No matter new or old version, the same date code rule is followed.

You saw the 4 numbers(sometimes numbers+letters) on the bottom of the battery? They indicate the battery manufacture datecode.
1. The first digit = year(0 = 2010, 1 = 2011, 2 = 2012, 3 = 2013, 4 = 2014, 5 = 2015, and so on).
2. The second digit = month(1 = Jan., 2 = Feb., 3 =Mar., 4 = Apr., 5 = May., 6 = Jun., 7 = Jul., 8 = Aug., 9 = Sept., 10 = X, 11 = Y, 12 = Z).
3. The third and the fourth together = day(01, 02, 03, 04….29, 30, 31).

According to the rules, the battery above is made on 2013-01-26.

However, from the year of 2010, Samsung changed its code rules. Moreover, Samsung lithium batteries are divided into SDI ( are manufactured in Korea) and SDIEM ( are manufactured in Malaysia). And the date code rules of SDI and SDIEM are different.

The battery below is from SDI, and on the second line, we can see “SDI”.

On the third line of the PVC, there’ re 4 digits.

1. The first digit = Version
2. The second digit = Year ( A = 2010, B = 2011, C = 2012, D = 2013, E = 2014, F = 2015).
3. The third digit = Month (1, 2, 3…..9, A= 10, B = 11, C = 12).
4. The fourth digit may mean Day, not so sure. It seems that, 3 means the day of 03, 13, and 30 at the same time.

So can be figured out that it was manufactured in July, 2014.

The battery below is from SDIEM, and also has 4 digits.

1. The first digit = Version
2. The second digit = Year ( A = 2010, B = 2011, C = 2012, D = 2013, E = 2014, F = 2015).
3. The third digit = Month ( O = 1, P = 2, Q = 3, R = 4, S = 5, T = 6, U = 7, V = 8, W = 9, X = 10, Y = 11, Z = 12).
4. The fourth digit may mean Day, not so sure. It seems that, 3 means the day of 03, 13, and 30 at the same time.

Therefore it was made in May, 2013.

1. Official Data Sheet
2. Appearance Inspection & Battery Code Interpretation
3. Size Measurements & Weight Measurements
4. Discharge Test & Analysis
5. Resistance Test & Analysis
6. Conclusion

Official Data Sheet

Before you check this test, you can open the Samsung ICR18650-26F Data Sheet first here, which is convenient for you to do a comparison with our test results.

Appearance Inspection & Battery Code Interpretation

Samsung 26F has a purple PVC, on which there’ re three lines of codes.
1. On the first line, “ICR18650″ shows the model, and “26F” tells that the capacity is 2600mAh, and also from “F”, we can figure out it was manufactured in Korea, because the 2600mAh batteries manufactured in Malaysia are called “26F M” or “26H M”.
2. On the second line, “SAMSUNG” tells the brand, and “SDI” also indicates that it was manufactured in Korea. It’ll be written “SDIEM” if it is manufactured in Malaysia.
3. On the third line, we’ll find out the manufacture date is in May, 2015. As for how to identify the battery date code, please check this post Recognize Samsung 18650 Battery Manufacture Date Code.

Size Measurements & Weight Measurements

The weight of this battery is 44.50g.

Measure it with a digital caliper. The length is 65,0mm.

And the width is 18.3mm.

Discharge Test & Analysis

In the whole discharge test, the instrument we will use is EBD MINI V3 Battery Tester / Power Bank Tester. EBD MINI V3 is a low – amp testing tool. Even though the maximum ampere discharge is locked at 3A not the full 20A, it can still test the battery performance very well, and the data is very accurate.

1. Picture above is the discharge test result. We observed that the capacity is 2662mAh, which is much more than the official nominal capacity 2600mAh, even if it’s discharged at 2.60A, a relatively high-ampere. This shows its super performance.

2. On the picture it can be seen that the curve is flat in a way. This suggest that the discharge is peaceful and stable. Indeed a good battery needs peaceful and stable discharge characteristic. When working if a battery can stabilizes in a voltage 3.6V for a long time( actually the higher voltage and the longer time, the better), this battery must be very good. From the curve, we find that the voltage over 3.6V has stayed for about 30 minutes( the whole discharge time is 1h).

3. Additionally the professional guy should know that the higher average voltage, the better, and the average voltage had better be more than 3.6V. We see that the average voltage is 3.58V. It is not so perfect, but not bad.

Resistance Test & Analysis

EBD MINI V3 can also test the resistance. The tested resistance is 55mR. Resistance less than 60 can be ranked as Grade A. 55mR is not so perfect but OK.

Conclusion

Base on all testings above, it can be concluded that Samsung ICR18650-26F battery is very good. Especially when we combine its performance with its low price, we’ll find it a perfect choice.