Shipping lots of Li-Ions

I’ve only ever mailed a few li-ions at a time, but I’m hoping soon to sell and ship several dozen probably by USPS. Is it any more expensive by weight because they’re li-ion? Or do I just slap a sticker on the side and it’s otherwise the same procedure and cost? I want to be fair with pricing but not kill myself with unexpected costs.

edit: Should have specified: I’m in the US and will be shipping to the US.

Not positive but I think the Wh limit imposed is for a parcel, not just per item, so that may put the brakes on using the post office. If you get on the USPS site and click the easy link for lithium batteries it should have another link to the Domestic Mail Manual and the full lithium restrictions. Might have to go with UPS or FedEx and their hazardous ground options (pricey and unless they’ve changed you’ll have to schedule a pickup because they won’t let you drop off to any location for hazardous). You could also give a call to Illumn or Liion and ask their advice, which I’m sure either would be happy to give.

Scroll down to 349.222(d)……rechargeable cells, not installed in equipment. 20Wh which is around 5400mAh cells, any size……parcels cannot exceed 5 pounds (including packaging and you’ll need special packaging to satisfy their requirements). Not sure how they’d handle the “originally sealed packaging” or the Wh requirements with our usual industrial cells that don’t spell all of that out on the wrap or come to us in oem packaging.

https://pe.usps.com/text/pub52/pub52c3_027.htm

Excellent info, thank you! I’m slowly mentally digesting it so bare with me here :innocent:

A theoretical package of 25 18650 batteries, 50g x 25 = 1.25kg = 2.75 lb is well under the 5lb limit leaving room for packaging.
Any individual cell is well under 5400mAh
As you say, the “originally sealed packaging” is ambiguous but I could ship them at least as well
isolated and cushioned as when I received them.