These tests below only note my personal opinion for the ESTIMATED ratings for the batteries I tested at the time I tested them. Any battery that is not a genuine Samsung, Sony, Murata, LG, Panasonic, Molicel, EVE, Lishen, BAK, or Sanyo can change at any time! This can be one of the hazards of using “rewrapped” or batteries from other manufacturers so carefully research any battery you are considering using before purchasing.
Misusing or mishandling lithium-ion batteries can pose a SERIOUS RISK of property damage, personal injury, or even death. Never use them outside of a fully protected battery pack and you use them at your own risk. Never exceed the battery’s true continuous discharge rating (CDR), never let it get colder than 0°C or hotter than 60°C to help lower the risks and extend cell life, and keep the plastic wrap and top insulating ring in perfect condition. Never use a battery that is physically damaged in any way.
Testing batteries at their limits is dangerous and should never be attempted by anyone who has not thoroughly studied the dangers involved, understands the risks, has the proper equipment, and takes all appropriate safety precautions.
If the battery has only one current rating number, or if it only says "max", then I have to assume the battery is rated at that current level for any type of discharge, including continuous.
Test Results
In my testing these 40T5’s delivered up to 10% less energy than the 40T3 at higher power levels. The resulting shorter 40T5 run times might be noticeable in some applications.
I don’t know if this is something seen in all 40T5 cells. Samsung says they increased cycle life a little so performance might have dropped a bit (there is always a tradeoff)? The DC internal resistance (IR) of the 40T5’s was a bit higher than the 40T3’s I tested. There are no “bad batches” so it’s not that.
I know what some of you are thinking…are these lower grade cells? There’s no way for us to know but I purchased these from a known, reliable vendor that I trust and have used for years.
The 40T5’s also ran hot, reaching almost 90°C at 30A down to 2.5V, so the datasheet’s 35A rating is too high IMO for the cells I tested. Samsung’s have always “run hotter” than other cells for me and the 40T5’s were the same.
I am giving them a 25A continuous rating and 35A temperature-limited rating (stay below 80°C). At its 45A temp-limited datasheet rating there was just too much voltage sag IMO.
The 40T5’s I tested did not have the new Samsung model numbers but I’m sure the wraps will be updated soon. There is a “5” in the lower left corner of the printing on the wrap to indicate that this is the 40T5. The base model number, “40T”, is also on the metal can (near the top).
For the 40T5, Samsung has improved the nickel plating on the can and top contact. Switching from an electroplated coating to an electroless one makes it smoother and offers more consistent and higher-strength resistance (spot) welds when assembling battery packs.
Samsung also claims slightly better cycle life at 10A compared to the 40T3 and about the same cycle life at 40A.
This is still a good performing cell! But the Molicel P42A, its former closest competitor, is now the clear performance winner if that is the priority.
Some 40T5 specs:
Continuous Current Discharge Graphs
Ratings and Performance Specs Graphic
18650 Ratings & Performance Table:
20700/21700 Ratings & Performance Table:
I want to work for the community full time! If you feel what I do is worth a couple dollars a month and you would like early access to battery availability, battery testing and news, and a say in what I test, then please consider becoming a patron and supporting my testing efforts: Get more from Battery Mooch on Patreon.
Misusing or mishandling lithium-ion batteries can pose a SERIOUS RISK of property damage, personal injury, or even death. Never use them outside of a fully protected battery pack and you use them at your own risk. Never exceed the battery’s true continuous discharge rating (CDR), never let it get colder than 0°C or hotter than 60°C to help lower the risks and extend cell life, and keep the plastic wrap and top insulating ring in perfect condition. Never use a battery that is physically damaged in any way.
Testing batteries at their limits is dangerous and should never be attempted by anyone who has not thoroughly studied the dangers involved, understands the risks, has the proper equipment, and takes all appropriate safety precautions.
If the battery has only one current rating number, or if it only says "max", then I have to assume the battery is rated at that current level for any type of discharge, including continuous.
Test Results
In my testing these 40T5’s delivered up to 10% less energy than the 40T3 at higher power levels. The resulting shorter 40T5 run times might be noticeable in some applications.
I don’t know if this is something seen in all 40T5 cells. Samsung says they increased cycle life a little so performance might have dropped a bit (there is always a tradeoff)? The DC internal resistance (IR) of the 40T5’s was a bit higher than the 40T3’s I tested. There are no “bad batches” so it’s not that.
I know what some of you are thinking…are these lower grade cells? There’s no way for us to know but I purchased these from a known, reliable vendor that I trust and have used for years.
The 40T5’s also ran hot, reaching almost 90°C at 30A down to 2.5V, so the datasheet’s 35A rating is too high IMO for the cells I tested. Samsung’s have always “run hotter” than other cells for me and the 40T5’s were the same.
I am giving them a 25A continuous rating and 35A temperature-limited rating (stay below 80°C). At its 45A temp-limited datasheet rating there was just too much voltage sag IMO.
The 40T5’s I tested did not have the new Samsung model numbers but I’m sure the wraps will be updated soon. There is a “5” in the lower left corner of the printing on the wrap to indicate that this is the 40T5. The base model number, “40T”, is also on the metal can (near the top).
For the 40T5, Samsung has improved the nickel plating on the can and top contact. Switching from an electroplated coating to an electroless one makes it smoother and offers more consistent and higher-strength resistance (spot) welds when assembling battery packs.
Samsung also claims slightly better cycle life at 10A compared to the 40T3 and about the same cycle life at 40A.
This is still a good performing cell! But the Molicel P42A, its former closest competitor, is now the clear performance winner if that is the priority.
Some 40T5 specs:
- 3900mAh minimum, 4000mAh typical capacity.
- Standard charge rate is 2A, max is 6A but I am sure that will shorten cycle life.
- DC IR for the two cells I tested measured 14.4mOhms and 14.4mOhms. This is extraordinary consistency.
- Capacities for the two cells was 4159mAh and 4170mAh, fantastic consistency and well above the 4000mAh typical rating (as it should be).
- This IR and capacity consistency helps when assembling battery packs. The self-discharge rate consistency is also important when sorting cells for battery packs but I have not tested that for these cells.
Continuous Current Discharge Graphs
Ratings and Performance Specs Graphic
18650 Ratings & Performance Table:
18650 Battery Ratings and Performance Table
You are responsible for your own safety! These batteries are designed, manufactured, and sold only for use in a battery pack with the proper protection circuitry and battery management system. They were not designed for vaping (electronic...
www.e-cigarette-forum.com
20700/21700 Ratings & Performance Table:
21700 Battery Ratings and Performance Table
You are responsible for your own safety! These batteries are designed, manufactured, and sold only for use in a battery pack with the proper protection circuitry and battery management system. They were not designed for vaping (electronic...
www.e-cigarette-forum.com
I want to work for the community full time! If you feel what I do is worth a couple dollars a month and you would like early access to battery availability, battery testing and news, and a say in what I test, then please consider becoming a patron and supporting my testing efforts: Get more from Battery Mooch on Patreon.
