Hi guys
I have an Elektro Lumens ST90 Search & Rescue, 2200 lumens, 150,000 lux from 2012 so now 5 years on I am thinking of updating the ST-90 LED but what with ?
If anybody can help with a suggestions on what currant LED’s would work that would be a great help. The goal is max output run-time not important.
The light is Direct drive at approximately 9 amps with four 18650 batteries in parallel.
The original sale thread is Here
Thanks for any help.
Change battery carrier to 2S/2P and XHP70.2 with TA driver
7500 Lumens
The ST90 AFAIK does not have a driver originally, just two switches, one with and one without current limiting resistor. You can leave it like that with the XHP70.2 but be careful to mount the led on a DTP-board and in very good contact with the body because it draws about twice the power of the stock SST-90.
Thanks for the help guys.
So you are saying I can just replace the LED with a XHP70.2 mounted on a DTP-board and I can still use 4x 18650 IMR batteries ?
Best place to buy the XHP70 from does anybody sell them already mounted on a DTP board ?
I am new to modding so sorry for my lack of knowledge.
thx
you have to change the battery to 2S/2P wiring to get 8.4V
Kaidomain sells good XHP70.2 on DTP stars, you can even choose the bin of color, and get top P2 output bin
1A are cold white http://www.kaidomain.com/p/S026861.Cree-XHP70_2-White-6000K-LED-Emitter-with-16mm-x-1_5mm-DTP-Copper-MCPCB-6V
3B are neutral white http://www.kaidomain.com/p/S026865.Cree-XHP70_2-Neutral-White-5000K-LED-Emitter-with-20mm-x-1_5mm-DTP-Copper-MCPCB-6V
5C is warm white http://www.kaidomain.com/p/S027211.Cree-XHP70_2-Neutral-White-4000K-LED-Emitter-with-20mm-x-1_5mm-DTP-Copper-MCPCB-6V
Like I said I am a major Newbie at this so sorry for the dumb questions.
To wire 4x 18650 IMR into a 2S/2P that would be 7.4v right ? What is the best volts for the XHP70-2 ? I am a little confusted because the led is 6v on the website.
thanks for any help.
Leds are listed to have a certain voltage while in actual use the voltage varies with current. It is just not lineair like regular resistors or incandescent light bulbs (ok, those are not completely lineair either, but close).
Here’s the current to voltage (and output) relation of the XHP70.2 (graph borrowed from TLF-member Kof3):
The grey line is the voltage, you can see that when the current goes from 2-20A, the voltage goes from 5.7V to 7.3V
On the other hand you have the battery voltage which gets lower with higher current
Of course you got some losses on springs and wires
Here 2 good IMR cells with comparator from HKJ
