anything.  Not even a link to that article.