On 12/11/2015 08:41 AM, Clifford Heath wrote:

have an 18V 2.4AH battery pack for Ryobi power tools that will no
longer take a charge and that the charger indicates is defective.
I've taken it apart and found that it has five pairs of cells that are
labeled:
"LS IMR-18650BB
18650 is the physical geometry: 18mm diameter, 65mm long, 0=round.
Any Li-ion 3.7V 18650 will do as a replacement (peak charge voltage
4.2V) - but get a matched set of 5.
If I have to get a matched set -- of ten (five *pairs*)

When did your need for five cells become ten?

Reread my original message in which I referred to four *pairs of
paralleled cells* showing 4.1x Volts and the other *pair* showing only
2.1mV.

-- rather than of two, I might as well get two 4AH ones for $99.

To my knowledge, no-one has worked out how to make a 4AH 18650 cell yet.

That's why they use *paralleled pairs* of 18650 cells.

The best cells are below 3.5AH, and five of those are already more than
$49 without building a case. Ryobi is Chinese now, so they're almost
certainly lying.

If you value high capacity, buy your own branded cells.

BTW, a few years ago I found a Web site dealing with battery packs for
power tools that reported that all the packs they had disassembled used
the same Sanyo 18650 cells -- including the RIDGID packs with the
lifetime warranty and the Craftsman "19.2-volt" (for how many seconds
after they come off the charger?) ones.

Perce