I have a few buck converters like that. They usually have ripple and are not that great but work fine for what we do with an LED. How they are able to do that so simply is what I don’t know. Same for flashlight drivers, not sure how all these buck drivers you see work so well and are so cheap. I don’t see much we could really cut costs on except the inductor.
Looks like the jumpers are going to get more expensive, not cheaper. Those Yaego's and many others are surprising only rated as <50mohm and a couple of amps. Our sense resistors would make better high current jumpers than those. I found some vishays 1210 or 1218 at 12 or 20A rated, < 4mOhm:
http://www.vishay.com/docs/20043/crcwhpe3.pdf
But those are going to be about $0.41 a piece. Personally, I'd probably just strip some 14awg solid wire. But I can put some Vishay's in the cart. I'll look a little more for something cheaper, but that's probably about it.
Actually the 1218s are $0.59 each.
I think I'd go with them though as a stock smd suggestion. I need to know if that 0.18 width will interfere with the batteries though. The 1210's have the same resistance rating, probably just don't take heat quite as well.
Wow, the 2512's are rated for about 4kW ... for a microsecond. Yeah, at 4mohm that's a thousand amps. Good to know, just have to set that turbo timer a bit short.
You’ll need some VERY high drain batteries too!
I personally would also just use a solder bridge / wire myself. I have not forgot about this, just got another project I am working on right now that is a bit more pressing (got to figure out a driver for the BLF GT).
It's not bothering me at least. I'm not ordering anything for it until I have a Q8 in the mail.
I hooked that cheap buck between 4S LiIon and a 12V halogen. Put about 40W through it. Roughly 95% efficient, scratch that, battery was falling off during measurement, just remeasured with fresh battery, getting 100% within the precision I can measure, probably limited to about a percent by clamp meter current accuracy, anyway, it's darn efficient, but that's basically direct drive. It remained very cool (it's only 3A). It's an infineon FET, so that's a good sign. They're about $.50 each for 1000. They'er actually To-220's which are a bit bigger than D2paks because of their heat sink.
Anyway, this halogen is a great way to test. I've a couple of housing and higher power bulbs, could probably get up to 130 watts with two over-voltaged 50W bulbs. They can take straight 16.8V without frying for a couple of hundred hours anyway.
Which buck are you talking about? I must have missed that.
The little one from the Amazon link we discussed a few posts up. Nothing to do with flashlights really, just observations of a cheap buck. I haven't hooked it up to a scope. It's may have enormous ripple for all know. Anyway, there's no particular point to the story.
Talking to myself and off the trail, but hey... so I plugged that amazon buck into a 2s2p xm-l2 setup I just hacked together driving the buck with 16.0V bench power. That's a more realistic use probably. At 20W or 35W output it gives 94% plus or minus half a percent efficiency. Not bad, and I'll be using it. You can probably literally drive low output panasonic batteries to destructively low charge levels before losing much output with a setup like that, and with 94% driver efficiency and high capacity batteries, that seems like a bunch of constant-output runtime to me. Oh and at the battery running half the current and twice the series battery resitance mean I^2R losses in the battery are twice lower too compared to using 2S battery, again making up some for low drain batteries.
I like higher voltage, it is simply better then higher amps for most things.
No question. It's all kind of making me think expensive buck drivers are alright again. Although cheap ones and pots are also ok for some things. With these two pot bucks you can set a failsafe limit with voltage and then use current to control the light.
Those cheapo buck modules are not bad actually. The ripple can be high and they are analog but if you just want a set it and forget it option they work fine.
Or if you want to wire a remote pot.
Really, I only have two problems with anolog. You can't predict battery life if you don't know exactly what mode you're in, (true of ramping too) and it can be hard to make one-hand use knobs/dials. Buttons work without releasing your grip.
Yeah, a remote pot works but it is still analog. I am a much larger fan of digital control myself.
I've got a few appliances with digital control that have absolutely no reason to and they annoy me endlessly. For comfort of use alone, analog any time. But needed features often end up outweighing that.
Ok, I think I will be working on getting this put together for an “official” release later today or sometime this week.
So last chance to change anything.
If the parts list is updated I will quote it in the OP, post 226?
Ok, I put it all together and uploaded it to oshpark. It is totally a build at your own risk type of deal. I won’t be building one, for that kind of money I would rather buy a flashlight lol.
Details in the OP.
Thanks a ton Flintrock! He is the only reason this was completed at all, I did not remotely have the time or skills to pick through all the components to make this work.
I am also aware that the 3D render is not perfect, I didn’t have time to find CAD’s for the missing parts or correct the CAD for the diode with the correct style.