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Thread: Single Lithium cell COB driver

  1. #1

    Default Single Lithium cell COB driver

    I recently picked up a couple of mini work lanterns that have a small COB strip - all leds in parallel, running from 3 x AA cells - and a series resistor.

    It has a magnetic base as well as a hanger and was good value at $3 in Ace hardware last week, since it provides an even illumination.

    Not wanting to use disposable batteries long term, I'm looking to mod to Lithium. I can fit 2 x 18650 cells in (I've been harvesting, testing and matching dozens from old laptop packs) together with necessary BMS and charging electronics, but am looking for a physically small LED driver.

    I can configure the two cells in series or parallel and have BMS/charger from USB input for both. It works, but very inefficiently, with a single Lithium cell to 5V USB boost circuit, but needs a very wasteful dropper resistor, so far, I've not had any luck on Ebay on a small enough PCB, so looking for advice/sources. I only need a few hundred mA, but can only find chunky 5A or so ones there.



  2. #2

    Default Re: Single Lithium cell COB driver

    humm 4.5v with current limiting resistor direct drive is the old way they were driven what i would do if i was you is i would get one to use as a test subject i would see what the lowest safe voltage is and what the highest is. And depending on answer and configuration options you can get 3.7 v 6v and 12v flashlight pill drivers no reason you can't just solder wires to the outer ring and inner pad https://www.amazon.com/dp/B07JMF3PNR...v_ov_lig_dp_it


    making one yourself is about the only way to get it smaller.

    also these?
    Last edited by lunas; 03-04-2019 at 03:09 PM.

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