Suggestions on Batteries with High Volume to Capacity Ratio

I’m making a costume that is going to involve a lot of LEDs, and I’d like to power it for a while.
What type of batteries are good for this?

90A at 5V (450W) is my worst case estimate of its power draw. Half or even a third of that current is more likely.
I’d like 10+ hour battery life.
So my need is in the 2-5kWh range. Or just the highest feasible amount.

Edit: 58W is a better estimate. The above assumed each pixel used 60mA. When measuring mine, they use 7.7mA each.

So far, it seems like USB power banks are the most dense batteries I can find.
I have one that is 74Wh from Anker and 70×150×26 mm (2.7"×5.9"×1 in). So far, that’s been more energy dense than any battery I’ve checked, even though that volume includes a controller and casing.

But I would need 20 of those just to reach my lowest estimate. And trying to manage power from 20 USB sources sounds like hell.
Also that would cost $600. I expect this to cost hundreds of dollars. But not that much when it barely meets my minimum guess.

5KWh with current technology is going to be a real challenge unless a large and heavy backpack or similar mechanism can be incorporated into the costume.

You wouldn’t want to use LiFePO4 for this as it’s on the heavy side but it’s easy to use as an example; You’d have a largish box with a mass of about 100# to get to 5KWh.

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A bit of context on how I intend to store and possibly cool them.
This is the character I’m making the costume of:

When people make these costumes with animal-like legs, this is what’s going on underneath:

I intend to use the space in front of the knee and upper leg to store the batteries along with the control board.
And if you look back at the character, you’ll see the speaker looking thing on their shoulders/thighs. That would be my plan on ventilation.

Funny, I’m helping another furry with theirs, you going to TFF?

I would say power up your LEDs and get very accurate readings on how much current you need so you can better estimate it. 90A of 5V is going to be pretty much not do-able (and doesn’t seem reasonable) considering the size of wire you’d need to keep the voltage drop low enough at 5V.

You have some spec sheets on the LEDs? If not hooking them up with a power supply in elab and estimating will help you. If 1/2 draw, 45A is still pretty high, but you could maybe separate the loads into smaller sections. You’re going to have a really hard time powering all of that. For the 10+ hour battery life, I would strongly consider battery pack swaps back in the headless lounge or room and just having two or three packs so you can air out and swap a pack on/off the charger.

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The blue parts of this character change color. I’ll be making those parts with white fur and using LEDs to produce the color.
So I’ll be needing dense lines of LEDs under all of the white parts that are always on to achieve that.

I’m using WS2812 fairy lights with 1.5cm spacing for this. I got my estimate by measuring how many it would take to wrap around each part (giving a lot of extra room on the legs). Then I doubled that, since I’m not quite sure if 1 row of them would be enough.

lol, yeah. My goal is to have this done by TFF.
But I’m putting the body last, so I can pivot to making a partial if I don’t think I could finish it by then.

I feel like part of my issues it that the size of the leds depends on how many batteries I intend to store in them.
But the LEDs run over that area. So the amount of leds depends on how big the legs are.
As a programmer, this short circuits my brain, leading me to avoid tacking it.

There are RGB COB LED strips available that might be simpler than using fairy LEDs.

(first reasonale result, probably many many more options out there)

Otherwise… 450W is a lot of power.

It is, and I’m suspicious of the math that gets there. What exactly are the parts and quantities you are planning on using?

Thanks for the suggestion, but I don’t think the strips would work that well for this.
Flexible LED strips tend to be really fragile, and repeated flexing will break them. I’m not sure if those COB ones are the same. I’ll have to check them out sometime, I’ve never used them before.

Also I already spent $300 on fairly lights for this, so I’m kind of locked into them at this point.

Well this was based off the assumption that each WS2812 pixel consumes 60mA @ 5V at full white. I’ve just heard everyone repeat that for years, so I didn’t question it.
I just measured the draw of a string of 19 and averaged it. Mine draw 7.7mA each.

So that brings my 450W estimate down to 58W.
I was only off by 87% of my original estimate.


Fairy Lights are even more fragile than tape. They are just poorly coated magnet wire. All you need is to loose one connection of the wire on one pixel and your string is done. Seen some really poor soldering on those.

A flexible matrix may have the density you need but again they are pretty delicate.

Glad you got the power draw more closely estimated. I don’t think all the LEDs on my house draws 450 w.

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The battery is still gonna be chonky. Here’s an example of a high-density pack.

You’re gonna want a case or something to keep it and you separate. Our electric drift trike invokes the right amount of fear with the giant battery pack right below you.

After googling "fairy lights, I realized what I have aren’t normal/tradditional fairy lights. Google is showing a lot of images like this

But these are the ones I have. (Which I got here)

These ones are pretty durable. I’m unable to break a string of them with my bare hands and haven’t been able to cut through the resin on each pixel with any tool I’ve tried.
I was specifically recommend this brand/seller from someone who has build fursuits wit tons of LEDs and tested these one’s durability already.

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Yeah, big difference. I have some of those top ones, and even on a small Christmas tree, I worry about movement flexing the solid wire until it breaks.

Am I correct that what you found are stranded wire? If so, a much more durable solution when in motion.

Ok, great. Those are much more durable. I have some on my eBike and they do very well.

I just came across these batteries: Vapcell 26650.
They’re about 3 times as energy dense as my power bank (in terms of mWh/mm³). So they’re looking like the best option for me right now.

Yeah, the wires are stranded. And the covering of all 3 wires is a single piece of plastic.
The ones in the picture have 1.5cm spacing. I have a bunch with 2.5cm spacing. So I may go with 2 rows of the 2.5cm ones for a bit more flexibility too.

A couple things to note, those cells are most likely “favorably” rated. I seriously doubt you’ll get anywhere near that kind of ampacity out of them.

Don’t neglect the difficulty of building a BMS and DC/DC to get your 5V out. If you really want to you could go for a step down and use unprotected lipo, but I wouldn’t recommend it and a suit fire doesn’t sound fun.

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