There are only a handful of big name makers.
LG
Panasonic/Sanyo
Sony
Samsung
Almost everyone else is just rebranding cells from those companies.
For a battery, as previously said, a high capacity (above 3000mAh and absolute maximum capacity is currently around 3500mAh, any higher and they are lying) from one of the above.
Eg.
Samsung 35E in the UK:
https://www.fogstar.co.uk/products/samsung-35e-18650-battery £5.45
Other options are the LG MJ1.
In the US, shouldn't be paying more than $10 (usually $7) for an 18650 from one of the above.
https://www.illumn.com/https://www.18650batterystore.com/
Previous Topic
Index
