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Frequently asked questions

What is this?

Everyone with an 18650 battery should look up its production date before using it. It's the first and only tool to look up the production date of any brand name 18650 battery. Find out when your cell was produced just by entering part of the code found on its PVC wrapper.

Who can use this?

Anyone with an 18650 battery from Panasonic, Sanyo, LG, Samsung, or Sony can use this tool to find the date the cell was produced. From individuals who are curious, to large manufacturers who want to verify their supply.

Why should I care?

Looking up the date code of your cell can help confirm or deny whether it is a counterfeit or not. It can also help you determine if the seller is honest about the production date of their cells. Learning the date of production can also help you more accurately predict the cell's capacity without special tools.

Finally - safety. If a cell is old you should be more cautious.

What does it mean if my 18650 battery is old at the time of purchase?

Preface: It all depends on storage conditions (namely temperature, and then voltage). Read about storing 18650 batteries here.

Typically the big manufacturers (Samsung, LG, etc.) will guarantee their cells for up to 6 months after production. (Note: this is only when buying direct from a manufacturer. If you are buying from a smaller distributor in China there is likely no guarantee.) At Battery Bro we have a 21-day guarantee.

So if your cell is 6 months old or less at the time of purchase - it can be considered in "pristine condition" as the original manufacturer is confident enough to guarantee them at this age.

Most 18650 batteries can be happily stored for up to between 1 year to 2 years without a significant loss in capacity - but only if storage conditions are right.

My battery is more than 2 years old, is it dangerous?

It all depends.

There are many people who use their cells for many years and have no problems. A cell that has been properly stored for two years can still be a very good cell! It is often capacity fade that renders a cell unusable rather than more tangible deterioration (rust, leakage, scratches, etc.).

Many 18650 cells, including the Panasonic batteries in the Tesla Model S, are rated for up to seven years of use. But this is under optimal conditions. If you are stressing your battery (high temperature, high current) and it is getting old - you may want to think about a replacement.

Where did you get this information to look up 18650 date codes?

Chinese language battery and flashlight forums. About a month ago on a popular Chinese forum an individual collected a bunch of resources together (many were screengrabs of spec sheets) and created an app to look up 18650 production dates. We took what was available, along with our own internet sleuthing, and created this English version web app - free for all that have internet access.

Can I use this free of charge?

Yes, but please tell your friends about it! Everyone with an 18650 battery should look up its date before using it.

My brown lg's start with 0329k The tool requires a letter in the first slot though, what should I do?

Actually the first character is the letter 'O' as in Ohm, not the numerical '0' zero. Please enter the letter O instead of the number 0. Thank you /u/Player1Dad for this question.

My cell says "invalid date code" - should I worry?

Perhaps. It's very possible our tool is incomplete, but it is also possible you have a counterfeit cell. Please send us a message via our contact form so we can investigate further.

What cells are currently known to not work with this tool?

The Panasonic-Sanyo GA, and the Samsung 30Q are both not currently functioning with this tool.