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5v WS2812 5m led strip from battery?? :(

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SiliconWizard:
Yeah as already said. If you really need up to 45W during up to 4 hours continuously, that would be 180Wh.
Let's add to that a conservative 80% overall efficiency (including switching converter and various losses), you now really need  225Wh. This is huge.
Even on a 12V battery, that's 18.75Ah. Quite big stuff. Were you prepared for that?

As also said above, your LED strip probably won't draw that much power continuously. But still. Let's assume it only draws 1/10 of that on average. You'd still need 22.5Wh. Getting that from AA batteries is going to be tough. In theory, the raw capacity of 8 very good AA batteries should be close to 8x3x1.5 = 36Wh. Not that bad. Problem is, with so many batteries in series, their internal resistance will add up and yield significant losses at this relatively high current. Even just one AA battery will not quite have 3Ah of capacity at high current draw. If you really want to use this kind of batteries, using the bigger ones may be an option, such as R14 or bigger. Good R14 batteries can typically have up to 8Ah capacity and much lower internal resistance, so that could be an option. 6 in series followed by a step-down converter would be enough.

Anyway, those numbers are just estimates. I'd suggest measuring the actual average current draw of the strip powered by an external power supply in the typical lighting scenarios you're going to implement so you have a more realistic idea of the required power, and then chose an appropriate battery. It will probably be a relatively chunky 12V battery, or maybe a smaller/lighter LiPo battery pack (2S or 3S) such as those used for RC models. As said above, maybe 6 GOOD NiMh R14 batteries in series would do.

Also check the efficiency of the step-down converter you're going to use. I don't know what you tried.

mariush:

--- Quote from: frozenfrogz on August 12, 2019, 01:29:38 pm ---
--- Quote from: mariush on August 12, 2019, 12:41:04 pm ---These WS2812 leds don't allow you to control the individual brightness of each led, so you get approximately 60mA for each LED when it's powered on.

--- End quote ---

How so? That is nonsense.
Main point for using this type of LEDs is that they are individually addressable - hence the WS2812 driver chip per three diodes cluster in a 50/50 case. It is not simply on/off, but rather PWM control for three channels per "pixel". You can have any configuration of R/G/B you like (or warm white/cool white for the white variety of those chips).

--- End quote ---

What I meant to say is that there are LED driver ICs which can control up to n channels (ex 18 channels, 6 x 3 colors) and allow you to send commands like "set brightness to x % on channel  n " , separately from "set r,g,b to values x,y,z"
The WS2812 don't seem to have a way of setting brightness with a command, and then leaving the work of PWMing the leds to the controller inside the led.

Considering the fixed frequency the leds expect and the long chain (150 leds) it may take quite some time to pump the 3 bytes per led x 150 leds , so I don't think it's quite that easy to pwm the leds as in turn them on and off hundreds of times a second ... 100 updates a second should be doable.
So if an Arduino is used and groups of leds are turned on and off , at least you know you'll have a sort of constant average power consumption
If you PWM 150 leds, you still have to deal with higher peaks of current, so you'd probably have to add some capacitance on output of the dc-dc converter to reduce the "stress" which can make the "control box" bigger.

Steelman , that controller is kind of a black box, I'm not sure you can control the brightness or implement these tricks to reduce the power consumption. You may be able to find some other solution that allows you to customize these things.

frozenfrogz:
@mariush

Please read up on WS2812B LEDs and how controlling them with e.g. an Arduino and FastLED library or similar is done before posting more ridiculous assumptions.

1024 individual addressable "pixels" driven @ 800 kHz will give you about 30 FPS refresh rate on the whole strip.

The main issues you are running into with these LED strips are related to voltage drop, so best to make sure you have a couple of insertion points.
Depending on the micro controller you could run into SRAM issues, when addressing a lot of these LEDs. However, if you do not need to address every single LED but could live with repeating animations among several strips, just connect the data line in parallel.
Signal strength on the data line is usually no problem if powered correctly since every WS2812 controller acts as a repeater.

Steelman14a:
Ok guys here is an update:

Ive removed 8 AA batteries holder and soldered an usb a connector. Then plugged it to my portable 20000mAh powerbank.

It worked but usb socket was hot a bit.

Then i soldered dc-dc converter in between usb and controller.\

AND))  8) 8) 8)

It working for 1.5 hour now and there still 60 percent capacity in power-bank left. )))

I dont know why is that so, because on dc-dc converter there is 4.8v on input and 4.8v on output!!?? So it doing nothing actualy. But usb port and powerbank batteries is still cold.

Plus i've connected the USB Doctor in between power-bank and dc-dc and it shows 2.6 amp max...

I'm frustrated now why is that so... :o

mikerj:

--- Quote from: Steelman14a on August 13, 2019, 09:43:57 am ---Ok guys here is an update:

Ive removed 8 AA batteries holder and soldered an usb a connector. Then plugged it to my portable 20000mAh powerbank.

It worked but usb socket was hot a bit.

--- End quote ---

That suggests you have a USB socket or plug with a poor connection.  Adding the additional DC-DC converter will only reduce efficiency (increased current draw from power bank) but it's possible that you simply have a better connection on the USB plugs/sockets of the converter and power bank which is reducing the heat.

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