The Qlite has routing under the chips, in the dozens (100?) that I’ve used, it’s never been an issue and so far I’ve run em up to 4 high and over 6A. Lucky maybe, don’t know.
Every cheap 7135 board I’ve seen has the output trace crossing under the chips. It doesn’t mean it’s good design but does seem to work. Breaking up the output into groups could be done just by cutting the output trace in a few places and soldering an led- wire to one of the chips in each isolated group. For a high voltage Zener mod it would be better maybe to have the entire bottom of the chip available for ground trace soldering but maybe not as important for normal 4.2V usage. The natives have been getting restless waiting for an SRK board and this is a sort of stop gap measure. I like that Mattaus is willing to put things out there knowing that his first effort can be improved on and that Texaspyro takes the time to make suggestions. We all learn from them and gain by their efforts.
Very much looking forward to that. Ordered some and I'm off to your thread to figure out how to wire them into this board.
On TexasPyro's point above about contact pads for cells and the battery tube. If there is a problem with this design, I imagine one could reflow some copper sheet cut to the appropriate size over the positive contact ring.
I guess part of the accidental 'charm' of this (or any 7135 based driver) is the relative ease of which the boards can be 'hacked' up. Seriously - I've seen some of the boards people have created, even some I've made, and they look like they've been put through a meat grinder. And yet they still function. Boards with chips stacked 4 or 5 high (sometimes more). Traces ripped up with jumper wires running left and right. Extra components tacked on. AMC chips being driven above and beyond their factory rating. Master/slave setups. The list goes on.
All this board will really ever be is a NANJG driver sized to natively fit a very popular light. If you're concerned about a large group of AMC chips running LEDs parallel then just go to town on the board. Leave a few chips off and stack them else where if you need room. Swap out the MCU for another. Zener mod it. Hell; you could just use it as a simple contact board for an all together completely different driver for all it matters lol.
Use it how you see fit and do what people around here do best - make up for its shortcomings by ghetto engineering the crap out of it.
The problem is not with the contact ring, it is with those pads/holes for wires at the center of the board. The positive contact for the cells can touch them… even if there are no wires protruding. The center part of the driver board really needs to be empty. If I remember correctly, anything within around 0.2” of the board’s center is a risk for shorting with some cells.
It's worth a shot if you already have some, but it wasn't tough enough to work with my reflector and probably wouldn't here either. Fujik should work though.