Lipo Battery Standards, open discussion

[johnrobholmes]

This thread is not for debate of any particular brand, only to propose guidelines that may help standardize the ratings of lipo batteries. If nothing else, it will allow comparison between batteries on a level playing field. If you have hard discharge data on a particular cell, fell free to post it up with your interpretation on how it may fit in with said proposed guidelines.


I will start. This is what I think could be a good basis for battery ratings.



Continuous discharge rate with average voltage no lower than 3.3v/cell
Continuous discharge rate with no lower than 90% of 1C discharge capacity
Starting and ending temperature noted, along with any cooling and setup details. Temperature could be overlayed on the discharge graph.
Cutoff voltage should be 3.0v.

Burst ratings are much more difficult to pin down, but duty cycle may be a useful parameter to use with this.

10% duty cycle for burst rating (maybe 5%?), average pack voltage of 3.7v for instance.
Sustained duty cycle at 50%, average voltage at 3.7.
Pack should never drop below 3.05v or 3.1v under load.


To compare with enerland, they rate capacity aggressively. Their 2100LP cells generally hold closer to 2050 at 1C discharge, but at the continuous rated discharge at 18C yields right at 3.4v/cell and more than 90% of rated capacity. They do not show temperature or pack cooling during testing. They are up front that there is 70% capacity retention at 16C discharge after 50 cycles.


Please add your thoughts, objections, additions to this.