I’m probably not the one to answer. Are you saying no switch, or just using a switch in the control circuit, so that it only sees very low amperage? I use many of the DrJones programmed NANJG drivers where a momentary switch is used to fire the driver and yes, it does have parasitic drain. I believe that’s one of the problems with doing that style switch, like an SRK or Rook and others. There’s parasitic drain to contend with. I don’t worry about switches much until I get over 10 amps. The Judco switches work well for up to ten amps. I worry more about springs getting brittle from the current thru them.
He's wondering if hooking the 7135's up directly to the battery, with the MCU only being powered up through the switch, would cause parasitic drain. I've heard about 7135's leaking current when not even switched on, but the verdict seemed to go back and forth on that.
It's a very simple solution though that never crossed my mind :)
Yes, just using the switch to turn the MCU on/off, and leave the slave boards powered all the time bypassing the switch. The MCU would work exactly as in a single board driver with a mechanical switch. I don't see any downside other than finding room for an additional board, pending info on the slave boards' power use when the flashlight is off.
You also eliminate some resistance in the drive path.
Very cool. I like the battery holder/tray thing too. Will be tricky to make all the connections clean and isolated, but a very cool creation. Plus it’s parallel, so you can just pop in/out single cells if you’re in a pinch. Good luck with the new job post.
It should be easy to check to slave boards parasitic drain, if you're interested. Just use jumper cables to connect one to an LED and cell with an ammeter. Cheap DMM leads should suffice at that low, if any, current.
Beautiful battery holder! But how are those white wires run down the backside? Are they glued to the backside of the copper pipe so as not to have slop in them and get caught sliding into the body?
When I soldered the discs into the tube, I used a vise. I squeezed on the sides of the tube, just enough to hold the disc from slipping. I also did the squeezing a little back from the disc, so I could still heat it with a torch, otherwise the vise would have taken the heat away from the copper. The couplers are really just to keep the wires from touching the body. More for spacers than anything else and they are epoxied on. If I had realized I needed them to begin with, I would have soldered them on when I did the discs.
