To answer your questions about trimmer +1k it should work fine.
But why would you want a trimmer on your charger? I assume you are building an independent charger to charge multiple battery types? With out an easy way to read the trimmer, incorrect adjustments could ruin the battery. I would suggest using a 2 or 3 way switch with 1k,2k,3k resistors. That way you are less likely to make mistakes dialing in that middle range.
Then again i could be wrong about the purpose
You are correct about the purpose. I'm building a DC jack into my boxmods for onboard charging. The charger will be in it's own enclosure with male USB on one end of the cable and 1.35mm DC Barrel on the other. The grand plan of the trimmer is to be able to charge 10440's or 18650s with the same charger. 330mA for the 10440s and then dial it up when needed for the larger
batteries so that charging doesn't take 12+ hours.
I plan on making index marks for the trimmer (similar to how some people will mark their
mods for 4v,5v,6v,....,) that coincide with the charge rate. I realize that it's not precise, but I plan on setting the charge rates no higher than .5C so that there is a little room for error. Now that you mention using a switch, I could use a muti-position rotary detent switch and fixed resistors to take out the tolerance variable. Now to go find a small rotary switch......
The rate is I=1000/kOhms. You typed the mistake but didn't make it in your calculations. Just wanted to make sure you didn't get confused and screw that up later.
Not real keen on the proper labels when trying to explain electronic formulas. I can do the math and understand everything in my head, but then it gets lost in translation between brain and fingers or brain and mouth. Thanks for the correction.
