Buck driver for 3.5A @ 3.7V

[MrNaz]

I am trying to get the most out of my scuba light. I have replaced the emitters with P4s, and would like to drive them a bit harder. Currently they are wired in parallel with 4 NiMH batteries supplying them with a resistor in series.

In order to power them with as little modification to the head as possible, I need a buck driver that can take the ~4.8V coming from the NiMH batteries and regulate it to 3.7V @ 3.5A. Does anyone know a buck driver that can do this?

 

[HarryN]

The highest current buck drivers I know of are the ones from taskled.com (georges80), but even these are not at this rating. - and they are quite beefy.

Your best bet for a regulated setting is to wire them in series and use a boost driver such as maxflex.

The other option is to drop the resistance a bit more - perhaps wire 2 resistors in series instead. Under load, the voltage delta will be relatively small, so 1 ohm should be more than enough.

 

[ambientmind]

You could connect 3 of the 1400mA 7135 boards from DX or KD together for up to 4.2A of output current :naughty: theres a thread here somewhere that shows how to connect them, its real easy! Although it might just be better to run each LED off of its own driver to avoid thermal runaway at that current.