The ‘R’ in X7R signifies that its specified uF value varies +/- 15% over its specified temperature range. Worst case will be at 125 C, where it will be ~15% less than at 25 C. This should be good enough for what we are doing.
If we assume that most of this effect is due to the temperature (in)stability of the OTC, this indicates that we have an xxU capacitor. Not a good choice for this application. ‘U’ would be –56% capacity at its upper temperature rating. If it is a x5V in addition, this temperature is only 85 C.
If I have time this weekend, I will remove an OTC and put it on a meter while heating it. Or just swap out with an X7R and try to compare with an unmodified light.
Finally got my 25R cell to work with my 3D. Turbo is impressively bright, UI is great, the light works flawlessly. Thanks to all who make this GB happen, really appreciate all your hard work.
This is the one I’ve used for all my builds and I notice mode change problems when hot. It’s also the part specified in the original driver build thread.
I've been using only X7R 1 uF caps for all my OTC driver build/mods and I still see the temperature related problems in most of the lights I modded using it. Now I did buy the caps off of eBay at the time, so no guarantees I got caps as labeled. I suspect though they won't make much a difference, but it would be interesting to try. In my next DigiKey or Mouser order, I'll definitely will be ordering some 0603's and 0805's - cheap enough.
The inconsistencies with the OTC's is some of the reason why I much prefer e-switch's now -- you have true control of timing under the MCU. I've also used the NOINIT (brown out) method as well, but still seems to have some timing inconsistencies.
Obviously the first batch was rushed, and now we are seeing the spotty QC as a result of it.
I am down for four, but have thus far only ordered one. - Received (3D), and I am very happy with it - But some it seems are not so lucky…
I just thought that one would be enough to play with to start, and wanted to see how things would go before I order the other three. - I think that was a good decision.
Many, Many thanks to all involved for Continuously working to make this GB Right! - It can’t be all that much fun
Mitko - If a reflash brings back the moon...please let us know. Actually if you could directly flash TK's UI and tell us that would be a big help to all.
Will do that- its actualy a black space instead of the moon mode, only on one of 3 lights, maybe a glitch or smth- i usualy get glitches like that when i overhear the a13 while soldering