These tests only note my personal ESTIMATED ratings for these batteries at the time I tested them. Any battery that is “rewrapped” (not in its original factory wrap) can change at any time! This is one of the hazards of using these batteries 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
At under 4A (this cell’s continuous current rating) this is a good performing cell. It’s a touch better than the EVE 35V and just a bit lower performing than the Vapcell N40/N41. I don’t think you’d notice a difference between any of those cells in actual use.
This cell had a self- adhesive top insulating ring. I haven’t seen one of those in years and were typically used by the small rewrapping companies who had mostly-manual rewrapping setups. None of the automated wrapping done by the established companies use these type of rings since they come in sheets and can’t be handled by the machines. I don’t know why SAFD has done this but it is not a good sign in my opinion.
Some other info…
***China Compulsory Certification, additional testing now required for all cells made or sold in China after August 1, 2024. The logo and certain information must be put on all cells once they are certified. This typically won’t be done by a manufacturer until the cell is ready to go into full production.
Continuous Current Discharge Graphs
Ratings and Performance Specs Graphic
18650/21700 Ratings & E-Scores and Recommended Batteries Tables:
The links are in my public Patreon pinned post: https://www.patreon.com/posts/pinned-post-137974946
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
At under 4A (this cell’s continuous current rating) this is a good performing cell. It’s a touch better than the EVE 35V and just a bit lower performing than the Vapcell N40/N41. I don’t think you’d notice a difference between any of those cells in actual use.
This cell had a self- adhesive top insulating ring. I haven’t seen one of those in years and were typically used by the small rewrapping companies who had mostly-manual rewrapping setups. None of the automated wrapping done by the established companies use these type of rings since they come in sheets and can’t be handled by the machines. I don’t know why SAFD has done this but it is not a good sign in my opinion.
Some other info…
- The 40ME has a datasheet 10sec pulse rating of 12A. The voltage of a fully charged cell dropped to a bit under 3.5V for this pulse so it’s a reasonable rating if done only occasionally.
- The max allowed cell surface temp is only 60°C.
- There’s no CCC*** logo so IMO it was either made before Aug 1st, 2024, it’s not being sold in China (and wasn’t made there), or it’s a pre-production cell. Or SAFD is selling them illegally.
- Standard charge rate is 800mA.
- Max charge rate is 2A but that will shorten cell life IMO. Stay at 1A or lower to help with decent cycle life.
- The two cells I tested delivered 3972mAh and 3991mAh. This is above the cell’s 3900mAh minimum capacity rating but just below the 4000mAh typical rating. Since I cannot have the lowest capacity cell in the batch I am rating them at 3950mAh.
- The two cells had DC IR’s of 55.5mOhms and 59.2mOhms. This is not good consistency and is incredibly high, contributing to this cell’s low current rating.
- The datasheet weight is 48gms, +/-2gms and size is 18.35mm dia. (+/-0.15mm) x 65.0mm long (+/-0.2mm).
***China Compulsory Certification, additional testing now required for all cells made or sold in China after August 1, 2024. The logo and certain information must be put on all cells once they are certified. This typically won’t be done by a manufacturer until the cell is ready to go into full production.
Continuous Current Discharge Graphs
Ratings and Performance Specs Graphic
18650/21700 Ratings & E-Scores and Recommended Batteries Tables:
The links are in my public Patreon pinned post: https://www.patreon.com/posts/pinned-post-137974946
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.
