Samsung 25R Blue Wrap 20A 2500mAh Bench Test Results...a great 20A cell

[Mooch]

Tested at 10A-25A constant current. Cells were purchased from Orbtronic and donated for testing.

Dropbox - samsung 25r blue wrap.jpeg

Dropbox - samsung 25r blue wrap can.jpeg

Dropbox - samsung 25r blue wrap top.jpeg

Dropbox - samsung 25r blue wrap bottom.jpeg


Disclaimer
Testing cells at their limits is dangerous and should never, ever, be attempted by anyone who has not thoroughly studied the dangers involved and how to minimize them. My safety precautions are the ones I have selected to take and you should not assume they will protect you if you attempt to do any testing. Do the research and create your own testing methods and safety precautions.


Bottom Line
A true 20A continuous discharge current (CDR) cell with good capacity that runs at moderate temperatures. This cell deserves its good reputation.


Test Results
Dropbox - samsung 25r blue wrap 20a 2500mah 18650 constant-current tests.bmp


Comments

• These are the blue wrap cells. The newer green wrap cells will be tested soon.
• Great capacity and moderate maximum temperature of 75°C-78°C at 20A.
• Five additional cycles at 20A showed only 1.3% loss in capacity and almost no voltage sag. A 10A discharge done after this also showed only a 1.3% loss in capacity.
• While operating any cell at its rated maximum current causes damage to the cell, I would expect decent cycle life from the 25R at 20A.
• A discharge at 25A brought the cell temperature to 90°C and dropped the voltage considerably. That's too hot and will significantly speed up the damage done to the cell. This is a 20A cell.
• See my blog for info on the testing procedure and equipment used.

 

[Froth]

Any chance of the same 35A pulse test that you did with the 30Q?(I'd love to side/side compare them...) I've been pounding the crap out of my 25R's at 0.12 daily and they take it like a champ so I've got to assume it would do better than the 30Q.

 

[Mooch]

The 30Q's ran longer than the 25R's to 3.2V at 20A.
No time to do more pulse tests for a while but there will be a 20A cell shootout after I finish the HE4 testing that's running now. From what I've seen so far, when comparing two cells, the pulse tests pretty well mirror the constant-current test results. Not directly, in terms of capacity or run time, but in showing which cell might be a better choice at what current levels.

 

[Mooch]

Goofed up, ignore.

 

[Monotremata]

I thought the green wrapped ones were older?? I just bought a couple more last month from Illumn and got blue ones..

 

[Mooch]

There are newer green ones with a slightly different electrolyte...
Samsung 25R Upgrade - Green Samsung 25R5 vs. Blue 25R2 – 18650 Battery Bro | Let's Spark a Revolution

 

[JKuro]

Any chance of the same 35A pulse test that you did with the 30Q?(I'd love to side/side compare them...) I've been pounding the crap out of my 25R's at 0.12 daily and they take it like a champ so I've got to assume it would do better than the 30Q.

If you are using a mech, a 25A pulse test would be more suited to you with a .12 build. The battery resistance, combined with the mod and atty resistance will give you 25 amp drain at 3 volts at best.

 

[Froth]

If you are using a mech, a 25A pulse test would be more suited to you with a .12 build. The battery resistance, combined with the mod and atty resistance will give you 25 amp drain at 3 volts at best.

3 volts at best? Give my mods a little more credit than that...

Copper EDS SMPL + Fresh Samsung 25R gives me 3.61V across the posts during firing at 0.12, which is ~30A.
Singray X + Fresh Samsung 25R gives me 3.13V across the posts during firing at 0.09 which is just under 35A.

I'm a lifelong tinkerer with a lot of mechanical background so I've done my work on conductive mod losses, I only use direct to battery mods with copper or brass as the majority of the metal and the reason I use the Samsung 25R the most is because it can actually output enough voltage to reach 35A in a mechanical, the LG HE2 falls short, the VTC5 can do it too but it generates more heat doing it in my experiences.

 

[JKuro]

Froth, I'm not knocking your mods, but sometimes just reading voltage can be misleading. I have just tested a 25R connected to a .12 ohm electronic load and recorded a voltage of about 3.2 v at 26.5 amps. A higher resistance seen at the battery will give you a higher voltage reading.

 

[Froth]

Froth, I'm not knocking your mods, but sometimes just reading voltage can be misleading. I have just tested a 25R connected to a .12 ohm electronic load and recorded a voltage of about 3.2 v at 26.5 amps. A higher resistance seen at the battery will give you a higher voltage reading.

Not sure what to tell you, I'm measuring during firing with the RDA mounted to the mod with a modified RDA which accepts alligator clips on the positive and negative post, the voltage I get is the average after 10 firings of 3 seconds each and I'm measuring the resistance of the same RDA I use for the testing, then measuring the voltage going through that resistance which gives me enough inputs to solve for ohms law.

Really not sure why you're getting a lower number because during a pulsed firing even the Samsung 30Q only drops to 3.30V at 35A pulse which is a larger drain on the battery with more internal resistance than your 25R results. Seen here - Samsung 30Q vs LG HG2 Pulsed Discharge Shootout Results | E-Cigarette Forum