CR2032 vs. CR2032L

Wisdom often is earned through frustrating “learning experiences.” I recently had one of these experiences with a CR2032 lithium battery.

Previously I thought that all CR2032 batteries were essentially the same—3 volts in a package 20 millimeters wide and 3.2 millimeters tall.

There’s more to it though.

I was replacing the battery in a Lutron Pico remote and grabbed a new-in-the-package CR2032. I popped the battery in, but the remote worked only intermittently and not as expected. Button presses would only register every few minutes.

I thought maybe the contacts in the remote were corroded. I took apart the remote. Inside the gold contacts were super clean, so that was not it.

I got out my multimeter to test the battery voltage. Batteries do lose voltage over time, even when not in use. Perhaps that was the problem? Nope. This new battery tested 3.1V, which was what it should be.

I had another Pico remote that was working properly, so I took the battery out of it and tried it in the other remote. And suddenly it worked perfectly. I tested the voltage on the older battery and it read 2.8V.

I put the new battery in the other remote and then it didn’t work. Clearly the problem was the battery not the remote.

After more than an hour of troubleshooting I was still scratching my head. Why didn’t the battery work?

Then I noticed that the new CR2032 battery I had been trying to use was actually marked CR2032L. The cardboard package the battery came in said CR2032, but the battery itself had a “L” on the end. I had never seen this before. What could be the difference?

This Quora post hinted at a possible explanation for why the CR2032L didn’t work in the Lutron Pico remote. The “L” likely stands for low discharge. I couldn’t find much else that gave a completely definitive answer, but this certainly makes sense.

These “L” batteries are apparently intended for applications where discharge is low and slow, like keeping the date and time set on your PC when the power is turned off. Lower discharge rate could explain why these CR2032L batteries might not work in the Lutron Pico remotes, which likely require quick bursts of power to send out pulses of radio signals.

Armed with this new knowledge, I looked for another CR2032 battery without the “L” and popped that in the remote. Sure enough, it worked immediately and as expected.

Lesson learned.

2 Comments >