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.
cheers,
Dermot
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.
cheers,
Dermot