SBT90 or SBT70 which is better thrower?

Fresh Light · Oct 15, 2012

I'm curious what you think will be the better thrower. Please notice the tint of the 90 is 6500k and the 70 is 7000k.
Digikey has a MB flux bin SBT90 1485-1590 [email protected] it is $78.95
Mouser has a SBT70 1710 [email protected] it is $39.00

I know the increase in flux with increase in current isn't linear, but 1590* 117%(amt of rated current of the SBT70 vs SBT90)= 1855. If I take 1855, actually with droop it will be less, and multiply that by 0.778(difference in mm sq to the smaller SBT70)= 1443 lumens. 1443 lumens is a lot less than the SBT70s 1710, 15.6% less. So, if that makes any sense, it sounds like the SBT70 may be a pretty bright LED. I don't know which is better. 39.00 vs 79.00 is a significant difference, but considering the cost of the lights and how important the LED is I would want whatever is better.

Epsilon · Oct 16, 2012

Can you link to the SBT-70? I am looking for that since the paper release :)

Edit: Those sites s**k (mouser and avnet), filtering through the parts I am not able to find them. But the search does, and lots of them. They are put in the "HB led" section, where all the SST-90 and SST-50 variants are, not the CBT-90 etc.

Avnet (hope this works, but it's worth the try):
https://avnetexpress.avnet.com/stor...m=sbt70&N=0&Ne=100000&action=products&x=0&y=0
No stock and data yet

Mouser (this will probably work):
http://www2.mouser.com/Search/Refine.aspx?Keyword=sbt70
stock and prices.

Datasheet:
http://www.mouser.com/catalog/specsheets/PDS-002014_Rev 0X_SBT-70 Production Specification.pdf
up to ~1650lumen for cool white
up to ~1350lumen for 90CRI
up to ~ 900lumen for 95CRI

Fresh Light · Oct 16, 2012

I honestly don't know if it's ok to post links to selling sites even after going through the Rules. Sometimes it's ok but if it's a Dx or Kd link, it is removed. I've found posted links to be helpful. I'll PM you.

Gunner12 · Oct 16, 2012

I know we aren't supposed to post dealer links in the recommendation forum, but outside that forum I get the feeling that it's ok, as long as they aren't advertisements and aren't overdone. Could a mod please correct me if I'm wrong?

mvyrmnd · Oct 16, 2012

I can't imagine there'll be any issues as you're discussing components, not actual flashlights.

You're not spruiking a product, you're being helpful.

Gunner12 · Oct 16, 2012

Now, as for which LED would be a better thrower, I got 170-190 lumen/mm for the 90 CRI cool white, and 190-240 lumen/mm for the 70 CRI cool white with the SBT-70 @ 10.5 A rated current (higher bin = higher lumen/mm of course). 140-175 lumen/mm for the 70 CRI white SBT 90 @ 9 A. Assuming both LEDs are driven at the max current, the SBT-70 would throw further.

Numbers are estimates from the datasheet. Actual lumen/mm is probably higher due to my truncation of numbers, and after subtracting the current spreader areas. A good heatsink ant thermal path would help hold the output level of course.