Can A Battery Flip Polarity?

I often use 14500 lithium cells (most are protected) and a shunt cell. Though as you said sometimes the voltage is wrong. Also the enloops are nice but iirc i've had one or two of those leak something.

Aaron Nadler

I'm sure that gave you a 'start'. Glad to hear you are safe. Had a few gotcha moments in my test career. Once, i forgot to put an insulating piece of "super thick wax paper" I don't know what it was really made of ... in the brush cavity of an alternator. When, it was reassembled, I fired up the test stand, the battery began "puking" acid out of the overflow/gassing vents. turns out, the regulator was bypassed and ... well, I spotted this right away. so nothing was damaged. even the the battery was OK. (Phew)

oh, I wanted to say that I do that "series the heck out them" with batteries that do not have enough power to do their "normal" jobs. They generally will run down the rest of the way. other get the joule thief and LED. Mostly AAA,

I once had what I'd call an extreme example of battery reversal! I put a totally dead car battery on charge on the bench. After a few days it read high enough to try to installed it, only to have it spark when connecting the last cable! Only then did I actually pay attention to the meter reading enough to notice that the polarity was reversed. Fortunately the alternator lived through the event, unfortunately attempting to recharge the battery in the correct direction failed to work.

HarveyB

Congrats on video 3.0.1

Timothy P Elliott

While I appreciate you popping videos like this out, don't stress yourself by trying to get content out before you are ready

Dr Andy Hill

I use low self-discharge NiMH almost everywhere. Not huge capacity, but they support hundreds of cycles and NEVER leak. I have about 50 of them installed in various devices. Only the 9V NiMH batteries have proven totally inadequate, so I use rechargeable Lithium 9V batteries instead. I do use AA Lithium disposable batteries where the batteries are difficult to access and/or have such low current draw that the battery life is essentially its shelf life. And, in rare circumstances, in equipment that won't work with the lower NiMH voltage. Still, even with both of the above, I pull the batteries from less-used gear, such as my kitchen scale, my "spare" multimeters, my label maker, and so on. Mainly to keep those batteries in active use.

BobC

I have definitely heard this reverse polarity thing somewhere, can't remember where!

Dr Andy Hill

I "somewhat often" do what they say never to do. Mismatch batteries of different strengths. Using AA batteries, I series the heck out of them and connect that to a buck converter to 5.0VDC and have the output to a USB plug. I often find batteries that read 0 VDC but about every other time I check, one has reversed itself. Fun.