Yes, I’m pretty sure that is possible. If one 7135 is shorted by accident then there should be a minimum of 0.350 amp going through the driver and the light will not go dimmer than this.
I took a quick look at MTN E to see what he offers on that driver with ATtiny13. Besides Bistro, you can use Guppydrv Dual if you have access to it. That’s all I know, sorry.
The correct answers are to take them to either a battery bin at your local hardware store or Best Buy, or to take them to your local household hazardous waste center
I used to do a lot of laptop cell pulls, so at one point I had a 10 lb bag of dead cells. The hazardous waste center wouldn’t take it, as they said they only took household waste. I said, “This is from a household, but I know what you mean.”
I ended up taking them to a Batteries + Bulbs, and they took the cells no questions asked.
I’m not sure what you mean by this, this CPF post is very helpful for making a decision on a lube. I use Super Lube on everything. I bought a big tube a couple years back and I haven’t even used a quarter of it yet. Not sure how easy it would be to get that where you are though.
So why are batteries round? well most of them aside from 9v, lantern, car batteries etc, does the round/cyclinder serve a purpose or is it just easier to manufacture?