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 genuine and in the original plastic wrap from a known and trusted manufacturer can change at any time! This can be one of the hazards of using “rewrapped” batteries or ones from smaller 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, 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
An amazing performer! The 50D2 is equal to the Amprius 50Q and Reliance RS50 and slightly better than the Ampace JP50P1, EVE 50PL, and Tenpower 50XG at all current levels.
At up to 20A though the BAK 65E and Reliance RH60 are better performers. They’re all fairly close so test the cells you are interested in to see if one might be noticeably better in your particular application.
BAK mentions a “solid-state electrolyte coating” which is supposed to help with thermal stability. I don’t know what this tech is but it could be an additive to reduce flammability or something coating the anode or cathode particles to reduce bad reactions with the electrolyte at high temperatures.
- These might be pre-production samples since the printing on the wrap does not match the layout shown in the datasheet and there are no CCC***, CE, or polarity marks on the cell.
- The two cells I tested seem to have been made in Jan 2026.
- The 50D2 has a 60A “max discharging current” rating with an 80°C temperature limit.
- It reached about 75°C at 40A down to 2.5V so a 40A continuous/60A temp-limited (to 80°C) rating seems reasonable.
- There is no datasheet pulse current rating for the 50D2.
- Datasheet capacity is 4950mAh rated/5000mAh typical. I measured 5212 and 5224mAh, fantastic consistency and well above the spec (which every cell should be IMO).
- Charge rating is 2.475A standard/15A max. I recommend staying below 2.5A for longest life and 4A for a compromise between cycle life and (fast charge) convenience. Charging at high current levels will shorten cycle life.
- Datasheet AC IR rating is <=5mOhms. I measured 2.98 and 2.73mOhms, good consistency and far below the max limit.
- I measured DC IR at 5.44 and 5.12mOhms, good consistency and among the lowest I’ve measured for a small round cell.
- Datasheet cycle life for the 50D2 is >= 600 cycles at +8A/-40A down to 2.5V before dropping to 60% of original capacity.
- Datasheet max weight is <= 69g. I measured 66.88g max for the two cells I tested.
- Datasheet max size is 21.45mm diameter x 70.75mm long. I measured 21.33mm x 70.52mm max.
Thank you DIY500AMP.com for donating these cells for testing!
***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. A manufacturer can apply for an export-only exemption from CCC testing though if the cells will only be sold outside of China (or for engineering/evaluation samples) so lack of a CCC logo does not guarantee that the cells are pre-production. They could be production-ready cells that were tested and have passed and newer cells will have the new CCC marked wraps
Continuous Current Discharge Graphs
Ratings and Performance Specs Graphic
18650/21700 Ratings & E-Scores Tables and Recommended Batteries Tables:
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https://www.patreon.com/posts/pinned-post-137974946
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