# LED voltage setting for WS2811 COB 12V

**URL:** <https://wled.discourse.group/t/led-voltage-setting-for-ws2811-cob-12v/12900>\
**Category:** Questions\
**Created:** [October 10, 2024, 7:11am UTC](https://wled.discourse.group/t/led-voltage-setting-for-ws2811-cob-12v/12900 "2024-10-10T07:11:02Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![pascal](https://avatars.discourse-cdn.com/v4/letter/p/e9a140/32.png) [@pascal](https://wled.discourse.group/u/pascal)\
**Post date:** [October 10, 2024, 7:11am UTC](https://wled.discourse.group/t/led-voltage-setting-for-ws2811-cob-12v/12900/1 "2024-10-10T07:11:02Z")

</div>

Hi all, I have a 12V WS2811 COB strip set up with 720LEDs per m and 36LEDs per addressable group [BTF-LIGHTING FCOB SPI RGB Flexible Hohe Dichte COB LED-Streifen WS2811 IC LED Strip 3M 720LEDs/m 21W/M DC12V IP30 Nicht Wasserdicht Chasing Farbe DIY Dekoration(Nicht inhalt Controller&Netzteil) : Amazon.de: Beleuchtung](https://www.amazon.de/dp/B0BW5BMTSN/ref=pe_27091401_487024491_TE_item)

Im struggling with the voltage setting per led. I’d assume it’s 12V, but is it 35mA or something else?

I’m not sure how to get that info - any help would be very much appreciated 🙂

My guess based on following calculation:

- 21W/m
- 720leds/m with 36leds per addressable zone (which wled sees as an led) → 20leds/m
- 12v
- 1.05W/LED at 12V
- → 0.0875A → _ **87.5mA** _

Would that be correct?

---

<div class="post-metadata">

**Author:** ![divsys](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@divsys](https://wled.discourse.group/u/divsys)\
**Post date:** [October 10, 2024, 3:34pm UTC](https://wled.discourse.group/t/led-voltage-setting-for-ws2811-cob-12v/12900/2 "2024-10-10T15:34:51Z")

</div>

That’s probably _approximately_ correct, no way of knowing for sure without actually measuring.  
Suppliers are notoriously inaccurate with their LED data.

The real question is: Why does it matter?

Whatever power supply (and wiring, injection points, fuses, etc.) you use to drive these needs to be adequate for the whole setup. The specs of 21W/m will give you some reasonable numbers to deal with the worst case power (100% White).

If you design the power supplying these properly, WLED doesn’t really care what each LED (or block it can address) actually draws. The Automatic Brightness Limiter is just a bit of a Kludge to deal with improperly powered setups. For me, it’s most useful feature is that it gives me an idea what my setup might be drawing in real time without hooking up a meter. But in order for it to do that even close to accurately, I typically have to have measured the LED’s actual draw in worst case - with a meter.

So to sum up, you can use the info you’ve got to get a rough idea of what you’ll need power wise. Design your power cabling, etc. with some reserves in mind and you should be OK. If you want to know for sure what’s going with your worst case power draw - measure it.

Don’t rely on WLED’s ABL power figures when designing your setup’s power requirements.

---

<div class="post-metadata">

**Author:** ![pascal](https://avatars.discourse-cdn.com/v4/letter/p/e9a140/32.png) [@pascal](https://wled.discourse.group/u/pascal)\
**Post date:** [October 14, 2024, 10:03am UTC](https://wled.discourse.group/t/led-voltage-setting-for-ws2811-cob-12v/12900/3 "2024-10-14T10:03:00Z")

</div>

> [@divsys](#):
>
> The real question is: Why does it matter?

Well, I saw the setting and figured I’d have to set it up correctly 😃 plus I was hoping a bit that it would optimize brightness similar to the mA limiter. But doesn’t seem like it.

the brightness/mA-limiter is set to 4’800mA for my 12V, 5A power supply, so I guess I should be all good on that front.