Easily measure current in AA - AAA - C - D - 18650 or any round cells that fit in a battery holder.

Using your ammeter to measure current can be a fiddly affair getting access to the cell's contacts. Here's an easy low cost (or no cost) solution.
COIN CELLS : To measure coin cell current you can make a thinner blade by missing out the plastic piece and sticking the copper tapes back-to-back - but leaving one of the backing strips on for insulation. See my instructable www.instructab...
A commenter below suggested using a piece of double-sided PCB for the blade. This is how I used to do it many years ago, before I discovered copper tape. I filed the leading edge of the board thinner so it slid easily between the cells. However, battery holders these days have a tighter fit so I wanted somthing thinner. This method was so easy and worked first time. And it was fun to make!

[@grahamdriver7534]

Like it. A useful test, generally fiddly to do, made easy. Elegant.

[@richardlangner]

Thank you. It's nice to have helped.

[@gblargg]

I made one of these with aluminum foil on double-stick tape way back. Radio Shack used to have a nice one with multimeter probe ends.

[@davidberrien9711]

This is really clever

[@richardlangner]

Thanks for the feedback. I've been doing this for years using a meter, and It was only when I made the video that it occured to me to use the 'scope.

[@2OO_OK]

Very clever!

[@richardlangner]

Thank you!

[@newmonengineering]

This is a great idea. Love it.

[@richardlangner]

Thanks, I hope it helps you in future.

[@DaveEtchells]

This is a great tip! I actually made something almost identical but using thin brass strips with kapton tape separating them. It was rather fiddly to use though, your idea of using the adhesive copper tape is brilliant!

[@richardlangner]

Thanks, the most obvious ways are usually the best!

[@Batmule]

Nice idea. Thanks.

[@richardlangner]

You are most welcome

[@t1d100]

A thought to add... If the builder has a thin piece of double-clad copper board (the type used to etch a DIY PCB,) that might be a good material with which to make the probe. I am not speaking of perf board. That would not work, of course. HTH someone.

[@richardlangner]

That was the way I used to do it back in the day, so it's worth me adding a mention in the description. Thank you for the reminder. The only issue I had was the PCB was sometimes too thick and It also depends if you have some board to hand.

[@t1d100]

👍👍👍👍👍

[@richardlangner]

Thanks for the thumbs-ups

[@alexkelly757]

Why do they pulse charge?

[@richardlangner]

Battery chemistry is complex, and there are many reasons to pulse charge. Perhaps some other commenters can explain.

[@2OO_OK]

@@richardlangner Can measure bat voltage between charge pulses.

[@richardlangner]

@@2OO_OK Another reason is for burp charging

[@ehjones]

The charging current increases the voltage as measured across the cell due to internal resistance. To accurately measure what the resting voltage is across the cell the charger needs to stop charging briefly. If the charger simply waited for the charging current to drop, then the final voltage would be different depending on the cell's internal resistance.

[@richardlangner]

@@ehjones Thanks for the explanation.