I’m new to LEDs, I’ve only been working with them for about a year. And, I’m definitely a novice when it comes to power/batteries.
I’ve been running my led jackets off of rechargeable power bricks( for charging tablets, cells phones), I used about 100ct. WS2812B on the jacket. Is there any better way to power them?
I’m also making a large art bike this year for burning man and I’m not sure what will be the best way to power the lights. I wanted them to be really bright and those power bricks I’ve been using only give max of 2A through the USB port.
Im working on some led vests with 650 or so leds. Currently also trial testing a few different usb charger battery packs. I used these for smaller wearables with good success in the past.
@Robert_Atkins had a concept to create two power bus grids to use two ports, so the leds could get around 4A intead of 2.
I havent come across a better solution yet. these usb charge pack are awfully convenient.
I ran my kid’s halloween costume (720 WS2812Bs) with a 12-volt 5000mAh lipo battery that I use for my home-built quadcopters. The arduino tapped into the full voltage and I used a buck converter to step down the voltage to 5v for the LEDs. I ran everything at half-brightness (which was still too bright for night time) with no problems. I don’t think I could have done full white though because the converter handled 3A max. I’m currently rebuilding the power distribution to get 2 or 3A available per 144 LEDs.
I didn’t do a “time test” to see how long the whole thing would run – but I suspect I’d be measuring it in hours, not minutes.
However, with lipo’s, you’ll need a monitor that will let you know when your voltage is getting low. You don’t want a lipo to drop below 80% of it’s full charge (which still gives you lots of time). And you’ll need a charger capable of handling lipos.
I’m using them because I already have them.
You could also try a battery pack from a cordless drill or other tool. They tend to provide a lot of power because of the torque they need to put out. You’ll need to step down the voltage though.
I also thought about using those rechargeable power sources for jump starting cars… but, it doesn’t seem like I’ll get much more power out of them compared to the smaller bricks.
It’s too bad the WS2812Bs don’t draw the same power as “regular” LEDs. I have a homemade hat that runs animations (not FastLED) with 192 blue LEDs and it’ll run for at least 48 hours straight on a USB power pack!
Make a 2s x 2 pack (2 in series with 2 in parallel) and you get 6800mAh
with a usable voltage range between 8.2 and 5.5V.
You can draw up to 10,000mA (!)
Put 3 parallel then you have 10200mAh with 15Amps, and so on.
Special cell holders are available as well
Scalable and ultra-light. If you have charged spares on you, you will shine through Burning Man
Yeah, definitely go with the USB power bricks (I like Limefuel: http://www.limefuel.com/pages/product-blast —honestly, I’m not on the take, but I have a few and they work well for me.)
The other thing about the Limefuels is that you can get 2A out of two ports simultaneously. If you split your power bus so the +ve from each port powers a separate section (tie all the grounds together) that gives you 8A in total—which will be HEAPS bright for a wearable (my 640-LED jacket runs at 4A, because it doesn’t need to be any brighter and that gets me more runtime.)
For a “rollable” like your bike, you could cope with the weight of sealed lead acid batteries and a great big 12V-5V DC-DC converters:
As well as lead acid (heavy, cheap) consider LiFePO4 SLA-replacements (light, expensive, but longer lasting):
@Robert_Atkins did you use two of the packs for the vest? (4.2A max each). thinking of just running one, and swap it when it dies for the other. they’re pretty big for wearables. mission for this week is to figure out wiring.
Yeah, I’m using one port each off two packs—so 2A in total (capped with FastLED’s power management features), but the bigger capacity across the two packs gets me longer runtime (up to about 7h depending on which patterns I use.)
Right. I might try using both ports from the one supply (2.4 * 2). and also try two packs 1 port (2.4 *1 per pack). And see. With the first one, i’ll have to swap the pack at some point, but less packs/wiring needed at one time.
I did run it at 4A max cap and the leds are plenty bright at that level.
Note the spec on the Limefuel page again @Randal_B —it’s 2.4A max from each port, 4.2A total per pack, so if you use both ports you can only get 4.2A total, not 4.8.
Also, again, don’t cross the streams—split the +ve side of the power bus per port (but tie the grounds together). The boost converters in the battery packs really don’t like being connected in parallel. I killed two this way.
I did have both ports (same pack) +ve side on the same stream on my test rig and it didnt blow up but I’m wondering if the ‘smart’ circuit is actually allowing the full 4.8A output or not.
@Randal_B Oh, they’re new, nice find. Those may indeed survive wiring the outputs in parallel, I guess it does depend on the circuit used. I’m not a power supply expert, but it would be surprising to me if there was a separate boost circuit per port in the same pack. But if it’s just one circuit for both, how do you prevent a device from drawing more than 2.4A from either port?
@Danielle_Dougherty , what I meant was connecting both the positive and negative outputs of USB ports of different battery packs together in parallel (… and then on to the positive and negative on the LED strips.) I found that if I did that with one particular brand of pack, the DC-DC converters “fought” with each other and burned themselves out. I got around this by splitting my power bus in two, effectively connecting half the strips to one battery pack and half to the other. Note that when you do this you have to connect the ground of both packs together, just not the positive 5V.
thanks!