CGR18650H Li-Ion - what are the chances it'll recharge?

Thread Starter

Tonyr1084

Joined Sep 24, 2015
8,006
Yesterday I was looking for some tools. Decided I really needed to clean up some of my mess. In doing so I found several very old things, including a battery pack for a video camera that is long long gone. I cracked the case open and found two 18650 batteries spot welded together with an old charge control board. I disassembled them from the board and from each other because I have a dedicated smart charger for such batteries. I've placed the two of them into the charger, each has its own charge cradle. One of the two batteries is showing fully charged after having been on the charger for (guessing) around 36 hours and the other is showing 50% charge (based on two of the four LED indicators).

What are the chances the one battery is truly fully charged? Can its output be depended upon to last a "normal" time? The battery is a CGR18650H Panasonic but it doesn't state any Amp Hour ratings on it - so "normal" is all I can give you.

The other battery (same type) is showing 50% after 36 hours of charge. What are the chances it will take a full charge and how likely will it be able to last a "normal" time?
 

Thread Starter

Tonyr1084

Joined Sep 24, 2015
8,006
No - no books. Just that these batteries have sat uncharged for several years. You can't leave Lead Acid batteries uncharged without consequences. And I'm by far NO EXPERT on batteries.

[edit] I also had a new 18650 that I mistakenly left on in an LED flashlight. That battery no longer takes a charge. I saw on line that you could piggyback a good battery across it (in parallel) and trick the charger into charging the battery, but having tried that and failed I'm wondering if my endeavors will be rewarded or become a disappointment.
 

Audioguru again

Joined Oct 21, 2019
6,786
I have the Lithium battery from my daughter's first cell phone. Its cells are a little smaller than an 18650. It has been at the same "storage" voltage of 3.7V for 19 or 20 years. It still has lot of power to light a light bulb or run a motor.
 
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