Terms, safety and privacy
This is a design aid, not an engineering sign-off, and there are designs it will not produce at all.
What this is not
It is not an engineering sign-off, a certification, or a substitute for someone qualified reviewing a pack that will be charged unattended or carried by a person. Lithium packs assembled from a bad calculation are a genuine fire hazard, and every result here states the assumptions it rests on precisely so they can be challenged.
What it refuses to design
Lithium chemistries with the battery management system declined; lithium cells in series without balancing; cells asked to carry more current than they are rated for; and charging lithium below freezing. These return a refusal and no numbers, because a refusal printed next to a working design is a design somebody will build.
What is stored, and about suppliers
The calculator runs in your browser and nothing you enter is sent to us. No cell page carries an affiliate link today. If any ever does it will be disclosed on that page, and the ranking will still be computed from electrical fit alone.
Questions
Are these designs safe to build?
They are a design aid, not an engineering sign-off. Every result states the assumptions it used so you can check them, marks which figures rest on a typical value rather than a measurement, and always includes the protection the pack needs. Anything that will be charged unattended should be reviewed by somebody qualified.
Can I charge lithium in the cold?
No. Charging a lithium cell below 0 °C plates metallic lithium onto the anode. It is cumulative, invisible from outside, and eventually shorts the cell internally. Discharging cold is fine — it is only charging that does the damage, and a BMS worth having refuses to.
Do you recommend where to buy cells?
Not currently. Every cell page links to the manufacturer’s datasheet and nothing else. If supplier links are ever added they will be disclosed on the page, and the ranking will still be computed from electrical fit alone — a designer that recommends the cell paying the most commission is worthless, and it would look exactly like one that does not.