Many thanks to SWLing Post contributor, Adi, who writes:
Hi Thomas,
Recently I received from AliExp two 18650 3000mAh batteries to replace the aging original XHDATA for my D-808.
As you can see they are ~3mm longer than the original.
They still fit, but the spring is crushed to its minimum and the cover will not fit nicely unless I trim its inning a bit, with a knife .
A shorter one was on the page pictures when I order on AliEx, but I did not have the option to select it and I didn’t ask the seller.
The added 3mm is a new protection circuit
I charged them in the D-808 and, so far, they preform very well.
In order not to damage the spring, I decided to use these batteries only on long listening sessions and then put the original 18650s in, when the D-808 is at rest.
So when one is out there shopping for 18650s, it’s important to take note of their size.
Regards, Adi
Many thanks, Adi. I do see where the seller is noting the increased length of each cell to accommodate the protection circuit. It might be difficult to judge in advance, however, if a particular radio or device can cope with these slightly larger cells. Thank you for sharing this, Adi!